Pars

That is channel to gnd DC offset? The +/- offset pretty much takes care of itself. I wouldn't mess around too much with the 2 trimpots by the 255R's. From what I found, you can chase your tail trying to get it closer and closer and then wind up with one of them at a near dead short and things go south quickly from there. The differences you are seeing are probably transistor variances. The resistors from the BOM are all 0.1%, so should be fairly close. The ones I built, I got offset dialed into +/-2mV without the servos in.

340mV is rather high for a mini (17mA). What does your DC offset look like without the servo opamps in? I would check the bias across every 20R resistor for starters. Reset all trimpots to midpoint (with an ohmeter) and go from there. The 2 pots by the 255R bias resistors can cause some wonkiness if you go too far in the adjustment of them (same with the full size amps).

RIP Adam Schlesinger, Fountains of Wayne co-founder. Wow... https://www.cnn.com/2020/04/01/entertainment/adam-schlesinger-dead/index.html

OLEDs in the house. UGS Muse preamp (x2). This one is for HC user DrizztDo (who I am building the Carbon for and previously built an SS Mini Dynalo for). The previous processor pic(s) were from my board (in the mini T2 build thread I believe). The 0.5mm 100 pin LQFP-100 package caused me to buy a USB microscope to see what the fuck I was doing... Jose had posted one in that thread.

Having stencils for the board wouldn't hurt...

RIP Terrence, Albert, Bill and Alex. #fuckcancer #fuckcovid19

Well, it was $48 shipped, but got it the other day. Still figuring out how to use it. Here is an ARM processor, LQFP-100 package, soldered in. I had the alignment perfect; it moved slightly when I was tacking down a couple of corner pins. I'll go thru and verify with my Fluke.

RIP Kenny

I run it on a 2012 Mac Mini i7 and it seems to work fine. 16GB Ram, 500GB SSD.

Would you be able to run Windows IE on your Mac using Wine or WineBottler? I've used this on mine to run the Windows versions of LTSpice and DipTrace. It seems to work pretty well. https://winebottler.kronenberg.org/

No shit... coding for IE? what a piece of fail.

B normally... the equivalent of the Toshiba BL grade.

Happy Birthday Al!

Good god! Those things are almost approaching what where they, K1000 AKG silliness in their looks (from the front)! Back in the '70s, my brothers and I were looking for a set of speakers and the Heil AMT-1s were the runner up (to the Infinity Monitors with the Walsh tweeters). We used a single recording for evaluation... the 1970 or so CSO/Solti Mahler 8. It wound up that we would buy the speaker that didn't break up playing it at a good* volume. The Bose 901's sadly didn't make that cut... * i.e., loud

I know that Kuei Yang Wang (Thorsten Loesch) one of the principals of Abbingdon Music Research really liked the Campfire Andromedas. He modded a set of KZ ZS6s to try to mimic them, but was given a pair of the real thing. I'd like to listen to them sometime. I modded a set of the KZs as he did, but didn't like the sound (but they did sound a lot better than stock).

Happy Birthday!

I ordered one of the microscopes that you recommended Jose. It says mid-April for delivery

Since I don't have a laptop (other than my work one) readily available, or a computer down in my workshop, I'm wondering if something like these might work better for me? https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=600X-8-LED-USB-Portable-Digital-Microscope-4-3-LCD-Screen-Tool-Zoom&_sacat=12576&LH_TitleDesc=0&_osacat=12576&_odkw=8-LED-USB-Portable-Digital-Microscope-4-3-LCD-Screen-Tool-Zoom

Damn, I might have to get something like that. I was trying to touch up a 100 pin uProcessor and am having a hard time telling what I am doing with my Optivisor. Sent from my iPhone using Tapatalk

I used KOA Speer 1/2W on everything I could. The 121R are Vishay/BC MRS25 (0.6W, 350V). I’ll either get some RN60 or Xicon 1/2W for the 174K. Sent from my iPhone using Tapatalk

Those were what was on the BOM. I’ll get some 1/2W, though I think people have built from this BOM before? Is a 350V rated part sufficient? Thanks! Sent from my iPhone using Tapatalk

Happy Birthday Nate!

Thanks Michael. Yes, I was going to get some heatsinks something like you used to bolt the angles to (as well as the PSU angles). And thanks for the tip awhile back about putting standoffs upside down for mounting the resistors, etc. to get them spaced off the board. Worked pretty well! They aren't perfect, but pretty good I think.

A pair of Carbon boards complete other than JFETs. I used Soren's pre-adjustment method on the CCS's. They all came up at 15mA initially; adjusted them to 17mA for a start. I still need to clean the boards more. These are the .6G boards and appear to have a ground plane (haven't looked at the gerbers), so all resistors, etc. are up off the board. If any of you Stax mafia dudes see anything amiss, please let me know. I was careful building these... Also, I got some pluggable connectors, Hirose DF5A (DF5A-5P-5DSA(35), DF5A-5S-5C) which are 500Vdc rated, and would fit just fine. They have one small nub or pin on the bottom, but it looks like you could either cut it off, or drill a small hole in the PCB for it.

Happy Birthday Craig! Hope you have a great one! Sent from my iPhone using Tapatalk