After a lot of time and work the new T-Amp measurements are up on my site. Please have a look.
New Measurements
All these measurements were done by a buddy of mine, who is an amp designer for a very large amplifier company. All measurements were plotted with an Audio Precision tester, the industry standard for audio measurements.
You will notice that these tests are not as pretty nor as good as those you will see from manufacturers. The reason for that is that these are real world tests, done without tweaking the test conditions to make the dives perform for measurement. What you see is what you get. The results are much more likely to match the results you will obtain than "optimized" results published by chip and amp makers.
I hope you enjoy the information. Please feel free to ask questions, I'll do what I can to answer them.
New Measurements
All these measurements were done by a buddy of mine, who is an amp designer for a very large amplifier company. All measurements were plotted with an Audio Precision tester, the industry standard for audio measurements.
You will notice that these tests are not as pretty nor as good as those you will see from manufacturers. The reason for that is that these are real world tests, done without tweaking the test conditions to make the dives perform for measurement. What you see is what you get. The results are much more likely to match the results you will obtain than "optimized" results published by chip and amp makers.
I hope you enjoy the information. Please feel free to ask questions, I'll do what I can to answer them.
Any chance you guys could test my board if/when I get a couple prototypes built?Just wondering panomaniac, would it be advisable to use a separate SMPS PSU for the amp6, bypass the rectifiers and the volt regulator, then connect the output of the SMPS directly to the big 16,000uf cap? Will this setup somehow improve amp6's score on the S/N ratio test or on the large spikes on the amp's crosstalk? Thanks for the test results, very informative.
D0Hbert said:
You could easily do that, if you wanted to. I was surprised by the 60 Hz spike on the graph, you sure can't hear it. There might have been some induced hum on that test, I don't know. None of the amps tested with SMPS had the hum. But after all, the 60 Hz does come right onto the AMP6 board. But having power regulation that close to the chip also has many advantages.
I am experimenting with using a 15V SMPS in front of the regulator, and running at 13V. Also am trying a 20V SMPS and running the linear regulator at 14.5V. Should at least give stable power!
I think that will be possible. Will check with the guy doing the tests. You get it running, we'll test it! Look forward to seeing/hearing your board.
Very useful. I'd love to see the frequency plot for a "lightly-modified" Sonic T-amp, ie, the 'stealth' method 2.2uF input caps, replaced 680uF power cap and a decent power supply.
That's about as far as I dare go with smd boards.
Another thing I've not seen addressed in other threads - the Sonic T lift above about 5kHz with 8-ohm speakers - can that be calmed down with something across the speaker terminals?
That's about as far as I dare go with smd boards.
Another thing I've not seen addressed in other threads - the Sonic T lift above about 5kHz with 8-ohm speakers - can that be calmed down with something across the speaker terminals?
New stuff!
Got the modified Sonic measurements up.
Look in the same place as the recent AP measurements, the modified results are overlayed on the stock results.
Same PSU for both, the Super-T SMPS.
Mods to the amp were basic, just bigger input caps and a bigger, better onboard electrolytic. Same case, same connectors.
PSU measurements tomorrow.
Got the modified Sonic measurements up.
Look in the same place as the recent AP measurements, the modified results are overlayed on the stock results.
Same PSU for both, the Super-T SMPS.
Mods to the amp were basic, just bigger input caps and a bigger, better onboard electrolytic. Same case, same connectors.
PSU measurements tomorrow.
Re: New stuff!
Very well done.
A pair of questions:
-the mod is the one you refer to as "version 2" in your site?
-which caps did you use?
-measurements aside, how big is the listening difference? How does it compare to, say, amp6?
-did you use the 12V, 3A stock Super-T PSU?
Keep up the good work.
Davide.
panomaniac said:
Very well done.
A pair of questions:
-the mod is the one you refer to as "version 2" in your site?
-which caps did you use?
-measurements aside, how big is the listening difference? How does it compare to, say, amp6?
-did you use the 12V, 3A stock Super-T PSU?
Keep up the good work.
Davide.
More new stuff.
PSU measurements are up. Super-T SMPS and B+K Precision model 1660 lab supply.
The mods to the SOnic amp were simple.
New input caps 47u 16V BP Nichicon (!!)
New onboard electrolytic - 470u 25V Nichicon PW series low-ESR type.
Battery wires removed, Super-T PSU for power.
The mods were not done by me, but by Mr. Shultz who is doing the testing. He later changed the 47uF input caps to 4.7uF. That should not effect low end measurements.
We may get new measurements after reboxing.
PSU measurements are up. Super-T SMPS and B+K Precision model 1660 lab supply.
The mods to the SOnic amp were simple.
New input caps 47u 16V BP Nichicon (!!)
New onboard electrolytic - 470u 25V Nichicon PW series low-ESR type.
Battery wires removed, Super-T PSU for power.
The mods were not done by me, but by Mr. Shultz who is doing the testing. He later changed the 47uF input caps to 4.7uF. That should not effect low end measurements.
We may get new measurements after reboxing.
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