What's made a good amp.. ?

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Hi Mike,
Let's say, symasym shows a good seperation of instruments.
I'll agree with that statement. I found the SymAsym 5.3 to be a surprising little amplifier. Better than I thought it would be. So now instead of just using it as was the original intention, I plan to investigate this amplifier further.

I recently was able to acquire an HP 339A, 334A (fundamental to 600 KHz) and 654A (audio generator). I still have not got a DSO yet. The HP 339A will allow me to really get into the design of this little amplifier. Also, Clem (thanks Clem!!!!) sent me a Tektronix AA-5001 THD analyzer. Once I have that tested and ready to go, I should have very good ability on the bench. I'll let you know what I find.

-Chris
 
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Hi Gaetan,
I've repaired both those amplifiers in my service career. It's difficult to draw comparisons. The Naim didn't impress me very much, it's a Naim thing I guess.

I will say that I am very pleased with the sound of Mike's amp design. It is a better amplifier than many commercially available models. I do like some of those better than the SymAsym. The only thing that is easily said about the SymAsym is that it does most things right.

You know, why not just build a pair? It's not an expensive project and if you don't like it the parts can be used for another. Very little to no loss to you at all..

-Chris
 
anatech said:
Hi Gaetan,
I've repaired both those amplifiers in my service career. It's difficult to draw comparisons. The Naim didn't impress me very much, it's a Naim thing I guess.

I will say that I am very pleased with the sound of Mike's amp design. It is a better amplifier than many commercially available models. I do like some of those better than the SymAsym. The only thing that is easily said about the SymAsym is that it does most things right.

You know, why not just build a pair? It's not an expensive project and if you don't like it the parts can be used for another. Very little to no loss to you at all..

-Chris

Hi

I'm limited in budget so I have to wait before starting that kind of project, but I will do it soon as I could, I will have to chose between Dx amp, Gem100 and SymAsym.

Gaetan
 
Dx amplifier is simple and cheap, cannot beat GEM or Symassym

Will not loose for a big distance...but for sure will loose.

At least, lost in my home.

I prefer my high end compared to Symassym...but Dx amplifier loose to all others characteristics.... worst sound stage, less bass, less power, more distortion, worst voices and in special..what i love in symassym:

"It is excelent to hold 4 ohms speakers and also produces enormous dinamic of power during peaks....you may fell down from your chair when the small giant amplifier decide to show himself to you"

Each one have good points..... selecting one of them will be hard...you will always loose something.

I am still searching for the one can beat all amplifier in all characteristics...my prefered is Aksa...but cannot beat all them related all qualities we want to have.

Also my preference goes to the more simple from the Aksa family...the model 55 Nirvana...and this one, is worst related measurements, and some sonic aspects, compared to Lifeforce that is the new model from Aspen.

Also i have never listened the Symassym big brother.....maybe this one can be very special and a real complete amplifier.

Well....those supositions make us excited and alive..as we have something to try, something to search, something to dream..some hope.

Now a days i am thinking that an amplifier able to hold 2 ohms loads, without too much losses, may be very special to hold difficult speakers...and those ones, difficult speakers, are almost all them.... say...enclosure having many drivers and the damn passive crossover.

I have not listened the last GEM.... someone in South Africa is having problem to sleep, as people do not want to go out from his home...they want to stay there, listening that last GEM.

regards,

Carlos
 
All I can say is; that if an amp doesn´t sound good in a system, there may be other things to blame. Room acoustics is an essential part of our perception of the fidelity of sound.

As far as amps goes, there seems to be no beneficial distortion whatsoever!

You can´t hear the sound of an amp, you have to have a source and a transducer. Well , some cables as well , but very often we get information about a specific part of an entire system , without references to the interaction between parts of the system.
Sometimes one part of this system can hide or compensate faults in another part of the chain.
What I´m trying to say is this; it´s a complex matter, and simplifications may lead to false assumptions.

Some more discussion;http://www.redesignsaudio.com/faqs.html
 
DX 100

Dear Destroyer X

Even your amp cant beat others but i think your amp maybe
one of favourite amplifier, you can look how much view and
posting in there

Theres 1770 posting and 73128 views
you have the generic concept now

theres a lot of head think about that, maybe you cant beat
in quality now but you have a lot of fans who will think what
can i do to make this amp better ?

congratulation to carlos as a luckiest man in the world
http://www.diyaudio.com/forums/showthread.php?s=&threadid=101948&pagenumber=4
 
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I've to see a doctor to improve my listening before I build something. My friend tested to 18KHz, but me, topest to 14KHz.

Your age has a lot to do with upper frequency limits... hearing begins to deteriorate from around 20 years of age.
Most hearing tests I believe are performed only up to 6 or 8 khz.
It's not just frequency either... it's how loud sounds have to be.
 
The most critical part is the trafos and their thread-thickness, specially on secondar side. You can add all the caps you want, the oomp-factor depends on the trafo.
Thick massive internal wiring improves breathing too.
I don't agree.
The current capability of an amplifier has a lot to do with the way it sounds and what it is capable of doing before the limits are hit.

This current ability is affected by the size of the output stage and the drivers and that these must present a high enough impedance to the voltage amp stage.
The next effect is the protection/limiters that are in place or not.
The main smoothing bank and the decoupling capacitors determine the short term current supply.
The transformer simply tops up the charge in the main smoothing bank periodically.
This whole amplifier design should be balanced for good performance.
 
Money isn't everything in amp designs.... I have an LM3886 based gain clone and a fairly high end implementation of the JLH class A and I would say that although the JLH is the best, there's not much in it. Parts cost for the JLH must be around x10 that of the gain clone!
Either of them will wipe the floor with the awful Naim NAP 250. I have repaired a few of these and tried one to see what all the fuss was about... to say I was not impressed would be to put it mildly!
 
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