This is not just another gainclone

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Just to add some fodder (hearsay really), my local 47 Lab dealer told me that Kimura goes through more than a hundred IC's to find a pair suitable for use in the Gaincard. Alluding that while the sum of the parts are not costly, there's a lot of labor involved.

Grains of salt and happy new year.

Noam
 
Brian,
The top view pic looks similar to a photo my friend was looking at when he built his gainclone. His photo showed the amp in place in the case but you couldn't see the front of it to tell if it was an actual 47. He said it was a photo of an early version but was now a much neater build.
 
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Noam said:
Just to add some fodder (hearsay really), my local 47 Lab dealer told me that Kimura goes through more than a hundred IC's to find a pair suitable for use in the Gaincard. Alluding that while the sum of the parts are not costly, there's a lot of labor involved.

Any clue to what would possibly go into selecting ICs? Do different chips vary much in terms of DC offset and such?

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Brian
 
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Well... I decided to start my gainclone tonight while waiting for the ball to drop. I am going to make it cheap for my first one. I picked up heatsinks for $1 each from a surplus store, Allen Bradley resistors (recommended by Thorsten) for $0.06 each at another surplus store, $2 solen cap, panasonic fc caps from digikey, $2 radioshack 100k stereo alps pot. I will use my aleph 5 transformer for this (25v secondaries). I calculated ~$17 in parts not including transformer or chassis for the 2 channels that I am making for my first gainclone. This should fit in the Fruglephile(tm) category.

I kept the feedback resistor path as short as possible.

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Brian
 

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47 Labs a con job outfit?

Rod Elliot writes a cutting but probably true critique of 47 Labs and their bogus and flakey engineering claims. I am looking forward to completing my Gainclone but I have no illusions that it will be any better than my JVC reciever which also uses Ampchips of some sort. My Alpine car amps use Ampchips and they are reasonable sounding. Why not put those in the house?
Greg
 
This thread is interesting. A bunch of people are getting excited about an IC amplifier when under normal circumstances, these things would not be given any respect whatsoever. Why? because Peter Daniel's does a really nice (and I mean REALLY NICE) job of packaging the things. Could it be that people are more impressed with packaging than content? Could that be the reason why so many "high-end" pieces of equipment appear to have far more $ in the metal work than in the circuits? Could it be that an amp is an amp is an amp?

It's one of those things that make me go "hmmmmmmm...".

MR
 
I too follow this post with interest, but I think you give people here too little credit. If you read the entire thread, you'll see that most are interested because of sound quality, not packaging. Even though Peter D. did an impressive job on the packaging, I believe he did so out of sonic concern, not pure athestics.
 
DC Offset
I used this circuit for my gainclone.
You can buy PCB´s from an Elektor-like magazine.
If you disconnect the pot R1 you´ll get a real big DC offset.
A friend of mine fried his speakers like that.
I installed an additional resistor from the input to ground which resolved the problem.
Any comments? Is this circuit useable as it is?

To the last posts:
There are a lot IC amplifiers that are crap but chips like TDA7293/4 or the complete overture series from National Semiconductors are definitely an exception.
This thread is not not only interesting cause of Peter Daniels creations but that somebody actually let a "high-end" design compete with a gainclone and be honest about the result.
We want to hear about sonical differences and reasonable circuits for the DIY´er.

Jens
 
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A bunch of people are getting excited about an IC amplifier when under normal circumstances, these things would not be given any respect whatsoever.Why? because Peter Daniel's does a really nice (and I mean REALLY NICE) job of packaging the things.

