Vox VT15 stuck in power up loop.

[drewl]

Hmm, thought I solved this.

These amps sometimes have a problem where it will randomly go into power up mode, where the lights flash in sequence and it gets stuck in this loop.

Sometimes at power up, other times while it's been on for a bit.

Anyone ever find a real cause, or random DSP failure?

There's another model that fails where it Powers up but doesn't pass signal.
By connecting a chip pin to Vcc, it fixes the proble
I can't find my notes on that, but I was wondering if there was a similiar fix for these someone found.

Anyway, I'll pull it apart and see what I can find.

It was working all week and just crapped out again.

[drewl]

Finally found the right schematic for this.

Re-worked the reset circuit and so far it seems to be working properly, we'll see if it holds.

[Jazz P Bass]

Cool!

[J M Fahey]

Funny that kids buy one of these, and think "hey , I have a 30W VOX" ... same as Queen, Beatles, Status Quo, etc.

"Small difference" considering the real one has 4 x EL84 to begin with but more important a 3X larger cabinet with two impressive >100dB VOX Blue speakers, which enable it to play side by side along the loudest drummer or fill a Club on its own, while a humble TDA2050 driving a, what? ... 94/96 dB generic chinese 10" speaker will struggle (to put it politely).

Oh, but it has a 12AX7EH, suppose that saves the deal.

The sheer SPL and "cut through noise" difference if played side by side says it all.

That said, the Digital ones sound very good and are very versatile when recording.

Why not? ... after all they *are* Korg pedalboards with, in my view, a monitor small amp and speaker attached for convenience.

Of course, dressed in iconic Tolex and grill cloth.

[drewl]

Ha,ha,. Complete with an LED to make the tube glow.


If I find a dead SS Cambridge or Pathfinder I'll guy it and turn it into a tube amp.

[Kdude3]

I know this is old thread, but I have the exact same problem with my VT15. It’s stuck on power and displays an LED sequence. What did you do Drewl to rework the reset circuit? My VT15 is permanently stuck on the power up sequence. I haven’t been able to find any solutions for this issue & i contacted Vox/Korg tech support and they less than helpful to say the least. Any input would be greatly appreciated. Thx