Simplistic NJFET RIAA

[Salas]

How's the parallel tracking arm grounded?

 

[alexkosha]

Scott hi,
Other tested earthing schemes to possibly try are a. The one described in post #17797 and used in most FSP builds, b. The one from Alex reported working well with his non metallic TT and arm in post #17902. The raw psu board has two diodes safe lift and resistors network already so not necessary to also use the full bridge he had shown there. You can just wire to the mains earth connected psu chassis lug from the PE --E pad instead.

My mistake since I supplied partial info ...
I use different Raw PSU board in my final build for Ult and that specific board does not contain these diodes and 10r/1r resistors. I used it due to the fact that I already have it assembled and set for right Vout for Ultra. This is why I used external full bridge with 10R and two of 1R resistors. Original Raw PCB has positions for all elements need for lifted GNDing.

 

[longspeak]

I've got mine up and running, listening to it now and I like it. Big thank you to Salas and Teabag!



Now I need a couple of cases like SRMcGee - very nice work btw.

 

[Salas]

Congrats. You are welcome. AT VM540ML cart?

P.S. Use an independent secondaries transformer

 

[longspeak]

Yes, wow Salas very good eye! Speakers are 50+ year old Altec Flamenco's 16ohm 98dB spl and the UFSP is really quiet even without a case or really proper grounding. I'm going to listen to vinyl all night. Thank you for such a great design!

 

[longspeak]

P.S. Use an independent secondaries transformer

Will do.

 

[alexkosha]

Beautiful speakers!!! Enjoy your new UltFSP.

 

[longspeak]

Thank you Alex - I've enjoyed reading through your posts with Salas.

 

[Salas]

What are your C3, C4? Does the Flamenco benefit from a stand?

 

[longspeak]

C3 & C4 are Vishay 1839HQ. I tried the Flamenco's on stands (felt covered cinderblocks ~16" off the floor) but they actually do better on the floor in my room. I did replace the capacitors in the xovers, but otherwise they are original.

 

[Salas]

I'm going to listen to vinyl all night.

How is it going with the listening? Opening up? What C2Y sounds best with the Audio Technica VM540ML the Dynaco ST 70 and the Altec Flamencos?

 

[iTiberius]

Sorry to polute with my "old" simple folded, but it took me lot of time to finish this.

Wanna thank Salas and Tea-Bag for this gorgeous project !

Regards,
Tibi

 

[Salas]

You are welcome. Big trafos!

 

[Salas]

But you did not use C2x right. It does not have connection to R5x. Use a form factor that can reach the pad next to R5x. As it is it can't, goes to the rail straight on instead. Now its put like using an electrolytic but such a cap has series resistance of its own for the purpose. To properly damp the open loop gain of the reg. Else OLG is peaky.

From the guide:

C2x 4.7uF>63V 2 Wima MKP4, MKP10, or alike. 22.5 27.5 37.5mm pcm, MCap EVO
Elcap 22uF/63V 2 Alternative termination to C2x+R5x. Normal ESR, skips R5x. See notes

 

[iTiberius]

Thank you for your observation !

I had these overkill trafos for a while and now they have a scope in life.
C2x is 4u7/63V Wima and make connection to R5x.

BTW, the notation or resistors RxN and RNx make me pull my hair several times.:-D

Regards,
Tibi

 

[Salas]

Are those trafos magnetically shielded?

Look at the PCB detail.

 

[iTiberius]

Yes, are magnetically shielded.
Ok. Thanks ! I'll correct that.

Regards,
Tibi

 

[Salas]

Let us know how it will play!

 

[longspeak]

Salas last night's listening went well and it did open up. Today I'll start playing with C2Y values and get a second transformer wired up and report back. I really like the versatile design, again thank you (and Tea-Bag) for all the effort to bring so much enjoyment to others.

 

[Salas]

It will possibly play even better with second transformer. Keep us posted.