Johan's Phase Linear 700B Fully Comp Conversion

That frequency response looks fantastic. The response is dead nuts flat to 20 kHz and you haven't even hit the -3 dB point at 80 kHz - nice.
 
Signal to noise ratio,,,,
 

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Max output...
 

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It's got a killer signal to noise ratio, decent crisstalk, world class frequency response..
 
Ands that was sine wave testing. I was testing a stock to destruction once but didn't get the reading after I had put in some 8 amp rail fuses in after blowing the 5's repeatedly. They suggest that in the manual. The output section was audibly screaming when it went. My guess was it went somewhere around 800.
 
laatsch55 said:
Signal to noise ratio,,,,
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Those are some really nice numbers. Have you ever played around with the wiring to see if the crosstalk changes after you've tested it. From looking closely at Joe's board he does an excellent job of keeping the channels separated (big surprise there) so it would seem that the biggest offender would be the wiring. Again no surprise but I was curious if you ever dicked with it and retested. It's amazing what some shielding and wire separation will do to improve crosstalk. Nice job with this amp - Johan is getting a kick ass amp.

How many audio companies would test the way you do and publish it? Not many (if any) - cool stuff Lee.
 
I think the AP has to go back to Beaverton. I'm showing 1.9 to 2.2millivolts on residual noise, my Fluke measures it at .4mv. It is a VERY QUIET amp at idle, that figure does not represent reality. Distortion figures are not what I would call what we are used to seeing...
 
The nice thing about this Dennis is you can have it under test and move things around in real time and watch exactly what happens to whatever test is running when ya do it...
 
laatsch55 said:
I think the AP has to go back to Beaverton. I'm showing 1.9 to 2.2millivolts on residual noise, my Fluke measures it at .4mv. It is a VERY QUIET amp at idle, that figure does not represent reality. Distortion figures are not what I would call what we are used to seeing...
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What about the self test? Any issues there? Of course the self test doesn't cover all so... Calibration of these dudes can be costly but this is a wonderful instrument. I'm very jealous but very happy you have one of these amazing pieces of test equipment.

Oh yeah - is the Fluke in cal?
 
Dennis I've never had the Fluke calibrated since I bought it, a 179 4 years ago. The AP passed the self test, but there is no way this amp has 2.2mv of residual noise. I don't mind spending the money to get it right. There has got to be something you can believe besides the ear. I want to have em throw in an IMD card while it's there..
 
I don't think the Fluke can read all the noise up to 80K hz...
 
laatsch55 said:
I don't think the Fluke can read all the noise up to 80K hz...
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The Flukes are good meters but they certainly have their limits. The IMD card will be a real score and have the AP calibrated will now get any funny readings down to a hardware problem or a test set up problem. :tongue5: That put's you in the hot seat - but I know you don't mind a bit. We love you man! Did I say that out loud? :shock:
 
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