Simplistic NJFET RIAA

[vgeorge]

Thanks again.
I wanted to make sure.

George

 

[Salas]

You are welcome. Post pics when ready.

 

[RCruz]

Hi Salas

I can not find a C11 in my schematic... Maybe it is C10 ?

Can the same be done with C5 (Use 470u BG´s what voltage minimum?)

I am using 220 ZA but find the sound too forward.

Ricardo

 

[RCruz]

After burning for 24 hours, the bypass has "healed".. sound is now powerfull and very detailed... Outstanding.

And I did not replace the resistors yet ....

The Benz is singing as never before !!!

Ricardo

PS (I did not decide between mundorf mcap supreme / obbligato "dry" / ClarityCap SA + 0.47 Mundorf Supreme bypass)

I want depth and wideness in the soundstage with loads of detail.... Please advise

Ricardo

 

[psgr]

Hi,

I`m interested in building this preamp, but I have a few question.
I`m looking at the MM version posted at post 178 and PSU.
My questions:
- are 220uf caps electrolytic or NP
- the value of C3, I have found a 16n should I use this or go with 9.1+6.8=15.9 or 8.2+7.5=15.7
- I have found metalized polypropylene caps that I`m thinking of using, they are from Vishey, Panasonic and Epcos. Any suggestions on these manufactures.

Thanks.

 

[johnm]

Hi folks - I'm having problem sourcing suitable caps for C3 and can't find the 15.72nF Russian others have mentioned here. I'd be greatful if someone has a link for a source of these please?

Many thanks

- John

P.S. Found some 0.1uF Russian Teflon caps I forgot I had - I'll use those for the interstage position. Always nice when you find suitable parts already there and waiting to be used!

 

[Salas]

Hi Salas

I can not find a C11 in my schematic... Maybe it is C10 ?

Can the same be done with C5 (Use 470u BG´s what voltage minimum?)

I am using 220 ZA but find the sound too forward.

Ricardo

For C5 and C10 in your schematic you can freely try 220uF and over in any quality you wish to audition. C5=35V min, C10=25V min.

 

[Salas]

After burning for 24 hours, the bypass has "healed".. sound is now powerfull and very detailed... Outstanding.

And I did not replace the resistors yet ....

The Benz is singing as never before !!!

Ricardo

PS (I did not decide between mundorf mcap supreme / obbligato "dry" / ClarityCap SA + 0.47 Mundorf Supreme bypass)

I want depth and wideness in the soundstage with loads of detail.... Please advise

Ricardo

So far so good. Bravo.

I would replace the resistors first. See where I arrived and then make final focus with the output cap. Obbligato aluminum-foil MKP 630VDC is best value, and then can be tuned with some bypass.

 

[Salas]

Hi,

I`m interested in building this preamp, but I have a few question.
I`m looking at the MM version posted at post 178 and PSU.
My questions:
- are 220uf caps electrolytic or NP
- the value of C3, I have found a 16n should I use this or go with 9.1+6.8=15.9 or 8.2+7.5=15.7
- I have found metalized polypropylene caps that I`m thinking of using, they are from Vishey, Panasonic and Epcos. Any suggestions on these manufactures.

Thanks.

Electrolytic can be Non Polar too. Use polarized electrolytic, no problem. Panasonic FC or Elna Silmic II are OK. Black Gate NX Non Polar even better.

Use a single 16n cap preferably but be sure its really 16n if it can be checked on an LCR meter.

Epcos by far.

 

[Salas]

Hi folks - I'm having problem sourcing suitable caps for C3 and can't find the 15.72nF Russian others have mentioned here. I'd be greatful if someone has a link for a source of these please?

Many thanks

- John

P.S. Found some 0.1uF Russian Teflon caps I forgot I had - I'll use those for the interstage position. Always nice when you find suitable parts already there and waiting to be used!

Use 15n polypropylene and bypass with 1n Silver Mica if you cant find the big one right now. I works OK for me and saves space for a better layout.

 

[Salas]

Sorry guys for the late answers but I was doing the final voicing and measurements on the crossover I made for a large Apogee hybrid speaker with its main element replaced for a third party 1m long new ribbon. I listened to our phono through that a lot too, plus the Bench valve cascode one with my HV shunt supplying it, both through a 12B4 pre with Mosfet cascode anode load I designed for it. Amplifiers were a couple of 8XEL34 monos 140W nominal, their circuit is revised.

 

[psgr]

salas,

Thanks

 

[vgeorge]

Just to show some images of my progress.
The cases have been recycled from previous projects!
Shunts have been soldered and work fine. On the RIAA, may begin soldering today.

 

[vgeorge]

One more picture.
RIAA in a separate box.

 

[vgeorge]

And one more with a view outside my balcony.
It's cold and windy today!

 

[Salas]

Nice weather for building a project.

 

[nicoch58]

HI Ricardo

As alway the Salas suggestion are golds

back I have put some link on caps guide...

by the way start to thinks on amp/speakers (bypass pre) before you push in a wrong directions....ie buy a 50€ caps

or duelund 250€

 

[nicoch58]

for "depth and wideness in the soundstage " use open baffle

PS decent pot make difference ....

 

[RCruz]

Thank you nicoch46 !!!

Of course I would not think of 50€ caps before tunning the rest of the system.

I already built two pedja buffers to bypass the preamp but I am not sure it is the best choice due to the lack of gain and the additional caps. (My pre does not use caps in the signal line)

The Mundorfs Supreme cost 20GBP and the obbligato 15€ ... I will follow Salas indications and use the china caps.

About a decent pot, I believe you indicated something from Australia before... can you point me in the right track ?

Regards

Ricardo

 

[iko]

And one more with a view outside my balcony.
It's cold and windy today!

OK, I had to laugh Just goes to show how relative it can be. The words "cold and windy" have a totally different meaning on our side. We've got a winter so long already... snif, snif.