[strohmie]

The basic idea I've heard regarding RS's amps is that they portray the character of the source in question. Not sure how correct that is or if that applies to the full range of his amps, and I'd certainly be interested in seeing response graphs as well.

 

[bhd812]

hey earwax why dont you come over to my place and listen for urself

where are you located?

 

[GoRedwings19]

Quote:

Originally Posted by strohmie The basic idea I've heard regarding RS's amps is that they portray the character of the source in question. Not sure how correct that is or if that applies to the full range of his amps, and I'd certainly be interested in seeing response graphs as well.

So what if he has DCS verdi/elgar/purcell.........

 

[gsferrari]

With Meridian source / Sony D-25 PCDP and Audio CD's -> I did not hear any roll-off in any spectrum of sound. Stealth/HR2 sounded close to MPX3/Maestro and careful listening could tell the differences. These are warm but they dont lack treble and detail - this is something I can pick up

The midrange is NOT bloated/colored - this is as neutral as it gets unless you consider sterile sound like the PPA/Gilmore amps.

 

[KenW]

I can't hear it in my system but perhaps I don't have golden ears. Heck, I've liked just about everything I've heard. Guess it's a blessing as I can't get sold on anything and therefore, I save $$.

 

[photographlondon]

It's unlikely that this discussion is going to be able to continue with any semblance of sanity, but what the hell...

*IMO* the SR-71 is a warm sounding amp, I don't think that it is necessarily true to the source in that respect (in fact I'm fairly sure it's not). However I don't really think it has rolled off highs, but it doesn't have forward highs either.

I like a warmer sound, so this suits me just fine.

What I think needs to be stated by some is that no one can claim to know what is neutral, or true to the source - everyone has sonic preferences and these are the basis of each individual's opinion. Therefore it is inevitable that some will favour one amp over another, but to claim your opinion as fact (however well-informed) is misleading. Opinions and preferences vary, and so no one can really claim to be right - unless of course there is some proof such as measurments to back it up.

 

[ampgalore]

Quote:

Originally Posted by photographlondon Opinions and preferences vary, and so no one can really claim to be right - unless of course there is some proof such as measurments to back it up.

The high frequency noise should either be there or not, and that high frequency IS present in the source.

Ray Sammuels' amps did not reproduce those high frequency noise. Other amps did. This is a fact, not an opinion.

 

[photographlondon]

So this hiss you were hearing, was it really at a frequency extreme? I mean was it 12k, 15k or higher? Could you hear any cymbals with your amp, and if so were they less high-pitched than the sound you mention?

These are serious questions, and not meant to doubt what you say, but several things could have contributed to what you've heard and to me it doesn't necessarily point to high frequency roll-off (where the frequency range is cut off before it peaks).

 

[Wodgy]

It's possible that the high-frequency noise ampgalore was using to test came from a noisy ground, rather than a noisy signal, since he was using a broken tape out to generate it. In that case, an amp with a better ground scheme may not reproduce the noise.

That said, Ray's HR-2 was among the most warmly voiced solid state amps I've ever heard. Almost too much for me. But I doubt it was rolled off.

 

[Steve999]

You're right, earwax. If it is that rolled of in the highs it will show up easily on frequency response testing. If it's that pronounced, it'll show up as maybe at least two or three decibels low and likely starting somewhere well below 10 khz. Rocket science it ain't. All this other idle chatter means very, very little.

You're right too that impedence mismatches can affect the sound, but these effects tend to be very minor and usually are within the "just noticeable" range, as they call it in the audio industry -- in other words, hardly worth fretting over.

EXCEPT THAT Wodgy makes a truly excellent point too about the possible ground problem. It could possibly be something the Ray Samuels amp is doing RIGHT or a chance immunity to certain ground problems. I recently returned a headphone amp because of ground-reletad hiss and hum and emphasis of high frequencies. Learning about ground and ground loop noise is part of working your way up the audio learning curve (I don't know too much about it myself, but I have a very helpful audio industry professional I ask when I run into problems). My Corda HA-1 seems to have a very nice ground scheme, such that it does not pick up ground loop hum and other ground noise that some other amplifying equipment I have had (and returned) does pick up. Interestingly enough, my Behringer UB802 mixer ($60), which I am totally in love with as a headphone amp, also seems to have excellent ground noise immunity.

As for the idea of a warmly voiced amp, that would show up as a gross frequency response aberration in the frequency response graphs, IMHO, and as I understand it, it's extremley difficult to "voice" and amp to empahasize middle frequencies (as opposed to roll off or emphasize high or low frequencies) so I respectfully disagree with Wodgy there, that is to say, I find the idea of a warmly voiced amp unlikely. And let me qualify that by saying I have no doubt Wodgy is more knowledgeable than I am about many things audio. I suppose if the amp has a VERY high output impedence and the phones have a VERY uneven impedence curve with a high impedence in the mid-bass region this could account for a noticeably "warm" voicing, but I think it's all extremely unlikely. But in the end I suppose I chalk it up to my relatively strong objectivist tilt; "warm" amps are not really consistent with my audio belief system. I suppose nearly anything is possible.

