Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Platefire on January 10, 2017, 01:04:34 pm

Title: New switch for Vibro Champ--switch off Pop?
Post by: Platefire on January 10, 2017, 01:04:34 pm

Hello, Trying to answer a question for someone else posed to me. I've never encountered this problem so I have no experiance with it. Some of you may have? His question as follows:
Thanks, Platefire
 
 I have an early 70s vibro champ and I just bought a new after market cone switch for the vibrato.
 
 It's silent when turning on the vibrato but when turning off vibrato there's a good POP sound.
 
 I replaced the 2 0.01 caps that are just ahead of the vibrato switch jack to no avail.
 
 Thoughts?

Title: Re: New switch for Vibro Champ--switch off Pop?
Post by: Platefire on January 11, 2017, 04:58:34 pm

Bump?

Title: Re: New switch for Vibro Champ--switch off Pop?
Post by: sluckey on January 11, 2017, 05:13:36 pm

What is an after market cone switch?

Title: Re: New switch for Vibro Champ--switch off Pop?
Post by: PRR on January 11, 2017, 05:38:25 pm

I think he means the chrome "bump" with two switches which sits on the floor. If just one switch it may look like a "cone".

Ah: (http://www.elderly.com/images/accessories/ELA/FFS15.jpg)

I think I want to know WHICH VibraChamp with link to schematic.

Title: Re: New switch for Vibro Champ--switch off Pop?
Post by: PRR on January 11, 2017, 06:00:39 pm

me > WHICH VibraChamp

Argh, knowing a friend-of-a-friend won't get back on that, I researched:

The Vibro Champ circuitry went virtually unchanged throughout its 19 year history.
http://vibrochamp.org/schematics (http://vibrochamp.org/schematics)

http://vibrochamp.org/wp-content/uploads/2011/06/vibrochamp-schematic.jpg (http://vibrochamp.org/wp-content/uploads/2011/06/vibrochamp-schematic.jpg)

Hey, did it pop before the new switch? Or did it never have a switch in this owner's custody?

Title: Re: New switch for Vibro Champ--switch off Pop?
Post by: Platefire on January 12, 2017, 07:47:13 am

Thanks very much PRR for the research and links.


Just a thought, since the trem signal is shorted to
Ground in the off position, and there is no Pop when turned on, would
It be possible that some kind of voltage is in the chassis and transmitted
To the amp circuit when switched off to chassis ground???