Archive through June 24, 2006

 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2716
Registered: Dec-03
I didn't meen to make it sound that 450 was max on the new 350B tube, I meant to
say that 450 is suppose to be a safe voltage for them to run at, I run 440 just fine.

But no biggie I doubt your looking to replace your outputs anyways. There are a
few guys over on AK running them in some mac amps and say they enjoy them. FWTIW

Like I said I was just talking about them because I'm running them and wanted
to share the specs and my impressions of there performance with others.

It's all good!
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2717
Registered: Dec-03
Hey Bill one thing to keep in mind is that not all of the newer tube amps have
multiple output taps to where you can choose 4, 8, 16 or whatever and with your
speakers you my be better suited for the 4ohm tap, so just keep that in mind.

I have a tube buffer, tried it in the tape loop and it really didn't do much, but
when conected to my cd-player then into the preamp works great, that's how I use it. YMMV
 

Silver Member
Username: Bcollins

Rockport, MA United States

Post Number: 104
Registered: Nov-05
Jan & Kegger,

Thank you for all of your help. You've given me some things to think about. I may look into a tube buffer as a temporary solution to my present situation until I finally make a decision regarding an amp. I hope to borrow the Cary from my dealer for a home trial soon. The others I am interested in unfortunately are not availible in my area for audition. This makes your feedback and advise even more valuable. Thanks again,
-Bill
 

Gold Member
Username: Nuck

Post Number: 2596
Registered: Dec-04
What kind of leaway can I expect from 4 or 8 ohm taps?
Are the taps meant more for the benefit of the amp or for speaker selection?
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2719
Registered: Dec-03
Basically one side of the output transformer is matched to the output tubes impedance
then the other side is matched to the speakers impedance, so goes the freq response.

So you won't hurt the amp or the speakers by using different taps on different loads.
But you may get better frequency response from your speakers by using the right tap.

Personally I'd want to have an amp that at least has 4 and 8ohm taps to experiment.

That's the quick and dirty of it that should give you the idea. With Bills speakers
if I had to guess which tap would work best for his speakers it would be the 4ohm tap
but it's still very possable the 8ohm tap may sound the best with them on a certain amp.

So I wouldn't be hesitant at all to put Bills speakers on the 8ohm tap or use them
with an amp that only had 8ohm taps but I'd hate to be limited or be stuck on one.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8474
Registered: May-04


There are a few amplifiers available today with a transformer tapped for only one impedance load. On these amplifiers, you can typically specify from the manufacturer/dealer which impedance tap you want the outputs set to. But, changing taps by simply disconnecting the speaker cables isn't possible.


Any transformer coupled amplifier can benefit from experimentation with the outputs and the speaker connection. Obviously the tap determines the output impedance of the amplifier and mismatching the ouptut impedance of the amplifier to the impedance curve of the speaker will result in several variations in signal quality. The most important item to acknowledge here is the curve of the speaker's impedance load. A four Ohm speaker is unlikely to remain at four Ohms over most of its operating range.

Experimenting with which tap to use will give different results with each amplifier/speaker combination and with each listener's preferences. The most obvious change will be, as Kegger suggests, a frequency response variation away from flat response. The higher the output impedance of the amplifier vs. the actual impedance and electrical phase angle of the speaker, the more apparent the changes will become. In a typical push pull amplifier the negative feedback circuit will be connected to the highest impedance tap. If you have a NFB circuit connected to the 16 Ohm tap and you connect you speakers to the 4 Ohm tap, you are drastically altering the parameters and transfer function of the feedback circuit. You will usually find the control at bass frequencies changes quite audibly. With the best combinations of mixing taps to speakers, you can get results which seem to combine the best of both solid state control in the lowest frequencies with tube's more typical openness in the mids and high end. Or, when done poorly, you can send the amplifier into oscillation. We seem to have largely removed ourselves from the time when "hot-rodding" an amplifier meant removing all traces of protection circuits, but there are still amplifiers which eschew any additional circuitry and can easily be destroyed, along with the speakers, by uninformed but well intentioned attempts to change the sound of an amplifier.


The flexibility of tubes offers many opportunities for tailoring a system to your tastes and situation. Depending on your preference you can bring the amplifier's response much closer to neutral or you can "create" a sound to suit your ideas of what you like.


 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2720
Registered: Dec-03
Interesting you mention the NFB usually being on the 16ohm tap.

The original ST-70 was there also, I had read something online that had said
the second generation of ST-70's used the 80hm tap which gave less feedback
and sounded better. I did this on my ST-70 and use the 8ohm tap with my ADS
speakers which are a pretty solid 8ohm load and it does sound better, TO ME.

Just FYI.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8477
Registered: May-04


For those who haven't gone back to read the archived posts in this thread, I suppose I should also mention that changing taps will change the power output of the amplifier along with both the distortion product and the manner in which the amplifier clips.


The advantage of a transformer coupled amplifier in relation to power output is the consistency of the amplifier. When you are using a nominal eight ohm speaker on the eight Ohm tap, the transfer functions of the amplifier work, more or less, the way the designer intended. This is, of cource, relative to where the NFB circuit is connected and will vary from amplifier to amplifier. If the NFB is connected to the sixteen Ohm tap and you are using a nominal sixteen Ohm speaker load, you should have the amount of power the circuit can develop under best conditions and the distortion product should remain as low as possible. If the NFB is connected to sixteen Ohm tap and you are using an eight Ohm speaker load, you will get slightly less power and slightly higher distortion than you would with the more proper sixteen Ohm load. In a well designed amplifier, the differences should be minimal at this point but this is largely dependent upon the amount of global NFB used in the amplifier as it will determine gain from the circuit. Logically, if you have the NFB connected at the sixteen Ohm tap and you use the four Ohm tap for your speaker connection, you've placed the point where the speaker's back EMF enters the amplifier as far away as possible from where the NFB circuit takes its cue. The result will be less gain in the amplifier and higher distortion product. So do experiment with the various taps on your amplifier to find which produces the best sound quality, but keep in mind you can easily turn your forty watt amplifier into a twenty watt amplifier with high THD by severly mismatching the amplifier's output impedance to the actual speaker load.


 

Gold Member
Username: Nuck

Post Number: 2606
Registered: Dec-04
Those values are valid in reference to the way the amp clips, Jan, but what about playing well under clipping values?
Oh course halving the output of the amp is not necessarily desirable, but may add some gain to guitars that sound pretty good.
Of course this is guitar 101.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8479
Registered: May-04


THD, Nuck, THD. Not to mention IM, TIM, ringing, poor damping and so forth.


