[fewtch]

Just to say that I'm not really a DIY'er, but a believer in audio minimalism... imo, the less circuitry that comes between the source and your ears, the better.

That said, has anyone considered trying an ultra-minimal discreet headphone amp design? I'm picturing something battery operated, perhaps with regulator circuitry to keep the voltage absolutely constant. Other than that, maybe just a few hand matched transistors and resistors of the highest available tolerances and quality, the most basic "electronics 101" amplifier imaginable (without using an op-amp). Zero features, except maybe an *optional* volume pot -- on/off "switch" would be some sort of solid connector, not a switch with a tiny contact area. Hand wired (maybe pure silver wiring), no circuit boards. EMI/RFI shielding inside the case and around the circuit itself. 99.9% attention to detail and 0.1% electronic parts.

Anyone ever considered doing something like this? One of these days I may give it a go myself, although it's been a long time since I've taken any electronics classes... probably would be relatively simple to do with some public domain circuit, tho.

If any of this sounds nutty to someone, remember the Grado RA-1 and its reported "transparent" sound with very few parts (if only they'd used higher quality parts...

). The best amp would be a straight wire that amplifies.

 

[ServinginEcuador]

Try adding a stepped attenuator or potentiometer directly to your CDP's output and hook you cans to that. JaZz is a big fan of this and does it all the time. There is no way to get anything less into the chain, and since you have high efficiency cans this might just work for you. PM JaZz and ask him about this.

 

[fewtch]

Quote:

Originally posted by ServinginEcuador Try adding a stepped attenuator or potentiometer directly to your CDP's output and hook you cans to that. JaZz is a big fan of this and does it all the time. There is no way to get anything less into the chain, and since you have high efficiency cans this might just work for you. PM JaZz and ask him about this.

I had in mind something that would actually amplify, yet come as close to a "straight wire" design as humanly possible. Not looking for attenuation, thanks (and this was just an idea I thought I'd throw out there to see if anyone had thought about or implemented as a DIY project).

Something like the PPA is a nice design, but there's an awful lot of stuff there in the signal path to potentially degrade the sound. No matter the quality of parts, the potential for degradation is ever-present and grows with complexity.

If I ever did build something like this, I'd probably use it with my turntable and a simple phono stage. Heck with CD players...

 

[guzzler]

the Szekeres amp is about as simple as it comes, just one MOSFET, although you can't power from battery and the sound is very dependent on the quality of the power supply & the MOSFET you use!

g

 

[ServinginEcuador]

ALL amps attenuate the sound to some degree before amplifying it. Unless you run a 2v signal from the CDP to the amp, and a 2v signal to the cans, you are attenuating the signal somewhere in the chain. And what's the difference between attenuation and amplification anyway? Why is it alright to amplify the signal and not attenuate it? Is one supposedly worse than the other?

And BTW, the 2v signal from the CDP can be enough to drive most headphones quite loud. Using some quick Ohm's law we find that a 2v signal into a pair of Grados will produce some 125mW of power, which is enough to make the average person quite deaf with extended wearing when a mere 1mW is enough to get a good 96dB from a set of cans.

 

[Tomo]

Hey,

I beg to differ. According to the theories of electrical engineering, the best amp is a straight wire with amplification. However, that does not include "AUDIO" amplifiers.

We are biological organisms with with biochemical and biomechanical sensory systems. On top of that, there is something we "LIKE" to hear. Most of the time, we like to hear "DISTORTIONS."

Dispite our standard knowledge, DISTORTIONS are our powerful FRIEND in business.

If low distortion was all that is required to make a good "AUDIO" amp, life would be much simpler and very boring for audio-enthusiasts. Less # of component equal reliability of the circuit, but it doesn't equal better or even low distortion. (Some of the components work to stabilize the circuit etc)

Also, how powerful can a pair of headphone be driven means very little. How WELL the amp do so with good euphonics. That is what is important.

Tomo

P.S. Most of the individuals who praised RA-1 never made comparative studies with other headphone amplifiers. So I found their reviews hardly reliable. (From EE point of view, it's one darn-expensive-I-can-build-for-pennies junk.)

 

[fewtch]

Quote:

Originally posted by Tomo Hey, I beg to differ. According to the theories of electrical engineering, the best amp is a straight wire with amplification. However, that does not include "AUDIO" amplifiers. We are biological organisms with with biochemical and biomechanical sensory systems. On top of that, there is something we "LIKE" to hear. Most of the time, we like to hear "DISTORTIONS."

Baaah... put 'em in the recording, then. I don't want an amp that distorts the music "pleasingly," especially if you're paying $5000 or something for what amounts to a ridiculously expensive tone control with gain. Give me an amp that's true to the source -- the less "there" it is, the better.

Admittedly, I'm a SS guy all the way -- I just don't care much for tubes. Also, I'm big into vinyl, but most emphatically not for the colorations and distortions of the format.

Quote:

If low distortion was all that is required to make a good "AUDIO" amp, life would be much simpler and very boring for audio-enthusiasts.

So what you're saying is that you find it complex and interesting to pay big bucks and/or expend large amounts of time and energy in adding a bunch of "euphonic" colorations and distortions to the music?

Who am I (or anyone) to object, but I wonder what attracted you to this thread? You sound like the type of guy who might walk out of a live concert because it didn't sound as good to you as your home stereo system.

