Like

Amp camp amp

 

Gold Member
Username: Magfan

USA

Post Number: 3510
Registered: Oct-07
This amp, as a kit, might be the 'giant killer' Some amps pretend or hope to be.

https://diyaudiostore.com/products/amp-camp-amp-kit?variant=7072933085218

A couple days ago, they were at 40% of the 'new' batch sold. Now? Seem to be all gone.

If I see this again, I'm buying one, even if the uberfuhrer objects.

I see many 'small' amps, from just a few watts to maybe 20 a side. I suspect his will go to the short list of 'best' upon hearing.
Huge DIY community support. Comes with a 5a/ 24v switcher. That's gonna make so much of the build easier.
Comes with everything from soup to nuts. You bring a soldering iron, a selection of hand tools AND a meter to adjust bias. DONE.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18600
Registered: May-04
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I received an email about this amp a few days ago. Nelson Pass. Not much to dislike IMO.

Research is in your hands, leo.


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Gold Member
Username: Magfan

USA

Post Number: 3511
Registered: Oct-07
You can't trust what I say. Our listening values might be enough different.
Besides? My panels are VERY low sensitivity and certainly not suitable for this amp except maybe at headphone levels.

I'd LOVE some high sensitivity speakers to test this with. I suspect anything north of 90db would be a good start.
Where to start with some high sensitivity speakers?

Which reminds me. Do you think this would be a good amp for headphones? Lower sensitivity stuff like planars and 'stats, maybe.
or higher impedance stuff where the power of this amp would translate to a more useful level?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18601
Registered: May-04
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High sensitivity goes with most SDFR's. Check the Omegas I mention in the B&W/Monitor Audio thread. Lots of SDFR drivers available if you want to stick one in a piece of plywood and have a dipole infinite baffle system. No box, just a sheet of plywood with a hole in it.

It's actually a bit too high powered for most headphones. That's not a problem if you are aware of how quickly the phones can be destroyed. I would expect this amp to be designed for a solid 8 Ohm load and most headphones are well above that spec. Loading the amp down with a significantly higher impedance, say, 32 Ohms will change its transfer functions. Frequency response will be thrown off and the amp will become more and more of a Voltage source vs a current source at 8 Ohms. Power will go down but, if you start off with more than necessary, that's not a bad thing.

You can always suck it and see or give Pass an email and ask his advice. I seem to remember the email I received said the seller was there to assist buyers.

This amp caught my attention due to its description and the "reviews" it was given for the price they're asking. Sounds like lots of amp for low bucks.
The kit seems very well laid out and complete with a pretty simple assembly compared to many of Pass' more recent diy amps. I just have no need for another amp and, if I did, it would still be tube based.


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Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18602
Registered: May-04
.

How about a vintage Altec; https://www.tnt-audio.com/clinica/altec_604_onken_e.html

This is a killer system. Drivers are available alone of you want to build your own cabinet.


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Gold Member
Username: Magfan

USA

Post Number: 3512
Registered: Oct-07
ACA has very good documentation. I've been thru much of it while wearing drool bib. (no cracks, please)

Very attractive amp at an unbeatable price.

And for the overachiever? It can be builts with balanced inputs as a bridged version of I think 15 watts.......4 of those on my panels in biamp? Now 'yer talkin'.

Yes, some Fostex or whatever 5" would be fine for testing. And encourage me to build something.

Time for Coffee.......
 

Gold Member
Username: Magfan

USA

Post Number: 3513
Registered: Oct-07
Looking at some of the Madisound kits with the 4" Fostex full range driver.

Others choices with a slightly larger driver might include a tweeter and a simple capacitor for the crossover. Nothing exotic.
A 90db sensitivity 2-way without wacky loading should be fine for the ACA.

Looking at plans for the required enclosures with an eye toward getting some High Quality Balitc Birch plywood down at Rockler.
I'd have to borrow the neighbors portable table saw, but that's not a big deal.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18604
Registered: May-04
.

MDF works fine.
 

Gold Member
Username: Magfan

USA

Post Number: 3515
Registered: Oct-07
How much $$$ we talkin' for the Altec drivers?

I've seen some other stuff from SEAS and Morrel, none of which really got me going.

Fostex 8" full range crossed about 7khz to a Fostex tweeter?
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18610
Registered: May-04
.

I didn't say the Altec was cheap, I said it was good.
 

Gold Member
Username: Magfan

USA

Post Number: 3516
Registered: Oct-07
Wish I had the LOOT and the SPACE for some big-box stuff.
Not to mention the MEANS to actually build 'em.
Need as a minimum, a good table saw.
I've done enough improv to know the right tools makes a huge difference.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18614
Registered: May-04
.

