Bi-Amp Question

 

Bronze Member
Username: Magfan

Post Number: 28
Registered: Oct-07
Speakers: Magnepan MG 1.6qrs
Current amp is a Rotel RB1070 of 2x130....clearly at its limit when played loud.

Question:: another RB1070 and Bi Amp or go up the line to the 2x200 RB1080 and sell off the '1070?
Other amp suggestions can and will be considered, but I am not rich.

Also, the ENTIRE system is considered 4ohm. The X-over is as simple as I've ever seen. A cap and inductor on the bass side of the panel and 4 caps in parallel = 1larger cap on the hi end...not a radical load, by any means.
Would the impedence of either driver by itself be too low for either of the suggested Rotels?
 

Gold Member
Username: Nuck

Post Number: 8969
Registered: Dec-04
Leo, I like the bi-amp idea. Seperating the range of delivery makes life much easier on the amps, and will smooth out impedence swings for one of them. The reduced load makes it way easier for the 'smaller' amps to handle the load that way.
Although the Maggies are a low impedence load, they are quite stable, I think, not dipping really low, and not presenting a big swing in phase angle, so yeah, I would bi-amp.

There is also the presentation of multiple amps on the floor beside the speakers t be considered(I like that).
The Rotel amps won't balk at any load that way.
Of course, the accomanying wiring needs to be neatly sorted out, and a sepeate circuit would be a good idea.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11575
Registered: May-04
.

While Nuck seems to be enamored with the concept of bi-amping, I tend to think a single high quality amplifier applied full range is best in the mid price ranges. The disadvantages of bi-amping far outweigh the advantages at this price point IMO. I don't know and you don't say if your speakers can easily be bi-amped or whether a separate active crossover would be needed. If a crossover must be purchased, I would definitely advocate for the single better amplifier.


While the Magnepans are not a highly capacitive load, the simplicity of the crossover is misleading. The construction of the main diaphgram makes the speaker a fairly high inductive load and this along with the low nominal impedance makes the speaker a somewhat difficult load for most amplifiers.


Overall, I find the combination of Rotel and Magnepan to be somewhat odd as neither company's signature sound is similar to the other. I would suggest you listen to a higher quality amplifier capable of greater synergy with the speakers before you begin searching for another Rotel and all the asssociated "stuff" required to bi-amp. Bi-amping with another Rotel will give you more or less the same sound you have right now. If the amp is running out of steam due to the load, bi-amping will only lighten the load on the high frequency amplifier, which isn't likely to be the problematic area in this speaker. Buying 70 (50%) more watts is probably not a solution of the current amp is having difficulty driving the speakers. Buying a different amplifier to compliment the high end of the speaker will present problems with cohesion of the whole. Upgrading to a better full range amplifier will, if the rest of the system is capable, improve everything downstream of the pre amplifier. It seems the most cost effective way to achieve an improvement. It might not look as cool as multiple amplifiers astride the panels, however.


.
 

Gold Member
Username: Nuck

Post Number: 8975
Registered: Dec-04
It's cool Daddy'o.
 

Bronze Member
Username: Magfan

Post Number: 30
Registered: Oct-07
The 1.6's can be bi-amp'd by simply removing a pair of jumpers and plugging in.....the Jan hated Bananas are the connection of choice.

Further questions, though....even a pair of SAME amps have problems with cohesion/image?
Also, the whole thing is fronted by a NAD tuner/pre, so there is another possible mismatch!

I am going to rethink this. I'm not rich, and have extended myself as far as possible for now, but may in the future buy 1 larger amp.....The Rotel is worth bucks aftermarket/trade/audiogon, to help finance any proposed change.
What are some 200x2 amps of <1500$? Are there any integrateds? NAD has a 180x2 integrated which will also save me some shelf space, which is is short supply.
This whole thing is shelved until after the 1st of year and I settle up for Christmas!
 

Gold Member
Username: Nuck

Post Number: 8978
Registered: Dec-04
Well maybe back up a bit, Leo.

What is it that you need to improve on the system?
If you like the Nad presentation and everything else, is it just power?
Does the Rotel get hot? (It should not).
quite warm is best.
 

Silver Member
Username: Nickelbut10

Post Number: 633
Registered: Jun-07
True indeed Nuck.

