Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mresistor on October 31, 2021, 11:16:50 am

Title: 5E8A clone coming out of standby
Post by: mresistor on October 31, 2021, 11:16:50 am

Hi guys     have this 5E8A clone here     have sub'd every tube in it. Checked bias and HV.  The charge on the filter caps is draining rather quickly when placed in standby.   When taking it out of standby this is the sound I get volumes were at minimum.   

Anyone every heard anything like this ?

Title: Re: 5E8A clone coming out of standby
Post by: mresistor on October 31, 2021, 11:23:46 am

Discovered it's related to V3. 


https://el34world.com/charts/Schematics/files/Fender/Fender_twin_5e8a_schem.pdf

Title: Re: 5E8A clone coming out of standby
Post by: SILVERGUN on October 31, 2021, 03:50:28 pm

I'm only seeing this

Title: Re: 5E8A clone coming out of standby
Post by: mresistor on October 31, 2021, 05:45:33 pm

Try the link now   and note this amp has a very loud hum..   I poked around the components on the board and V3 tube socket and can't seem to replicate the crackly sounds it was making when you wiggled the tube.

Title: Re: 5E8A clone coming out of standby
Post by: SILVERGUN on November 01, 2021, 07:45:39 am

Quote from: mresistor on October 31, 2021, 11:16:50 am

The charge on the filter caps is draining rather quickly when placed in standby.

Was there a bleeder resistor added to the B+ buss?
If no, then it's a solid guess that you have a bleeding cap

Title: Re: 5E8A clone coming out of standby
Post by: mresistor on November 01, 2021, 03:18:31 pm

Well put that one in the memory book.  The speaker jack wasn't grounded.   Installed a new Switchcraft 12A and the amp sounds great.  That nasty noise in the video was a dirty volume pot.


I will check and see if theres a bleeder resistor..  The owner may want a re-cap too  I don't know yet.