Which amp to build?!?

[jul059]

Hello everyone!

First of all I want to say that this forum is marvellous! So much information and great designs... and because of this, I could use your help.

I want to build a power amp to use as my main stereo system. The question is which one. There are so many! Sometimes I can't even figure out how many versions of one single amp there is. For example, the DX family (the Original DX, the HRII, the Precision I, the Blame ST, etc.) Then there is also the Elliott Sound P3A, the Leach amp, etc. You probably know more amps than I do...

I would greatly appreciate your input concerning the sound quality of these amps, their strengths, their weaknesses. If you heard more than one, please compare! I am obviously also interested in numbers, so a frequency response graph, THD, TIM, and such are interesting. Also concerning the DX family, which do you recommend and why? Also please recommend any amp I have not listed.

So, which is best?

[Jay]

Originally Posted by jul059

Hello everyone!

First of all I want to say that this forum is marvellous! So much information and great designs... and because of this, I could use your help.

I want to build a power amp to use as my main stereo system. The question is which one. There are so many! Sometimes I can't even figure out how many versions of one single amp there is. For example, the DX family (the Original DX, the HRII, the Precision I, the Blame ST, etc.) Then there is also the Elliott Sound P3A, the Leach amp, etc. You probably know more amps than I do...

I would greatly appreciate your input concerning the sound quality of these amps, their strengths, their weaknesses. If you heard more than one, please compare! I am obviously also interested in numbers, so a frequency response graph, THD, TIM, and such are interesting. Also concerning the DX family, which do you recommend and why? Also please recommend any amp I have not listed.

So, which is best?

There have been many of similar questions, but as far as I know, there has been no satisfying answer because of the complexity of the answer, and because the question is too general.

You seem to know enough about amplifiers, but similar questions usually come from beginners, probably because they don't realize the complexity of the answer.

But IF what they (the questioners) really need is assistance in choosing the correct amplifier so not to waste money and time, I believe that special consultancy is required. Questioners should explain their preference of music, previous amplifiers, their previous best amps (you don't want to suggest a Citation12 to those who have built Quasi amp, do you?), their speaker, expected power level, what parts already on hand, etc etc...

I believe this kind of consultancy thread is an effective way for (mostly) beginners to choose a suitable amplifier.

[jul059]

Thanks four your reply!

I am indeed a beginner concerning DIY Power Amplifiers, but I do know things about frequency response, impedence, Total Harmonic Distortion, Transient Intermodulation Distortion, etc. (Egineering student).

You are also right that I want assistance in choosing an amplifier so as not to waste money and especially time. I love amplifiers, but it is not (yet...) my main hobby.

So here are some infos :

I want to listen to a wide range of music (electronic, rock, pop, jazz, some classic).

I corrently use a pair of Camber speakers, ancestors of paradigm. They are 2 way vented speakers and are fairly efficient. Please note that I may have to return them to their owner, so I might have to change them.

Expected power level : Not huge. I would say 50w RMS is good.

I have owned a Cambridge Audio Azur 340A.

Also note that I am NOT interested in a class A Power Amplifier for heat reasons.

Cheers,
Julien

[Jay]

Originally Posted by jul059

Thanks four your reply!

I am indeed a beginner concerning DIY Power Amplifiers, but I do know things about frequency response, impedence, Total Harmonic Distortion, Transient Intermodulation Distortion, etc. (Egineering student).

You are also right that I want assistance in choosing an amplifier so as not to waste money and especially time. I love amplifiers, but it is not (yet...) my main hobby.

So here are some infos :

I want to listen to a wide range of music (electronic, rock, pop, jazz, some classic).

I corrently use a pair of Camber speakers, ancestors of paradigm. They are 2 way vented speakers and are fairly efficient. Please note that I may have to return them to their owner, so I might have to change them.

Expected power level : Not huge. I would say 50w RMS is good.

I have owned a Cambridge Audio Azur 340A.

Also note that I am NOT interested in a class A Power Amplifier for heat reasons.

Cheers,
Julien

First, there are tube amps, bipolar amps, mosfet amps....

