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Classic Marantz and Citation vs modern

that's what I'm being tested on, right?
Your claim was that Adcom amps sounded "bright," which was contrary to my (and others') experience. Your attribution to rising distortion with frequency was just another layer of speculation and your purported reason to reject using Distort. Please name another amp you have found bright where measurements can be located for duplication.
 
From the owners manual for the 565.

So is this basic distortion profile suitable for brightness?

View attachment 397408
Here's Stereophile's measurements of this amp. Like most solid state amps, third harmonic is dominant. And of course, like the majority of engineered amps, the rise happens about 10kHz where the harmonics are inaudible. But maybe this one isn't bright either. I don't have any at the moment, but I used them for some time and couldn't hear that supposed brightness.
 
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Huh, Brystons also seem to not exhibit the purported behavior, either.

Link: https://www.stereophile.com/content/bryston-28b-sst-monoblock-power-amplifier-measurements

I think Ralph is going to have to dig up the unicorn that he claims is bright.
 
From the owners manual for the 565.

So is this basic distortion profile suitable for brightness?

View attachment 397408
This does not look like what I recall- and I'm starting to doubt my memory on this. I recall seeing graphs, and the distortion not only higher than that, but rising considerably more. Really wondering what I saw since I'm having trouble finding the same data.
Your claim was that Adcom amps sounded "bright," which was contrary to my (and others') experience. Your attribution to rising distortion with frequency was just another layer of speculation and your purported reason to reject using Distort. Please name another amp you have found bright where measurements can be located for duplication.
Yes- I did play the amps after they were refurbished. DC Offset and Bias were set to spec. We ran them several days and it was a relief to send them down the road. My mistake was the assumption that other Adcom amps shared the same design characteristics. But now that I've seen a number of the measurements of their later amps over the last few days, it appears I was simply wrong. It is nice to see that these amps don't have that problem and correlates with your experience of them.
 
But now that I've seen a number of the measurements of their later amps
My 555 is vintage 1985. The 565 was vintage 1991. Hardly "later."

So after we (especially Paul) took the trouble to put together a test of your claims, you've changed your mind and these amps aren't "bright." This is starting to look like Sagan's dragon in the garage.
 
My 555 is vintage 1985. The 565 was vintage 1991. Hardly "later."

So after we (especially Paul) took the trouble to put together a test of your claims, you've changed your mind and these amps aren't "bright." This is starting to look like Sagan's dragon in the garage.
My contention that rising distortion with brightness hasn't changed. I don't see what I thought I saw with the GFA 565 so I can't say they are bright.
 
My contention that rising distortion with brightness hasn't changed. I don't see what I thought I saw with the GFA 565 so I can't say they are bright.
But you DID make that claim. And you've just repeated it.
Yes- I did play the amps after they were refurbished. DC Offset and Bias were set to spec. We ran them several days and it was a relief to send them down the road. My mistake was the assumption that other Adcom amps shared the same design characteristics.
With, of course, which Adcom now unspecified (after making the incorrect claim that the "later" amps didn't have that issue), and with clearly no listening controls. And a commercial interest which could certainly cause bias (no pun intended).

So step up. Name an engineered solid state amp that you will unambiguously claim is "bright" and where measurements are available so that the spectrum can be built into a processed file.

Or admit that your claim is entirely without any evidentiary support and you have no intention of ever testing it. That will at least bring clarity and Paul can stop wasting his time with your dragon.
 
BTW, If a Google search or some other search engine on Adcom amps should land you here, the below link to the Hoppe's Brain website is a good one.
The gentleman on that site has about as much knowledge on Adcom amps as any around. That site hasn't any affiliation whatsoever with ASR, I only have a limited amount of knowledge about them from about 20 years of experience with them.
 
But you DID make that claim. And you've just repeated it.

With, of course, which Adcom now unspecified (after making the incorrect claim that the "later" amps didn't have that issue), and with clearly no listening controls. And a commercial interest which could certainly cause bias (no pun intended).

So step up. Name an engineered solid state amp that you will unambiguously claim is "bright" and where measurements are available so that the spectrum can be built into a processed file.