I built my speakers using a $199 contractors table saw, leo. I've had that saw for a number of years and looking at what's currently available, my saw it pretty crude and rude compared to a new $199 saw. You can probably pick one up for less than $200 at one of the outlet stores or a pawn shop.

Besides, this is experimentation, right? What are you thinking you're going to build? A full line of speakers to sell in the stores? You're gonna be building a couple of boxes at the most.

Set up is what matters. If you can't lock the blade at an accurate 90 and 45 degree cut, then that's a POS saw. Do that, even with a cheap saw but with a good blade, and you can build speakers. You can build speakers with a circular saw if that's all you have. There's no tricky joinery in building a box. It's you that makes the difference. Don't get in a hurry and triple check everything before you make a cut.

You can look at my enclosures and think you could cut your finger running it along the edge of the cabinet. They are perfectly joined at 90 degree angles along the entire 6' height of the boxes. That was done with a $199 table saw that is no one's idea of a great tool. Edges were matched with 45 degree angle cuts and they lined up perfectly.

I'm not bragging, there's really nothing to brag about. This is all basic carpentry, and not even sophisticated carpentry at that. Just saying this isn't as hard as some would make you believe. It's all in the set up.

The only small problem I had was on my very first cut. Because I was building 6' tall transmission lines, I needed a large out feed table to support the work. I used two horses and a scrap sheet of plywood to form the out feed support. On my very first cut, the farthest away outfeed support shifted just a bit and the first edge that I cut had a small deviation at its one end It's off by about 1/8" off from perfectly straight on the last two inches of the cut.

This was at the very top of the side piece so the joint was unaffected and you have to look carefully to notice the error. If I hadn't been cutting down the full 8' length of the MDF to make that first cut, there would have been no problems. I strengthened the supports, reclamped the plywood table top and finished the cuts in about an hour's time for the pair of speakers. I probably should have done the first cut down with a circular saw but that would have involved another blade on my saw and I got a bit lazy.

Think it out - and don't get lazy - and you can build a pair of speakers in a day or two.

If you build an infinite baffle, there's no enclosure. You need a piece of MDF large enough to contain the driver. That's all you need to cut. The baffle can be made out of cardboard if you like. It's only function is to be large enough (1/4 wavelength of the lowest bass note plus 1") that the pressure wave doesn't wrap around and cause cancellation. The largest part of the baffle is there only as an obstruction. It doesn't care about stiffness or resonance.

Back in the days of mono recordings, people would build IB's in their fireplace or a closet door. It's the simplest method possible and yet gives surprisingly good results.



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Gold Member
Username: Magfan

USA

Post Number: 3517
Registered: Oct-07
New saws called 'contractor' have postage stamp size tables. The saws at Harbor Freight are cheap and potentially dangerous.

Yes, infeed / outfeed tables can be fabricated and YES it's not rocket science.

Craigslist has a selection of table saws. From ancient 'cast iron' Rockwell (think 400lb) to the new stuff which, IMO isn't worth a (Wind Passing) in s stiff breeze.

My target saw is one of the mid-size folding Ryobi or similar. This is SoCal, so EVERYTHING costs 25% more than it would anywhere else.

I have a cheap-o Skil Chopsaw. And a Skil contractors saw older than I am. it's a 6 1/2" model. And made for 'lefties'.

Using just the chopsaw, a good Dewalt Trim Router and a selection of clamps, I built my 30 cubic foot BBQ box. I used Pocket Screws / glue for the project.
My End Grain Maple Chopping Block was made with ALL hand tools including HOURS of sanding / finishing. I really wish I'd had access to the planer from class.
The diagonals are +- about 3/16" or so. Maybe better.

And speaking of class? Not only did they have the Planer from a Battleship (no joke, a real monster) but a brace of SawStop Cabinet saws, all sorts of goodies, a real nice bandsaw, a shaper, (giant router) and various power sanders, a couple joiner / planers and enough clamps for the army. I learned a LOT.

Buddy of mine is selling his ShopSmith. A 5-in-1 tool with extension tables and other goodies. I have to go see it, but can't go the 1500$, nor do I have the need.

I'm also considering a reframe of my Panels with PlyBoo. I'd use 3/4" Neopolitin. I have drawn most of what I need in Sketchup. That's where I start all original projects.

Another useful tool for a small project is one of those Saw Guides for circular saws. the Festool and others are fairly $$$ while I could fabricate a minimum type for just a few $$$. Skip the table saw, altogether.

But if I DID have a table saw, I'd make a 'sled' and a few other add-ons.

Hope you have a good blade for your saw, and a Dado Stack if you need one!

And now that you mention it? We are at the time of year when people sell stuff for Christmas Money. Maybe I can find something worthwhile on Craigslist,
go for a short drive and save some $$$??
 