Guitar 201b says THD, et al, should be applied judiciously and, most importantly, must be controllable. But then I listen to Les Paul and you to Nirvana. By moving the speaker connection as far away as possible from the NFB connection, the feedback circuit is less able to "see" the effect of the speaker's back EMF. The speakers begin to drive the amplifier, albeit they are actually "driving" the transformers which are connected to the output tubes.



Well, the speakers are connected to the outputs,
The outputs connected to the feedback,
The feedback connected to the 'formers,
The 'formers connected to the tubes,
And the tubes are connected to the drivers.
All doing the work of the Lord!


'Dem amps, 'dem amps, 'dem dry amps ...




This is where oscillation can begin. Whether you're playing at one watt or clipping, the feedback loop is essentially out of the circuit. That might once again sound good on the surface, but not if the amplifier is designed to run with some amount of feedback as would be the case with any push-pull amplifier not running triodes. The ringing might not develop into full blown oscillation but the effects of the poor match between amplifier outputs and speakers will be heard as rining, poor dynamics and a hardness that comes from the distortion product. Admittedly, this is a severe mismatch I'm describing and I don't want to discourage anyone from experimenting. Just giving a bit of information about what you might hear.




Kegger - You are beyond my abilites to truly describe what happens when you change where the feedback circuit is connected. When you say "second generation" I assume you are talking about the ST70 re-do which was built in the mid 1990's; as I know of no major alterations to the design of the ST70 while under the original Dynaco banner. (Admittedly my knowledge of the ST70 over its twenty years plus of production by Dynaco is limited and I constantly find out something new about that amplifier.) If we are talking original vs. 1990's ST70, however, I think you find several changes to the original's circuitry were incorporated into the "new" ST70. These changes would also be taken into account when the feedback connection was changed. It is rather uncommon to find a tube amplifier today with a sixteen Ohm tap; and those that do have this provision often still make the feedback connection at the eight Ohm tap. This is mostly a matter of convention since most speakers on the market today represent an eight Ohm or lower load. This wisely places the feedback connection at the point where it will do the most good with contemporary speakers. Not so when the original ST70 was designed. Same for my Macs and I suspect Dak's Fischer has a sixteen Ohm tap. By changing the feedback connection on the orignal ST70 to the eight Ohm tap you might have improved the sound when using the ADS speakers. But, you have altered the original circuit and, as I said, I can't really tell you what the effects would be and definitely not with other speakers which might be a more difficult load. I would guess you've altered the gain of the amplifier somewhat though probably not severely. And, this isn't that important as long as you can drive the amp to clipping with your input. But, I would also think you've changed the damping ability and the distortion product of the amplifier. How would be dependent upon the speaker load and I don't know that this is easily predicted. Did you check the amplifier with a dummy load for output power and distortion when you made the switch or did you just do it and listen for what you heard?


 

Gold Member
Username: Nuck

Post Number: 2619
Registered: Dec-04
Nice little rhyme there Jan.
I put it to a Bo Diddly beat.

In fact, I am as likely to listen to Les or BB or T-Bone Burnett as anyone else.
And not Nirvana(gag) but Van Halen(you gag).

I get the point.
The oscillation and rapid increase to tube/circuit over-run I understand.
The THD factor is something to be massaged, IMHO, and Global feedback is essential.
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2721
Registered: Dec-03
Yes it was a version II that came out in the nineties.

The 3 main differences were, the front end used a tube with more gain, it
was solid state rectified and the feedback was moved to the 8ohm tap.

They could move the feeback to the 8 ohm tap because the input stage had more
gain. Was done this way to move the feedback closer to todays speakers. (Like you said)

The board that I run has even more gain then the gen2 and I could run feedback from the
4ohm tap, but since I'm presently running 8ohm speakers and like the sound, the 8 it is.

I know the board designer, he's a friend of a friend and after contacting him about
moving the feedback to the 8ohm tap like I had wanted and felt it would be a good
thing he agreed and suggested I even try the 4ohm tap as he's tested and it's fine.

After all of the mods I've done I took the amp to a local tube amp builder friend of
mine to run it on his test bench, we got less then 1% distortion at 40wpc and even
better yet we got a frequencey response of 7hz-30khz with 3db or less of variance.

Most tube amps ecspecially push pull types need very little NFB to achieve a fairly flat
response while having distortion measurements that are well within an acceptable range.

A little bit of NFB is good, to much sucks the life out of the amp and kills transients.
 

Gold Member
Username: Nuck

Post Number: 2630
Registered: Dec-04
Great numbers, Kegger!
Was the 40wpc very near clipping?
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2723
Registered: Dec-03
YEP!
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8493
Registered: May-04


Kegger - Had you tested the amplifier before you made any changes but with new tubes?
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2724
Registered: Dec-03
NOPE.
.
.
.
.
.
Unforuntaly, other then it worked and sounded good but a bit wooly sounding.

 

Gold Member
Username: Nuck

Post Number: 2643
Registered: Dec-04
But not Baaaaaaaad.
Sorry, the wine while making stew.
 

Gold Member
Username: Nuck

Post Number: 2661
Registered: Dec-04
The thread has been quiet for a bit, so I don't feel guilty about chang the subject a tad.
I have been looking at toobs for a while, and have decided to take some of my own advice as to what type of tube setup to persue.

I have looked at Rogue as well as PL, and have considered a custom set-up (with all the help I would need from y'all), but given my limited time at home and the weather, that would have to wait until winter.

I have decided to look into McIntosh, and the 275 is right there.
However, the Mac mono's are lovely and can be had rather comfortably, along with the visual impact of singles.

Please bear in mind that this aquisition will be for a lifetime(gee I hope THATS a while).
Also please consider the following.

I will only consider a product capable of heating a room with awe-inducing, retina-seperating levels of power.
If only opened up once a year, I would be remiss to ignore that requirement.

I am going to shell out high 5 figures for the equipment of a lifetime, the speakers will follow.

I am not going to buy kief, I have enough mid-fi as it is.

Any opinions on the matter would be appreciated, suggestions welcomed and experience required.

I would not bring this up anywhere else.

Thank-you in advance.

p.s. Should anyone forward their phone# I would welcome the opportunity.

Kegger, I am very close to Port Huron, if you feel that a visit would be appropriate, I bring beer.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8500
Registered: May-04


Buying McIntosh? Do you really think I would discourage that? If you wish to own the large Mac monos, be my guest. I will have meter envy.