Mrehorst, you did not read the posts otherwise you would not say this nonsense. Peter Daniel & friends compared it with Aleph X and guess what amp was better. Please reread posts and not only the headlines before making comments. :idea:

Crap in a nice case would still be crap and comparing with tube or Pass DIY gear would be out of the question. Made by Peter Daniel or not, case made of solid gold or not. Even the "revealing" pics of the inside of a real 47 Labs Gaincard don't bother me as the endresult is what counts. Maybe National will come up this year with an audio IC that doesn't even need the resistors and other extra components.Imagine a 1 part amp with a 2 cap PSU that sounds better than some tubeamps and/or expensive semiconductor gear. BTW I think a lot of the latter possibly attract people with their looks and golden binding posts etc. Till recently I had a 300B push pull amp that was noticed immediately by everyone entering the room. Not that they listened, only the sight made them often say what a beautiful amp it was....

BTW there are more than just a bunch of people that like this amp.
It can be very refreshing to build one and at the same time see that some of your "audiobeliefs" can go overboard. Good audio is good audio whether it is realised with IC's, MOSFet's or those colouring devices that glow in the dark. ;)
 
amen......!
and btw, check out the intire range from jeff rowland, it uses lm 3886 chips - and sounding extremely good.......not only because of the ampchips but because they did a splendid job all over.
as far as i'm concerned - that means the potential is there.....!!!!!
:att'n: :att'n: :att'n: :att'n: :att'n:
 
Hopefully we will start to see more systems with many amplifiers and no passive XOs

I'm working on it!

MRehorst

If you look back over a few months you will see many of us have been extolling the virtues of gainclones, but I think it took Peter's superb presentation skills to bring it to the fore. I am now on my 4th or 5th version, and although I have never produced something as spectacular looking as his gainclone, my experiments have lead me to belive it is one of the best methods of driving speakers around, I was just loathe to praise it as highly because I suspected the reception that the idea would get. I was also reticent because I have not built DIY amps before, and so could only compare it to commercial offerings, not amps that many people on the board are familiar with.

If you doubt us, give it a go, it's cheap enough to experiment with, and if you hate it, come back and tell us, I for one will listen to well reasoned arguements, but build one first, and then comment from experience.
 
MRehorst hit the nail right on the head. The only thing the LM 'whatever' has going for is that is cheap, easy to build, sure short signal path but so do all ICs, if it's built with good components it's probably going to sound better than 99% of the stuff of what the target clientele is used to/can afford, and all of this in relation to the speakers it's going to be paired with.
I have read the thread carefully, l see nothing to support that the chip sounds better than anything else. Now, if people want to take an Hoccam razor through the whole thing and convince themselves that they have the ultimate amplifier on their rack they can be my guest.
As far as I am concerned I have been down the IC road and I know exactly where it ends.
The underlying principle of this IC is the classic class B amp with current sources and mirrors, well studied protection circuits, nice bias adjustment (with diodes which should sound better). Coming from a single chip everything is probably well matched up. Throw a few components at it, come home from work, get a cold one, flip the switch sit on the divan and music is going to come out. It will probably be performing as well as your AKSA or the class B amp from Rod Elliot or thereabouts which is to say very well. Sorry Hugh and Rod don't mean to **** you off.
As far as comparing it to a class A, award-winning design that is such a crock I can't even begin to describe. It's actually offensive.
 
I have read every post in this thread.

I have nothing against IC amps. In fact, I like them (and op-amps), for the same reason many DIYers do, whether they admit it or not- they are easy to work with, and success is almost guaranteed. I think though, that if someone had presented such an amp built into a pie tin, and claimed that it holds its own against expensive commercial gear, the person presenting it would have been laughed off the forum.

What does it say about the need for a high-end industry when $15 worth of parts can be turned into something competitive with multi kilobuck gear?

Of course, the listening test was done with specific sources and speakers and rooms and cable and yadda yadda yadda... There is no way a REAL high-end product could be beaten or matched by such a cheap assemblage of parts (especially not by an IC) under a broad range of test conditions, sources, speakers, cables, rooms, and etc., right?

Finally, Jean-Paul, where I come from, calling another person's statements "nonsense" is considered pretty rude. But hey, this is the internet, what should one expect?

MR
 
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