VHT Pitbull 45 Cuts Out

[g1]

It doesn't settle, it keeps cycling.

Try from ground to the cap - terminal, then from ground to cap + terminal.

[ca7922303]

Try from ground to the cap - terminal, then from ground to cap + terminal.

Ground to cap (-)(000)
Ground to cap (+)(1008)
Photo shows setting on Commercial Electric (MAS830B) DMM.

[ca7922303]

Take it off autorange an you should get a better measurement.
nosaj

Took it off autorange and got (OL) both positive and negative ends on caps. Used a non autoranging DMM on post #17.

[g1]

Ground to cap (-)(000)
Ground to cap (+)(1008)
Photo shows setting on Commercial Electric (MAS830B) DMM.

Seems this is a meter that can't measure AC volts when DC is present. Try measuring a 9V battery with the meter set to AC volts, a decent quality meter should measure 0VAC.

[nosaj]

I will mention even if it is irrelevant but when i was starting out a weak battery in my dvm gave me fits for a while.
nosaj

[The Dude]

Ground to cap (-)(000)
Ground to cap (+)(1008)
Photo shows setting on Commercial Electric (MAS830B) DMM.

The fact that your meter shows 1,006V on the 600V range should tell you that something isn't right with the readings.
I agree with Jon (post #3) - check bias.

[ca7922303]

Seems this is a meter that can't measure AC volts when DC is present. Try measuring a 9V battery with the meter set to AC volts, a decent quality meter should measure 0VAC.

9v battery with meter set to ac vo lts(photo).

[g1]

9v battery with meter set to ac vo lts(photo).

That is not the meter from post #17.

[ca7922303]

That is not the meter from post #17.

Yeah, the green one from post #17 reads (019) on the 9v battery, so I went back to the one I was using at first and it does read (0.00vac) on the 9v battery. But this is the one that is reading from (0.06-117 vac). Just tried it from ground to - (0.00vac) and ground to + (let's call it 25.3vac). It's not a steady reading, but it's the one I keep seeing in the middle and it would be around 5% of the (460vdc) I'm getting on the (500v) filter caps.

[nosaj]

ripple should be less than 1 volt preferably less than half a volt.
nosaj

[ca7922303]

ripple should be less than 1 volt preferably less than half a volt.
nosaj

The first number I see when it's cycling is (0.06vac), then (25vac), then (117vac).

[nosaj]

i suggest getting a meter you can trust. Even an electricians fluke 117 would be ok as i used one before getting an 87. A meter you can trust should be above all your most important purchase.
nosaj

[g1]

ripple should be less than 1 volt preferably less than half a volt.
nosaj

We are talking about the main filter caps in a tube amp. Here is a direct quote from The Valve Wizard:

"The ripple voltage is often expressed as a percentage of the maximum DC voltage. A typical figure might be 10% for a push-pull amp or 5% for a single-ended amp, though this is highly dependent on individual circuit requirements of course. Thus if we were aiming for a 400Vdc supply with 5% ripple we would want no more than 400×0.05 = 20Vpp ripple voltage."
https://www.valvewizard.co.uk/smoothing.html

I'm not sure why we're chasing ripple in this thread, I think he has a B+ with a stable DC voltage of expected amount and there is no excess hum reported.
The oddball AC voltages he is reading seem to be more of a test equipment issue, but it would be good to get that sorted out so he can make proper ripple measurements in the future.

[nosaj]

i had mentioned it post 2 and then OP answered it sometime later and his measurements have been quite confusing. So at best we have uncovered faulty test equipment.
nosaj

[The Dude]

............I'm not sure why we're chasing ripple in this thread, I think he has a B+ with a stable DC voltage of expected amount and there is no excess hum reported.......

^^^^That.