Simplistic NJFET RIAA

[RCruz]

Originally Posted by Salas

I visited Vgeorge's house on Poros island given an opportunity he was in Athens and returning, so to listen to his DIY system and to contribute a bit of opinion and tune up. He uses the Simplistic Riaa fed from a Shelter 901 on a VPI, then a #26 with double SSHV2, autoformer pot, transformer XLR outputs, or DCB1 alternatively, to a 4 way dual amplified 100dB sens speaker system. A Baby Huey EL84 push pull drives 2 in series 12'' midbasses, Altec (Great Plains) driver on Le Cleac'h wide band horn (Azurahorn) and a Fostex bullet TW, all those with passive cross and no low cut, when an active analogue crossover handles the 280lt Lambda 15'' subs powered by a McCormack DNA amp.
I had designed the passive crossover originally with measurements he had .

Did you get any fotos of the simplistic... build details ?

[Salas]

George had shown it before so I did not open it up to photo again. Maybe he has a couple saved to remind by posting again if he will may.

[vgeorge]

Here a recent picture of the internals of the riaa.
PS is on a separate box with double R-core transformers and C L filter.

[Joao@AltheaMusica]

Originally Posted by vgeorge

I use Rod Coleman regulators for dc and they are completely silent.
Care should be taken as to their mounting on the chassis (use some form of damping), in order to avoid feedback from the music, especially with globe tubes.

That's what I expected and I'd use as well.
Another question regarding flicker noise. Any problems here? I had my problems with this issue using some WE 205D (Shugang clones) as preamplifier tubes...

[vgeorge]

No, I do not have any problems. Salas also listened to my system, and did not hear anything unusual.
Keep in mind I use a LL1660 4.5:1 at the output, which I think is essential to keep output impedance low enough.
I had some noisy tubes, but that is to be expected as most of them are used.

[RCruz]

Thank you for the pic vgeorge. Nice choice of components BTW.

[merlin el mago]

Originally Posted by vgeorge

Here a recent picture of the internals of the riaa.
PS is on a separate box with double R-core transformers and C L filter.

George congrats nice system, if you want send me a pm with your address so I will send you a couple of FT-3 0,1uF for your interestage coupling capacitors, I see you have mixed Kiwame with Shinkoh & Takman is for the sound in the position used? what mains filter cap are you using? in the separate psu box are you using also 10.000uF, wich value are you using for L?

[vgeorge]

Thank you for your offer Felipe, I already have some FT-3 capacitors.
Here I use K72P-6 0.047uF for interstage, which replaced the FT-3 I had before. They are covered with a grounded cooper foil.
Regarding resistros, I use kiwame in the power supply and shinkoh in the signal route. Takman 1M resistors.
Last filter caps are 2 x 22000uf mundorf.
In the PS box I use 2 x 4700uf and 2 x 10h choke.
Coupling cap is 3,3uf silver foil mundorf.

[merlin el mago]

The chokes are 100mA or more? Wich DCR?

[vgeorge]

Chokes are 200mA. Regarding DCR I do not remember exactly.