Triode Electronics 6AU6 driver board for Stereo 70

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Triode Electronics 6AU6 driver board for Stereo 70

Postby burnedfingers » Sun Jan 13, 2008 10:01 am

I was looking at the Triode site and noticed they have a 6AU6 driver board.

Would anyone have the schematic for it?
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Postby burnedfingers » Mon Jan 14, 2008 6:00 am

I've looked at all the information that I have downloaded so far and I don't have it in anything.
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Postby Shannon Parks » Mon Jan 14, 2008 6:16 am

I would guess that this is Sheldon Stokes' board. I looked at the PDF on his website, and the schematic is indeed not in the manual. Maybe you could email him? His website is here:
http://www.quadesl.com/index.html
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Postby TerrySmith » Mon Jan 14, 2008 10:23 am

Here is a schematic, looks to be the same basic circuit as stock.

http://site.triodestore.com/ST70Instructions.pdf
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Postby burnedfingers » Wed Jan 16, 2008 5:33 am

separks,

The quadesl.com site worked once and now the area I want to look at won't function. At least it worked one time.

TerrySmith,

Thanks for the link. I am assembling all the information about all the stock dynaco stuff in one notebook and all the available aftermarket circuits and add ons in another. I am still on the fence as to what aftermarket board I will put in my 70. All of this helps to make an informed decision after being able to view the different schematics and tube choices.

Thanks
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Postby Blackburn Audio » Thu Jan 17, 2008 11:50 am

The schematic for the 6AU6 board is the same as our EF86 board except that the plate resistors are changed from 220k to 330k. This board was done by sheldon at SDS Labs. We still need to do some tweaking of the values for the 6AU6 versions since the measured distortion is higher than our EF86 version. I haven't gotten much time to tinker around with it but if anybody has I would be interested to hear their results. Basically the first time I installed on of these boards with the stock values given to us by sheldon the biasing of the DC coupling was not right and by changing the plate resistor to 330k we got in back in range but the operating point needs to be adjusting by fiddling with the cathode and screen resistors to get the best linearity out of it. In my opinion these boards don't sound as good as the EF86 version but with a little tweaking I think they could come close. The nice thing about these boards is that you can roll quite a few different tubes that are compatible with the 7BK and 7CM basing that are readily available and cheap, everybodys got a handfull of 6AU6's laying around in their plinker box. If anybody has feedback on rolling other tubes besides the 6AU6 I would be interested to hear the results.

-Matt at Triode
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