Sound Quality Vs. Measurements

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Well said, dvv and bcarso. That is what audio engineering is all about. Not everyone can do it well, EVEN if they are trained engineers. You have to note, (inside) that something is wrong, and go after WHAT IT IS! Then hope you can find a solution that will fix it.
Everything else is 'academic' or worse.
 
dvv,
OK you have two CDs One stamped, one a copy. Use good software and rip them both to the hard drive in a loss-less format. Do a bit comparison to verify they actually are the same. If so, play them both back through your best DAC and listen. It would be hard to come up with a reason that follows what we know about physics if there were a difference. This removes the transport and media from the equation.
 
No, I just could not get it to sound 'right' and audio reviewers leveled with me and told me that I had a problem. Fixed it, and got a B rating on the amp. HCA2200 MK2 Right where I predicted it should go.
Years later, I lost my way again, but for other reasons, WITHOUT an IC as something to note by a reviewer (as if that made any difference). Fixed it too, but that is beyond our discussion here as to how I saved the design from obscurity, and I now have an A rating on its successor.
 
Hi,



I have encountered binary files that passed the "checksum" test (even extended checksum algorithms as found in Binary Usenet Posts [only legal downloads of course]) and still where corrupt nevertheless. It does not happen often, but it does happen. Unless you do a full direct binary compare you cannot claim the files are identical.

Ciao T

Don´t know what you mean "extended checksum algorithms found in Binary Usenet Posts", but if two files have the same md5 checksum they _are_ identical, period.
 
dvv,
OK you have two CDs One stamped, one a copy. Use good software and rip them both to the hard drive in a loss-less format. Do a bit comparison to verify they actually are the same. If so, play them both back through your best DAC and listen. It would be hard to come up with a reason that follows what we know about physics if there were a difference. This removes the transport and media from the equation.

How did we get to burnning discs? We were talking about ripping to hard drive. Did we all agree thats pretty much error free, and safe mode makes no difference?
 
How does the md5 come into this? It is used for RSA encryption and not developed until 1991.
Anyway, if any of the various checksums are the same, then there is a very high PROBABILITY the files are the same if the checksum is of sufficient length. Very high. High enough I would not go there looking for the problem.
 
How does the md5 come into this? It is used for RSA encryption and not developed until 1991.
Anyway, if any of the various checksums are the same, then there is a very high PROBABILITY the files are the same if the checksum is of sufficient length. Very high. High enough I would not go there looking for the problem.

md5sum is more or less the standard used on Unix and Linux, but there are others of course, sha-1 or sha256 for example.
 
Looking at the ST-140 to see what I can learn. No input RF filter, no output filter, 476 Ohm degeneration on the IPS LTP. A trimmer in one leg I presume so they did not have to match the pair. 1K gate stoppers on both N and P. I wonder if that slowed down the outputs so much that they were stable? No isolation between the IPS and output power rails. Simple resistor for the bias spreader. I can't find data sheets for anything. It did have a 47u input cap, which I remember when I bypassed with a film made a clear improvement. Two pairs of outputs, but no source resistors. 200pF Miller comp is the only compensation. Darlington VAS.

So what do I learn? 10 times the IPS degeneration is not the magic bullet for the wifes test. Neither is a Darlington VAS. And don't blow one of these up as the parts are not available.

Reading the press, for what that's worth, my wife is the only one who did not love this amp. I know I compared it to over a dozen at home listening tests of other amps and it was a clear winner for me. Bedini, Brown, Adcom, Transnova, Onk, Denon, Hafler, PS, and I can't even remember some of the rest. There might have been a used SAE in there. The tests spanned two states and a couple of months. Back then we still had stereo stores. Only the Aragon was better to my ears but was almost 3x the price. So the B&K was good, but not for the one unknown issue she can identify. I had Ditton 44's back then.

The old Motorola book does show things like load lines. I feel better.
 
Looking at the ST-140 to see what I can learn. No input RF filter, no output filter, 476 Ohm degeneration on the IPS LTP. A trimmer in one leg I presume so they did not have to match the pair. 1K gate stoppers on both N and P. I wonder if that slowed down the outputs so much that they were stable? No isolation between the IPS and output power rails. Simple resistor for the bias spreader. I can't find data sheets for anything. It did have a 47u input cap, which I remember when I bypassed with a film made a clear improvement. Two pairs of outputs, but no source resistors. 200pF Miller comp is the only compensation. Darlington VAS.

So what do I learn? 10 times the IPS degeneration is not the magic bullet for the wifes test. Neither is a Darlington VAS. And don't blow one of these up as the parts are not available.

Reading the press, for what that's worth, my wife is the only one who did not love this amp. I know I compared it to over a dozen at home listening tests of other amps and it was a clear winner for me. Bedini, Brown, Adcom, Transnova, Onk, Denon, Hafler, PS, and I can't even remember some of the rest. There might have been a used SAE in there. The tests spanned two states and a couple of months. Back then we still had stereo stores. Only the Aragon was better to my ears but was almost 3x the price. So the B&K was good, but not for the one unknown issue she can identify. I had Ditton 44's back then.

The old Motorola book does show things like load lines. I feel better.

If it is very important to also please your wife's perceptions, perhaps you should also at least briefly investigate the probabilities of the perceptions themselves.

I just ran across this thread, yesterday:

Planar Speaker Asylum

Read the second post. Does your wife happen to have any mid-range hearing loss? Has it been tested accurately, versus frequency?

Good luck.
 
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