Pars

sbeylo, it is the slots for the TKD CP2500 that you have to make sure they plate.

I ran some numbers yesterday at finer points and came up with this. I used a bench supply set for 1.007V (and had to adjust as I was running these to keep it there), feeding both deck inputs at once.. I used the same DMM on both sides (HP3468), moving the test clips at each pot position. I took the voltage from wiper to ground for each deck (V1, V2) and used 20 log(V1/V2) to calculate the dB difference. It was slightly above 0.5dB around the area that I was listening in (position 39). If I didn't do this correctly, let me know

Nah, he just said "that other forum" or something like that...

Happy Birthday Al! I hope you have a great one!

I'd adjust for max or close to the bias you are looking for (750mV??) and then measure ohms across the trimpot(s). Even though they are parallel to the 500R, you should be able to tell approximately what end of their travel they are at, and go from there as to what needs to be done.

Because of the 1k in series with the pot, the lowest you can go with the pot at minimum is ~333 ohms (1k || 500R). Normally, the 500R is replaced with a 620 or 680R because you can’t go high enough in resistance. It appears that on this amp, the problem is going low enough? If that is the case, replacing the 500R won’t do anything to solve this. I was looking at R23/34 because in the Ss Dynalo, there aren’t trimpot such as you have here. These resistor positions are what is used to change bias, unless I am not analyzing the schematics correctly. Sent from my iPhone using Tapatalk

I'll have to defer to those that have built this version of a dynahi as I have not.

No, not the ones by the trimpots (I don't think). This is the schematic I have; not sure where R23/R34 are on the board layout. I would definitely change out the 500R by the trimpots (R1 and R4 on the schematic) with the 620R or 680R. I see that there are 1K resistors in series with the trimpots; even so, you cannot get the effective resistance of 11K || 500R above ~478 ohms. With 620R, you can get it to about 586R. I wouldn't think that putting the OPA445 in should have the negative effects that you are seeing. dynahibalbjt.pdf

Had to refresh my memory on the original dynalo/dynahi. Yes, you should replace those resistors with the 620/680R to give yourself adjustment range. What do you have in for the bias resistors (R23/R34)? The schematic I have shows 100R, but I think most use 500R?

Mouser had the MJF15xxx parts in stock, but is out of the MJW2119x parts. Arrow has all of them in stock, and are reputable. I'm not sure if you could use the MJW21195/21196 instead (which Mouser does have in stock). I seem to recall Kevin saying those are fine. Looking at the datasheets for both, I can't spot any difference, but of course there must be something. https://www.head-case.org/forums/topic/12269-goldenreference-low-voltage-power-supply/?do=findComment&comment=732948

Yes, you're right, and an oversimplification on my part.

“Voiced” is the other term I see used for I assume the same thing. As in “voiced to produce the designer’s signature sound” or some such inane bullshit. If this is a tube amp with coupling caps (and between stages), etc. then there are things you can or could do. A direct coupled SS amp, not so much. Sent from my iPhone using Tapatalk

RIP Stephen Hawking!

Ugggh! Sorry Nate and other NEers!

Added some lines; hopefully didn't screw formulas up, though I'm not sure if the paid/remainder formulas at the bottom were correct to begin with.

Blue... and I would go 1.6mm on the adapters. With good sockets it takes a bit of force to install/remove these. Sent from my iPhone using Tapatalk

Kerry, I believe he was going to put 4 different THAT-340 adapters on a strip (v-score) and do them that way. LSK for both the TO71 and SOT23 packages were 2 of them. Toshiba dual FETs and the dual BJTs were the other 2.

No more up to date schematic. When in doubt, follow the board markings. Sent from my iPhone using Tapatalk

The point at 9 is 4.1815V (L) vs. 4.0713V (R). I believe this is about 0.25dB (0.23). It was definitely audible but was at the point where I initially was wondering if I was hearing things or not This is in a known amp; the TKD 4CP601 I was using doesn't exhibit this behavior, nor does a 2CP2511 25K pot I also have. I don't know if partsconnexion will do anything about it (or TKD), but I guess I will ask them and supply the data.

Shit, didn't even realize they carried them. That isn't too bad...

To give the wiring a better shot at shorting out against the case, hopefully before the owner realizes what a pile this thing is?

^Yep, thanks! I hooked up a 9V battery to the input-gnd and plotted 11 points wiper-gnd (around 15 deg rotation/point) and moved from channel to channel without varying rotation. They actually plot out pretty close. There is one point at around the 9th point where the L is louder than the R, which was probably close to where I was listening at.

^ https://www.head-case.org/forums/topic/13242-dynalo-mini-enclosure-group-buy/?do=findComment&comment=786111

I bought a TKD 2CP2500 10K from partsconnexion awhile back (when they had their 25% off sale) and just installed it yesterday and did some listening. There seems to be a channel imbalance. Any suggestions on how to run a curve on this to compare channels? Or is it simply compare and record ohm values at individual rotations at various intervals? Would I only be interested in wiper to gnd, or do I need input to wiper values as well?

Looking at ebay, this one popped up: https://www.ebay.com/itm/OKi-SmartHeat-PS-800-Single-Port-Soldering-System-Kit-Pen-Tip-Holder-PS800E-OK/132491900159?epid=2238602788&hash=item1ed921f4ff:g:Cl4AAOSw9p9adI3M It doesn't seem complete... what else would I need? This one does seem complete though: https://www.ebay.com/itm/OKi-Single-Output-Solder-System-with-SmartHeat-Six-Solder-Tips-BRAND-NEW/192469300137?hash=item2cd01073a9:g:vfsAAOSwOFBaiDfI