Leo- do you like the sound of the system until the volume is pushed to what seems to be the amp's limit? If money is a problem, and a two channel amp is what you want to add. Have you considered the NAD C272? Its rated at 150 watts a channel but when put on a bench for benchmark testing it has been known to push as much as 182 watts per channel at a 0.01 percent distortion. Thats pretty good, and you can have TWO of them for 1600 CDN. Just a thought. Tones of amps out there though.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11577
Registered: May-04
.

No, a second of the 130 watt amplifier will give the same presentation if there is no intervening active crossover. But, ...


A 130 watt amplifier for the high frequencies is killing ants with a jack hammer.


The passive crossover, as simple as it is, remains and would be better replaced to minimize phase errors, assuming that is, you will buy a high quality active crossover. There aren't many audiophile grade active crossovers available and what's out there isn't cheap. Too bad since passive crossovers suck in all kinds of ways.


What exactly do you think you'll have gained by adding the second amp?




My feelings toward NAD equipment should be well known by now. But NAD and Rotel is a combination I wouldn't rush to recommend. This would appear to be the "put a 'warm' pre amp with a 'bright' amplifier" approach to system synergy. That approach never made sense to me.



There are a few good 150 watt integrateds though they are not cheap. I wouldn't buy one. And considering watts is missing the point.



I think you need to reconsider what you're trying to achieve. Whether you like the speakers or not, Magnepans are not a speaker that plays loud with most amplifiers. The larger Magnepans can play relatively loud just by the vast amount of air the diaphragm moves, but that's not why you buy them. No offense but your system sounds like a bit of a mish-mosh without enough planning or references. I'd sit down and take stock of where the system should go before I did anything else.


.
 

Gold Member
Username: Nuck

Post Number: 8984
Registered: Dec-04
Nick, Leo has panels and Rotel power.
The Nad is chockeing up the line there.

Leo, your source again?
 

Bronze Member
Username: Hawkbilly

Nova Scotia Canada

Post Number: 51
Registered: Jul-07
I knew Maggies were a bit of a load, but didn't think they required 200+ to drive them. That's unfortunate, as there are a lot of wonderful small amps out there under $1500, more if you consider the used market.

Juice like that costs money, and as JV implies you are getting out of integrated territory, and into separates....meaning even more $$$$. I've read reviews of Maggies with Blue Circle gear before, and allegedly the pairing is just smashing. You could get a used BC-22 for around $1000, but you'd need a pre to go with it, and you'd still only have 125W. However, I'm not convince BC's 125W wouldn't drive the heck out of those speakers.
 

Silver Member
Username: Nickelbut10

Post Number: 634
Registered: Jun-07
"Nick, Leo has panels and Rotel power.
The Nad is chockeing up the line there."

Nuck, if you could explain this, that would be great. Are you saying Rotel power is better than NAD power?lol.???

Anywho, for some reason now that I actually read the thread when Im not at work, I see Leo wants uses Bi-Amp. As in using one AMP for the highs and one amp for the LOWS. Like Jan is saying, I cant see that being a benefit to use a 130 watt amp for the Highs. What about buying a second amp, and bridging both of them. One amp per speaker. To double your overall power to the speakers. Am I wrong to say this? Jan, Nuck, your input.

But wait, you say Panels. I believe my knowledge of these speakers(NONE WHAT SO EVER) and my knowledge of panels(pretty much NONE) is confusing me. Perhaps he doesnt have two speakers.lol. Im going to go have a beer now. Let me know how dumb this post is when you have a chance.Thanks.
 

Silver Member
Username: Nickelbut10

Post Number: 635
Registered: Jun-07
Well well well, turns out my dealer in belleville is a Rega dealer but only carries it for special order. Boys, im buying a Apollo.lol yeahhhh. Ok back to your discussion.
 

Gold Member
Username: Nuck

Post Number: 8987
Registered: Dec-04
The 1070 does bridge at 390watts.
I would not bet on the bass control in that configuration.
 

Silver Member
Username: Nickelbut10

Post Number: 636
Registered: Jun-07
Got ya.
 

Silver Member
Username: Nickelbut10

Post Number: 637
Registered: Jun-07
Ok just checked out his speakers, so why not buy another 1070 and bridge the pair of them?
 