 

[Tomo]

Hey,

Quote:

Baaah... put 'em in the recording, then.

Ok tell that to the recording company. See if they ever listen. They are more worried about their equipments clipping and doing other nasties.

Anyways, I like less coloration as well. However, I like this certain tone at high that make it feel like going through the roof. This has to be done with control to prevent excessive brightness and clarity so that delicate nature what it represents can be expressed. (I built a system just for that.)

But then I do like impact when I listen as well. So I have another sytem just for that.

T

P.S. Of course, I built them!

 

[ServinginEcuador]

Tomo,

Excellents points in your post. I guess the question that begs to be asked is, "are we talking about a minimalist design to the AUDIO path, or voltage path?" You can make a rather simple audio path, but voltages fluctuate considerable, so regulating and stabilizing them is the real trick. Even batteries drop voltage quite rapidly from brand new until they are spent, so a battery will only work as well as you can try and stabilize the voltage output to your circuit. As Tomo so aptly put, it seems that harmonics are as big a part in the sound of an amp as anything else. I believe that solid state tends to produce even harmonics, and tubes produce odd harmonics. (I could have it backwards.) That's why it takes some complexity to get the sound sounding better. You have to use components to pick off the harmonic of choice and reject the ones you don't want.

This issue has come up before, and I don't think it was ever resolved. How can an amp with an incredible amount of parts in the signal path sound so much better than a simple one with almost no parts in it? Does the complexity or sheer number of parts necessitate a bad sounding amp that distorts or changes the music? Does the amp with the most parts in the signal path sound the best? Who knows!

 

[fewtch]

In the audio path, of course. The voltage path doesn't matter, but the supplied power itself should be as clean as possible (that's why I suggested battery operation -- in an extremely simple amp, perfectly clean power would be the single most important aspect of design.

 

[Tomo]

Hey (again!)

Theoretically, more components stabilizing the amplifier would be ... "GOOD" thing to do. However, again nothing is straight forward. You can't just expect more and more performance as you add more and more.

Smarter approach is to utilize different designs. However, this discussion should be left for another thread.

Odd-Even-Harmonic stuff can be done with solids as with tubes. For example, Szekeres amp is likely to produce Odd-Harmonic distortion because its swing capability is not symmetric. I found this amp to sound faintly warmer however it could be due to caps I use.


Tomo

 

[fewtch]

Quote:

Originally posted by Tomo Hey (again!) Theoretically, more components stabilizing the amplifier would be ... "GOOD" thing to do. However, again nothing is straight forward. You can't just expect more and more performance as you add more and more.

Depends on whose theory... there's a school of audio that advocates extreme simplicity, and it interests me.

I'd like to hear other engineer/audiophiles like ppl or jeffreyj chime in on this, however... I don't know know enough about the electronics and engineering aspects of the whole thing. Best would be to hear from someone who actually built an extremely simple amp with just a few super high quality discreet components (simplest possible design that's stable at the low levels required to drive typical dynamic headphones) and has an opinion on its sound.

 

[Tomo]

Hey (again and again! I must be super bored),

You must be careful with battery operations. It is a clever but tricky tactic. Lead Batteries are weird so always check for noise before using. (This has come up in discussions on GainClones some place.)

Question is how much of clean power you need. Surprisingly with opamps, I do not need uber clean power. I get extremely good performance with normal LM317/337 setup (with BG and ELNA). I have a feeling it won't get noticeably better with upgrade from here.

However, I do use uber PSU for my Szekeres amp. This amp has NO stabilization scheme imbedded. The sound quality does get better with higher PSU performance. (With extent! Don't go paying 1 million, k?)

Some amps are very susceptible while others are very immune. Again, topology is highly important aspect and should be discussed more often. It changes your boundery condition as to what you can do and cannot do to improve performance. Only then will you know what is good upgrade and what isn't. (My opinion)

Tomo

P.S. I am sure Per-Anders has few things to say.

 

[aos]

That's all fine but if you really want to go fanatic on that, you should start right at the source. I.e. start right at the DAC chip pins, because what about the analog stage of the DAC (which is a filter/amp, usually utilizing opamps). Or go even further and use a DAC chip that doesn't contain an opamp inside (most do). If you're going to start minimalism at the RCA outs of the CD player, that's just doesn't make much sense.

One suggestion would be to go and get a digital amplifier. Doesn't have any D/A.

And Tomo's correct - go to Headwize and you'll find some of the simplest amps you can make. With opamps you can't go any simpler that CMOY. With transistors, with something like Szekeres. Just one transistor and some bias resistors, and coupling caps. And of course PS, where I also agree with what Tomo said.

 

[Tomo]

Hey,

Quote:

Best would be to hear from someone who actually built an extremely simple amp with just a few super high quality discreet components (simplest possible design that's stable at the low levels required to drive typical dynamic headphones) and has an opinion on its sound.

Yes, I did. Do you people ever read addendums? Go to the articles on Szekeres amp and go to addendums. You see several entries by an individual by name, Tomo. It is ... me. (Man! Do I sound so untrustworthy? ... mmm ... must be my poor English ... ) Oh yeah, I think I made few observations there you can use.

As for uber simple with opamps, I have made few entries under Mr Moy's article. You will also find postings of my primary amp ... CUBE. (The amp is still under renovation after impact testing. ... lol)

T

P.S. DAC chip is actually a better idea. I wanted to build one like aos but I chickened out.