Simplistic NJFET RIAA

6L6

Moderator
Joined 2010
Paid Member
Scott,

You should know by now that I don't do that... My ears are not your ears, my speakers are not your speakers, room, turntable, cartridge, etc... and that's just equipment before we get into musical taste and what makes a system really work for me... So I'm always hesitant to do so.

Generally if I like something, I say so, but if I don't like something, I don't really talk about it much...

(Now I will talk about the sound of the Firstwatt amps because they are 1) all good, and 2) do, in fact, have different sonic signatures, however, it's always in reference to where is said Firstwatt amp on the arbitrary and made-up scale that has the Aleph at one end and F5 at the other...)

But, as for Phono -

In no particular order I've built and/or had;

Dynaco SCA35
VanAlstine Omega
Meridian 101
Hafler DH110
Quad 34
Quad 44
Steve Bench RIAA 5
Pass Pearl 1
Pass Pearl 2
Pass XP-17
Conrad-Johnson PV3
Elliott Sound Labs P06
Hagerman Bugle 2
Muffsy Phono Preamp
Salas FSP
Millett LR phono

And I feel that I'm forgetting something, but it's not coming to me at the moment.


Anyway, with all that in mind, please re-read post #19,418.

:)
 
  • Like
Reactions: 1 user
diyAudio Chief Moderator
Joined 2002
Paid Member
UFSP version was made to be flexible vs FSP regarding multiple gain settings. Due to that its differently sorted out in layout. Has a newer companion shunt regulator as well (V1.3S). Builders of both report that UFSP also offers a bit upgraded sound. Lets see if you will also hear something towards that or not.
 
  • Like
Reactions: 1 user
I have been thinking about getting a DS 003 optical cartridge. It has a 70mV output. The cartridge has really good write ups and is neutral which I like. Is the FSP adaptable to that output. I love my system sound. SP10, EPA tonearm, AT PTG33/2 cartridge, FSP, DCG3, M2x Monoblocks with Norwood and Monkey Tower Speakers. I would very much like to change the cartridge only.
Thanks,

Don
Hopefully not too off topic,

I would like to have a FSP design optimized for both MM/MC and DS audio cart (Merry Christmas to all!).

Here is the ds audio latest docs for public design,
https://ds-audio-w.biz/cms/wp-content/uploads/2021/11/Technical-information20221212_c.pdf

I just modified my tube LCR phono for DS-E1, single best pentode stage of 40X using transformer output (4.5:1), since L/R are out of phase per design.
 

Attachments

  • ds-e1-6j49p.jpg
    ds-e1-6j49p.jpg
    74.9 KB · Views: 41
I have been thinking about getting a DS 003 optical cartridge. It has a 70mV output. The cartridge has really good write ups and is neutral which I like. Is the FSP adaptable to that output. I love my system sound. SP10, EPA tonearm, AT PTG33/2 cartridge, FSP, DCG3, M2x Monoblocks with Norwood and Monkey Tower Speakers. I would very much like to change the cartridge only.
Thanks,

Don
Don, I love that our setups are so similar (J2s in yet? :p). I do agree with 6L6 and his optical cart opinion and cost/vs subjectivness of goodness therein. Try a Hana ML in your system if you haven't. Of course I'm running 2 arms at the moment FSP + SUT (2 varieties) on one arm and Ultra on the other arm. I've balanced out a few carts for easy swapping and eval on both arms.

Happy holidays to all you audio nuts.
 
Don, I love that our setups are so similar (J2s in yet? :p). I do agree with 6L6 and his optical cart opinion and cost/vs subjectivness of goodness therein. Try a Hana ML in your system if you haven't. Of course I'm running 2 arms at the moment FSP + SUT (2 varieties) on one arm and Ultra on the other arm. I've balanced out a few carts for easy swapping and eval on both arms.

Happy holidays to all you audio nuts.
The cost of cartridge itself is not too bad with a diy equalizer. A friend prefers 003 over VDH crimson.
 