Gold Member
Username: Nuck

Post Number: 8991
Registered: Dec-04
Need feedback from Leo in San Diego before posting more.
Bridging works, but gives up bass control in Rotel amps, in my experience.
 

Bronze Member
Username: Magfan

Post Number: 31
Registered: Oct-07
So far, thanks for all the help....I am rethinking my chain of components. No matter what, the Maggies stay!

Tuner/pre is a NAD1700 of about '88 or so. Very nice w/semi parametric tone controls, absolute phase, MM/MC phono input, 2 tape monitor loops and an external processor loop. And has proven 100% reliable.

Rotel will bridge if speaker is 8ohm. I doubt it would work into Maggies.

Next 'upgrade' may be a new preamp....Rotel makes a new one which in addition to all standard preamp has a sub out w/bass management features.

I wouldn't exactly say mish-mosh covers my system.
I believe ad hoc is about right, though. Can I have an amen?

Don't forget that until the recent demise of my cube, I hadn't changed anything in nearly 2 decades.
About 6 months ago, I nearly bought an Adcom 555II of about 10yrs+ age. Bought new, instead.
 

Silver Member
Username: Huron

Post Number: 278
Registered: Mar-07
nice thread can I sit in?
 

Gold Member
Username: Nuck

Post Number: 8994
Registered: Dec-04
leo, did the bridging info come from Rotel's website? I hadn't seen that before.

Where you been, Angelo?
 

Silver Member
Username: Nickelbut10

Post Number: 638
Registered: Jun-07
Angelo and I have been over at Home Theater Forum. Angelo is the man.

I was thinking the same thing as you Nuck, never heard of a amp only bridging at 8ohm's before. A bridge is a bridge, and if the amp can handle the 4ohm normally, why cant it handle it bridged. Or perhaps Rotel only gave a wattage rating of 8ohms bridged. Leo, have you contacted Rotel Tech support to make sure of this?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11583
Registered: May-04
.

A "bridge" is not a "bridge". You can parallel the outputs or you can run the outputs in series. Each gives different results and each has its advantages and disadvantages. Depending upon the topology of the amplifier, you can probably only bridge this amplifier one of the two ways possible. An amplifier that goes from 130 watts in stereo to 390 in mono doesn't sound very stable to me. This would appear to be mostly voltage and very litle current will be at work in this configuration. This doesn't appear to be the ideal choice for a rather difficult load at high SPL's.

.
 

Bronze Member
Username: Hawkbilly

Nova Scotia Canada

Post Number: 52
Registered: Jul-07
I've never done the whole bridging thing, or the bi-amping thing. I'm still wondering why a new or used single component with decent bang wouldn't be preferential to all this complexity.

I don't think there is any guarantee that two Rotels would sound the same as one.....only louder. It could sound worse....or better I suppose. But it still strikes me as a crap shoot.
 

Bronze Member
Username: Magfan

Post Number: 32
Registered: Oct-07
Rotel does not specifiy 8ohm output for this amp.
They also specifically say 8ohm only in bridged mode. I can't believe I read the book!
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11589
Registered: May-04
.

"They also specifically say 8ohm only in bridged mode."


So that is a warning against using the amplifier with a lower than eight Ohm load when the amp is bridged?
 

Bronze Member
Username: Magfan

Post Number: 34
Registered: Oct-07
Yep, Jan, 8ohm only in bridged mode.
Also, a correction. Rotel doesn't specify 4ohm output on this amp.
Rotel DOES have a 4ohm spec for the RB1080 of 200x2, so this omission was not an accident.

I am beginning to think that, power aside, this may not be the right amp for these speakers. I think the same 130x2, with better low impedence characteristics would be a better bet.

Would it be better if the amp doubled up into 4 vs. 8? at least on paper?

I may make a trip to to OC and check out another dealer with a selection of other gear. I'd love to hear Bryston/ Arcam/ and maybe the 'M' series NAD's..........among others.
 

