Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Madison on October 23, 2011, 11:10:33 pm

Title: 5E3 troubles
Post by: Madison on October 23, 2011, 11:10:33 pm

Having some problems with a 5E3 build.

Feels like waaay too much sag when picking fast; the amp can't keep up at all

I had a typical 70mA Champ PT in there.
I am almost certain it couldn't keep up.
I ordered a bigger PT and waiting for it to arrive.

In the mean time I hooked up a 290-0-290 140mA PT.
Seems to be pooping out on both the Ch1 inputs.
Like the grids are being over loaded?
Especially with guitars that have a lot of treble.
The Ch 2 inputs seem just "okay".

Here are some voltages.
I am running NOS 5Y3.

V1
Pin-
1-104
2-5.8mv
3-1.4
6-102
7-5.6mv
8-1.4

V2
Pin-
1-130
3-1.0
6-161
7-14
8-38

Power tubes-
Pin-
3-312
4-270
8-16.5

Title: Re: 5E3 troubles
Post by: DummyLoad on October 24, 2011, 01:16:04 am

In the mean time I hooked up a 290-0-290 140mA PT.
Seems to be pooping out on both the Ch1 inputs.

what size is the first filter cap?  the 5Y3 may be sputtering with that lower source impedance PT.




EDIT: never mind... i see channel 2 is OK.  bad connection perhaps? re-flow joints?

Title: Re: 5E3 troubles
Post by: Madison on October 24, 2011, 01:42:42 am

what size is the first filter cap?

They are all 16uF.
This is a Hoffman layout/board.