Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Diverted on February 21, 2019, 09:46:07 pm

Title: Eye tube question
Post by: Diverted on February 21, 2019, 09:46:07 pm

I do a lot of old radio recapping, mostly 30s stuff. One of my favorite things about those old sets is eye tubes (6G5, 6U5, 6E5). THey're usually used to visually indicate the amount of negative voltage on the AVC (automatic volume control) line. The grid on these tubes requires anywhere from -5 to -20VDC for the eye to deflect.
Anyway, I always thought it would be cool to install one in an amp. I thought it might be possible to hook up an eye tube to a bias wiggle tremolo circuit like on a Princeton Reverb. The tremolo circuit puts out about -30 to -40VDC to the output tubes ... Would I be able to somehow take this voltage, reduce it after it hits the outputs and use it to feed the eye tube grid? I would love to try it if possible. I think it would be a cool tremolo indicator.

Any thoughts? Thanks!

Ted

Title: Re: Eye tube question
Post by: sluckey on February 22, 2019, 03:09:02 am

Tubegeek and some of the members were using eye tubes in amps several years ago. Search the forum for eye tube.

Title: Re: Eye tube question
Post by: John on February 22, 2019, 10:28:46 am

https://el34world.com/Forum/index.php?topic=12741.0


I had to use google to find that, didn't show up on forum search.


Anyway, I think PRR has a good point. Those tubes are valuable to radio restorers, and they're not being made anymore. Probably never will be.


On a side note, I'm thinking of making a small amp inside an old Heathkit case, and using the big meter as a vu meter, if I'm smart enough to figure it out on my own. If not I'll ask.  :icon_biggrin: