Simplistic NJFET RIAA

[stajo]

What do you plan to do with such uge chokes ?

Read Zen Variations 7. Cant link it now almost out of battery. Zv7-T.

 

[stajo]

www.firstwatt.com/pdf/art_zv7.pdf

 

[RCruz]

thank you stajo

 

[le´flu]

Hi Salas and all,

i´m just about to stuffing the Folded Boards. Having on mind that the Gate
resistors in the PSU have to be non magnetic carbon ones i just fount metal-
film magnetic ones in the group buy package.
So what is to prefer as R4x/R2x ? Carbon? Nonmagnetic? that size, 1/2W, 1/4W?

Thanks and greetings Ulf

 

[Salas]

This one has been tested with normal metal film and works fine. No worries.

 

[le´flu]

I´m sorry
but just another question:
what about R11 at the pcb? There is no Value in the pdf.
What are the preferences for C3 and C4 at the moment?

Thanks Ulf

 

[Salas]

There is R11 listed as 1.5k 2 pieces for stereo. 1/2 or 1/4w will be OK.

 

[Salas]

Maybe you need download the PDF again? There is a link from post 1. For C3 & C4 you can use whatever you prefer in coupling caps generally, but don't go below Mundorf Supreme level caps if you intend it for a primary use phono with an expensive cart.

 

[skouliki]

Here is a pic of my build so far. Still waiting for parts to arrive
I was in a dillema between tnpw and rhopoint miniohm for R14, and finally i decided to go the expensive way 🙂

 

[le´flu]

Hi Salas,

There is R11 listed as 1.5k 2 pieces for stereo. 1/2 or 1/4w will be OK.

just looked at the "salas folded simplistic pcb build guide". R11 is not mentioned.
In Post 1 the other guide to the folded there is 1.8k for R11.

Greetings

Okay, just found the new version with 1,5k for R11 - Thanks

 

[Salas]

Here is a pic of my build so far. Still waiting for parts to arrive
I was in a dillema between tnpw and rhopoint miniohm for R14, and finally i decided to go the expensive way 🙂

Using different passive parts mix than others, it will be nice to know about your results when ready.

 

[Erlend Sæterdal]

But where do you buy the miniohm ? I sent a mail to rhuepoint but they did not even answer.

 

[skouliki]

But where do you buy the miniohm ? I sent a mail to rhuepoint but they did not even answer.

Rhopoint Components - Precision in Electronics

You have to register an account first. Then you can choose the product you like and ask for a quote. They will answer in about a day or so, and then you can confirm the order and pay with credit card

 

[RCruz]

They have IFN363 (a 2SK363 replacement)

 

[quan]

zobel out put cap

Hi Salas, how large can the zobel cap be? . Can i use 20uF MKP cap?(i have a few different values ie 2.2,3.3, or 20uF Wima).
Quan

 

[Salas]

4.7uF only. Sorry no play there. Its calculated in the OLG response shape. If you want to try bigger value, only 22uF/50V electrolytic non low ESR as suggested in the guide.

 

[MASantos]

I missed the 1st group buy and will try to get in on the next one when it happens.

I was reading tea bag's minikit info and he has the 2sk117gr listed for the 2sk389bl positions. Is it a replacement?

Also, if building initially for a mm cartridge, and if I want to change for LOMC at a later date, is there any change in the power supply section or do I just need to change the audio section of the boards?

 

[Erlend Sæterdal]

Rhopoint Components - Precision in Electronics

You have to register an account first. Then you can choose the product you like and ask for a quote. They will answer in about a day or so, and then you can confirm the order and pay with credit card

Thanks 🙂

 

[Salas]

I missed the 1st group buy and will try to get in on the next one when it happens.

I was reading tea bag's minikit info and he has the 2sk117gr listed for the 2sk389bl positions. Is it a replacement?

Also, if building initially for a mm cartridge, and if I want to change for LOMC at a later date, is there any change in the power supply section or do I just need to change the audio section of the boards?

There is no 2SK389BL, that one was a common die double 2SK170BL equivalent for use in differential front ends demanding best Tc tracking.

There is 2SK369BL in the FSP front end which is a single high Yfs low GR noise Jfet implemented in folded cascode alone or doubled up in parallel depending on gain target.

2SK117GR are used for peripheral tasks in this circuit. Three 2SK170BL in the 2nd & 3d signal stages also.

No changes in PSUs or in the regulators will be needed when you would want to modify the voltage gain later. Its down to manipulating 3 components in the signal's front end stage.

I suggest you download and read the concise build guide in PDF format linked from post #1 in this thread. That should settle all your questions.

 

[MASantos]

There is no 2SK389BL, that one was a common die double 2SK170BL equivalent for use in differential front ends demanding best Tc tracking.

There is 2SK369BL in the FSP front end which is a single high Yfs low GR noise Jfet implemented in folded cascode alone or doubled up in parallel depending on gain target.

2SK117GR are used for peripheral tasks in this circuit. Three 2SK170BL in the 2nd & 3d signal stages also.

No changes in PSUs or in the regulators will be needed when you would want to modify the voltage gain later. Its down to manipulating 3 components in the signal's front end stage.

I suggest you download and read the concise build guide in PDF format linked from post #1 in this thread. That should settle all your questions.

My mistake regarding the 2sk369, I wrote the wrong part. 😛

I already read the guide a few times, but then comparing some parts names in the tea bag minikit description got confused. I'll ask the question on the GB thread!