Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: pbman1953 on January 17, 2026, 09:16:23 am

Title: Ampeg B15, there's still sound when the standby is on
Post by: pbman1953 on January 17, 2026, 09:16:23 am

I noticed that ,even though, it reduces over time, I can still hear the bass when the standby is on. It's distorted but doesn't completely shunt the sound

Title: Re: Ampeg B15, I still the bass when the standby is on
Post by: mresistor on January 22, 2026, 02:58:46 pm

By chance has a high value resistor been wired across the standby switch, as explained in this link https://www.valvewizard.co.uk/standby.html

Title: Re: Ampeg B15, I still the bass when the standby is on
Post by: pbman1953 on January 22, 2026, 03:57:51 pm

Quote from: mresistor on January 22, 2026, 02:58:46 pm

By chance has a high value resistor been wired across the standby switch, as explained in this link https://www.valvewizard.co.uk/standby.html (https://www.valvewizard.co.uk/standby.html)

no resisitor

Title: Re: Ampeg B15, there's still sound when the standby is on
Post by: ac427v on January 23, 2026, 07:47:08 am

Looks like this standby switch works by cutting the high voltage center tap connection to ground. I've never seen this and do not understand how this relates to your problem. Maybe another member has better insight???

Title: Re: Ampeg B15, there's still sound when the standby is on
Post by: pbman1953 on January 23, 2026, 10:29:54 am

True, it's the design and it's really not a "problem". I just don't like it, because if the cable's is touched there's noise, compared to  a more traditional standby like Fender and others which is a total disconnect.