Quote:

Originally Posted by Earwax You may not believe this, but I actually did think this would be something that could be objectively put to bed. A few frequency response graphs under various loads would satisfy me. [oh dear, look at the time. Good Night folks]

 

[gaboo]

From my limited experience with SR-71 samples at the MD meet, it was not rolling off high freqs. Not anymore than the 5-6 amps I've compared it with, using at least four different headphones. My hearing may not be "golden", but sure it's good enough to distinguish reverse phase, and I can hear easily up to 18Khz (and a with a volume increase up to 19.5).

About the "not hearing hiss" issue: I posted in another thread that I perceive hiss in fairly non-linear fashion. I had a similar experience of "disappearing hiss" (that actually was present in a recording) when I switched to a soundcard with a lower noise floor. I don't know much about psychoacoustics, so this may or may not apply to others. So, to me, Wodgy's explanation of lower noise floor seems plausible. YMMV.

Btw, frequency response and noise floor should be easy to test. Somebody here can do a RMAA (with load present) and publish the results. Or use scope. No need to fill lots of pages with subjective arguments...

 

[Steve999]

As to measuring frequency resopnse and noise floor, absolutely, I agree!

I think what Wodgy was saying was a little more subtle, that the broken tape out one user was using as an output may have had a noisy ground, which the Ray Samuels amp may have had better immunity to for one reason or another (perhaps a better ground scheme, perhaps a chance immunity to the particular problem). This relative immunity to ground noise would be a little different than the basic noise floor of the amp, and would be more complicated to measure, I imagine. I think the measurements would be different depending on the level of ground noise coming from the source and overall system used. One amp might measure better under ideal conditions, while the other might measure better under conditons where there are ground noise problems.

Quote:

Originally Posted by gaboo Btw, frequency response and noise floor should be easy to test. Somebody here can do a RMAA (with load present) and publish the results. Or use scope. No need to fill lots of pages with subjective arguments...

 

[Wodgy]

Quote:

Originally Posted by Steve999 As for the idea of a warmly voiced amp, that would show up as a gross frequency response aberration in the frequency response graphs, IMHO, and as I understand it, it's extremley difficult to "voice" and amp to empahasize middle frequencies (as opposed to roll off or emphasize high or low frequencies) so I respectfully disagree with Wodgy there, that is to say, I find the idea of a warmly voiced amp unlikely.

It's not so much the frequency response. Any quality solid state amp should have a flat response at least from 20 Hz to 20 kHz. The distinctive "voicing" generally comes more from the amp's distortion profile.

I personally suspect that the distinctive sound of Ray's amps comes from his multi-level power supply bypassing. He uses ceramics and tantalums (in parallel with film caps), which most op-amp datasheets recommend but audiophiles generally scorn. I think the "audiophile" consensus is wrong on that and Ray is closer to right, at least from an engineering perspective, since each type of cap has a lower ESR at different frequencies. The PIMETA for instance is a pretty similar design but only uses film caps and does tend to sound a little sterile. Despite the typical audiophile scorn for tantalum caps, I suspect some small tantalum bypasses on the PIMETA would improve the bass/lower midrange with high speed op-amps.

 

[Steve999]

Interesting... and you are way over my head... you know a ton more than I do... but I still disagree. I feel that any audible difference would show up in the frequency response graph. As I understand it, the harmonic distortion levels would have to meet or exceed one percent over a significant range of frequencies to even be audible to the best ears. As I understand it, most amp harmonic distortion measurements are way, way, way below this. Though they are usually still not audible, the harmonic distortion from the headphones theselves far exceeds and utterly swamps the minute levels of distortion from the amps. This of course assumes driving within the amp's capacity and below clipping levels.

But thanks for the reply and I enjoy your posts. I'm little more than an intrigued novice and I learn a lot from them.

Quote:

Originally Posted by Wodgy It's not so much the frequency response. Any quality solid state amp should have a flat response at least from 20 Hz to 20 kHz. The distinctive "voicing" generally comes more from the amp's distortion profile. I personally suspect that the distinctive sound of Ray's amps comes from his multi-level power supply bypassing. He uses ceramics and tantalums (in parallel with film caps), which most op-amp datasheets recommend but audiophiles generally scorn. I think the "audiophile" consensus is wrong on that and Ray is closer to right, at least from an engineering perspective, since each type of cap has a lower ESR at different frequencies. The PIMETA for instance is a pretty similar design but only uses film caps and does tend to sound a little sterile. Despite the typical audiophile scorn for tantalum caps, I suspect some small tantalum bypasses on the PIMETA would improve the bass/lower midrange with high speed op-amps.

 

[kunwar]

Quote:

Originally Posted by gsferrari With Meridian source / Sony D-25 PCDP and Audio CD's -> I did not hear any roll-off in any spectrum of sound. Stealth/HR2 sounded close to MPX3/Maestro and careful listening could tell the differences. These are warm but they dont lack treble and detail - this is something I can pick up The midrange is NOT bloated/colored - this is as neutral as it gets unless you consider sterile sound like the PPA/Gilmore amps.

Hey GS
why do you feel that the sound on the gilmore's would be termed sterile.
Far from it, discrete designs are very true to the recording and can sound exceptional with cans that need the oomph to come through.
the talisman which is a discrete component amp presents music beautifully.
All I will say is Op amps do colour sound and to compare an opamp based amp with a discrete amp would of course bias results.

As somebody said before, if coloured sound floats your boat, that is good, but a different presentation style such as exhibited by the Gilmmore's floats other members boat's as well.