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Both the ssdyna 15 and 17 files are SMT, didn't check the others. The top image of the 15 file is shown below (dynalobal15.zip) The MPSW thru-hole transistors were discontinued, forcing the move to SMT.

Schematic for the SMT SS Dynalo, not the mini.

That sounds similar to a problem I had with one of mine (2 pages back in this thread) when I brought it up on a variac. D1 was lit, but D9 not. Input voltage was too low and the opamp was locking up. Is your transformer actually putting out 16Vac? That should be plenty for a 15Vdc output.

Same number of output devices (8 per +/- channel, or 16 per L/R channel). Mini uses 16 PZTA06/56 and 6 MMBTA06/56. Full uses 22 MPSW06/56 (thru-hole, not available anymore), or 22 PZTA06/56 (16 output, 6 biasing/VAS) for the SMT version (current). I don't see a schematic for this version (the thru-hole schematic is still on Kevin's site).

Got both boards up and running with mods 1 and 2 above. Ran RMAA on it at 150mA, 100mA and 75mA bias. I think 150mA is probably the best. See what any of you think of the plots attached. Also brought my T50RPs down and listened to some tracks on it. I think this may be my favorite amp! I'll have to do more listening though. Dynafet_both_75_330L.pdf Dynafet_both_150_330L.pdf Dynafet_both_150_33L.pdf

Thanks all, got a couple of BOMs now. You guys don't like putting the output devices in your BOMs, eh? EDIT: also, can MJF15030/31s be used in place of the MJE15030/31? Specs seem the same with the exception of rated for 36W instead of 50W.

Does anyone have a BOM for this (SS Dynahi)? The one that Vortex posted in the 1st post is blank, and I suspect for the Toshiba boards anyhow. Lil Knights also was for Toshiba parts.

Happy Birthday Nate! Sent from my iPhone using Tapatalk

I know the thread is 15 pages, but this info is in here multiple times. Sent from my iPhone using Tapatalk

Yes, you only change one of the two resistors. ((R8+R7)/R7) x Vref ((750 + 1500)/1500) x 10 = 15 Sent from my iPhone using Tapatalk

Happy Birthday Craig!! Sent from my iPhone using Tapatalk

Linear Systems makes one now. Trendsetter has them, and they also have the LSK389. Sent from my iPhone using Tapatalk

Hmmm... interesting.

I am planning on using 1 and 2 above on both boards (ferrites and gate zobels). Bias is currently at ~150mA. I will decrease bias to 75mA and maybe 100mA and take a look at things including RMAA results before deciding where to leave it. The outputs seem to be fine at 150mA temp wise. The buffer transistors previously mentioned run hot but that appears to be unrelated to the bias level. The sim is only showing around 8mA or so running thru any of these, so not quite sure why they are getting toasty. Because of the layout tightness, it is hard to get in to take measurements. Sent from my iPhone using Tapatalk

Yes, that was good (and intense). You kind of need to factor in the unbelievable portions (released?), but good nonetheless. Tom Hardy is something else! Sent from my iPhone using Tapatalk

Put a toggle switch in the load box (33/330) and ran RMAA on the #2 board (Cordell gate zobels only). Still looks good. I had a scope on the outputs and saw a touch of oscillation when I first fired it up. None after. So the 3 "cures" for the oscillation that I have found: Ferrite beads Cordell gate zobels Amb output zobels Board #1 has the ferrite beads. #2 has the Cordell zobels. I think I will put the beads on #2 also and the zobels on #1 and be done. Dynafet2_33_3.pdf Dynafet2_330_4.pdf

I had heard some rumblings back when these were still in production that some users were experiencing failures of the HV BGs at less than their rated voltages? Sent from my iPhone using Tapatalk

Many (many) years ago... I'd have to dig out one of my books to even remember how.

Yeah, I'll rig something up. Any suggestions? The 33 and 330 ohm that I have good?

Put in the zobels (100pf-90.9R) in which seemed to cure this problem. I haven't done much testing yet, but didn't find any oscillation. Hard to find any ground points close by on the bottom (gnd plane is on top). Closest is about 2". Put the cap right on the gate pin. Resistor and teflon tubing later (x4) and done. That is the only change (other than Vbe multiplier resistor values) that I've done to this board from std. config.

Dontcha love marketing? I was laughing reading some of the article titles and thinking how self-serving these were "Television Replaced With Black Gates is Superior to Any Ordinary TVs"... I didn't realize you could watch blackgates?

Of course the 2nd board was too good to be true. Put the 2nd pair of outputs in, oscillating to beat hell now without volume up, nothing plugged in. 70+MHz (0.7 div @ 0.2us/div). Board was acting strange even before I powered it (wasn't even plugged into AC). When I put the scope probe on the R output, it showed some fuzz on the trace. Board was plugged into all I/O. Strange. When powered, the oscillation was independent of volume setting, and with no phones plugged in. Varied at times by just approaching the bench, moving hands, etc. Fun. I'm going to try Cordell's zobels on this one first. Probably use some 100pf Wima FKPs I have with 90.9R or 120 or 150 ohms to gnd. Or I have some 33pf Mica caps. Also had noticed that I hadn't gotten the devices all the way onto the angle brackets (drilled like my dynahi ones), and recalled getting pissed at not being able to accurately hit a good center punch (Starrett) dimple with my drill press, so bought some cheap center bits from Harbor Freight. Redrilled the angle bracket for the good channel. Much better. I'll redo the other one presently. Also discovered my load box is broken; Lorlin rotary switch wasn't working correctly.

Happy Birthday Naaman!

RIP Bill Paxton... http://www.cnn.com/2017/02/26/entertainment/bill-paxton-dead/index.html?adkey=b Wow... 61 way too young.

Speaking of older electrostats, anyone recall the Marantz ones from the '70s, ES1 or something like that? My brother and I used to have a set; he may still have them. Were these any good? I can't say I recall being impressed with them.