However, as I've said on the forum many times (at least six or seven), Mac is Mac and whether you buy the 275's or the mono amps, is merely a matter of choice and what you intend to drive in the way of speakers. Keep in mind you get your volume from the speaker, not the amplifier. And the 275's can be strapped into a mono amp with 150 watts rated output. I repeat, rated output. How much louder will you need?


Other than that, I happen to think the 275's retro look is quite appealling.



I would, however, look at the Mac integrated which combines the basic C-22 and MC275 circuitry on one chassis.



 

Gold Member
Username: Nuck

Post Number: 2663
Registered: Dec-04
Thanks, Jan.
Blue eyes are hard to ignore.

I repeat, this is a once in a lifetime proposition, and bearing in mind my listening(although blues and others will come as I get more mature), I must have the highest quality that fits.

The i'c's will be handmade from rollstock.
The power cables will be hardwired to the mains.
The cabinet will be lexan with an electric cooler.(or Vortec).
I need to do it on Nuck-bucks, but 5 large for the power.

Everyone please chip in.
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2725
Registered: Dec-03
Well Nuck I need to know the rest of your system and what you prefer to hear in your system.

More importantly the speakers you will use.
And what room they will be in.

How do you listen to music?, the more in depth the better.

I would never knock anyone for wanting or owning a great piece of Mac gear.

And by all means you and anyone else are welcome to come by my place, anytime!
 

Silver Member
Username: Bvan

Cape Town, Copenhagen,...

Post Number: 213
Registered: Jun-05
nuck you lucky man!

i cant offer any advice being the tuboneophyte, but i can suggest what i might do for amplification if i had to spend 5k.

2x prima luna 3
2x prima lune 5

i'd run biamped, and once a week or so i'd bring the second preamp into play for a 4-channel sacd session. though i might wait for the new prima luna DiaLogue with remote so's not to have to balance front and rear speakers each time i touch the volume(which aint actually very often.)

take that very unlikely suggestion for what its worth:-) enjoy the hunt.

b.
 

Bronze Member
Username: Ravbains

MelbourneAustralia

Post Number: 82
Registered: Mar-06
Hi Nuck,

just noticed that you have decided to perhaps "shop the Mac".......

Way to go dude..........

I am not a tube junky, so I cannot advise. The only tube amps I am familiar with is Musical Fidelity's Nu-Vista, Tri-Vista and Mu-Vista series of integrated amps. These are hybrids, with tubes providing voltage gain, and solid state final output stage. These are nice, but later I heard Gryphon amps (all solid state), and I like those even more than the hybrids I heard.

I cannot advise at all, it is you and your ears all the way.

But can I ask another separate question whilst I have your attention.

How are you going with your Alegria Lings, and what are you amplifying them with?

Is there somewhere else in this forum where I can read in detail about this stuff.

Jan's eloquent posts and reviews on the T-amps, have got me interested in T-amps and SDFR stuff. I guess at heart I like simplicity.

cheers
Rav

 

Gold Member
Username: Nuck

Post Number: 2665
Registered: Dec-04
Thanks fo your interest, folks.

Kegger, my present music selection is classic rock, although blues and 50's stuff is gaining more interest.
I will not listen to classical or opera.
Presently, i use Psb Stratus Silver with upgraded XO's and a changeout of tweets, metal and soft dome. These are replaceable.

I have looked at Stats, Martin Logan included, with subs.

The present room is quite awful, but non-changeable. Long and thin, 12x35 ft, but seperated at about 22' of length, the drum studio is in the small end, with the mic amps and recording stuff.

Thanks, Bvan, the input is great, since the Nuck curse has again raised it's ugly head.
As soon as I am ready to make a move, the spending serpent raises it's ugly head.

This time it is A/C in the Dodge, and in the house as well.
Rats.(sigh).
The big move might take until fall, but is still on the front burner, and a further consideration of speakers is in order.
A bad time to exhibit my impulsiveness, I suppose.

Hi Ravi.

At present, I have run the Lings with, in order, the T-Amp. Pure stock form, laptop cd, had to max the sources for volume. No surprise, as the Lings are a bit shy, known well in advance.
2; The lings with the Rotel 1072 and H/K AVR55.
I was not disappointed with the combo at all.I listened to 50'srock and Gospal in this config, with and without subs.Better with.

Ling's using 1072 and Rotel 985 amp. Paydirt!
The speakers really lit up nicely, under more balanced power.
Tim runs a pair with 35w of tubes, I think I fed about 25wpc, again, the Sun Studio cd was the choice.
My Lings are pre-re-do, Tim has addressed some issues that he had perceived.
I have no issues, however, the nature of the beast is such that I buffer the input power a bit.
The Lings at close listening range is a real treat with the T-amp.
If you are willing to pay a lot more money, there is a lot more to the chip amp.
More money puts you in a different caregory,as well.

Greetings from Winnepeg.
 

Bronze Member
Username: Ravbains

MelbourneAustralia

Post Number: 84
Registered: Mar-06
Hi Nuck,

so your in Winnepeg, good to know.

I love Canada, have lots of family in TO (I am Indian so no surprises). So I have been to TO many times for family stuff, weddings etc etc. Don't know anyone in BC though or the rest of west.

I spent an entire winter once in Ottawa was quite interesting. I like skiing so we did some trips into Quebec.

Thanks for the comments on the Lings. I am interested in the T-amp down the track, but work is killing me at the moment, and I have lots of other projects in the pipeline (speaker mods, and my old JVC for which I am slowly collecting parts for mod work (I will do this one myself)). I finished some mods on my old A60 amp, results were superb (beautiful airy transparent mids and highs, lean taut nimble bass. But the old girl does not get any air time, since the A60 cannot match the Avi for bass slam.

all best wishes -Rav
 

Gold Member
Username: Artk

Albany, Oregon USA

Post Number: 3300
Registered: Feb-05
Nuck lives in Ontario. With "Greetings form Winnepeg" he's telling us that he is currently working there.
 

Gold Member
Username: Nuck

Post Number: 2671
Registered: Dec-04
Thank-you, Art, I should have skipped the Greetings line, anyhow.
As usual I follow the forum from a hotel room somewhere.

What did you do on the A60, Rav?
 

Gold Member
Username: Artk

Albany, Oregon USA

Post Number: 3301
Registered: Feb-05
I like the greetings line. It's kind of fun to see where you are working.
 

