Stereomour Troubleshooting

[Filthymidget]

I finished assembling my Stereomour amp but the tubes failed to glow.  All my resistance checks passed.  The voltage check is measuring 2.5v AC between A1 and A4, likewise with C1 and C4.  My 12AT7 tube in the nine pin socket gets warm but doesn't glow and neither do the 2A3's.  Where do i begin?

 

[JC]

Have you checked in a darkened room?  If your heater/filament Voltages are showing up on the correct pins of the sockets, and there is warmth, it is hard to imagine a situation where the heater/filaments are not working on all three tubes.  Sometimes the glow can be pretty subtle, and on the miniature tube, of course, it's mostly inside of the cathodes.

How are your other Voltages?  If they are within tolerance, your tubes pretty much have to be at operating temperature.

 

[Grainger49]

JC has got it.  Tubes don't often glow well in the light.  Last week I thought there was a problem with the 2A3 tube in my left amp since the heater didn't glow.  Last night I remembered to check and everything is fine.  I just couldn't see the glow in daylight.

There is also a nice blue glow at the top of the tube.  I think it looks cool!

 

[Thoburn]

Hi,

My tubes do not glow if there is any sort of light in the room. It worried me at first, but my Stereomour makes glorious music anyway.

 

[Grainger49]

If the tubes get warm then there is a glow in the right place even if you can't see it.

 

[Filthymidget]

Thanks guys!!  It helped to put the tubes in the right pins!  That's what I get for wanting the red 2A3 label facing forward!  I'm a rookie!