Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: davidwpack on August 09, 2020, 03:38:15 pm

Title: Heaters
Post by: davidwpack on August 09, 2020, 03:38:15 pm: Ello. I had an abrupt problem with an amp that I've been playing for a while. Turned it on after having played it yesterday. It worked fine yesterday. Anyways, V2 and V1 suddenly have no filament voltage. I'm measuring 3.1 v to chassis on pins 4/5 and 9 but nothing between. Shorted together somewhere probly? I'm going to rewire the filaments for V1, V2 starting at V3. I just wanted to run it by everybody because I've been playing through this for a long time with no issues. Thanks
Title: Re: Heaters
Post by: sluckey on August 09, 2020, 03:44:52 pm: Probably a broken wire or bad solder joint between V3 and V2.
Title: Re: Heaters
Post by: davidwpack on August 09, 2020, 03:51:33 pm: That's what I was thinking. Thanks Sluckey!
Title: Re: Heaters
Post by: PRR on August 09, 2020, 06:49:07 pm: > Shorted together somewhere

The heaters are a near-short 4/5 to 9.

Pull those tubes. Now one side may show 3V, and the other side not.
Title: Re: Heaters
Post by: davidwpack on August 28, 2020, 08:43:23 pm: Sorry PRR, I didn't know I had a reply from you. I went ahead and put in new Belton sockets in all the preamp tube positions (V1-V4) because they were cheap. Out of a lack of aesthetic abilities or laziness I decided to do a straight Soldano style heater wiring job. At first it was noisy and sounded terrible. After a day of probing and tube replacements I found that the resistor leg on V1 connecting pin 2 to pin 7 was only soldered on pin 7. I went back and soldered pin 2 and now it's dead dead quiet. I thought I had inadvertently destroyed something else in the process until I plugged in a guitar but it's just that quiet. I think I'll try using that approach for wiring heaters more often. Anyways, thanks Sluckey and PRR..
P.S. Does anyone make tube shields for bottom mount sockets. I don't think they do but I thought someone might know something more about it.
Title: Re: Heaters
Post by: acheld on August 28, 2020, 08:55:08 pm: Could you explain what a "straight Soldano style heater wiring" is please? How is it different from the Fender style?
Title: Re: Heaters
Post by: davidwpack on August 28, 2020, 09:46:52 pm: Wires are run straight as opposed to twisting them. Here's a pic from the internet.
Title: Re: Heaters
Post by: sluckey on August 28, 2020, 11:51:39 pm: Quote from: davidwpack on August 28, 2020, 08:43:23 pm
P.S. Does anyone make tube shields for bottom mount sockets. I don't think they do but I thought someone might know something more about it.
Get some of these collars...

https://www.ebay.com/itm/4-x-Tube-Socket-Collar-Base-For-9-Pin-J-Slot-IERC-Tube-Shields/293301400131?hash=item444a203243:g:5akAAOSws-xdtw5c
Title: Re: Heaters
Post by: davidwpack on August 28, 2020, 11:59:11 pm: I ordered 3 sets. I like the extra height the pins have from being bottom mounted. I believe I'll stick with that type. Thanks again Sluckey!