Bronze Member
Username: Ravbains

MelbourneAustralia

Post Number: 85
Registered: Mar-06
Hi Nuck,

on the A60, since I originally bought this amp back in 1987 I did a kind of restoration / update project.

o Replace all electrolytic caps with Nichicon Muse Kz series, and some Black Gates (dependant on stock availability).
o Upgrade Iq pots with multi-turn cermet types.
o Reset quiescent current to run at a higher level, than specified in the manufacturers service handbook.
o Replace stock diodes in the PSU, with high speed soft switching types.
o Replace stock LM317, LM337 regulators in pre-amp section with uprated regulators.
o Re-place mains wiring with a shielded mains flex.
o Remove loudspeaker fuses, replace with solid links (amp is very stable never had any issues, not even during student parties!!!).
o Replace main reservoir caps with low-ESR Panasonic parts. And also fit non-polar bypass caps across main reservoir.
o Replace internal weedy wiring to loudpspeaker posts with Supra Rondo stranded wire.
o I stuffed up on the phono stage, I replaced the stock NE5534 op-amps with AD811 -doh. I did not realise that AD811 is a current feedback amp. Silly me! I am gonna fix this up sometime later.
o Lastly as a final flourish I replaced the red LED power indicator with nice twinkly Agilent blue LED. This indicates that this amp is the ultra-rare Rav Bains signature edition.
o Also cleaned the fuses with Caig De-oxit, and cleaned the pots and did the full sweep thing.

It sounds very nice, but the A60 always was a very sweet amp.

I need to go back into this amp to fix my AD811 error, at the same time there is a mod to the biasing for the amp, known as the amplified diode mod, I will implement this also when I get time.

cheers
Rav
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8536
Registered: May-04


"Amplified diode"? An oxymoron to be sure.
 

Bronze Member
Username: Daniel_canada

Canada

Post Number: 42
Registered: May-06
Winnepeg? It's Winnipeg! I should know, I live there! or here? How ever it should be said. :-)
 

Gold Member
Username: Nuck

Post Number: 2673
Registered: Dec-04
Drinking in the bar at the Greenwood Hotel by the airport tonight.
 

Bronze Member
Username: Daniel_canada

Canada

Post Number: 44
Registered: May-06
Nuck, if you have time check out Creative Audio.
http://www.creativeaudio.ca/

214 Osborne Street South
Winnipeg, Manitoba
R3L 1Z3

Tel.: 204 452.5921
Fax: 204 452.5950
 

Gold Member
Username: Nuck

Post Number: 2683
Registered: Dec-04
I will so, Dan, thanks.
I check out audio shops in various places I go, but usually online only, as a curiosity.
I cant really buy anything and ship it(hassle), and my days usually run too long.
And I never know where the heck I am in so many cities.
It is kinda fun, however to be in a town where another member is from, and get store names.

Cheers!
 

Gold Member
Username: Stu_pitt

Irvington, New York USA

Post Number: 1320
Registered: May-05
Wouldn't it be more fun to get the names of Bars?

Out of curiousity Nucko, what do you do for a living?
 

Gold Member
Username: Nuck

Post Number: 2687
Registered: Dec-04
Field service technician, packaging equipment and combination weighers.
Service across North America and some Mexican adventures.
Service, support and training.
 

Gold Member
Username: Nuck

Post Number: 2693
Registered: Dec-04
Uhh, was that offensive?
 

Silver Member
Username: Dakulis

Spokane, Washington United States

Post Number: 952
Registered: May-05
Must have been, you left everyone speechless. LOL

Now, you tell us you're backing off the tubes, NNNNNNOOOOOOOO!!!!!!!
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4204
Registered: Dec-03
Nuck;-

Not offensive. Puzzling.

Beatles DTS 5.1 fraud on ebay... "Posted on Friday, May 19, 2006 - 11:44 pm: I'm a lawyer!"

I guess one or the other is a joke. Or you are moonlighting!

After much soul searching.

...?
 

Gold Member
Username: Nuck

Post Number: 2707
Registered: Dec-04
Oh John, the lawyer line was indeed a toss-in!
I am too thick to try argueing any point.
My service description is accurate.

The other post reflects the affirmation of my musical preferences. You see, When I purchased the Rotel amp, I had compared to a Nad amp in the same store. Both played through B&W speakers, they may have been 602's.
The Nad sounded nice and full, kind of happy happy.
The Rotel sounded forward, accurate and fast, with higher highs and lower lows.
I decided that the Rotel amp(and subsequently Rotel 1072 cdp)were far more to my liking.

Therefore, although I have been impressed with the toob forum, and have been considering a toob set-up, I have deciced that the presentatin of tubes is likely more suitable for Tchaikovsy than T-Rex.(Thats oversimplified, but quick).
My musical tastes are evolving, but not to the point of great classical appreciation, as most of you folks here do have, and share a great deal with everyone.
Gotta be a rebel in the crowd, I guess thats me.

I will, however consider a small tube kit for the Lings for upstairs.
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4207
Registered: Dec-03
Thanks, Nuck. Give me a field service technician over a l*wyer any time.

On the other thread someone suggested Musical Fidelity might be up your street.

I used to worry about power, after I blew up my cherished 40 W per channel solid-state Armstrong amp (playing Mozart Mass in C minor, BTW). After home demoing a budget audiophile integrated which clipped, I decided on a Sony ES for "Quality brand" (I think it was, back then) plus high W/£. It never clipped and sounded OK; it is still in service in my little office at work where I go and shake the windows sometimes when no-one else is in.

But for real listening, at home, prizing detail and wanting "the closest approach to the original sound", I now like my 40 W Prima Luna PL2 with Quad ESL speakers, which are low efficiency (86 dB/m/W I think). Even with that combo I have to take care the neighbours are out before running it at satisfying volumes.
 

Silver Member
Username: Bvan

Cape Town, Copenhagen,...

Post Number: 221
Registered: Jun-05
art, as i remember you saying you might get some pearl tube coolers in the future, i thought i'd report on mine that arrived today.

they fit with a squeeze but there is not enough room to accomodate the rubber rings which are designed to hold the cooler to the tube.

the coolers fit fairly tightly without the rubber rings, and pearl say in this situation it is fine not to use the rings. but, there is an pdf article on the pearl website in which the author is very emphatic about not using the coolers without the rubber bands. recons they are then prone to picking up vibrations.

i'm undecided about whether to use mine.

b.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8590
Registered: May-04


Use a nylon tie wrap. Or, check out the gaskets Nuck referred to earlier.
 

Gold Member
Username: Artk

Albany, Oregon USA

Post Number: 3325
Registered: Feb-05
Thanks Bvan. I have decided not put anything on my tubes for now.
 

Silver Member
Username: Bvan

Cape Town, Copenhagen,...