The theorists will say that it doesn't matter what device you use, it is how you use it. But you can not make good sound from light bulb as amplifying devices!

Tube amps are slow and musical. Bipolar amps are fast, and that is also a minor part of musicality. Mosfet amp stands in the middle, doesn't have specific strength. Most of the time mosfet amps are lousy amps. Only a few people that seem to be attached to the sound of mosfet, including myself. VMOSFET doesn't work well in class-B amplifier. The best I have heard is in the stochino, but it is too complicated (slew rate about 300V/us). For class-B it must be LMOSFET, but the price may be high, only for mosfet lovers

So if you prefer the sound of a mosfet, many JLH amps are musical sounding. Search for Mooly amplifier, it is also based on JLH work, only one pair of LMOSFET per channel to give 60W. If you need fast class-B mosfet amplifier, there is new thread about Goldmund amplifier. I'm in the process of building it. But it uses 3 pairs per channel, and the remaining transistors might be difficult to find.

Bipolar amps are not my preference. I rarely like them. But Sanken 2922 output transistors seem to have bass similar to mosfet, and I prefer the sound that doesn't "hurt" my ears, hence any low PIM/TIM designs such as the Leach amplifier. Or scaled-up version of Otala amp (20W?) if any.

[TerryO]

As you seem to feel that you need 50 watts or so, why don't you build a chipamp?
They can be dirt simple, easy to build, pretty economical and don't give much away in overall sound quality. A LM 3875 or a 3886 chip will get you in the neighborhood of your power requirements. With the money you'll save, you can begin to upgrade other parts of your system.

Best Regards,
TerryO

[gaetan8888]

Hello

If you prefer a discrete amp, there is the Baby Aksa, very good and simple to build;

Based on Hugh Dean's AKSA 55


Or the Dx amp;

Destroyer x Amplifier...Dx amp...my amplifier


Bye

Gaetan

[Jay]

Originally Posted by TerryO

As you seem to feel that you need 50 watts or so, why don't you build a chipamp?
They can be dirt simple, easy to build, pretty economical and don't give much away in overall sound quality. A LM 3875 or a 3886 chip will get you in the neighborhood of your power requirements. With the money you'll save, you can begin to upgrade other parts of your system.

Best Regards,
TerryO

Possible option. But you have to search for your "future" amp first so you can invest in a proper transformer (the output voltage).

May be because transformer is the most expensive part, and that you may build another amp in the future, you should pick amplifier that uses the most "common" rail voltage. And your quality supply caps should not be underrated in the future project

[spTOH]

FYI, the 340A is a chip amp: It is using two LM3886 chips as its amplifiers. Pls refer to the following link:

http://www.audioupgrades.co.uk/manua...PARTS+LIST.pdf

[jul059]

Ok thanks everyone.

I never gave the chipamp much thought. Perhaps it's a good option. But which implementation is recommended? I guess the one specified by the manufacturer is good. I found this : PA100 DIY 2x LM3886 in parallel gainclone audio amplifier. What do you think?

gaetan8888,
Concerning the Dx, can you explain me the differences in the different versions? I guess the "plain" Dx is the one most commonly built, but I'm not sure.

also, I think I read that the Baby AKSA is a "tweaker's dream". considering that I do not have access to all the equipment I might need, is it a good idea for me to start building it?

[CBS240]

Originally Posted by Jay

First, there are tube amps, bipolar amps, mosfet amps....

The theorists will say that it doesn't matter what device you use, it is how you use it. But you can not make good sound from light bulb as amplifying devices!

True, but a good triode amplifier stage is hard to beat with sand. But components made from sand are cheaper, use a safe voltage level, more efficient, and not nearly as fragile. I agree with the 'theorists', but it is important to note that all those different devices work in different ways with different properties and have to be used differently.

Vertical mosfet class AB can be made to sound very neutral with very little distortion but it is not so straight forward. It requires local correction loops and is more complex than typical LIN BJT circuits, at least if you want to do it right. Most people are scared of the complexity, but for a beginner, simplicity is better. So stick with devices that are more suited to a simpler design.