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Hello All,
First 18 Watt TMB build and I have some questions about some voltages that don't seem in line. Let me say that the amp seems to be operating fine and sounds fantastic.

It is basically the Ceri@tone layout without the Diode setup on the Rectifier tube. Mojo trannies.
Tubes are Electro Harmonix 6CA4, Ruby EL84CZ, Ruby 12AX7AC7 HG, Ruby 7025SS HG, and an EH12AX7 PI.

I installed a Tube/SS rectifier setup with a switch. IN4007 off of pins 1 and 7 V6 to Pin 6 to one side of switch, and a wire from pin 3 to switch. Voltages are-

V6- Pin 1-7= 301v
Pin 3= 370v, 392v SS

V4 and V5- Pin 3=8.2v, 9.2 SS
Pin 7= 247v, 262v SS
Pin 9= 257v, 272v SS

Curious as to why V6 pin 3 seems high, and V4-V5 voltages seem low. I didn't check V1-V3 since I did the rec mod. Thoughts?

Thanks in advance!

Mike

I pretty sure pin 6 as with all other unused pins of an ez81 / 6ca4 are internal connections. So you probably don't want to use pin 6 as a tag point. But what you want to do is us a tag board for this instead. And looking at the Ceri@tone layout the diodes don't seem to be hooked to a rectifer switch. but along with the cap they seem to be a safety feature (could be wrong about the last part)

Thanks Saz,
Yes that diode configuration is a protective circuit. I did not employ that, I used a mod I found for the tube/ss switching. Upon further review, they used pin 9, not pin 6. I am going to use an isolated tag point and recheck things. Thanks!

Fixed! On initial fireup the resistor between the positive legs of the big cap can was DOA. So I replaced it and the amp worked but with strange voltages. I measured each side of the cap and was getting 366v on the standby side but only 250 on the output side. So I replaced the capacitor and all is good! Bad cap out of the box I'm thinking, took out the resistor on initial power up.