Pars

Happy Birthday!

Sure, I'd love a Metcal and I'm sure they are better than the Hakko I have. They also seem rather pricey, even on ebay. Also difficult to tell if you are getting the full soldering station or not as most sellers seem to sell everything separately.

I just looked (way) back. Amb apparently uses 2oz copper on the beta22, sigma22 and CK2III boards. The Dynafet boards were also 2oz copper. AFAIK, all of the prior GB boards (imagineering) were 1oz boards (the old Dynalo rev B and C boards, the original Dynahi, etc.) I'm not in for any dynalo mini boards, but this is from the experience of building 3 of them, plus talking to Kerry. I may fuck around with one of the spare boards I have and some new parts (which I still have). Reflow oven seems to be the best bet and I may commandeer the toaster oven briefly again. This worked pretty well for putting the tantalum caps on the underside of the last board I did. Even with my Hakko 936 and a 3.2mm chisel bit, cranked up to 750F +, I had to use a hot air rework station to get some of the connections to ground to flow well.

As for board copper weight, I believe it is based on trace width/cross section and current capability, but I could be wrong.

Hehe! These are being sold as Mjolnir Audio? Or did they just "use" your pics?

I think they are still talking 2oz for the group buy. I don't know what the basis for the current moar is better philosophy on copper weight is. All of the older GBs (dynalo, dynahi, etc.) were 1oz boards, many of which I have reworked several times with no problems. Some boards need the heavier copper (Stax stuff, the GRLV/GRHV). Most don't.

The links I posted above will take you to the current files. cfa2cmirror is the schematic and the latest edition of the CFA2, and is the basis for the boards in the GB. Kevin changed the servo layout and how it feeds back into the amp as some of us found the servo in the original to be audible. I've attached the original CFP2 BOM, and a BOM for the GRLV. I don't recall whether I updated the CFP2 BOM for the latest, but it should be close. The original 1 ohm resistors were wirewound; this BOM has the 3W Vishay metal film in it which is a better choice. CFP2 BOM.xlsx GR LV BOM_Sep26.xls

Agreed. I know mypasswordis and cspirou were two who managed it. I was trying to use the advice I got from mypasswordis in my last attempt. I would think the lighter copper weight on the GB boards would make this more doable. Many of the pins on the regs go to ground, and on the 3oz boards, difficult to heat. Kerry's prototype board that he did was 1oz copper, and he told me via pm that he doesn't think the board needs to be any heavier than that. I would agree.

I messed around on another board without any success (had a couple extra that I had forgotten about). The chip may be fried after my earlier attempts as well. I kind of lost interest in it also, probably doesn't help.

I seem to be the only one participating in this thread... hmmm Just got the heatsinks today (45x35mm). After reading what some have said regarding the heatsinks tunneling heat down the transistor rows, I'm considering drilling 2-3 holes in the heatsinks along the rows to allow them to vent. I'll run the thermal heatsink tape in rows just on top of the transistors. Anyone think this is a bad idea?

Stay warm and safe. Looks nasty, though my wife would think it was pretty (other than the downed limbs)

Paid. Thanks!

This is the schematic. As for your other questions, look at the golden reference LV thread and the "And now for something completely different" thread. That thread devolves into discussion of two or more amps. As far as build threads, there aren't any, nor are there guides, etc. You have to read the threads and take your best guess on some things. Kevin retired from Northwestern University, so none of those links work. The current archives are here: Documents: https://drive.google.com/drive/folders/0B7egryukiT7_TFlEQlBRejdVdDQ Gerbers: https://drive.google.com/drive/folders/0B_iJFfZStuVhSE5nOHBVdTByR1k cfa2cmirror.PDF

Happy Birthday!

Thanks Gael. Are the 4 corner screws going to be countersunk? Also, would you consider offering versions of the fronts/backs with countersunk screws for those of us who aren't going to use the Neutrik screws?

Here are gerber images of goldenreference6d: and goldenreferencelargecap: 6d may be closer to what people were looking for. The largecap version does not support the rectifier boards, but the TO220s rectifiers it uses are SiC diodes (which are schottky as well).

Don't think so. The one I posted above is the same as goldenreference6, but has dual outputs. The version with 35mm caps is goldenreferencelargecap.zip? That one has the 35mm caps, dual outputs. It is only setup for 1 bridge (center tapped) and TO-220 SiC diodes only. That one would be fine with me, but others may not want that one.

Steve, Is the GRLV version you are doing the one with the dual output blocks? This is the one I would prefer as I've had to modify a couple of mine for greater output capability. I attached the gerber file for this one (6d version). Not sure what your noted "v6 combined" in the signup spreadsheet refers to. goldenreference6d.zip

I think the prototype is probably a good idea unless you are satisfied with the design and are also convinced that the manufacturer will do everything as asked/requested. I'm good with the additional if you decide to get a prototype. These are still anodized after machining? Also, have you posted the final design? Thanks for all of your work on this!

OK... https://www.electrokit.com/en/lme49610ts.49676 This place seems to have them (Sweden), at ~$5.70 each. Don't know what shipping will run. And this place: http://www.kynix.com/Detail/223389/LME49610.html EDIT: a couple of chinese sellers on ebay as well, but more than $5 apiece. A related item (according to ebay) had me laughing: CL-A03 PRO high with fever portable amp

Is the +/-22V the one you're looking for? Partsconnexion seems to have some...

Also, I wonder how the KSA992FTA/KSC1845FTA would work in this? F grade is supposed to have hFe 300-600, and Mouser has them. EDIT: pinout is different

BTA is the newer B designation. Just wondering if MPSA06/56 could be used in place of these? Pinout is backwards (EBC vs. CBE for BCs).

Didn't Amb and Alex kinda work together at one time? Cavalli-Kan Kumisa III?

Nice! Looks like you have some sort of drill press vise? I need to get one better than the POS Harbor Freight one I have. Yours looks nice! Is it an add-on?