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Old 13th July 2010, 03:39 PM   #4151
massimo is offline massimo  Italy
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Quote:
Originally Posted by merlin el mago View Post
@massimo
Could you post photo with etched pcb & schematic?
I'll show you the populated pcb when ready. The pcb alone won't tell you anything. It's very similar to the design I post months ago: dual SSSRegs v1.2 + SNJfet Riaa 60dB in a 21 x 9,5 cm board
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Old 13th July 2010, 04:10 PM   #4152
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Quote:
Originally Posted by massimo View Post
I'll show you the populated pcb when ready. The pcb alone won't tell you anything. It's very similar to the design I post months ago: dual SSSRegs v1.2 + SNJfet Riaa 60dB in a 21 x 9,5 cm board
Could you sell/trade me one dual SSSRegs v1.2 + SNJeft RIAA 60dB please?
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Old 13th July 2010, 04:32 PM   #4153
massimo is offline massimo  Italy
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Originally Posted by merlin el mago View Post
Could you sell/trade me one dual SSSRegs v1.2 + SNJeft RIAA 60dB please?
First of all I have to check if it works later could be, maybe in a special version with "Forza Inter" etched on it Or do you prefer "We are the world champions" ?
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Old 13th July 2010, 06:37 PM   #4154
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Originally Posted by massimo View Post
First of all I have to check if it works later could be, maybe in a special version with "Forza Inter" etched on it Or do you prefer "We are the world champions" ?
"Forza Inter" sounds very good & similar to "Força Barça", "we are the world champions" sounds like a Queen song....
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Old 13th July 2010, 09:35 PM   #4155
NPower is offline NPower  Portugal
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Originally Posted by Salas View Post
Everybody does this cascode with a Q3. Its in the pdf for over a year now. Every different schematic you see member's made is this one backbone. Franz made it recently for 60dB on horn speakers for example, said many times its very silent. I have one 61dB playing with even double Q3 and 4 fets. Mystery is your case. But if you solve it by removing q3 and you still like it, its a way. Having made it cascode and non cascode, the former has better analysis. Lets think a bit, whatever comes from q3, can be 2 things. Either noise at its base (what kind of leds you use?) or easier EMI or magnetic field pick up since the cascode ups the impedance and opens the bandwidth. How far is the transformer, and do you have incidents of RF interference with other machines in your area?

P.S. One thing I see reviewing again your pcb, is that the LEDS are located far away from Q3's base. I hope that the track's inductance does not put it into oscillation. Stick a 33R base stopper on it, hard wired on the base pin, very small lead, AFTER the smoothing 220uF cap.
Probably I didn't make my self clear ( sorry Salas), When I removed Q3 I just want to remove it, and also Q1 from the signal path, so I listen to it with Q6 and led's working(only low level HUM), but of course no sound !
As you say, noise could come from Q3, and how about Q1?
I'm using four yellow led's, all the same ref, they give me Vref within the values (aprox 7.6V).
For the transformer, it's a R-core, 30cm away ( already tried 80 to 90cm).
I changed to a new ref led's and move them near Q3, installed a 33R base stopper, but noise is still there.

P.S.Right now I'm typing this and listening the phono, and sounds AMAZING ( except between tracks at medium volume)
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Old 13th July 2010, 09:50 PM   #4156
Salas is offline Salas  Greece
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Hey, box it first. You can't know when having a 56dB gain circuit in the open. Very nice looking.

P.S. Those black cables from channels go to the main filter cap's earth. Should go to the reg's terminal caps (-).
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Old 13th July 2010, 10:34 PM   #4157
NPower is offline NPower  Portugal
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Originally Posted by Salas View Post
Hey, box it first. You can't know when having a 56dB gain circuit in the open. Very nice looking.

P.S. Those black cables from channels go to the main filter cap's earth. Should go to the reg's terminal caps (-).
Thanks Salas
I will try that also
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Old 14th July 2010, 10:26 AM   #4158
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Originally Posted by NPower View Post
Probably I didn't make my self clear ( sorry Salas), When I removed Q3 I just want to remove it, and also Q1 from the signal path, so I listen to it with Q6 and led's working(only low level HUM), but of course no sound !
As you say, noise could come from Q3, and how about Q1?
I'm using four yellow led's, all the same ref, they give me Vref within the values (aprox 7.6V).
For the transformer, it's a R-core, 30cm away ( already tried 80 to 90cm).
I changed to a new ref led's and move them near Q3, installed a 33R base stopper, but noise is still there.

P.S.Right now I'm typing this and listening the phono, and sounds AMAZING ( except between tracks at medium volume)
Neat work congratulations, what output caps, resistor are you using?
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Old 14th July 2010, 01:31 PM   #4159
NPower is offline NPower  Portugal
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Originally Posted by merlin el mago View Post
Neat work congratulations, what output caps, resistor are you using?
Hello Merlin

Thanks for your kind words

Caps:
Cout - Obbligato Cu 3.3uF
C3 - Lemco silver mica 0.016uF
C2 - Lemco silver mica 0.047uF
C4 - Aluminum / teflon russian FT-3

Resistors
All of them carbon composition
R11 - Allen Bradley
R3 -Aircospeer
Rest -Tyco
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Old 14th July 2010, 04:07 PM   #4160
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How performs Cout - Obbligato Cu 3.3uF?

If you can afford better two regs & two psu, one for each channel.
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