Gold Member
Username: Magfan

USA

Post Number: 3530
Registered: Oct-07
I just got done building and experimenting with using a ROUTER as a hole saw. Works the charm.
And I can make repeat cuts JUST as easily.
Bisecting a circle to determine TRUE center is easily done with a pair of dividers. That's one of the issues with building speakers, the
round driver cutout and the hole needed for a potential 'port tube', if you go that route.
Even an Infinite Baffle speaker will need the round hold, sans port / enclosure.

I'm on the 2nd version of the hole cutter, the first being a functional prototype. V2 worked fine and allowed me to make pieces for my vacuum dust collector.
A plywood lid and a ring (2x) for the bucket. That DeWalt Trim Router is a wonder.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18644
Registered: May-04
.


Cutting a round hole is a pretty simple task IMO; https://www.google.com/search?q=circle+cutting+jig&rlz=1CAHKDC_enUS754US756&oq=c ircle+cutting+jig&aqs=chrome..69i57.6687j0j1&sourceid=chrome&ie=UTF-8

Even without the help of a jig, it simply requires patience and a sharp blade. Locating the hole's center is pretty simple too and mostly a matter of aesthetics rather than function.

If you're surface mounting either a driver or a port, the "neatness" of the cut is covered by the flange of the driver or port so making too big a deal out of perfection isn't really necessary.

So, what ya gonna do with your new found skills?


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Gold Member
Username: Magfan

USA

Post Number: 3531
Registered: Oct-07
Currently making a dust collector for my cheap-o shop vac.
Making lid and clamp system for a 5 gal bucket. Than will fit a 'dust deputy' type cyclonic seperator.
Filters for vac are $$$ and clog within seconds of install and are generally not washable.

The 'ring' I made for the bottom of the clamp fits exactly. Zero clearance and snug without being a 'press fit'.

I need a drill press for 10" to drill some holes exactly straight and in registration between the 2 clampable pieces.

Than some roughly 6" carriage bolts and wing nuts to apply clamping force.

I know about 'neatness of cut' but I KNOW what it looks like. Since I have few tools and NO table saw, I will spend time making a jig for repeat cuts so all
are the same. I frequently make templates for the same purpose.

I wish you could see the BBQ Box I made to hold all my stuff. All pocket screws and glued. Inset panels. Lid will NOT admit rain from any angle. I used ADA compliant offset hinges for the lid which is tight enough to have an Air Cushion close. You can drop it from all the way open and it Whooshes closed.

Box is about 30 Cubic Feet and you can stand in it while someone rolls it around. It easily holds Everything from extensive ceramics to pizza peel to up to 4 20lb bags of lump charcoal. I've never found even a BUG inside it, or a spider, for that matter. Lid is tilted forward to shed water.

When I make something I can usually think of improvements for the Mk2 version but not in this case.
 

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18646
Registered: May-04
.


https://www.google.com/search?rlz=1CAHKDC_enUS754US756&ei=3Y1hXI_1McrYsQXbjrnQAQ &q=drill+press+jig+for+hand+drill&oq=drill+press+jig&gs_l=psy-ab.1.2.0l4j0i22i30 l6.33810.43047..46694...0.0..0.71.815.13......0....1..gws-wiz.......0i71j0i13j0i 7i5i30j0i7i30j0i7i10i30j0i67j0i131.cn4BFigt4c4



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Gold Member
Username: Magfan

USA

Post Number: 3535
Registered: Oct-07
For the simple drilling I made a right-angle jig. Good for 3 or 4 drillings and quite accurate enough for what i needed.

The big hassle was plumbing. NO standards, or few, anyway, exist for tubes and such. I found something at the local Tool Mart
which fit the inlet of the vac. The plumbing department provided 2" PVC and clamp-on rubbber fittings.....one elbow and one inline.

After mounting the cycione on the lid and plugging in the pipe from it to the vac, the vac hose ALSO fit over the inlet of the cyclone.

I got lucky there.

Of all the DIY versions of this, I'm the ONLY one who uses hard pipe from cyclone to vac. Other very $$$ systems, usually built-ins with multiple
inlet ports have this feature, but none I've seen using a simple shop vac system.

Want to really ring your bell? Go to ROCKLER and check out dust collection. You can easily go 1000$ plus if you have a well equipped shop.

And it works the charm.. I sucked up a bunch of sawdust and trapped easily 95% or more in the 5 gallon bucket.

Now i need to make a few adjustments and build a roll-around cart which will also hold all the extras.....
 

New member
Username: Gabijohnson

Miami, Florida

Post Number: 2
Registered: Mar-20
How much $$$ we talkin' for the Altec drivers?

I've seen some other stuff from SEAS and Morrel, none of which really got me going.

Fostex 8" full range crossed about 7khz to a Fostex tweeter?
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