Tube Spring Reverb Trouble shoot

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sr1200

Well-known member
Joined
Dec 6, 2010
Messages
2,112
Location
Long Island, NY USA
I recently put together a unit based on the schematic/layout below:

https://www.tedweber.com/media/kits/5g15_layout.jpg

https://www.tedweber.com/media/kits/5g15_schem.jpg

I have pretty good voltages except at the 12at7 pin 1 where im getting around 120v instead of 105 (a little high). 
I noticed that the 12AT7 tube gets warm, (hot if left on for a while) but i dont see a filament glow. Is this normal?

All i get out of the unit is a strange (non 60hz) hum.  It goes away if i turn the mix all the way down, but does not pass audio from the input.  I will be trying to trace out the signal tonight on the scope.  Was just wondering if anyone had any experience building one of these and if they've seen similar issues or had some insight on what to look for.

EDIT: I would ask on webers forum, but it seems to no longer exist...

Thanks  :D
 
Do the other tubes have glowing filaments?  Have you tried swapping out the 12AT7?  If it is getting warm, the filament might just not be visible or you have wired it as 12v instead of 6v.  Are pins 4+5 tied together?
 
sr1200 said:
Yes pins are tied.  I have it wired exactly as the diagram shows.  edit: and yes the other two tubes are glowing.

Then it is likely that either the 12AT7 is bad or you have made an error, poor solder joint, etc.  Also worth checking that  the reverb pan is wired right way around, done that before  ::)
 
Post also your problem into this forum:

https://el34world.com/Forum/index.php

it's more specific towards the gear you built.

Quite nice and helpfull people over there, PRR is one  of the regulars also
 
Thanks for the link.  I actually got the unit running, theres some things on the ground scheme that i have to figure out to get rid of some noise.  These amp guys are hot on grounding... its like a religion to some of these folks.
 
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