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Old 22nd February 2012, 10:54 PM   #7291
atupi is offline atupi  Romania
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Resistors: 2,36k and 47,3k
2,38k and 47,07 k and i think they are carbon. Unfortunately our local dealers dont provide better options only basic stuff.

For 15,6nf i have tried poliester and mylar with same sonic results.

After setting 11V for the second stage as Salas recommended the sound changed to a better way for may ears but on some types of music the sound is muddy so i changed back to 13V.
Should i expect some noticeable sonic changes when i will have the shunt ready ?

Last edited by atupi; 22nd February 2012 at 11:14 PM.
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Old 22nd February 2012, 11:11 PM   #7292
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Originally Posted by Salas View Post
If they are lit brightly and you see no oscillation on the rails with your oscope as you thoroughly described, then I have no way to suspect something else. Stick a metal Pi shaped leaf on top of those transistors with some resin to keep them cool at least.
I've sorted it finally, I had mis-labelled my 3.3k resistors when I got them, so R5 and R6 ended up being 330 ohm!

I've replaced R5,R6,Q3,Q4 and D1 to be on the safe side. All is fine now. I'm usinr 4R7 for R1 and wouldn't want to go any lower, I'm using the pre-amp chassis as the heatsink and it gets to about 60-70C. Once again, thankyou Salas. The Simplistic phono just gets better and better!
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Old 22nd February 2012, 11:17 PM   #7293
Salas is offline Salas  Greece
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Quote:
Originally Posted by atupi View Post

After setting 11V for the second stage as Salas recommended the sound changed to a better way for may ears but on some types of music the sound is muddy so i changed back to 13V.
Should i expect some noticeable sonic changes when i will have the shunt ready ?
There is 12V midway also to check. Yes, the shunt helps in tonality and apparent ''body'' of sound.
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Old 22nd February 2012, 11:19 PM   #7294
Salas is offline Salas  Greece
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Originally Posted by df_genius View Post
I've sorted it finally, I had mis-labelled my 3.3k resistors when I got them, so R5 and R6 ended up being 330 ohm!

I've replaced R5,R6,Q3,Q4 and D1 to be on the safe side. All is fine now. I'm usinr 4R7 for R1 and wouldn't want to go any lower, I'm using the pre-amp chassis as the heatsink and it gets to about 60-70C. Once again, thankyou Salas. The Simplistic phono just gets better and better!
When there is smoke there is fire... it was a typical value mistake, now its explained. Fine, have many good record playing sessions.
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Old 23rd February 2012, 06:36 AM   #7295
vgeorge is offline vgeorge  Greece
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Originally Posted by atupi View Post
I have only a Fluke 177 and resolution for capacitors is 1nf.
With 1n resolution you can' t possibly know what values you have on the riaa capacitors. The first thing I would do is find a way to measure riaa caps with a better accuracy and then change other things.
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Old 23rd February 2012, 12:49 PM   #7296
atupi is offline atupi  Romania
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I used for my pcb the layout found in the Salas-Riaa-Package-V1 (the CRT stereo version) and there is an error on Q5 drawing. On that design G and D are shorted (this distroyed my Led's)and the correct way is to have shorted G and S.
I hope this can be useful for someone else
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Old 23rd February 2012, 06:09 PM   #7297
RCruz is offline RCruz  Switzerland
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Quote:
Originally Posted by atupi View Post
Resistors: 2,36k and 47,3k
2,38k and 47,07 k and i think they are carbon. Unfortunately our local dealers dont provide better options only basic stuff.

For 15,6nf i have tried poliester and mylar with same sonic results.

After setting 11V for the second stage as Salas recommended the sound changed to a better way for may ears but on some types of music the sound is muddy so i changed back to 13V.
Should i expect some noticeable sonic changes when i will have the shunt ready ?
Try placing a 1mega ohm resistor parallel to R4 (6k8r).. you can use miniature aligators to do it so you do not need to solder anything.
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Old 24th February 2012, 06:48 PM   #7298
atupi is offline atupi  Romania
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I will a.s.a.p.
Thanks for advice!
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Old 25th February 2012, 10:23 PM   #7299
atupi is offline atupi  Romania
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So i finalized my shunt. Worked from start. Thanks to Klewis i had a pcb design and work was faster. I need to find proper heatsinks also. I used IRFP9140 for Q1 and IRF9540 for Q4. For Q2 i used BF245A.
Q1 is just a bit warm but Q4 is really hot. Set the output voltage to 20V like Salas says.
Now, with the shunt, i think the sound changed a bit and tomorrow i will try some new adjustents for the buffer and maybe the loading. The preamp is not so bright now like it was before shunt.
Now i'm very nervous waiting for my new Nagaoka cartridge to see how it sounds.
Hopefully i will find some good capacitors for interstage coupling (teflon maybe) to see how they sound.
Thanks Salas and the other guys for help.
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Last edited by atupi; 25th February 2012 at 10:26 PM.
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Old 26th February 2012, 01:13 AM   #7300
Salas is offline Salas  Greece
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Its coming out nicer bit by bit, that is cool. The two black electrolytics in your regulator can be influential. You may try Nichicon KZ (balanced resolute sound), Silmic II (deeper rounder sound a bit slow) at a point for those. And of course a bigger sink for the output Mosfet. Keep us posted about your progress.
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