Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: mmilo on April 04, 2023, 11:27:06 am

Title: Amp starts and no sound
Post by: mmilo on April 04, 2023, 11:27:06 am
Another noob first build troubleshooting question...Monotone 5f1 tweed,  amp starts up voltage is going to the pilot light and the filament voltage is getting to all the tubes. Continuity is good.  No sound to the speaker. Here is the weird part and doesn't make sense and it probably has something to do with my bad soldering, but my ac voltage reading to the  fuse is 0. I know I screwed something up, not sure where.  I've checked the test points and they are within spec. Any suggestions?
Title: Re: Amp starts and no sound
Post by: sluckey on April 04, 2023, 11:56:18 am
my ac voltage reading to the  fuse is 0.
Most likely means you have the power cord neutral wire connected to the fuse.

EDIT... or maybe the meter is set to measure DC voltage.
Title: Re: Amp starts and no sound
Post by: tubeswell on April 04, 2023, 12:02:43 pm
Another noob first build troubleshooting question...Monotone 5f1 tweed,  amp starts up voltage is going to the pilot light and the filament voltage is getting to all the tubes. Continuity is good.  No sound to the speaker. Here is the weird part and doesn't make sense and it probably has something to do with my bad soldering, but my ac voltage reading to the  fuse is 0. I know I screwed something up, not sure where.  I've checked the test points and they are within spec. Any suggestions?


No VAC going to the fuse you say. Yet you have 6ish VAC on the heater winding.


Hi-res photos showing the amp guts may help us spot a wiring issue.


Otherwise print out the schematic and using your multimeter’s ohm-meter setting, check for continuity between all the parts of the circuit where you want continuity, and vice versa for where you don’t want continuity, marking the test points on your schematic with a highlight pen. Until you find the problem.
Title: Re: Amp starts and no sound
Post by: mmilo on April 04, 2023, 01:46:41 pm
Here is the fuse connection
Title: Re: Amp starts and no sound
Post by: mmilo on April 04, 2023, 01:49:27 pm
Rectifier
Title: Re: Amp starts and no sound
Post by: EL34 on April 04, 2023, 02:49:58 pm
Use these instructions and look at everything
https://el34world.com/Hoffman/instructions.htm