Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Toxophilite on February 10, 2019, 09:07:12 pm

Title: Vibro Champ with one tube reverb?
Post by: Toxophilite on February 10, 2019, 09:07:12 pm
Can a vibro champ be built with a one tube reverb? (4 tubes total if SS rectified)
Or would the lack of the mixer gain stage post reverb circuit be too detrimental?
Would sone have to use the normal fender 2 tube reverb so that one would have the extra gain stage for mixing?
Also would this have an adverse affect on the vibrato circuit which seems to wiggle the bias of the 2nd gain stage. yes?


 I have the regal chassis that I stole the cab from and thought it'd be a good champ platform
Title: Re: Vibro Champ with one tube reverb?
Post by: TIMBO on February 11, 2019, 01:36:43 am
This might help...
http://el34world.com/Forum/index.php?topic=24304.0
Title: Re: Vibro Champ with one tube reverb?
Post by: tubenit on February 11, 2019, 06:19:06 am
This uses 3 preamp tubes but is a "proven" design from a guy on AmpGarage. 

Champ Reverb                  http://el34world.com/Forum/index.php?topic=23328.0

With respect, Tubenit
Title: Re: Vibro Champ with one tube reverb?
Post by: tubenit on February 11, 2019, 07:39:51 am
Posted this idea with schematic and layout in it's own thread here:

http://el34world.com/Forum/index.php?topic=24326.msg261141#msg261141
Title: Re: Vibro Champ with one tube reverb?
Post by: sluckey on February 11, 2019, 09:06:17 am
Tubenit, that schematic looks very doable to me.

Toxophilite, you seem to be fond of reverb and tremolo. Have you considered building a revibe? You could have great reverb and tremolo with any amp.
Title: Re: Vibro Champ with one tube reverb?
Post by: tubenit on February 11, 2019, 10:06:27 am
OK,  I found two Champ Reverb schematics that were based off of Physconoodler's "proven" design.  Unfortunately, I don't know what was changed from his amp design but I suspect not much difference.  Physconoodler was a very active forum member for years and built amps in Canada, IIRC.  He came up with some incredible amps and some very innovative designs.

There is a "Broken Files" link in the ExpressSCH Library.  During one of the upgrades,  lots and lots of schematics and layouts got deleted from the Library but Doug was thoughtful enough to find a way to link to them. Some interesting and useful ideas in there.  The Champ Reverb ideas are from there.  I'm thinking this was from maybe 10 yrs ago or so?

Sluckey gave you a good idea with the ReVibe that would be worth serious consideration.  It sure would give you lots of options with reverb and vibrato on any amp.

With respect, Tubenit

Title: Re: Vibro Champ with one tube reverb?
Post by: Toxophilite on February 11, 2019, 09:20:50 pm
Wow
Lot's of cool ideas. Thanks so much !
Sadly I only have one 6BM8 tube. I do have 3 6GW8 tubes which are somewhat similar


I'd thought of building a revibe, but previously I'd been doing builds that were made to take to gigs. I already bring a box of cables (and little pedal board) a Roland space echo, a mini leslie, two large guitars, and up till I built my stereo amp..two amps. I sometimes had as much gear as the drummer!! So I wasn't keen on bringing an extra unit to a gig when I could have the effects built into an amp I was already bringing. I don't use them all the time. I just like to have them for some songs. However for at home fun and recording a revibe could definitely be an idea.
It would be cool to have one that you could run a vocal through too so it could be like a studio effect as well. Or even just have a line in type of input.



Title: Re: Vibro Champ with one tube reverb?
Post by: sluckey on February 11, 2019, 09:55:15 pm
There's a new thread that just started today. It's called "Fender champ reverb mod". Take a look. Could be something interesting for you.
Title: Re: Vibro Champ with one tube reverb?
Post by: Toxophilite on February 12, 2019, 12:06:38 am
Indeed, good stuff.
Thanks for pointing it out.

I guess if one used a 12AD7 version for the fender reverb circuit one could use another tube for vibrato and a post reverb mix circuit.