OTL Asylum

Fired up the amp with variac and dim bulb tester...nothing

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djn

In Reply to: RE: How to fire up a 20 OTL??? posted by djn on April 08, 2020 at 14:10:05

The bulb started coming up at around 30v and just kept getting brighter as I increased the voltage and stayed bright. No tube filaments lit up. So that is a dead short somewhere right?.

Follow Ups:

The tubes can't be in the amp when you do the light bulb thing. - Ralph 09:14:15 04/20/20 (0)
The load will light up the bulb otherwise!
RE: Fired up the amp with variac and dim bulb tester...nothing - Cory M. 05:10:08 04/20/20 (1)
Yep, sounds like a dead short if that's all that's happening. The tubes' filaments probably wouldn't be visible 'til around 70 volts. Did you bring it up to full power? Excuse the question, but the incandescent bulb is wired in series with the AC output socket, right? (The duplex receptacle has me guessing).

Cory
- RE: Fired up the amp with variac and dim bulb tester...nothing - djn 06:07:14 04/20/20 (0)
  Yes, in series. Here is the schematic I used.

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