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August 24, 2019, 07:27:53 AM

Author Topic: Eros 2 - Shunt Regulator Voltage Question  (Read 559 times)

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Offline armaloney

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Re: Eros 2 - Shunt Regulator Voltage Question
« Reply #15 on: March 09, 2019, 03:53:34 PM »
Update:

I ordered a replacement shunt regulator and assembled that.  Upon testing, I had the same result as on the original build (about 230V on A tab, kregA at 1.9V, 216V on B tab, kregB at 2.9V).

This led me to believe that the issue was not in the shunt regulator, as it seemed unlikely to have the same issue twice.  I swapped out the 12AU7 for another that I have been using in my Crack.  Upon doing so, I measured roughly 216 V on both sides of the board, and kreg around 3V on each side.  Seems the tube sent with the Eros may have been the culprit all along.
Andrew M.

Online Paul Birkeland

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Re: Eros 2 - Shunt Regulator Voltage Question
« Reply #16 on: March 10, 2019, 07:05:48 AM »
I would suggest reviewing the wired connection between pins 4 and 5 on the 12AU7 socket.  When I've run into problems like you're describing, it will sometimes simply be that this particular connection is not well made, so only half of the 12AU7 is heating (and only half of the regulator is working).

When installing a new tube, you may just jostle a loose connection enough to make the amp work, so it is certainly worth it to go back and have a look.

-PB
Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man