Post Number: 222
Registered: Jun-05
that for me jan?

not sure what i tie rap is, or a gasket. the teeth of the cooler are fully intermeshed so i dont know if there is space for anything between. maybe if its very thin and pliable. but wont nylon melt.

and art, the cage wont fit on. (this all for the output tubes only)
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8592
Registered: May-04

http://tiewraps.com/tiewrappage.html

Tie wraps be tie wraps. There is no explaining a tie wrap.


And, do you hear any difference when placing the coolers on the tubes with no rubber rings? If not, I would say the author of the pdf article is too A/R for my tastes.

 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2729
Registered: Dec-03
I have used just black rubber o rings from the hardware store on tubes.
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2730
Registered: Dec-03
Nuck no more Big Macs aye!
 

Silver Member
Username: Ravbains

MelbourneAustralia

Post Number: 104
Registered: Mar-06
Hi Nuck,

(its lunchtime), so just a quick comment from me. I must tell you that I have listened extensively to Musical Fidelity amplifier products (in the last 2-3 years). Anthony Michaelson's, self agrandizing hype, makes me vomit. But even I will admit that MF do have a few good products in their portfolio.

I am little out of date, 'cause MF are changing their entire product line every 18 months, this makes me suspicious also!!!!!

Here is what I know, I think some of it can be fairly safely extrapolated to the current range of amps.

All the MF integrateds, (excepting the super integrateds Nu/Tri/MuVista (KW series) are completely "vin-ordinaire". They offer similar mileage to a Rotel in my humble opinion.

Now the only MFs worth considering are those that use the choke regulated power supplies. Now I have listened at length, and I mean AT LENGTH, to the old A3.2 pre and power amp (now superceded by the A5 pre/pwr combo), and also at length to Nu and Tri-Vista hybrid "super-integrateds".

The A3.2 pre/pwr combo was very nice, sweet sound good midrange, but still hard hitting in typical solid state fashion.

The Nu and Tri Vista's were spectacular IMHO, amongst the best I have heard. They are just slightly to the warm side of neutral, and they have vast reserves of power, and they are low distortion, so they offer glass like clarity. The only proviso here is that these amps are highly critical of the source. If the source is deficient you will know about it in no un-certain terms. But on the speaker side these amps are un-fussy, basically they drive anything, and tonality is neutral, so pick speakers at will.

In summary, I don't think the current A3.5 integrated is good enough to achieve your goals. I think a good Bryston pre/pwr or Classe combo is more in your ball park.

But if on your travels you get a chance to listen to the current KW series mu-vista integrated amp from MF, dont pass up the opportunity.

Also, I imagine if the old A3CR pre/pwr combo is indicative, then the new CR (choke regulated) A5 pre/pwr combo will be nice too. And this is the miniumum I would recommend to you from the MF lineup.

Now in terms of reliabilty, what I can gather, is that the limited edition hybrid super integrateds have been very reliable in the field. The super integrated are UK built, and I think MF takes some pride in these products. All other products in MF lineup are now made by an OEM in Taiwan.

Okay all the best, just telling as I see it.

cheers
Rav

PS this post just qualifies for Tube Talk, since the KW integrated is a hybrid (Tubes for voltage gain, and bipolar transistors in the final output stage.)
 

Gold Member
Username: Artk

Albany, Oregon USA

Post Number: 3330
Registered: Feb-05
"In summary, I don't think the current A3.5 integrated is good enough to achieve your goals. I think a good Bryston pre/pwr or Classe combo is more in your ball park."

I've listened to the A3.5 with B&W's and it sounds very nice. It's not as good as the other combos that you recommended but it is $1600.00 as opposed to several thousand dollars. If Nuck has the several thousand dollars to spend I would concur with your recommendations and add Krell and perhaps McCormack to that list.
 

Silver Member
Username: Ravbains

MelbourneAustralia

Post Number: 105
Registered: Mar-06
Hi Art,

I am not aware what Nuck's budget is, but I made my recommendation on the basis that the goal is to move significantly forward from the Rotel stuff that he currently has.

I am sure that the A3.5 is a competent integrated amplifier (as was the A3.2 integrated, which I am very familiar with), but I dont feel that these amps are a significant step forward from let's say a Rotel RA-1062 integrated.

The old A3.2CR pre/pwr combo, which was 2000GBP, was in a different league from most of the integrateds that I have heard. And, it certainly was in a altogether superior league to its sibling A3.2 integrated.

Depends what the goal is?

I am not familiar with US prices for MF gear. In the UK the A5 pre/pwr combo is 3000GBP. The KW integrated is 4000 GBP.

This is just my opinion. I am sure Nuck can listen for himself and decide.

I am just saying that I don't think the A3.5 will represent the great leap forward that I think he is looking for.

Am I misguided, or do I fail to understand the brief?

cheers
Rav
 

Gold Member
Username: Artk

Albany, Oregon USA

Post Number: 3332
Registered: Feb-05
Not sure Ravinder because like you I don't know his budget. I do believe that the A3.5 is significantly better than the Rotel integrated, at least it was last weekend when I listened to them both.

We will both know a little more when Nuck let's us know his budget.

Another piece that might work well for Nuck would be the Krell KAV-400x1 integrated.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8602
Registered: May-04


"PS this post just qualifies for Tube Talk, since the KW integrated is a hybrid (Tubes for voltage gain, and bipolar transistors in the final output stage.)"


Actually, this post barely qualifies for Tube Talk as nuvistas were an intermediary step between tubes and transistors and share common traits of both varieties of devices. Nuvistas, with a metal encapsulated vacuum have more in common with tubes that transistors, but have always been viewed with suspicion by many tube afficianados. The fact that virtually all known sources for the device have been exhausted never helped the nuvista gain popularity. They do, however, because of their scarcity, rank as the unltimate NOS device.

http://www.stereophile.com/amplificationreviews/205/



 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8603
Registered: May-04


"PS this post just qualifies for Tube Talk, since the KW integrated is a hybrid (Tubes for voltage gain, and bipolar transistors in the final output stage.)"


Actually, this post barely qualifies for Tube Talk as nuvistas were an intermediary step between tubes and transistors and share common traits of both varieties of devices. Nuvistas, with a metal encapsulated vacuum have more in common with tubes that transistors, but have always been viewed with suspicion by many tube afficianados. The fact that virtually all known sources for the device have been exhausted never helped the nuvista gain popularity. They do, however, because of their scarcity, rank as the ultimate NOS device.

http://www.stereophile.com/amplificationreviews/205/



 

Gold Member
Username: Nuck

Post Number: 2777
Registered: Dec-04
Geez, I go for a day and y'all get all excited, like. Well, that's why we hang out here, I s'pose.
Present circumstances dictate that the move will be made in the Autumn.
Integrateded's such as the MF 3.5 might save a few nuck-bucks, but I noticed the power rating of that unit delivers about 130% into low impedence loads as compared to the 200%(or close ) that I think is appropriate.