Silver Member
Username: Huron

Post Number: 280
Registered: Mar-07
Im helping someone in home theater he has the same speakers, he was running the NAD T762 and it burned out on him, he wants to build a 5.1 srround with these speakers, funny how the first post I come across is this one, I know nothing of these speakers, so I will try not to sound stupid, jan, you got me thinking in your post 11577 wow thats a lot of posts, anyways, when a normal driver is being driven to far you can hear it, but what happens with these speakers do they give signs? I gess that these ribbons have a short range of movement compared to a normal driver and thats why the speakers are so big? I notice on there web site under (How much power do I need) it dont answer the questen, so I gess the questin is how much power untill the robbons run out of room? and is that the time to hange the Thomas English Muffins?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11591
Registered: May-04
.

"Would it be better if the amp doubled up into 4 vs. 8? at least on paper?"


The general opinion would be, no. It had long been considered ideal for the "perfect" amplifier to double power with each halving of the load but that concept started to give way as more and more speakers required more and more current. Since "power" in terms of wattage is measured only into a consistent resistive load, doubling the "power" doesn't mean much other than the amp can swing more voltage into a simple, non-reactive load. Voltage is relatively simple to pass through an amplifier and some (many) amps have literally drawn voltage and current from the wall socket to hit a big peak only to have the power supply be drained when the next transient comes along. Heavy amps have lots of "power" in reserve since they usually have lots of power supply capacitance.


If you're driving a simple non-reactive load as a speaker, then this doubling of voltage would possibly be a good choice for amplification in a direct coupled amplifier. If you're wishing to drive anything that will require substantial current, then an amplifier that increases by about 50-60% into a halved nominal load would likely be the better choice.


Looking for peak amperage would be the better way to determine which amplifier you should buy to drive a difficult load though this, like most specs, can be deceiving and still tells you nothing about how the amp sounds.


While not an absolute for excellent sound, I would be interested in the slew rate and the square wave performance of an amplifier. For several decades the better amplifier manufacturers have used a frequency response that extends about four times beneath the lowest range of hearing and about five times above. So, roughly, 4 to 100kHz should be stated as either the amplifier's frequency response or it's power bandwidth with lower and higher being generally regarded as better. (Don't get fooled by a DC coupled amplifier's "response" down to 0Hz. It's a spec you don't want since DC will end your speakers' life. And it's a spec usually put on paper by someone selling something they can't really produce in terms of real world conditions.) While this is still just a tiny portion of what might make a better sounding amplifier frequency response, slew rate and square wave performance are the first places I generally begin if I'm looking at specs or measurements. That still doesn't tell you how the amp will react under truly dynamic conditions into a reactive load but, as I said, it's a starting point. If the manufacturer doesn't state frequency repsonse other than in their wattage spec as required by the FCC, they usually don't have anything to talk about in this regard. None of this matters in SET amplifiers but any decent push-pull power amplifier should be able to do a good looking square wave at several frequencies. Transformer coupled amplifiers also won't generally do well on a square wave test due to the transformer's response times at frequency extremes but any direct coupled amplifier should perform well or you should probably pass it by.


As always, the first recommendation is buy the heaviest amplifier for the amount of power you want to have. Again, not a perfect recommendation, but it's a start.


.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11592
Registered: May-04
.

Magnetic planars generally begin to "flop" when they reach their physical limits. There's no "banging about" as with a dynamic speaker where the voice coil is beating against the pole piece or the stops of the motor assembly. Since in a magnetic planar the voice coil has been "unwound" and attached to the entire diaphragm the speaker looses control over the movement of the diaphragm and the speaker is best described as just "flopping" around IMO. Others might describe it differently but that's what I've always heard.


The ribbon high frequency drivers have very little relative motion and they tend to also sound poor without really distorting on their own. Then they stop working all together. True ribbon "full range" speakers just stop sounding good or getting louder. I've never heard one that "banged" against anything but rather just wimpered somewhat like overcooked pasta hitting the wall.


.
 

Silver Member
Username: Huron

Post Number: 281
Registered: Mar-07
Ok, there rated at 4ohm do they drop a lot lower or do they stay around 4ohm?

and you mentioned diaphragm, I will look at the diagram on how they work again I gess I wasnt paying attention I thaught the ribbons them selves made the sound, or are we talking about two things voice coil unwound attached to diapham, and then ribbon high frequency drivers, if you can piont me to some good diagrams that would help
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11596
Registered: May-04
.

http://www.hometheaterhifi.com/volume_8_3/magnepan-16-speakers-9-2001.html


http://www.hometheaterhifi.com/volume_8_3/magnepan-16-speakers-9-2001.html
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11597
Registered: May-04
.


