Yet another PCB-less Matsumin Valvevaster question

[Marcos - Munky]

It could be the power supply. Try to use another one (check the plug pinout).

[MontyS12]

What I'm plugging it into is just a standard 9v tap from my pedal board.

[MontyS12]

Ok. Swapped the DC power jack and i got the same behavior. With pedal plugged in and no tube, I get 9.04v. With tube inserted and plugged in to power, I get a reading of 8.61v

[Marcos - Munky]

How much current is the tap of your pedalboard capable to output? Tube circuits requires way more current than opamp circuits, so maybe your power supply can't handle the current.

[MontyS12]

Ah, good question. Apparently only 100ma or 200ma depending on which taps are used....

[MontyS12]

yeah, I've had it on a 600ma adapter separate from my pedalboard and it has not repeated the behavior. Hope that was it. Had complete forgotten that milliamperage on my dc brick was so low...

[Marcos - Munky]

So that's probably the cause of the issue. It's not your dc brick that have low amperage, it's the tube that draws too much current. A tube screamer draws about 7.5mA, so you can power 13 tube screamers with the 100mA tap. On the other hand, a tube draws 150mA just for the heaters when you power them with 12V.