Am I wrong in thinking that the low inpedence load factor is this important?
 

Gold Member
Username: Nuck

Post Number: 2778
Registered: Dec-04
Oh, BTW, this onr can be seen on soul searching in Amps, not to introod on toobs.
If you want to fallow, er, follow, I shall be there.

Domo arigato.
 

Silver Member
Username: Paulfolbrecht

Post Number: 197
Registered: Dec-05
mr roboto

nuck, I want you to buy the Mc tubes. I may insist.
 

Gold Member
Username: Nuck

Post Number: 2819
Registered: Dec-04
https://www.ecoustics.com/cgi-bin/bbs/show.pl?tpc=1&post=714095#POST714095

Thanks, Paul.
Further adventures are over here now, so as to leave the Toobers alone.
 

Silver Member
Username: Bvan

Cape Town, Copenhagen,...

Post Number: 241
Registered: Jun-05
hi all.

i felt like coming here to confess my sins and give you all someone to laugh about.

i've put up my entire system for sale, save my universal player, to buy a system i've never heard. out goes the dynaudios, rega and prima luna, and in go a 6 watt t-amp, 101db zu single-driver bookshelves, and dual martin logan subs.

why? well i'd have to say apart from not wanting to shlep my system half way around the world, and being able to sell it for more than i paid, i'd have to say the main reason is curiosity. i wasnt dissatisfied at all with my system, infact no system i've had in the last 5 years has failed to satisfy, its more a case of just wanting to experience all the far corners of this interesting hobby. unfortunately i dont have any audiophile friends or work in a store that i can borrow equipment from. i also think it takes me longer than most to appreciate the different qualities that different components and design philosophies bring to the party. so i feel it neccessary to live with components rather than just listen to them on the shop floor. what my premaluna/dynaudio setup does it does exceptionally well. but i cant persue its qualities any further without spending silly money. so i'm heading off in another direction for a few months to see what there is to see. i though i'd try persuing the one and only quality i've been missing to any noticable degree, PRaT. this is not meant to be an upgrade as such, but rather a maybe-risky experiment to persue the prat and involving-low-level-listening thing as far as will go. heck, i'm a young man living on a diet of rock, jazz and fast beat-driven electronic music who's ears cant handle more than 80db. if the new system doesnt cut the cake be surprised. but also happy to come back here pay penitence for my errand ways.

i definitely see tubes in my future, probably in the form of a preamp, something like minimax maybe?

anyway, i felt it safer 'comming out' here than the dynaudio or apollo thread. hopefully you guys will still talk to me.

cheers
 

Silver Member
Username: Paulfolbrecht

Post Number: 208
Registered: Dec-05
Cheers, Bvan, and let us know what you think of your new life! A salute you most admirably. You have real courage.

Hey, I've seen "PRaT" in print about 100 times and I still don't know what it means.
 

Silver Member
Username: Bvan

Cape Town, Copenhagen,...

Post Number: 242
Registered: Jun-05
thanks for the support :-)

yeah, i feel almost the same. a lot of those times it's marketing bs i suspect. but a naim system did once give me a taste. i'm betting electrostats or super high sensitivity speakers are needed for the real deal. will report back from the other side...
 

Gold Member
Username: Artk

Albany, Oregon USA

Post Number: 3375
Registered: Feb-05
Good luck and enjoy Bvan. Hopefully you'll stick with us and let us know how it goes.

I'm doing a little experimenting myself (nothing compared to yours I might add). I've just takin delivery of and placed in my PL2 some Mullard EL34's. Can't wait for some extended listening.
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4243
Registered: Dec-03
Good luck, Bvan.

It makes sense. Especially if you do not lose financially. You can take what you have learned and start again "down under".

I have always replaced one thing at a time, and even then, hung on to the old one. It creates a lot of baggage.

Art; I am interested to know what EL34s do compared with KT88s. I'll keep a look out for your comments, here. I am still on the original KT88s, now a year old, and no problems.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8667
Registered: May-04


Pace
Rhythm
and
Timing


 

Gold Member
Username: Rick_b

Orlando, FL

Post Number: 1377
Registered: Dec-03
Kegger, what's up my man????
 

Gold Member
Username: Nuck

Post Number: 2969
Registered: Dec-04
Thanks Jan.

Godspeed Bvan.
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2735
Registered: Dec-03
Oh I'm just a tubin along there Rick dude!
Workin on some stuff including some little Jolida thingy. LOL!

Plus I'm gathering some info and parts to build my first very own amp.
Using parts from some scott, fisher and dynaco pieces plus using one of those
same Tubes4hifi input boards that I had bought an extra one of with my first ST-70.

So it won't really be my own design but I will have to figure out how to make it all work. :-)
(You could mod up an ST-70 with all this and it would be much easier)

It'll run 3 triodes in the driver stage, 12XXX and octal sockets for the power tubes, wired
for your standard EL34,KT88,6L6 type tubes but running adaptors to permit the use of
6BG6G tubes (cheap TV sweap tubes in an ST shape) with a top cap anode connector.
It will run in PushPull for about 27wpc with 390vdc on the plates and 37ma current draw.
It will be able to run most of the EL34,KT88,6L6 type tubes by not using the adaptor and
could get more power output by using a different rectifier tube plus dialing up the bias.
(Could also get less power if I decide to wire the outputs in triode for experimenting)

I plan on using not to beefy of a power trannie with a single 5V4G rectifier (ST shaped),
because that is the type of power trannie I have, with it I could squeeze around 45wpc if
I go to a 5AR4 rectifier which would be about it for the output trannies I'm planning to use.
The output trannies will also work for other tubes like 7591's by rewiring the tube sockets.
So it should be a great learning tool for myself and very versatile for playing around with. :-)

Doing a lot of research and math to get this thing off the ground but the basis is solid. IMHO
It may be quite some time before I actually get somewhere with it, but you'll see it. I hope!

I stumbled across these 6BG6G tubes that just got me so jazzed to do this. There basically a
6L6GC in an ST shape and top cap but only rated for 20watt, the 6BG6GA is a 35watt version
that are not ST shaped, I have the tubes allready but still collecting more. :-)

What you upto?
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4260
Registered: Dec-03
Kegger; I take my hat off to you. What a journey we've been on, here. Wish I could go that far, too!

