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Old 29th May 2010, 11:13 AM   #3741
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Hi Salas

Thanks for your kind support offer!

I want to use a low output MC: Denon DL103R

Kind regards
Franz

/Edit
Most of my V's are measured 1mA more than I wrote earlier: between 15 to 16mA

Last edited by Franz Gysi; 29th May 2010 at 11:30 AM.
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Old 29th May 2010, 03:32 PM   #3742
Salas is online now Salas  Greece
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Here it is. Due to simulation model, the strong V JFETS can show somewhat different current draw so keep an eye on those 10V points. Second stage has a trimmer for it, first stage can be altered by R2.
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Old 29th May 2010, 04:23 PM   #3743
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Hey, very big thanks, Salas!

First question: the paralleled 2SK170 in the first stage are just for simulation purpose, isn't it?

Or are you really recommending,to parallel two SK170V in the first stage? Increasing the input capacitance and distortion?

Second question:

Did I miss a mod concerning C1? Not in parallel to the LED's? From gate to drain?

Franz

Last edited by Franz Gysi; 29th May 2010 at 04:28 PM.
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Old 29th May 2010, 04:26 PM   #3744
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No. They are actually two for better noise since this is LowMC. No problem with capacitance with a 14R Z MC as DL103R. Linearity no problem in such super low swing. There are even 4x JFET many examples like the Ono. Anyway, its cascoded. C1 is actually from cascode base to B+. Better PSRR when not associated with ground. In your practical build you can try it even from base (+) to ground and judge hum.
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Old 29th May 2010, 04:44 PM   #3745
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Thanks Salas

Of course, you are right! With the low Z of the R103R capacitance is not a problem.

I will try this circuit. First step with a simple LM317 power supply, so I have the chance to compare it later with the Salas shunt regulated psu.

I will keep you informed about my steps. This weekend, I plan to make my own pcb for this preamp.

Kind regards
Franz
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Old 30th May 2010, 11:18 AM   #3746
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Quote:
Originally Posted by Franz Gysi View Post
Thanks Salas

Of course, you are right! With the low Z of the R103R capacitance is not a problem.

I will try this circuit. First step with a simple LM317 power supply, so I have the chance to compare it later with the Salas shunt regulated psu.

I will keep you informed about my steps. This weekend, I plan to make my own pcb for this preamp.

Kind regards
Franz

Good lucky & welcome to the Salas Simplistic NJFET RIAA club.
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Old 30th May 2010, 11:33 AM   #3747
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Default Tweaking RIAA

After all this time tweaking the RIAA components I agree with Salas advice that it's better for C3 don't arrive till the 16nF, if you use 16nF high frecuencies suffer & the sound is made blots, not focused without vigor; C2 with less of 16nF the sound is more life, fast, real, dynamic. It's really unbeliable what can do changing the value in a critical component of the RIAA, congratulations Salas for your knowledge & to share with us, another:
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Old 30th May 2010, 11:49 AM   #3748
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Question Balanced?

I read some people that don't agree balanced phono preamps telling that noise level increased due to more electronic components, it's true?
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Old 30th May 2010, 12:09 PM   #3749
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In your specific configuration I saw less than 16n. Balanced gives +3dB noise, thats a consideration for those shooting for record low noise figures though.
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Old 30th May 2010, 03:23 PM   #3750
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Default Balanced

What about subjectively speaking?
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