Or admit that your claim is entirely without any evidentiary support and you have no intention of ever testing it. That will at least bring clarity and Paul can stop wasting his time with your dragon.
You seem to have misunderstood me. The Adcom GFA 565 I serviced out came off as bright in our system. What I remember when looking at the measurements (and I recall being impressed that they showed the DvsF as a graph in those measurements) was that DvsF was rising, turning over at about 1Khz. With all the browbeating I've gotten on this, I've come to doubt what I was looking at, but that is what I remember.

Since you think I'm doing something I'm not, how about this: set the turnover frequency to 1KHz and the slope to 6dB/octave and let's do it that way. Sheesh. Could you lay off with the personal attacks? Its not like you- I respect you, but tone it down a bit. You appear to be conflating 'evidence' with 'proof'. I have plenty of evidence, I just don't have proof.
BTW, If a Google search or some other search engine on Adcom amps should land you here, the below link to the Hoppe's Brain website is a good one.
The gentleman on that site has about as much knowledge on Adcom amps as any around. That site hasn't any affiliation whatsoever with ASR, I only have a limited amount of knowledge about them from about 20 years of experience with them.
The replacement boards I installed were from Hoppe's Brain. AFAIK, the new boards were the same circuit as the old one but with parts that were unlikely to fail as quickly as the originals. They are holding up fine FWIW and the new owner is very happy with them.
 
The replacement boards I installed were from Hoppe's Brain. AFAIK, the new boards were the same circuit as the old one but with parts that were unlikely to fail as quickly as the originals. They are holding up fine FWIW and the new owner is very happy with them.
The 565's were notorious for failing caps and the distruction of their boards due to their leaking and such.
It's highly possible your memories of a "bright" sound was due to some out of spec factor from these problems.
OTOH, my 5.2.4 system is comprised of 3 545MkII & 2 535MkII amps, all of vintage 1995 and other than setting bias and checking DC offset,
all continues to operate within spec AFAIK. ;)
 
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The 565's were notorious for failing caps and the distruction of their boards due to their leaking and such.
It's highly possible your memories of a "bright" sound was due to some out of spec factor from these problems.
OTOH, my 5.2.4 system is comprised of 3 545MkII & 2 535MkII amps, all of vintage 1995 and other than setting bias and checking DC offset,
all continues to opperate within spec AFAIK. ;)
If you recall, my comments were based on the repaired amps. When they arrived in my shop, they were not functional- all three of the bad electrolytics on each board had successfully contaminated it so the servo was overwhelmed to say the least.
 
Well Atmasphere proposed at one time rising distortion at 6 db per octave starting above 1 khz. You'll need to say what it is at 1 khz for the starting point. May I suggest more than one level. I'd suggest something obvious like 2% at 1 khz, then .5 %, then .1%, and then .01% (which is still above the spec for the 565 Adcom). Will take more time for Atmasphere to do, but if he agrees then it might tell us more than just a single level. Start at 2% if he can knock out 10 of 10 move on. If at some lower level of distortion he scores less than 10 for 10, then he can do additional trials as he wishes. If there is no 10 for 10 at 2%, then it pretty much has no need to proceed further.
 
My contention that rising distortion with brightness hasn't changed.
Have you listened to the files Paul prepared for you? This really isn't a huge task, and if you can actually demonstrate your contention, that would be interesting. Likewise, if you can't, that's also interesting.
 
Have you listened to the files Paul prepared for you? This really isn't a huge task, and if you can actually demonstrate your contention, that would be interesting. Likewise, if you can't, that's also interesting.
I hate to admit it but I've really not had the time to set up the demo on our shop system. My desktop isn't that impressive but its not that bad either (limited in the bass but otherwise images well). On that system I don't hear any differences.
 
I hate to admit it but I've really not had the time to set up the demo on our shop system. My desktop isn't that impressive but its not that bad either (limited in the bass but otherwise images well). On that system I don't hear any differences.
Well, it's been a couple months. If I lend you a laptop and a DAC, will you do the ABX?
 
Well, it's been a couple months. If I lend you a laptop and a DAC, will you do the ABX?
I've got a DAC, no problem there. Not having the buy a laptop for this would solve one of the bigger issues for this.
 
I've got a DAC, no problem there. Not having the buy a laptop for this would solve one of the bigger issues for this.
PM me your address and I'll make it happen.
 
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