Damn!

http://www.magnepan.com/magneplanar_technology
 

Gold Member
Username: Touche6784

USA

Post Number: 1214
Registered: Nov-04
Jan, what would be considered an appropriate slew rate for driving those speakers?
 

Silver Member
Username: Huron

Post Number: 283
Registered: Mar-07
Ok now I remember what confused me, I see the Quasi Ribbon drivers which should be attached to the mylar? and I gess its all suspended over the Permanet bar magnets so the magnets can push/pull? and why is the ribbon in between the magnets? and wouldnt the Mylar Diaphram be looser in the center than the edges?

the magnets are secure to the plate that has holes in it so air can move freely?

but wares the coils how are the magnets being worked? are the coils on the back side fallowing the magnets? sorry if I just sounded stupid but I have a wild imagination and untill I see what I want to see my mind gos into a Psychotic state

then in the other diagram it shows an aluminum ribbon just sitting in between magnets? and aluminum is paramagnetic unless you ad something to it.

anyways all this brought me back to the (How Much Power do I need thingy) reading between the lines, My gess is that you can create your own problems with these speakers, if your on a budget and cant afford an $8000 Mcintosh or if you wanted to go 5.1 what would that cost? you could use a arcam 300 or any high currant receiver or separates that can handle the heavy loads as long as you dont bring the amp to its limits, of course your not going to be able to crank it up loud, am I right or rong or just crazy or is there more to it than that or am i thinking to fast ghjy@#%^^tgy7yi
 

Silver Member
Username: Huron

Post Number: 284
Registered: Mar-07
wow I am being a retard, why would you power the magnets there just that, but all they have to do is show were the coil wires are and I would get it,
 

Silver Member
Username: Huron

Post Number: 285
Registered: Mar-07
MY THEORY by the extremely sexy angelo lombardi, the coils are between the ribbons on the mylar diaphram, and thats why you need a Paramagnetic material for the ribbon so it cant get magetized enough to effect the, I dont know the word, but basically so it wont all stick together, or am I still rong I dont feel rong but what,,,, if,,, I,, am, and of course there not showing the wires so you wouldnt see that, please show me
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11598
Registered: May-04
.

Angelo - Do you know how to use a search engine? Not being rude, but there's a lot of questions there that can be found if you do some looking rather than I just feed you the answers. Do some reading then I'll answer what still confuses you.
 

Gold Member
Username: Nuck

Post Number: 9010
Registered: Dec-04
Angelo, did you and Andre split a hit of acid?

Read, kid.

And have fun.
 

Silver Member
Username: Huron

Post Number: 286
Registered: Mar-07
yes I do know how to mudle threw a search engine, my mistake was when I asked you to piont me to some good diagrams I was convinst it ended there, but now that you have told me to use search engine, now I can see there are lots of technologies out there, I allways wondered why the martin logans looked so different, and there are a lot more speakers of this ribbon type than I thought, my visulisation skills from just reading are not up to par (learing disabilities) good diagrams are good for me, Im more to phisicly looking at how things work, I gess I lack in social skills to, but hay its all in good fun, funny Nuck, last time I talk out loud to myself on the net, now you know how my brain works ha, acid, crack, whatever
 

Gold Member
Username: Nuck

Post Number: 9014
Registered: Dec-04
That was meant in jest, Angelo, I hope you got it as such.
You are fine, kid, keep posting.
And reading.

And listening, above all.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11599
Registered: May-04
.

"Jan, what would be considered an appropriate slew rate for driving those speakers?"




I would once again encourage a search engine and finding some facts along the way. This would be important since not everyone agrees with the importance of slew rate to the quality of an amplifier's performance. Some have argued that minimal slewing rates still make for a good sounding amplifier. Others argue that each stage of the amplifier must be capable of high slewing rates and excellent square wave performance before it can measure well enough to sound good enough. Quite a bit of this is tied into trying to find those measurements that consistently equate with "good sound". It would seem unlikely there will ever be total agreement on whether an amplifier that measures well in certain areas will always sound good once we take the clips off the load resistor.