Bvan; Good luck, too! If you are minded of electrostatics, and are rich, consider the new Quads. Thread: New Quad ESL models. If not rich, consider any older model.
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2736
Registered: Dec-03
Thanks for the encouragement John but lets not get to far ahead of ourselves.
I have got a long journey ahead and am just starting to scratch the surface of
understanding this stuff. But I do really enjoy it and am learning a lot.

I wish tubes where taught in school instead of just transistors for me.
It would make the learning curve much much smaller I would think.
 

Gold Member
Username: Rick_b

Orlando, FL

Post Number: 1379
Registered: Dec-03
Kegger,

I'm just having fun in the sun, and living the dream. I just wanted you to check in and let us know you're well, TUBIN'! Sounds like a great plan for your amp. Keep us in the loop.
 

Gold Member
Username: Kegger

Warren, MICHIGAN

Post Number: 2740
Registered: Dec-03
Nothin new on my front, anyone else?
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8726
Registered: May-04
Nope!
 

Gold Member
Username: Nuck

Post Number: 3116
Registered: Dec-04
The Iris's were lovely this year...
Nothing!
 

Silver Member
Username: Dakulis

Spokane, Washington United States

Post Number: 974
Registered: May-05
Well, I just thought I'd check in to toobers paradise. Nuck is still no closer to pulling the trigger per this post and his other.

Art has had a mind altering experience and has tubes, new speakers and who knows what else those aliens have done to him.

Rick is hangin' around and sharin' the love and the knowledge. Ditto for Kegger and John.

I'm just enjoying the information, keeping a low profile and trying to figure out whether to roll some tubes and which way to head when I do it. You guys have way too much knowledge for you own good.
 

Silver Member
Username: Ravbains

MelbourneAustralia

Post Number: 131
Registered: Mar-06
I am keeping a weather eye on this thread also.

I am still taking baby steps, and trying to learn what I can in the area of DIY audio/mods as a hobby.

But, I do feel that one day I will become a tube user also. The main reason for this is that I don't think I can cope at all with all the new surface mount technology used in AV products these days.

I feel I will fare much better with old fashioned hard-wired tube based cicuitry!!!

But as I said I am still taking my first baby steps in this hobby, I have a long way to go and much to learn.

cheers
Rav
 

Gold Member
Username: Nuck

Post Number: 3121
Registered: Dec-04
Hi Dave.
I havn't discounted anything just yet, but have taken a nickel's worth of free advice.
I've decided to chase down the elusive speaker option first.
here's why:

1) I have an amp which is sufficient(if not hypnotic).
2) I need to decide on the speakers and then their placement, before deciding if I need a sub(which will change the scene somewhat).
3) The speaker placement will decide my componant placement somewhat, as I figgur to bi-amp new speakers(wire cost)? (Althugh the home depot rip cord has tested well).
4) componant placement will decide house wiring upgrade(potential) to a spur from the main bus and perhaps a power box.

After that, I should have a good handle(and a few more $) to decide on the final power amp decision.

I figgured I was going in too many directions, and since my room is not going to change, I would be best starting with good speakers with nice bass(I need), and dumping the dumpy sub setup(happy wife factor in that).

Cheers!
 

Gold Member
Username: Artk

Albany, Oregon USA

Post Number: 3421
Registered: Feb-05
Rav, for just taking baby steps let me tell you that you have learned very well. I think your advice has helped a good number of folks on this forum and I always look forward to reading your posts. I'm grateful that you have joined us.
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4307
Registered: Dec-03
I second that, Art.

Rav, no-one can read this whole thread and stay sane. Rick and Jan were the original tube proponents. A number of us have now moved over to tubes. No-one seems to regret the decision.

I made small discovery a few weeks ago. Probably it only affects me, here, but it relates to power output, one of those nagging concerns, and one reason why some people like to stick to solid state.

On paper, my notional 40 W per channel PL Prologue Two ought to be not quite enough for my Quad ESL 63 speakers, recommended 50 -100 W per channel.

In fact, as I began playing big music louder, I found the amp at just below 12 o'clock could occasionally drive the speakers into normal overload protection.

The solution was to switch from 8 Ohm to 4 Ohm output taps. After which, no problem. I imagine the amp is now delivering more current, and therefore power, for a given voltage.

Anyway, it works, and the clarity, even at high volumes, is just wonderful.

I would have no hesitation in recommending this amp-speaker combination. In all my experience, it is "the closest approach". I heard some live music recently which took people's breath away, including mine. I tried playing some similar material, when I got home, from a new CD which has some of the singers at the performance, doing similar stuff. As good as it gets, I think. Not obviously different from actually being there.
 

Gold Member
Username: Nuck

Post Number: 3146
Registered: Dec-04
I third that one Art, well stated!
And thank you Ravi, for keeping with the forum!
 

New member
Username: Bryce_nyc

New York, New York

Post Number: 2
Registered: Jun-06
Thought I'd jump on.

Nuck - Was in your shoes. Ended up very happy.

New housing move and rethought my priorities -- had been listening to a JVC receiver and excellent Energy Bookshelf speakers for 10 years and this meager setup gave me much pleasure.... decided MUSIC should be my main distraction (never cared much for TV). Spent four months educating myself and auditioning equip. and trusted my ears. Didn't make a move until got the speakers. I've had my new system up for a while and I believe -- considering my Audio Experience -- got really lucky, and didn't spend a fortune. Initially was put off by the weirdness of it all....and still am to a degree, first convinced myself of 2 channel, then full range speakers (no sub), then an Integrated Amp (didn't want to spring for separates). The toughest part was SS vs Tubes -- Liked em both. I listen to everything. Got off on detail and base more than liquid mids, so looked hard at hybrids but couldn't pull the trigger>>> $$$$. I'm also hung up on purity of execution and simplicity (No gimmicks and no microprocessor controls, these were deal breakers for me).

Ended up with Audio Physic Tempo IV speakers, Arcam CD73 & ProJect Turntable for source, Musical Fidelity A3.5 Integrated, MF X-10v3 tube passive pre, and MF PSUv3 preamp power supply.

Originally liked the setup with the X-10v3 tube buffer in place between my CD and Amp, however, when friends showed up with their I-Pods and old vinyl, they were lacking. Bought another interconnect and placed the X-10 in the tape monitor loop so all source signal paths would go thru those tubes. At that point (A/B) I could tell most of the magic was coming from the X-10. Looked at that damn wall-wart transformer, and decided to upgrade the power supply for the X-10, and that put the whole system over the top -- warm and it slams hard... anything you plug into the A3.5 sound great. The Audio Physics leave no stone unturned!! Only problem is I don't know what to do with my CD's that were mastered with the music industry in mind (lacking dynamic range) guess I'll wait for the high res remasters.

