New 12XXX brought to life

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Twistingcrow
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New 12XXX brought to life

Post by Twistingcrow » Wed Jul 18, 2012 3:13 am

Hi!
Here's my latest build.
Marstran T2562 PT
Marstran C1998 OT
Marstran C1999 3H choke
Brian's boards
Valvestorm's components
Metro chassis and plates

The only thing I'm a little concerned about is the B+ I get, measured at pins 3 of the power tubes. I have 528VDC there with power tubes installed... The amp sounds great anyway, I played it for three hours at a stretch but maybe I should find a way to reduce that? The tubes are biased at 33mA. I have a 228V wall voltage and the amp is wired for 230V operation... What do you think?
Thanks!

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vanhalen5150
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Re: New 12XXX brought to life

Post by vanhalen5150 » Wed Jul 18, 2012 7:42 am

Post a chart of all your pin values. That would be considered a bit high with North American wall voltage, but maybe thats normal with the higher 230.
12000 Metro Kit

vh junkie
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Re: New 12XXX brought to life

Post by vh junkie » Wed Jul 18, 2012 8:02 am

Might want to post over on the Marstran forum for ideas. I assume your PT is not one with the lower output voltage taps. His 1203-80 has the lower taps. You could try wiring it for 240v... that would lower the output some, but not a lot.
"With all due respect, sir, you're beginning to bore the hell out of me."
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Twistingcrow
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Re: New 12XXX brought to life

Post by Twistingcrow » Thu Jul 19, 2012 10:25 am

Hi.
Thanks for your input guys! Brian at Marstran answered me and said " your B+ is high but not too high". So I'll leave it as is... The amp sounds great anyway, so why bother... As musicians we should rely more on our ears, and leave the DMM for earlier steps...
Cheers!

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vanhalen5150
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Re: New 12XXX brought to life

Post by vanhalen5150 » Thu Jul 19, 2012 10:50 am

As your tubes, caps, resistors break in a bit, I'd bet your voltage will come down a little.
12000 Metro Kit

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rgorke
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Re: New 12XXX brought to life

Post by rgorke » Fri Jul 20, 2012 4:51 pm

Are you using a variac?
"If you make a mistake, do it twice and smile and let people think you meant it." Jan Van Halen.

Twistingcrow
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Re: New 12XXX brought to life

Post by Twistingcrow » Fri Jul 20, 2012 5:01 pm

Nope...

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