However, the "generally" agreed upon slew rate in a well designed solid state power amplifier would be in the 40-60V/microsecond at 1Khz into an 8 Ohm load. Some feel this spec would be dependent upon the output power of the amplifier with higher wattage amplifiers obviously capable of higher voltage delivery. Others, HK most importantly as this has been one of their main selling points for decades and falls in line with Otalla's research into T.I.M. distortion, promote this high slew rate from even the most modest amplifier.


Slew rate, however, has more to it than simply delivering voltage into a load resistor/oscilloscope. You must have a reasonably broad power bandwidth in the amplifier to manage high slew rates; and fast delivery of the voltage will facilitate good square wave performance. But that means nothing if the power supply capacitors are completely drained after the delivery of that voltage. This also has nothing to do with high current delivery into a reactive load as the slewing spec is typically quoted. But, if the power supply has the ability to deliver the second and third bursts of "power" into a reactive load (for which there is no generally agreed upon spec that I'm aware of), the chances are good it will have the ability to deliver current into a low impedance/high phase angle speaker load.



http://search.yahoo.com/bin/search?fr=ybr_sbc&p=slew%20rate%20in%20audio%20ampli fiers


.
 

Silver Member
Username: Huron

Post Number: 287
Registered: Mar-07
I got it right away Nuck, you made me laugh
 

Bronze Member
Username: Magfan

Post Number: 35
Registered: Oct-07
When my original MG-1s 'hit the wall' the sound stopped getting louder and there was distortion, what Jan said was flopping about. This is a not bad description. I believe there is some frequency doubling as the diphragm ceases to be controlled by the magnetic field. To me the sound 'bunched up' and was thick......Some of this effect may have been my old amp at 'redline'.

Another nutty question::
synergy is a big issue among audiophiles.
Equipment that brings out the best in each other and becomes greater than the sum of parts.

Now, Rotel and NAD are said to not work well together. I can't beef about this, but, would it make a difference if the Pre was NAD and amp Rotel, VS Pre being Rotel and amp NAD? I am wondering if there is a last component in the chain effect?
 

Gold Member
Username: Nuck

Post Number: 9015
Registered: Dec-04
Nice delivery on the sticky slew rate factor, Jan.
It still matters, but matters a whole lot more if the amp is backed by stout power, as opposed to just capicitance.
It can all get hot in a hurry, this is where big slew amps are Class 'A' and toast bread as well.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11601
Registered: May-04
.

"Now, Rotel and NAD are said to not work well together. I can't beef about this, but, would it make a difference if the Pre was NAD and amp Rotel, VS Pre being Rotel and amp NAD? I am wondering if there is a last component in the chain effect?"



You'll have to explain "last component in the chain effect". Otherwise, do you feel NAD and Rotel both have a "house sound" that is identifiable to each brand? If so, what would be the next most logical assumption?


.
 

Bronze Member
Username: Magfan

Post Number: 36
Registered: Oct-07
By last component in the chain, I mean the component closest to the speaker.
Since the maggies are considered to a revealing speaker, I would suspect being able to tell the difference between a NAD/Rotel/Mag chain as opposed to a Rotel/NAD/Mag chain, all else being equal, like music and similar loudness levels.

I do, indeed believe that NAD and Rotel have a bias difference in the sound. No problem there. And while not an assumption, but rather a conclusion would be to make these more in agreement. Long term plan was, when buying the Rotel power amp, decidedly mid-fi, but all the budget would allow, to eventually replace the NAD. I got side tracked by perceived power limits of the Rotel, at the loudest levels. I can live with that and target a better/more compatible pre-amp. I may go down to the local merchant and see if he will part with a RC-1082 for a week or so. This will give me a chance to evaluate this component in my system as a 'drop in' replacement for the NAD.....and I can then answer my own question.

That being said, the question remains about the last component effect, if it even exists. I know that sticking a can and string level preamp in front of a pair of Krell monoblocs will result in a can/string output. S(*& in / s(*& out! But we are talking a pair of reasonable components here, so which characteristic would prevail?
 

