Pars

Same here. Single sided sandwiched with double sided blanks? I'll give you an A for creativity! I personally will stop at 2-layer, and commercial houses are so cheap anymore I don't bother with those

Would any of those handle enough current? Sent from my iPhone using Tapatalk

^ I like that phrase, Dan. Accurate Sent from my iPhone using Tapatalk

Happy Birthday!!! Sent from my iPhone using Tapatalk

Ahhh, makes sense now. Carry on

Looks really good. I like the case(s)... custom? Or off the shelf? Nice clean look.

A couple of things: A torroid transformer doesn't put out DC... it is AC Those SOIC adapters will be a nightmare if the opamps you replace the existing with are fast at all. What opamps are you replacing and why do you think they need to be replaced? FOTM?

What positive comments?

I don't think we got more than 2", if that, further west in Chicago burbs. Partly sunny and not snowing out here (right now). Robins are wondering where they fucked up, however

I'd wait til you hear from the chef...

Happy Birthday!

Payment sent.

Agreed, not worth messing with. EDIT: And I found out last night what you were talking about regarding the two DC offset pots Marc. I didn't realize they would effect the bias as well, and had one board biased >300 mA for a short time. Pulled the board and found I had one side at around 45 ohms (pot || 620 ohm R). I may replace one side with a 500 ohm resistor. This is the most stable wrt DC offset of any KG design I've built. Sent from my iPhone using Tapatalk

^ I knew I forgot something in that post... disposal of that crap

I dunno John, you do such shitty work... sure, I'd love it if you shared that

http://www.antekinc.com/as-0528-50va-28v-transformer/ Earlier in the thread (had you read it) KG said you need ~35V raw dc, so 27 * 1.414 will get you ~38V minus the diode drops for the rectifier(s). I haven't looked at the schematic, but assume a bridge, so -1.4V, so you are at about 32.6V raw DC. Might work. 27-28V transformer will get you closer. 28V Antek above would put you at (28 * 1.414) - 1.4 = 38.2V. It appears some have built this with a 25V transformer.

I figured that. Same with bipolars, normally. If someone had a matched set of these I might be interested. Should be a bunch of them out there. I know I got the set I am using from you, and had been going back thru the GB stuff and my email, but didn't find where I had talked to you about them.

Went back to the 10K/1K feedback resistors, and all is well again. I've been reading online (Cordell, IRC, others) regarding using parallel mosfets with no source ballast resistors. Nelson Pass has been talking about it as well (Burning Amp talk). I know the Counterpoint amps used to do this (and were criticized for it). This apparently is without really tightly matching the FETs, but the gate voltage/current must be matched well and the Vgs should be as well. I measured Vgs on this, and while it is matched well between pairs of devices (N-ch or P-ch), it is not between the two types. I don't see any example schematics around either. I wonder what would happen if I decreased the ballast resistors to something like 0.1 ohms...

What I/V stage is that? Sent from my iPhone using Tapatalk

Thanks Kevin! The original DynaFET used a 100R input resistor (plus 100k to gnd), with a 1K/100R feedback resistors. I've changed these to 10K/1K (left the 100R input alone). The SS balanced DynaFET showed 200K/10K for the feedback resistors. Sent from my iPhone using Tapatalk

Failure finally; switched to the std. 1K/100R feedback loop, and getting oscillation with the crap phones plugged in only when the volume is all the way down (or nearly so). Turn it up and it goes away. This looked nasty though (nice sine wave), and appears to be the right channel only causing it (unplug right output and it goes away). About 4.5MHz, 17Vpp. Also, plugged in my load box. 33R looked ok, but different oscillation with the 330R. I guess I'll just stick with the 10K/1K feedback, and figure out what to decrease the compensation to. Kevin: any issues with increasing the actual feedback resistor values 10x over your design? In poking around, I didn't get a sense of how you determine the actual values, just the ratio. The balanced dynafet design went way above this (200K/10K), though I suspect that was because of the THAT340 input.

Someone more versed can probably help you more. Since the HD is dead, no recovery partition on it to start up from (and not sure how far back on OSX that went anyhow). What version of OSX were you running? Do you have the system DVDs (or whatever they are)? This page may be of some help: http://www.idownloadblog.com/2016/02/24/how-to-start-mac-recovery-mode/

Documenting how these are configured: Vbe multiplier: R17-R18: 3.3K R62: 1K VR3: 20K R19-R20: 2K Mods: Cordell zobels: 100pf / 90.9R from gate to ground (Cordell uses 39pf / 100R) Fair-rite ferrites (2773009112)) in series with gate resistor (cut gate traces) Gate stoppers: 47R Current feedback loop: 10K / 1K / 10pf (R55 / R56 / C1). I will try going back to the stock 1K / 100R on this. I would not even consider using the mid feedback point; last time I tried it (after board was working), it oscillated badly with no phones/output plugged in. I am going to solder the jumpers in place on this.

It isn't outdated nor redundant. It is the full-size SS Dynalo, vs. the mini that Kerry did the board layout for. The schematic you posted above is for the mini.

Yes, that is the mini. The kgdynalobal9 is the full size, but is also SMT for most of it. Use with the GRLV (or Amb sigma22, etc.) PSUs, normally at +/-20V. The kgdynalobal files seem to use SMT transistors, but thru-hole resistors. These are all full size; I'm not sure which is considered to be the latest. The kgdynalobal9.zip was what was used for the recent group buy, here. 6/5/2015 9:49 AM 242761 kgdynalobal5.zip 11/2/2016 11:09 AM 4298 kgdynalobal9.PKP 2/6/2016 8:25 AM 325771 kgdynalobal9.zip 11/13/2016 6:34 AM 88083 kgdynalobal9g.zip 11/12/2016 4:20 PM 79877 kgdynalobal9G2.zip 6/23/2015 6:59 AM 237220 dynalobal12.zip 6/23/2015 6:59 AM 235328 dynalobal13.zip 6/25/2015 4:22 AM 236564 dynalobal15.zip 6/25/2015 4:22 AM 252016 dynalobal17.zip