Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Reduction => Topic started by: jimiclow on June 15, 2013, 04:21:06 PM
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I just finished my build.
All resistance checked.
Resistance check on terminals 10 and 23 should have read 47.5K, not 475K.
I also found out that the triode is reversed in A and B. I think this doesn't matter since it's a similar triode.
I haven't checked the voltages.
I ended up using a Mundorf 0.1uf for the coupling and Clarity cap 1.0uf for the output.
As usual, the manual is well written.
Thanks.
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Hello Jim,
Terminals 10 and 23 should be connected to ground throught a 475K resistor, as is pictured, but it looks like there is an error and an extra pair of 47.5K resistors have been supplied and directed to be installed here instead.
Luckily, this isn't particularly detrimental to the performance of the amplifier, but for peace of mind we can send you a replacement pair if you like, or you can replace these with resistors between 100K and 500K.
-PB
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Paul,
I think he means its a typo in the manual; he read the correct should 475KΩ value at the terminals, but the manual incorrectly says 47.5KΩ. Correction: I just looked at the manual and saw the error on page 32. I'll fix it for later versions of the manual. Also this post reminded me I meant to ask if there was a reason for the swapped triodes. Any insight you'd care to provide?
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The triode reversal had a lot to do with the layout.
We could have moved one of the RCA jacks to the other side of its 9 pin socket, leading to a strange staggered look of the RCA jacks on the top of the chassis plate.
Another option was to rotate one of the sockets 180 degrees, which would disturb the symmetry of the screws on the top of the chassis plate, and it ended up causing an inconvenient amount of high voltage resistors crossing low voltage resistors.
Since the triode halves are idential in the 6922, the reversal is trivial.
-PB
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Thanks for the replies.
I just checked the schematic and page 32. The resistor should have been 475K instead of 47.5K. The picture is correct though.
I'll email Eileen for the part .
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Thanks for the replies.
I just checked the schematic and page 32. The resistor should have been 475K instead of 47.5K. The picture is correct though.
I'll email Eileen for the part .
Shoot an e-mail to replacementparts (at) bottlehead (dot) com, as Eileen will be on vacation next week, and we can send one out to you on Monday in her absence.
-PB