Gold Member
Username: Touche6784

USA

Post Number: 1215
Registered: Nov-04
Thanks Jan. I did try a search but ended up lost in the text. I tried searching through specs of reputable companies to see if there was a trend but I didn't get much out of it. I asked mainly because I have maggies too and have run into a similar problem but decided on one big amp which is Carver PM 1.5. No idea how it will sound together but I hope it is good. I appreciate your input. I am always amazed at your breadth of knowledge.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11603
Registered: May-04
.

"By last component in the chain, I mean the component closest to the speaker."



So, like, why didn't you just say amplifier? You're making this harder than it needs to be.




"But we are talking a pair of reasonable components here, so which characteristic would prevail?"



If the amplifier cannot adequately drive the loudspeaker, the sound of the amp failing will always prevail.

.
 

Bronze Member
Username: Hawkbilly

Nova Scotia Canada

Post Number: 53
Registered: Jul-07
Technology aside, isn't much of this about trying to drive $10 speakers with $5 amplifiers ? And perhaps $$'s isn't the right way to express it, as I'm sure a knowledgeable person can find a way to get a $10 amp for $5, but you know what I mean.

If you like the sound of the Maggies (however they create their sound), you'll have to mate them with suitable components to get the most out of them.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11608
Registered: May-04
.


Yep.
 

Silver Member
Username: Huron

Post Number: 288
Registered: Mar-07
wow I cant beleive how simple the ribbon and planar designs are, people all over the world are building and experimenting with them as a hobby, Im suprised no one belched out a paragraph explaining them to me. ribbon driver, has a thin and long aluminum foil suspended between two lines of magnets and clamped down on both ends, driving currant (audio signal) through the foil and the magnetic field created by the current causes the foil to vibrate in the magnets magnetic field.

the planar or diaphragm usually has multiple ribbons bonded to a membrane (usually mylar) connected in series and suspended in a magnetic field.
just a simple explaining.
I have only skimmed threw threads and sites so im still not strong on the knowledge.

I have been working with metals my hole life (fabricating) most of these guys are making these ribbons with nothing more than a few simple tools, with all the equipment, tools and skills that I have I could make a nice prototype and start experimenting, if I had the time and ambition, maybe in a year or two. apogee full range seems very interesting, I noticed the apogee full has a transformer that you can install 4ohm or without 0.3ohm
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11618
Registered: May-04
.


Keep on reading, al, this is interesting stuff.
 

Bronze Member
Username: Magfan

Post Number: 41
Registered: Oct-07
Angelo,
If you intend to build some drivers, keep a few things in mind. There are some tradeoffs to make. Strong magnets are necessary for higher efficiency.
Small gaps between driver diaphragm and magnets increase efficiency at the expense of loudness and power handling. Large gaps is the opposite.
Magnepans 'inventor/founder', Jim Winey worked for 3M, so it is no surprise that Magnepan wire is bonded to the diaphragm with 3M 77 aerosol cement.
If you have more curiousity, go to Magnepan Users Group site.....MUG, for short, where there are quite a number of user pics, systems, tweaks, stands and vintage materials.

The MG-1.6 is a tweakers delight. The crossover, for example consists of 22mfd worth of capacitance in series with the tweeter, and 25mfd worth of capacitance across the woofer section, which is in series with a small inductor......All in all one of the most simple crossovers known in mid->hi end. There is a vigorous market in aftermarket caps, by Hovaland, Jensen and V-Cap. Plan on 300$ for a re-cap'd crossover, however. Many people fabricate there own stands and there are several aftermarket companies providing same.
If you look, and not to hard, there is probably 8 tests of this speaker on the web. The stereophile test printed an impedence/phase angle graph which pretty much shows that this speaker is a fairly low impedence load and +-30degree phase angle, mostly near the crossover frequency of 600hz.
I read these reports with an eye for associated equipment / amps / preamps.
You may also want to read some back issues of 'speaker builder' magazine. I have heard, but not seen, that they have published information about home-brew planar drivers.
Have fun,
 

Silver Member
Username: Huron

Post Number: 290
Registered: Mar-07
If I did plan on building one, my strong point would be in the crafting of the materials, I played around with magnets when I was a kid I know if I did build one It would get the highest quality neodymium that I could and I wouldnt use segments, and I would get the ribbon so close, and figure out what kind of material I could use to take up the gap to help the ribbon stay true, and I wonder if you could pleat the ribbon in such a way that it would be longer than the total distance giving it more resistance? just a thaught probibly not and sorry for my spelling i hope i made sence
 

