5U4 GBEH on my Rocket V1 cathode lo-reading

[angelodp]

Just sent some voltage readings to gahult and rj. My rocket runs in the ball park of readings I have seen except for V3 pin 3, cathode which is 40 v instead of the expected 118?? All other readings are close. I have the chart sent to gahult & rj, and I reckon it will show up on the master Rocket Plate Voltages chart. I double checked that reading, but its at 40?? Any thoughts on why that would be so low.

ange

[M Fowler]

Did you post pictures of your build? I remember you were going to build an amp with VVR.

On pin 3 V3 how did you wire this tube socket? From pin 3 to pin 8 then to R14 (1k2)?

Mark

[angelodp]

That's V2 pin 3 ( cathode ) is at 40 v instead of 118 expected volts?? NO VVR yet.

Hang on.... its a bad tube, swapped it out and the new reading is 114v, right on the mark, and the amp actually has the correct level of power now. Oops.

Still would like to know if others have tried the 5U4 rectifier.

ange

[M Fowler]

5U4 is for 3amp and 5AR4/GZ34 is 2 amp but you could try the 5V4 that is 2amp as well to lower the voltage some. But the 5Y3 and 5V4 are for lower wattage 2amp use. Also, NOS GZ37 can be used in place of GZ34.

Mark

[solderstain]

...GZ34 is 2 amp but you could try the 5V4 that is 2amp as well to lower the voltage some...

That's an excellent trick, BTW. I swapped a 5V4 into my '63 AC30 to get the B+ on that amp down into a safer range, considering the 122-125vac I get out of the wall in my area during the day. Beats running a Variac all the time to bring the line voltage down to the 115vac range. My vintage EL84s are much happier!

[Structo]

I am using a 5U4 in my Hammond conversion amp.

The specs show a 44v drop @ 225ma DC.

I think it was used for it's voltage drop in this amp since the HT taps are 460v!

I had to use a 130v 50 watt Zener on the center tap to drop the voltage for the 6V6's.

[yalesmith]

So can you use a 5u4 in a Rocket? I put one in and i like it much better? I Just don't want to screw up my new toy!

[M Fowler]

So can you use a 5u4 in a Rocket? I put one in and i like it much better? I Just don't want to screw up my new toy!

Yes if your PT 5v tap is rated at 3A you can.

Mark

[yalesmith]

it is sweet and thanks!