Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: AHeck on June 30, 2020, 11:33:06 pm

Title: Low volume, heavily distorted output
Post by: AHeck on June 30, 2020, 11:33:06 pm
I just fired up a 5E3 build and the output is just wrong. It’s making guitar noises, just heavily distorted and with hardly any volume.  My voltages are good, I’ve tried three complete tube changes, checked resistance from tip to sleeve in all input jacks, tried two different guitars, and cables, also I reversed the output jack polarity.  One thing that I checked that seems suspicious is without the power tubes, the output leads show about 6M continuity with the plate pins and output transformer center tap.  I would think that should be an open lead.  Is that worth digging into?  Thanks for any help .
Title: Re: Low volume, heavily distorted output
Post by: Latole on July 01, 2020, 03:08:04 am
 " the output leads show about 6M continuity with the plate pins and output transformer center tap. "
-AHeck

Issue is there. Power transformer primary look bad....If you use the right wire   :laugh:
Title: Re: Low volume, heavily distorted output
Post by: 2deaf on July 01, 2020, 11:24:03 am
I just fired up a 5E3 build and the output is just wrong. It’s making guitar noises, just heavily distorted and with hardly any volume.  My voltages are good, I’ve tried three complete tube changes, checked resistance from tip to sleeve in all input jacks, tried two different guitars, and cables, also I reversed the output jack polarity.  One thing that I checked that seems suspicious is without the power tubes, the output leads show about 6M continuity with the plate pins and output transformer center tap.  I would think that should be an open lead.  Is that worth digging into?  Thanks for any help .

It sounds like you are measuring the resistance across your first filter cap. 

An actual 5E3 has two speaker jacks.  One is a shorting jack and the other open.  If you plug into the open jack, you just might get the symptoms you describe.
Title: Re: Low volume, heavily distorted output
Post by: 2deaf on July 01, 2020, 11:32:06 am
Issue is there. Power transformer primary look bad....If you use the right wire   :laugh:

There's this guy on the Marshall Forum called South Park.