Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => PC Express and JSchem - Schematics and Layout diagrams => Topic started by: tubenit on November 20, 2014, 06:10:47 am

Title: Blues Jr to HoSo56
Post by: tubenit on November 20, 2014, 06:10:47 am

Geezer's HoSo56 is one of the finest most touch sensitive amps I've ever played.  You could convert a Blues Jr. to a HoSo56 pretty easily, I think.  You could have the FAT 5879 tone, active FX,  mid boost, and PPIMV.  That should make the volume very controllable for playing at home.   Just a thought.  Same tube count.  Same number of potentiometers used.

Spacing the turret board with similar spacing as a tagboard & using Doug's turret board material and turrets,  the board would be 9.33" long.

 :icon_biggrin:

with respect, Tubenit

EDIT:  2-1-2019     I've added a reverb version.  CHECK for ERRORS!   Compare schematic with layout.  Any discrepencies go with schematic.

Title: Re: Blues Jr to HoSo56
Post by: tubenit on November 24, 2014, 06:34:00 am

Some more ideas .....................    for a Blues Jr. conversion

HoSo56 with paralleled 12AX7 in V1.

Pseudo Plexi

CHECK for ERRORS!  Compare schematic to layout.

With respect, Tubenit

Title: Re: Blues Jr to HoSo56
Post by: tubenit on November 24, 2014, 06:35:35 am

Another idea for a Blues Jr. conversion to a Tweed BluezMeister with an EL84 version.

CHECK for ERRORS!   Compare schematic to layout.

With respect, Tubenit

Title: Re: Blues Jr to HoSo56
Post by: moonbird on May 25, 2015, 11:53:06 pm

Hi tubenit --


Great ideas. I think I might do the HOSO56. There is a pot on the schematic feeding the send level and then another one between V2b and the PI. Which one would be best to use for the fx level?


Also -- what cap combo gave you the .00130uf value in the tone circuit?


Thanks.

Title: Re: Blues Jr to HoSo56
Post by: tubenit on May 26, 2015, 06:09:08 am

You can simply use a 22k to ground for the FX send pot like I did on my recent D'Mars ODS 5879.  And then use the 250ka for the FX level prior to the LTPI. I don't change much on mine except the FX level prior to the LTPI.   You also can probably eliminate the .1 cap going into the 22k "send" resistor to ground.  It's probably not needed.

You can use a .001 cap alone.  In fact, I've changed a couple of things in the schematic that make it a better match for EL84's.
Most of the changes are in the tone stack. 

IF you built it and found the EL84's are too easily overdriven, then you can change the coupling caps post LTPI from .02 to a lower .01.

I hope you build this and report back how it sounds!  I think this will be a fantastic build!

With respect, Tubenit