Last edited:
  • Like
Reactions: 1 user
Member
Joined 2019
Paid Member
Don, I love that our setups are so similar (J2s in yet? :p). I do agree with 6L6 and his optical cart opinion and cost/vs subjectivness of goodness therein. Try a Hana ML in your system if you haven't. Of course I'm running 2 arms at the moment FSP + SUT (2 varieties) on one arm and Ultra on the other arm. I've balanced out a few carts for easy swapping and eval on both arms.

Happy holidays to all you audio nuts.
Re the J2's. Building 2. (Not gunna be like guitar amps). Long skinny and Zen Mod. Waiting for parts. Zen Mods boards and Modushop Monoblocks. I can put just about anything in the Monoblocks. Thank you for all your work on the Monoblocks. Not sure why the diy store doesn't carry them but that's another topic. And, this post is off topic.
Sorry. Out. Merry Christmas everybody.
 
  • Like
Reactions: 1 user
crossposting this here because it's probably better than the group buy thread:
I've collected most of the necessary items and I'm about to start building tape head pre with these boards. Salas had posted some tape head circuits here: https://www.diyaudio.com/community/threads/preamp-for-reel-to-reel.222113/#post-3213006 Those circuits use 2sk170s for the first stage amplification and the ufsp uses 2sk369. Is someone able to calculate the db gain of the tape head circuits so I can set the proper gain in the ufsp? Or, better yet, provide a description on how to calculate the value?
 
diyAudio Chief Moderator
Joined 2002
Paid Member
There are enough gain steps in the switches to somehow set it near useful amplification levels I guess. Some tweaking is going to eventually be needed anyway because it was a theoretical curves approach back then plus you attempt to migrate it over to another alike but not same config. Good luck and let us know the outcome.
 
Hi all, I am going to build the UFSP (actually two units). Already a happy FSP camper playing with a Hana ML as my daily driver.

I had bought the boards, minikits, transformers about 2 years ago, but didn't find the time to proceed with the project. I was looking at the BOM to gather the rest of the parts and found out that the rectifiers for the raw psu seem to be no longer available (512-FFPF30UP20STU). What is a suitable substitute? Btw, just to cure my curiosity, they seem hugely overrated at 30A, 200V. Is this choice made to avoid using heatsinks?

Also for C2A in UBiB, I cannot find the suggested Panasonic. If targeting for low ESR alternatives, is 85C rating acceptable for this capacitor position?
 
diyAudio Chief Moderator
Joined 2002
Paid Member
Hi, the rectifier diodes can be fast & soft type. For reduced EMI. Like a Hexfred HFA08TB60 for example.

The ones in kits BOM were tried performance shared stock between heavier PSU projects I believe. With nice plastic encapsulation.

For C2A alternative 85C types are also welcome. Keep to the original capacitor's diameter for easy fitting.
 
Thanks! Thinking of combining one of the units with DCG3. One case including UFSP, DCG3, iSelect and possible a remote controlled motor driven pot and one case PSU with 4 or 5 transformers, raw PSU. Given that I manage to think of a reasonable layout, Is there going to be any issue regarding noise in the UFSP due to the low AC feeding the DCSTBs?

The DCG3 is going to be used as a headphone amp, at least in the beginning. But I would like to be able to use the combined UFSP with the main system too. Since the gain provided by the DCG3 will probably be too much for the tube integrated (Unison Research S8), is it possible in DCG3 to have an RCA output connected permanently parallel to the iSelect output to create a bypass? Or should I employ a switch there and select either volume pot or bypass, one at a time?
 
diyAudio Chief Moderator
Joined 2002
Paid Member
There could be a small issue if the AC DCSTB power cables will not be carefully tacked away as far as possible from the UFSP signal input. Especially when set for max MC mode gain.

Better have a switch to can select the full or bypass route. To avoid stages interaction that usually brings extra THD.
 
  • Like
Reactions: 1 user