Hight Voltage V1-V3

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iFrancisG
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Hight Voltage V1-V3

Post by iFrancisG » Fri Jul 10, 2015 6:20 pm

Hi there
I just finished a plexi 50 W kit after preliminary test I found the plate voltage are way higher than those written in the Metro 50 watt plexi kit voltage chart.
I got:

v1 1)160V 6)212V
v2 1)170V 6)305V
v3 1)350V 6)352V
Im using Classic Tone transfo, B+ is 450V, NOS Mustard caps, brand new 12ax7s


Any hints would be helpful

Thanks

SDM
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Re: Hight Voltage V1-V3

Post by SDM » Mon Jul 13, 2015 12:36 am

In case you haven't solved this yet,

V1 and V2 voltages look appropriate in relation to how things are listed. V3 is an issue, the most common cause of that issue is accidentally using a 470K resistor for the PI cathodes rather than a 470 OHM resistor.

So, on V3, follow where the wire that connects to pins 3 and 8 goes to on the board. That resistor it meets there needs to be 470 Ohms. Check that first.

iFrancisG
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Re: Hight Voltage V1-V3

Post by iFrancisG » Fri Jul 17, 2015 5:49 am

Hey
I re checked voltage on v1 to v3 with power tubes in this time, voltage are now way closer to those in the chart but yeah V3 is an issue, ill check resistor value.
Its my first built so im quite nervous about it.
Thanks for the tip :)

iFrancisG
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Re: Hight Voltage V1-V3

Post by iFrancisG » Fri Jul 17, 2015 11:19 pm

I changed the resistor and now voltage are closer to the chart value and now sound as it should
I'll check input/volume I cause there is sound even when the volume is closed.

Thanks :)

Elad E
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Re: Hight Voltage V1-V3

Post by Elad E » Sat Aug 01, 2015 6:36 am

how loud is the volume you get when volume pot is completely off?
IME, there is always some minimal sound going through when volume is on "0" on every tube amp I tried.

iFrancisG
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Re: Hight Voltage V1-V3

Post by iFrancisG » Fri Aug 07, 2015 12:17 pm

Hard to tell, I would say too loud, but i ned to plug it in a decent cab to evaluate.

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