Pars

I try to match complementary pairs, but going from N to P (both BJT and JFETs) usually doesn't match very well. It depends on the devices.

Really good news Jacob!! Sent from my iPhone using Tapatalk

Matching never hurts... not sure that they need to be though. Sent from my iPhone using Tapatalk

Happy Birthday! Sent from my iPhone using Tapatalk

Happy Birthday! Sent from my iPhone using Tapatalk

I tried this myself yesterday, though I bent the leg on the trimpot and soldered a jumper wire to it, so nothing in pin 5 of the dip socket. Seems to work fine, offset drifts some but nothing bad at all, probably in the +/- 3-4mV range while I was watching it. Listened to a cd with protection circuit in place and no issues. BTW, Kevin, this is a very very nice amp! Congrats! Sent from my iPhone using Tapatalk

I would guess this is because he lays out the sense lines on the board going right to the rails on the phono section. I would think if you ran not only V+ and gnd, but also both sense lines separately, having the reg onboard wouldn't make a difference (shunt PSU only). The GRLV is extremely low noise (see thread for screen room measurements), so I am hoping that just using GRLV (or dual mono) will be as low noise, maybe lower, than the shunts are. I did lay out his shunt on a separate board which would fit just like his single board, but have very short jumpers to the phono board, in case I think I am wrong.

Would it be a better idea to use the LSK489 (and LSJ689 for those needing 2SJ109)? And BTW, does anyone actually have the LSJ689 in stock?

Here is an updated spice file per Kevin's latest schematic (pls check). Still shows -51mV without the opamp. I guess the current mirrors purpose is just to take the servo out of the audio signal path, and not about offset without the servo? CFP2 1.10.zip

Those were dual BJTs, not JFETs, that Justin bought. They are the dual version of the 2SA970/2SC2240. Sent from my iPhone using Tapatalk

1. I have BOMs for both and the GRLV as well at home and can post or send tonight 2. Covered. My BOM has a “calculator” for this built in 3. Yes, you can use J74/K170 or equivalents. C-> D, B -> G, E -> S. Will plug right into the dip14 socket if you wish. 4. Maybe regarding the full vs. the mini. The mini uses the same devices, but the PSU is done using Meanwell AC/DC bricks 5. I am thinking about selling the mini boards and pots that I have (2). As for versions, the last GB earlier this year run by sbeylo would give you a handle on board versions. The MPSW06/56 thru hole devices are discontinued and not generally available so SMT with the PZTA devices would be the way to go. Both are setup to use the THAT340 for input. Sent from my iPhone using Tapatalk

Looks like you have the servo input going into the noninverting pin of the opamp? Is that right? Sent from my iPhone using Tapatalk

A 2x30Vac SumR is what I am using on mine. The Antek transformers seem to work well also, and much cheaper. Sent from my iPhone using Tapatalk You can do anything you want Whether it is a good idea or not is another matter. I know I asked Kevin a number of pages ago about using ceramics here and he said he couldn’t guarantee that it would meet the noise specs that he had measured. I would suspect electrolytic would have pretty abysmal performance here. Much higher ESR and leakage I would think. Sent from my iPhone using Tapatalk

Here's a revised ltspice model with the revisions made (I think, someone check this as it was done vs. the gerber file). The current mirrors get the offset down to ~10mV without the servo opamp connected. CFP2 v1.10.zip

Yes. Dale RN60s are military rated, and will handle twice the power that they are rated for.

I know the Salas stuff is well thought of on diyaudio. Normally a balanced Dynahi would use two GRLVs. I don’t think Kevin is a proponent of shunt regulators but I’ll let him weigh in. I am planning on building Salas’ Simplistic phono stage but was going to use a GRLV plus PSU (or maybe dual mono GRLV plusses) for this instead of the included Salas shunt. I did my own board layout with the phono only. The GRLV is very low noise. Sent from my iPhone using Tapatalk

Wasn’t quite sure where to put this so... Ran across a thread on diyaudio for an all tube I/v stage for an ESS9038. I haven’t looked at the chip, but I thought most of the ESS dacs were either v out or could be configured for either? At any rate, I would suspect this is good in a not good way Pure Tube i/V for ES9038PRO-9028, 9018, AKM... http://www.diyaudio.com/forums/showthread.php?p=5259820 Sent from my iPhone using Tapatalk

Happy birthday Gene! Sent from my iPhone using Tapatalk

Yes

Damn! RIP Charles! Sent from my iPhone using Tapatalk

That was quick Kevin Sent from my iPhone using Tapatalk

I had just run across them on diyaudio and hadn’t looked at them closely. Sent from my iPhone using Tapatalk

JFETs... anyone look at ZVP3310 and ZVN3310 as possible J74/K170 replacements?

B grade if going with Linear Systems. Most of the Toshibas used were BL grade. And yes you might be ahead to just use the current boards rather than hunting the stuff down for these. Sent from my iPhone using Tapatalk

Agree with sbeylo. The gain resistors in your silk above are the 200k/10k and cap next to them. Some of the sand shown could be problematic: 2sa1145/2sc2705 2sa1358/2sc3421 2sa1349/2sc3381 Sent from my iPhone using Tapatalk