5U4GB rectifiers?

[JJGross]

Hi, I'm just getting into building & designing simple guitar amps after spending about a year and a half fixing old, broken or otherwise screwed-up ones. I've come into some nice old 5U4GB rectifiers but am having a hard time coming up with schematics or designs that use these in guitar amps. I did find them used with EL84s and 12AX7s in late 50s Motorola Hi-Fi sets.

Any suggestions for guitar amp applications? I'm trying to stick with single ended rigs for now along the lines of early Champs/Princetons. Not that it means I wouldn't get outside that box.

Cheers

[Old Tele man]

...Fender used them by the "tons" when they switched over from 5AR4/GZ34's to 5U4GBs...circa early 1960's...check Fender schematics.

[stokes]

...Fender used them by the "tons" when they switched over from 5AR4/GZ34's to 5U4GBs...circa early 1960's...check Fender schematics.

Actually it was the other way around,the 5U4 preceeded the GZ34,which was touted as the "rectifier tube of the future" when they began using it in the late '50's.They did continue to use the 5U4 in some models in the '60's.Just be careful using the 5U4,it has a heater current draw of 3amps,be sure your 5volt winding is up to it.

[Old Tele man]

...the original posting refers to the later 5U4GB not the original 5U4.

...the 5AR4/GZ34 was used up until mid-1960s, then suddenly they were replaced with 5U4GB's which were much lower priced (CBS-era?)...check Fender schematics!

[TD_Madden]

Yep, both my '78 Princeton Reverb and '79 Vibrolux Reverb use the 5U4GB.

[stokes]

...the original posting refers to the later 5U4GB not the original 5U4.

...the 5AR4/GZ34 was used up until mid-1960s, then suddenly they were replaced with 5U4GB's which were much lower priced (CBS-era?)...check Fender schematics!

There are way to many "exceptions" to any hard and fast rules as to what they used and when.A lot of overlaps as well.But they began using the 5U4 and the subsequent G,GA and GB as they developed,in the '40's,well before the 5AR4/GZ34.CBS did go back to the 5U4's for economic reasons,since the 5U4 was more plentiful at the time.But without a doubt the 5U4,G,GA,and GB preceeded the 5AR4/GZ34.For instance,the 5E8 Twin had the 5U4GA till '57.In '58 the 5F8 went to an 83 then a 5AR4 and Im sure there are overlaps within just that model.Thats why you see so many tube charts written over in pen.If a circuit changed rectifier tubes and they still had a lot of the older tubes left or a lot of the old tube charts they would still use them,they wasted nothing.

[Old Tele man]

In '58 the 5F8 went to an 83 then a 5AR4 and Im sure there are overlaps within just that model.

...excellent history, now check the mid-1960's-on schematics and you'll find there was a whole-sale change from using 5AR4/GZ34's in the tube-rectifier models over to using 5U4GB's from then on...ie: Bandmasters, Pro Reverbs, Princetons and Deluxes, etc. ...and the time-frame from mid-1960's up until about 1985 (end of CBS-era, start of FMIC) is a fairly LONG time.

...obvisously, the ss-rectifier amps (Bassman, Twin, Showman, etc.) aren't being considered here.

[stokes]

We're just focusing on different era's.I was just pointing out that the 5U4 came first,I mistakenly read your first post to say the 5AR4 came first.