Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tubenit on December 15, 2012, 07:49:39 am

Title: Deluxe Bassman Reverb
Post by: tubenit on December 15, 2012, 07:49:39 am

This idea of a Deluxe Bassman Reverb was posted on the AmpGarage by Kwijabo.  I simply took his original idea and put reverb on both channels and made it possible to do relay switching between channels.

The .47 cap going into the first relay is to help keep the cap values in series reasonably similar.

Thought I'd simply share this as an idea for anyone who might be interested?

with respect, Tubenit

Title: 5F6-A & AB763 channel switching amp
Post by: tubenit on December 15, 2012, 08:21:21 am

OR .............................    :think1: :icon_biggrin:

you could have a "Hoffman style hotswitch" on the Bassman channel that is relay switched also.

Adjusting the two channels to be the same or similar volume could be done by:

1)  using the hotswitch boost

2)  lower the Bassman mixing resistor to a lower value (maybe 68k) or
     even eliminate it

3)  add a 250k pot where the V5-7 grid resistor is on the DR channel

Just other options to consider .................

With respect,  Tubenit

Title: Re: Deluxe Bassman Reverb
Post by: phsyconoodler on December 15, 2012, 10:24:51 am

Hey Tunenit,
  I just wanted to say thank you for your seemingly tireless efforts to come up with new twists on amp designs and sharing them with the community here.
  Kudos to you bro! :occasion14:

Title: Re: Deluxe Bassman Reverb
Post by: tubenit on December 15, 2012, 05:28:43 pm

It's kind of fun drawing this stuff up!  I enjoy doing it.  So you're welcome!   :icon_biggrin:

Lots of great innovation and contributors here on the forum including yourself. Thanks for all you bring to the forum also.

With respect,  Tubenit

Title: Re: Deluxe Bassman Reverb
Post by: Daradaramike3 on January 23, 2013, 02:15:25 pm

Hello!

Long time reader, first time poster.

I'm a bit new at this so pardon the simple question; but if I were trying to avoid relays, would I be able to use a DPDT in place of relay 1 and rely on the two 220K resistors before relay 2 to separate any activity between the two channels before heading to the PI?  What would be the down side to such an approach?

Any insight is greatly appreciated.

Thanks,
Mike

Title: Re: Deluxe Bassman Reverb
Post by: tubenit on January 23, 2013, 08:54:00 pm

IF I am understanding your question correctly, ................ sure you can use a simple mini-toggle DPDT switch where it shows relay switched DPDT's.

Downside is it won't be footswitchable so you could change it while playing.

with respect, Tubenit

Title: Re: Deluxe Bassman Reverb
Post by: Daradaramike3 on January 24, 2013, 09:08:46 am

Thank you Tubenit, I think that answers my question but after reading my first question I think I should clarify what I'm asking:

Could I use only one DPDT switch in place of relay 1, and get rid of relay 2?  This would leave the 220K resistors that would then feed into the reverb and PI?  Is it absolutely necessary to have the second relay there to separate the two tone stacks?

Thanks again,
Mike

Title: Re: Deluxe Bassman Reverb
Post by: tubenit on January 24, 2013, 09:22:33 am

Yes, I think so.  Use the one DPDT at the preamp and then just the 220k resistors.

With respect, Tubenit

Title: Re: Deluxe Bassman Reverb
Post by: Daradaramike3 on January 25, 2013, 02:37:52 pm

Great!  That answers my question.  Thank you very much for the help.

Title: Re: Deluxe Bassman Reverb
Post by: printer2 on January 25, 2013, 09:46:32 pm

I have not jumped into the relay end of things yet but have a great affinity for little three pole toggle switches. Rather than a separate path for pre or post eq I envisioned swapping positions with a switch.

(http://i406.photobucket.com/albums/pp142/printer2_photo/guitar%20amp/Marshall-FenderCross.jpg)