Just so I understand, 4 matched 2SK170BL for the difamp and one for the CCS?
Maybe I should invest and learn LT SPICE/ B2 SPICE. Where can I get a copy?
Maybe I should invest and learn LT SPICE/ B2 SPICE. Where can I get a copy?
The CCS is a mosfet not jfet - so you will something else for that. LT spice is free and free to download. You will need a spice model for 2SK170 - diy audio!
LTSpice is a free download, but you will have to acquire Most tube models, and a majority of discrete SS components yourself.
B2 Spice is a John Broskie product, that was put together several years ago, I got in on the ground floor, before the price was marked up. It will run close to $600.00, but it is loaded 1000’s of components, including ALL the popular tubes, OPT’s are another story, I haven’t been able to get any OPT model to work properly. I’ve asked for technical help but didn’t get very far.
But so far as accuracy, it’s been at least 90%. Which saves a lot of breadboarding, I’ve designed phono stages that have been better than 95% accurate with B2 Spice.
The DN2530 MOSFET for 1039 is the best match. The DN2540 is a little low on current.
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I really need to express my gratitude for all the help from everyone...you guys are awesome!
I downloaded LT Spice. Is there a "spice for dummy's"?
I downloaded LT Spice. Is there a "spice for dummy's"?
Hi All,
It's been a little while since we talked. If I wanted to add passive RIAA to this design, where should I add it? I'm thinking after Q5? Am I correct that there is a RIAA filter already there...just not the complete network? The second network (bass?) is the feedback loop...which I want to remove. I plan to use something like the passive RIAA network from the PASS or Salas designs.
Thanks
It's been a little while since we talked. If I wanted to add passive RIAA to this design, where should I add it? I'm thinking after Q5? Am I correct that there is a RIAA filter already there...just not the complete network? The second network (bass?) is the feedback loop...which I want to remove. I plan to use something like the passive RIAA network from the PASS or Salas designs.
Thanks
If you put it all there I think you will affect the noise performance. As the feedback will reduce both the signal and the noise at HF. If its all in one place you may struggle.
The Salas folded Simplistic and the Pass Pearl (1 & 2) have it between the input stage and second stage? Not that I need to copy them, just a question. I could put the second filter after the tube stage. Trying to remove the feedback...but maybe I should just trust ARC.
I know they are not the know all/end all in design. The changes I made to the power supply were a dramatic improvement over the stock design.
Since I'm now talking "analog source" should I move this question to that section?
I know they are not the know all/end all in design. The changes I made to the power supply were a dramatic improvement over the stock design.
Since I'm now talking "analog source" should I move this question to that section?
I don't think I can make comment without simulation. Just to say I find if you want the lowest distortion as with an op-amp have lots of gain and apply negative feedback. The circuit does look like an op-amp.
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Since this is a phono stage and a fet/tube hybrid, I would ask if a moderator could move, or link, all of this over to the correct section (analog source)?
I don't know how to move all of these posts?
I would like to continue the discussion over there, but I do thank all of you for your help and input.
I don't know how to move all of these posts?
I would like to continue the discussion over there, but I do thank all of you for your help and input.
I have it on good authority that Audio Research used the Toshiba 2SK117 in many of their front ends. Selected and matched, no doubt. This JFET looks like a "detuned" 2SK170. It is probably also hard to find now:
https://www.futurlec.com/Datasheet/Transistor/2SK117.pdf
https://www.futurlec.com/Datasheet/Transistor/2SK117.pdf