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Old 31st December 2011, 04:13 PM   #231
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Default Further Improvements

An update. The pre now runs with better ground pattern, ceramic caps from heater to ground on the base, plus a SSLVS(ver1) modified for filament duty. Attached is the FFT measurment. Red being before and Blue being current. 1Vrms Input = 0dB.

Measurements are good, but this may be a case where too much good is bad. While it is fully enjoyable, I almost prefer the way it sounded before. The majority of the 60Hz bump is my monitor sitting right next to it.
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Old 31st December 2011, 04:37 PM   #232
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....... but this may be a case where too much good is bad. While it is fully enjoyable, I almost prefer the way it sounded before.
why the blue peak at 1khz
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Old 31st December 2011, 04:39 PM   #233
Salas is online now Salas  Greece
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Maybe you would like to listen with just CCSing the heaters with the input part of SSLV1.
Your harmonic noise profile shows a major improvement non the less.
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Old 31st December 2011, 04:39 PM   #234
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why the blue peak at 1khz
Test signal for seeing THD.
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Old 31st December 2011, 04:46 PM   #235
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Salas is correct 1Vrms 1kHz test tone. Can see and measure THD with it.

I think I will take out the CCS as the cathode load first. The play with the heater.
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Old 31st December 2011, 04:51 PM   #236
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Me I use a resistor after several circuits as load. Maybe you will like it too. Curious to know your inclination after you test.
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Old 31st December 2011, 05:27 PM   #237
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why the blue peak at 1khz
That is the fundamental in the FFT measurement.. To the right are the harmonics of the fundamental, and to the left is the residual LF noise..
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Old 1st January 2012, 06:58 PM   #238
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Originally Posted by Salas View Post
Did anybody build or listen to a 6V6 triode connected line preamp? I think it may be interesting to build one since I have some NOS. Maybe SRPP.
I've seen it in the line stage of a tube comp I use.
but the whole thing is p-p line stage.
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Old 1st January 2012, 07:36 PM   #239
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Was it a pro sound compressor machine?
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Old 1st January 2012, 08:09 PM   #240
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Salas,
I have been poking around your threads and this one seems the most interesting or maybe the shortest, I don't know which. THat being said, anybody who listens to Sytem of a Down and owns tube gear, knows something, so want to build this and wasnt sure if this was the final schematic. I know you tried CCS instead of resistors but droppped because of gain and sound issues. Let me know so i can get building! First tube amp
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