Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => PC Express and JSchem - Schematics and Layout diagrams => Topic started by: tubenit on November 13, 2006, 05:15:46 pm

Title: Bassman 5F6-A, & Bassman w/Reverb
Post by: tubenit on November 13, 2006, 05:15:46 pm

Original schematic for the Bassman 5F6-A      The original Marshall BluesBreaker is pretty similar. Check Schematic Heaven for comparisons.  Note on the BluesBreaker layout, I split the V1 cathodes for more tone options.

Check for errors

Tubenit

*  I've added one confirmed to be a great sounding working model for a Bassman with reverb and tremolo by Tubeswell.

Title: Bassman with reverb
Post by: tubenit on November 13, 2006, 06:03:58 pm

I've used this type of D'Lite reverb successfully in numerous builds including the Little Wing Reverb (mini-Bassman), Texas Raptor and Plexi 25w Reverb.  Compare schematic and layout and CHECK for ERRORS.

Tubenit

EDIT:   I added another idea using a mosfet CF so one could have an extra triode allowing a 12AT7 reverb send.  Also to note:   2 input jacks instead of four,   split cathodes on V1,   mosfet CF and one extra stage of filtering.

CHECK for ERRORS!  Compare schematic with layout, if there is a discrepancy, go with the information on the schematic.

Title: 1 Channel Quasi-M schm
Post by: tubenit on May 01, 2007, 08:54:35 am

One of the forum posters PM's me and asked if I had a simple schematic for a one channel Marshall.  So I drew this up.  It does have a paralleled V1 which only give 30% more gain but adds some warmth in my opinion. I have this feature on all of my amps and love it.

You can use a 5751 or 12AY7 if you wanted lower gain.  OR .... you could simply hook up only half of the V1 12AX7.

I haven't built this, but one could use terminal strips or a Hiwatt style board and probably make a small sized 50 watt head.

Note with the SPDT (center off) on V1 that you can come pretty close to the original values for both Marshall channels.  I indicated some questions about some resistor values on the B+ and bias control.  I put what my best guess is. If you build it, maybe you'll let us know if these are accurate?

With respect, Tubenit

Title: Bassman and AB763 channel switching with relays
Post by: tubenit on December 15, 2012, 08:25:28 am

Some different ideas to consider here.....................

 :think1: :icon_biggrin:
  
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, 10thtx