Bronze Member
Username: Magfan

Post Number: 42
Registered: Oct-07
Angelo,
Research magnetic material. Some is 'brittle'.
You can hurt yourself with some of the large, very powerful magnets. Imagine clamping a finger between a pair of magnets with a gap strength of 1 tesla.
OUCH. The ribbon is not loose, but is under some tension. I suspect the amount and exact alloy of aluminum is proprietary. The ribbon must be clamped with something that won't pinch it off, and is an insulator, if the remainder is metal framed, as I suspect it must be. The frame for the ribbon must be very strong in compression...the long way...and also have a resonant frequency 'out of band'. Part of the damping can be from the surrounding frame.

A pleated driver has already been invented. It is called the Heil AirMotion Transformer. It was in some ESS speakers of a few decades ago. You can purchase these drivers as aftermarket items from a few vendors. Power handling/burnout was an issue.
I don't know of current OEM use.
 

Silver Member
Username: Huron

Post Number: 291
Registered: Mar-07
I know I would be working with the brittle magnets, I can build anything I need if I need a costom strong bench clamps and make tools to handle powerfull brittle magnets, I wouldnt want to damage one, I work with heavy equipment, concrete and steel, and Im a retired auto tech, I owned a genral repair shop, my favorite thing was building and fabbing things for street rods
 

Silver Member
Username: Huron

Post Number: 292
Registered: Mar-07
as the ribbon or diaphragm wear dos the sound change? I dont hear anyone talk about tuning the foil or anything for sound.

something that keeps poping in my head is taking a peace of weed and putting it between my thumbs and blowing threw it and making that weird sound and adjusting it and blowing hard or softer to get diffrent sounds, I really want to see how the foil acts when it vibrates,
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11620
Registered: May-04
.

"as the ribbon or diaphragm wear dos the sound change?"


What sort of wear are you expecting?
 

Bronze Member
Username: Magfan

Post Number: 43
Registered: Oct-07
Jan, just speaking of metalurgy....without relation to specific hi-fi uses.
Aluminum has NO fatigue strength. Every stress cycle eats into its eventual lifetime.
Steel will last nearly forever if never stressed above its fatigue limit.

So, if a ribbon IS made of aluminum, it will wear out eventually. Longer or higher power use will wear it out more quickly. Parts, like woofer frames, can be made of aluminum and last as long as the steel it replaces, but you won't have the full advantage of the weight savings aluminum can provide.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11624
Registered: May-04
.

The trick in a ribbon driver is to suspend the ribbon in an elastomeric damper which limits stress points while not interfering with the ribbon's (limited) motion. It's done in the same manner, more or less, as the damping block on a phono cartridge's cantilever. I suppose some companies might do it differently but that's how I've always seen it.


.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11625
Registered: May-04
.

"Longer or higher power use will wear it out more quickly."



If you're playing it that loud that long, most ribbon drivers will proabaly die from heat rather than "wear".
 

Silver Member
Username: Huron

Post Number: 293
Registered: Mar-07
people are replacing the ribbons,

slightly bending metal over and over, or vibrating the metal will fategue it and cause stress cracks (spring steel will stress over time) a engine block thats seasoned making it harder and more true can give away to flection forces, and now lets take a thin piece of metal that dos not take flexing very well and run current threw it, and then submerge it in a water and gallium bath, waite a few minnutes then light a match (just kidding)

the ribbons seem to last a long time so I gess its not getting stress as much as I thaught it would, I can find most of my questin myself but I thaught I would try to make freinds

making the foil longer (putting distance on the clamped areas) will slow stress on piont areas, pleating will provide rigidity in the short width, and allow for a spring like stretching ability on the long width, and maybe gain a little more impedents because its longer in a shorter area, but I have only had a short time on research so like I said Im not strong on the knowledge.

I started this post this morning and had to work all day so this is for jans 11620 post
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 11627
Registered: May-04
.


You seem to be learning a lot in a short time, angelo.
 

Silver Member
Username: Huron

Post Number: 294
Registered: Mar-07
somethings I can pick up on fast, just dont give me a popquiz on math.
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