Valve Itch phono

[stajo]

 

[RCruz]

RIAA 200VDC teflon caps working near 1 day without problems.

What type of caps are you using ?

Pics ?

 

[merlin el mago]

47nF USA, 15.70nF Russian ft-1 the same bought togheter Ricardo

 

[merlin el mago]

Finally I ordered Shinkoh for RIAA 50k 1w & 6k8 0.5w. Also ordered 820R 0.5w Shinkoh for first stage & 12k 2w Armtrans. When changed the RIAA caps also changed the 320R upper tube 2nd stage for Shinkoh 0.5w that I discovered in my stash.

 

[merlin el mago]

What type of caps are you using ?

Pics ?

Attached pics FSP build with teflon caps that are the same used in the Itch.

 

[merlin el mago]

Still working!!!!

 

[stajo]

Still working!!!!

 

[merlin el mago]

SQ is superb!!!! compared vs MKP

 

[merlin el mago]

Salas I use 47nF teflon film & foil cap as interstage, if I change to 100nF teflon film & foil I will improve the SQ?

 

[stajo]

The interstage coupling cap C4 100 nF is set for optimal frequency response at 20 Hz (19,4 to be precise) together with R8 820K. Minus 3 dB response it then at 1,94 Hz. Your 47 nF has optimal bass response down to 41,3 Hz with the 820K, minus 3 dB is at 4,13 Hz. I doubt you will hear any difference tho, and maybe its only doing good for rumble.

 

[merlin el mago]

Thanks for the good advice.

 

[RCruz]

47nF USA, 15.70nF Russian ft-1 the same bought togheter Ricardo

Thank you so much..... would you share your american teflon cap supplier ?

 

[fdegrove]

Hi,

If you want your frequency response to be close to what it is with a 100nF coupling then put two 47nF Teflon caps in parallel.

Cheers,

 

[merlin el mago]

Thank you so much..... would you share your american teflon cap supplier ?

Shared in the Simplistic NJFET RIAA thread http://www.diyaudio.com/forums/analogue-source/129126-simplistic-njfet-riaa-601.html#post2520618

 

[merlin el mago]

Hi,

If you want your frequency response to be close to what it is with a 100nF coupling then put two 47nF Teflon caps in parallel.

Cheers,

Thanks Frank, I have FT-3 100nF.

 

[merlin el mago]

I'ts worth to change the two 6SN7 for four 7193 to improve the SQ?

 

[rongon]

Is the 2C22 (7193) really all that different from 6SN7GT or 6J5GT? They're supposed to be electrically equivalent, I think.

 

[stajo]

More a question of samples and brands imho

 

[merlin el mago]

Salas what's the Zout of the first stage & the Zin of 2nd stage?

TIA
Felipe

 

[merlin el mago]

Salas there is an inversed RIAA to diy to check the accuracy of the RIAA?