Hope this helps.
 

Gold Member
Username: Nuck

Post Number: 3148
Registered: Dec-04
Good post, Bryce.
Thanks, and welcome to the forum.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8730
Registered: May-04
"The solution was to switch from 8 Ohm to 4 Ohm output taps. After which, no problem. I imagine the amp is now delivering more current, and therefore power, for a given voltage."

Generally a tube amplifier will produce the same "power" when the output taps are used at 4, 8 or 16 Ohms. Power does not change as you assume it would based on your experience with a solid state amplifier. And current is not a tube amps forte. Most modestly priced (read less than lunatic money) tube amps are hard pressed to manage more than a few amps into any given load. Certainly a tube amplifier is unlikely to produce 2X its 8 Ohm rating at four Ohms. There might even be a case where the lower impedance tap produces less power due to the intervening output transformers. It is totally dependent upon the load the amplifier works into. And, of course, varies with frequency. Driving a straight 8 Ohm dummy load resistor from the 8 Ohm tap might produce 40 watts while using the 4 Ohm tap might produce less power. In the case of driving the ESL's, I would guess you've found a happier spot for the amplifier's transfer functions to work into the highly inductive and capacitive load of the Quads.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8731
Registered: May-04
"MF X-10v3 tube passive pre"


Has anyone ever accused mr. Michaelson of poor marketing?
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4310
Registered: Dec-03
Thanks, Jan. Agreed. I am still trying to understand why the effect is there, but it certainly is.

The impedance modulus of the Quad ESL 63 (and I assume its newer replacements) is complicated, and another thing that might not look so inviting on paper. They say "nominal 8 Ohm" but there is a dip to 4 Ohms in the middle, I think around 1 kHz. The Quads go into protection over 100 V input, I think, and it was massed sopranos that threw the switch with the 8 Ohm taps.

In my kitchen physics, halve the impedence and you halve the voltage for a given current. Of course, it is what the amp output expects from the load that has been changed, not the load itself. I cannot quite get my head round that, I must say.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8732
Registered: May-04
The output tubes are running into virtually the same load no matter what tap you use. The output tubes are running into the load of the output transformer. The output transformer acts as a buffer of sorts and a step down device for the tubes' output impedance which typically runs at around fifty to one hundred Ohms before the transformer. That accounts for the mulitples of paralleled outputs from the tubes in an Output TransformerLess tube amp. The paralleled devices drop the impedance down sufficiently to drive a (very) constant load speaker with a minimum of problems. Tubes driving a transformer, however, makes for a totally different story. In that case the devices making the voltage and current never really see a different load. The taps on the transformer merely serve as a way to better match the transfer function of the amplifier to whatever load you are using. Therefore the transformer coupled (tube) amplifier produces essentially the same wattage no matter what tap is used as long as the tap matches the load properly. Your math works just fine with a direct coupled amplifier, John, or an OTL tube amp. But, put a transformer into the middle of the equation and see what answer you get.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8733
Registered: May-04
And, of course, the OTL amp still has major limitations delivering current into the lower impedance so it generally falls on its face when mated with a complicated load. Complicated in this case being any speaker that isn't pretty much a straight eight Ohm load. This is one reason you don't see many OTL tube amps any longer.
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4313
Registered: Dec-03
Er.....

Thanks, Jan. Will read that several more times, and do my best.

In lieu of incisive comment, let me paraphrase Eric Blair: "Four ohms good".
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8735
Registered: May-04
Not with fifteen Ohm LS3/5a's!
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4314
Registered: Dec-03
No, of course.

By the way the book "Sound Bites" has a whole chapter in the LS3/5a in its various incarnations. If I recall, the move up to 15 Ohms was the result of redesigning the crossover to cater for changes in the specified KEF driver. Also, the stringent specification was because the BBC's aim was to make it possible for any LS3/5a to work as one of a stereo pair with any other - ever produced, and no matter by whom, and with no audible difference in imaging or anything else. I would guess that disqualifies the new pretenders, like the Stirling.

I have some more things to say but realise I am on the wrong thread.
 

Gold Member
Username: Rick_b

Orlando, FL

Post Number: 1388
Registered: Dec-03
John,

Of the BBC LS3/5a clones, the only one that still builds to the above specs are the Spendor S3/5. Any speaker made will match with any other.

If there are others please enlighten me.
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4322
Registered: Dec-03
Thank you, Rick. There were six, I think, in the HiFi News "Wannabee shootout". They were all a little different from the original, in various ways. Yes, the Spendor S3/5 was strongly recommended. I know your view, too! I am not, personally, looking for speakers - just always interested.
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8738
Registered: May-04
What I've read makes it unclear as to the ability to pair the Stirling speaker with older 3/5a's. I have read it is built to the same specs as the older speaker, but, uses new and different drivers and is a reflex design enclosure. The reports are that it is slightly "crisper" on the top than the original. How all that can be built to the same spec as the original is something I don't comprehend.
 

Gold Member
Username: Nuck

Post Number: 3172
Registered: Dec-04
Best axe I ever owned.
4 handles and 2 heads.
Yep, the best axe ever.
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4324
Registered: Dec-03
Stirling Broadcast.

"This 'V2' version retains the LS3/5a License from the British Broadcasting Corporation and is suitable as a drop in replacement for any working pair of LS3/5as"
 

Gold Member
Username: Rick_b

Orlando, FL

Post Number: 1390
Registered: Dec-03
I am a little confused also. How can it be a direct replacement for the original, and not be an acoustic suspension design? I don't get it?
 

Gold Member
Username: John_a

LondonU.K.

Post Number: 4326
Registered: Dec-03
Good question, Rick.
 

Gold Member
Username: Nuck

Post Number: 3179
Registered: Dec-04
The designs seem to be farther and farther away from the original axe.

But good, no doubt.
 

Gold Member
Username: Rick_b

Orlando, FL

Post Number: 1391
Registered: Dec-03
Any thoughts or opinions on this Mr. Vigne?
 

Gold Member
Username: Nuck

Post Number: 3180
Registered: Dec-04
Wait, lemme get a scotch...
 

Gold Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 8741
Registered: May-04
.


As above.


I can only assume the BBC has let cash influence its licensing procedures. Or, possibly it depends what your definition of "is" is. " ... is suitable as a drop in replacement for any working pair ... " Possibly they can be dropped in as pairs but not as singles as the old style speaker allowed.


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