"Heresy"

[Clyde]

I think I'll call her "Heresy". Not quite finished, still waiting for PEC pots and a few other little things. I wonder how she'll sound. At least it's a proven design. I've been doing a lot of original circuits lately and the outcomes are always tweak-heavy. I hope you guys aren't too upset with me.

http://www3.telus.net/bgill1/IMG_3049.JPG

[Zippy]

Could you make the ground bus any longer???

[Clyde]

Nobody was happier than I when the price of copper plummeted. Ha.

[moonrock]

Nice build Clyde. Hey what type of eyelets are those? Are the tabs part of the eyelet? Thanks,
Bruce

[Clyde]

Hi Bruce,
The boards are available from AES, or CE if you have a wholesale account.
The tabs are moveable, the ones that are too loose I solder to the eyelets or
just give the eyelets a firm tap to tighten things up. You can rotate the tabs to join them or bend them up to take more leads, etc., I find them very handy.

[Structo]

Somebody said that Apex Jr. sells those tag boards.
He doesn't have them listed so I suppose a phone call would be in order.

[Clyde]

Well, "Heresy" is done, fired up today, no issues, hums or buzzes. I biased her to about 47 ma, 18 watts per tube. I didn't find the amp loud at all, no blossoming feedback or insane gain, it's a rather different tone than anything I've built before, holds together at all volumes, nice even tone, good touch sensitivity but $35K???-I don't think so. Am I missing something here?

[billyz]

If the Heresy is an Express then you definitely missed something, if it's not loud and blooming sustain. send more pics of the completed amp and double check all resistor values. Like a 10k for 100k in the NFB loop ex.
Do all the voltages check out ? there is a nice voltage chart here in the files section that Ron Worley did.

[Clyde]

Hi Billy,
All values are true to the latest Express schematic. My layout is my own and I use it on all my builds as it yields a very quiet result. I'll perhaps tune some components today and replace my "start-up" tubes with some Teslas and Mullard pre's. All voltages are well within tolerances.

[billyz]

Cool,

I would definitely verify the resistor values. I say that because I had a build that was not what it should have been. I found the Feedback resistor was a 1k or 10K not 100k. It was under the shrink wrap so I missed it initially.

I too start mine up with used throw away tubes, but they still sound pretty good and I can tell if there is a problem like the one you describe.

[Clyde]

Well, me bad, cold solder joint. It's a freakin' monster now, I'm impressed.

[soma_hero]

just curious, where was the cold solder joint?

[Clyde]

It was at the junction of the .1uf input cap and the PI grid. The amp is now extremely loud and aggressive, like it should be.

[ApexJr.]

Just saw this post and I do stock tagboards at $3.95 ea

http://www.apexjr.com/images/tagboard.JPG

Steve @ Apex Jr.

[Structo]

Thanks Steve