Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on March 01, 2015, 05:03:46 pm

Title: Fender Marshall channel switching idea
Post by: tubenit on March 01, 2015, 05:03:46 pm
Not planning to build this.  Just thought I'd toss an idea out for anyone who might actually be interested in it. I am not sure how "smooth" the OD would sound with this?  It might be more of a heavier chimey/chunky somewhat distorted tone vs. smooth OD?

- use A/B/Y box to switch channels

- simultaneously switch Relay 1 and Relay 2 to all either a blend pot ............ OR  A/B channel switching

- an 5879 OD (which I've used on a couple of amps successfully)

With respect, Tubenit
Title: Re: Fender Marshall channel switching idea
Post by: kagliostro on March 01, 2015, 05:14:06 pm
Very interesting idea Tubenit :thumbsup:

Franco
Title: Re: Fender Marshall channel switching idea
Post by: Glennjeff on March 01, 2015, 07:44:36 pm
It just so happens I will be starting a new 50W 2 X 6L6 build in a couple of weeks.

My DC B+ will be about 470 - 480  Volts. Is that close enough.

I could have a go at this and see how it works out.
( I might prefer a slightly earlier Marshall model pre if they are any different - late plexi or master vol.)

I'm not real sure about switching the inputs section like that, looks like switching noise/thump.

Has anyone here used that method of switching guitar input to 2 different valve (tube) grids with success or otherwise ?

Could one replace the 1 MOhm grid - ground resistors to 1.8 or 2.2 MOhm each and leave both grids permanently connected.



Title: Re: Fender Marshall channel switching idea
Post by: tubenit on March 01, 2015, 08:09:17 pm
Quote
I'm not real sure about switching the inputs section like that, looks like switching noise/thump.
Has anyone here used that method of switching guitar input to 2 different valve (tube) grids with success or otherwise

http://www.musiciansfriend.com/amplifiers-effects/morley-aby-channel-switcher?pfm=sp (http://www.musiciansfriend.com/amplifiers-effects/morley-aby-channel-switcher?pfm=sp)

I made an A/B box maybe 12 yrs ago and don't remember any issues with switching noise, IIRC.

with respect, Tubenit
Title: Re: Fender Marshall channel switching idea
Post by: MakerDP on March 02, 2015, 11:37:51 am
Quote from: tubenit on March 01, 2015, 08:09:17 pm
Quote
I'm not real sure about switching the inputs section like that, looks like switching noise/thump.
Has anyone here used that method of switching guitar input to 2 different valve (tube) grids with success or otherwise

http://www.musiciansfriend.com/amplifiers-effects/morley-aby-channel-switcher?pfm=sp (http://www.musiciansfriend.com/amplifiers-effects/morley-aby-channel-switcher?pfm=sp)

I made an A/B box maybe 12 yrs ago and don't remember any issues with switching noise, IIRC.

with respect, Tubenit

Same here. I made an ABY switch with a tuner bypass mode for my Matchless clone and it works great. No issues.
Title: Re: Fender Marshall channel switching idea
Post by: kagliostro on March 04, 2015, 05:33:26 pm
Is an AB box circuit so simple, or there are other components to be added as to prevent pops ?

(http://www.monkeyfx.co.uk/pictures/bestABY.jpg)

Franco

Title: Re: Fender Marshall channel switching idea
Post by: sgmezei16 on March 04, 2015, 09:26:32 pm
I have used an A/B for channel switching on my Marshall 18watt (with a vox channel) and haven't had any noise issues either. Just used a 3pdt so I could have LED's show me what setting I am on.
Title: Re: Fender Marshall channel switching idea
Post by: TubeGeek on March 04, 2015, 09:37:25 pm
Quote from: kagliostro on March 04, 2015, 05:33:26 pm
Is an AB box circuit so simple, or there are other components to be added as to prevent pops ?

(http://www.monkeyfx.co.uk/pictures/bestABY.jpg)

Franco


I built this design and was getting hum.  I never followed through with troubleshooting it further.  I'd be interested in seeing what designs you guys built and didn't have any issues.