Thank you Kerry and Ujamerstand for finding that out.

And just to clarify. I wanted to use a 500V PSU, my understanding is that it's Ok to use it for the onboard version,as long as I don't use the sa1968's, but that it will run a little hot. Is This assumption correct?

kerry is correct on all issues.

The 500 version runs only a fraction hotter than the 450 volt version.

Not an issue.

I need to do some writeups for all the various different configurations.

When i'm going to find the time for this, i have no idea.

Edited October 17, 201114 yr by kevin gilmore

We really need to get started on those clones...

Thanks Kerry.

I had a feeling there were a few resistors I needed to change the value of. I'll get those parts ordered this week, and let you know how it works.

I have a bunch of matched 2SK170 pairs (Idss matched at room temp) I am thinking of using on the amp boards. From your experience, how important is thermally coupling the JFET pairs? The other option would be to buy some LSK389's.

you should be fine without having to glue them together.

Its more important on the dynamic amps where a little DC can

cause major trouble.

The lsk389 does have a bit less noise.

When I built my reg. kgss, I set the input fets close to each other, but didn't bother gluing them. The dc offset never got too out of hand. It did move a bit more than I liked during warm-up, but it was still well within safe limits.

Just realized there isn't a 490K for the Xicon. You can use the 487K or you can leave the 442K and switch the 20K to an 18K. Either will get you close to 500V.

I swapped out R6 and R16 with 18K resistors (left R5, R15, R29, R30 at 442K), and I'm now getting +/-504V. The bias is also nice and stable at 580V without the voltage multiplier. Seems like my 500V power supplies are working well.

Edited October 23, 201114 yr by Horio

That is better than 1% accuracy which is all you should expect unless you get silly

and hand match the parts.

Great job, Greg. Sounds like you are getting close to having them make a little music.

Great job. Congratulations

Got my panels back from Front Panel Express, and they look great. I had them do the drilling/tapping for the heatsink mounted semi's. I'll try and post some pictures of that setup this weekend, when I start assembling the amp. Here's the front panel (thanks to ujamerstand for the layout).

hotdamn. They turned out great! How does the stax jack fit from the back?

Theres a typo I just noticed..."Electostatic"...missing 'r'. Looks nice though!

Oopsie!

... Just noticed it on my panel too. Man, that's an $120 mistake right there. Damn.

electo-static. I can live with that.

nothing a little stickon with a ^ and a tilted R won't fix.

Edited October 25, 201114 yr by kevin gilmore

Theres a typo I just noticed..."Electostatic"...missing 'r'. Looks nice though!

Oh snap! Not sure how I missed that one... I must have been to worried about the cavities and all the holes lining up correctly. Oh well.

The stack jack fits great on the rear side of the panel. The blind tapped holes all lined up perfectly.

Edited October 25, 201114 yr by Horio

Nice front panel!

Nice job on the panel. What are all of the epsilon 24s for?

The epsilon 24's are going to run the anti-vandal momentary power switch and power relay.

Looks great Greg. I looked at Yun's numerous panel layouts a few times and I never noticed the typo either (reminds me of that psychology trick where the mind will read the words properly as long as the first and last letters of most words are correct)

Guess we'll be taking a microscope and have our glasses on for the T2 one

I like the font chosen for “KGSSHV” and “AMPLIFIER”.

Electostatic amplifiers goes to eleven!

I like the front panels, too. Well done!

Electostatic amplifiers goes to eleven!

Heh, you noticed.