Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Toffe007 on September 18, 2019, 05:17:45 pm

Title: How to wire Standard powertransformer for a Blues jrIII conversion
Post by: Toffe007 on September 18, 2019, 05:17:45 pm

Need advise how to wire a standard powertransformer for my Blues jr conversion projekt. Cant find any info on the site. I´m in Europe so 240v schematics is what i´m looking for. How to wire the input side of the transformer is what i´m looking for. I have the orignal schematics.

Title: Re: How to wire Standard trafo Blues jrIII conversion
Post by: smackoj on September 18, 2019, 06:22:28 pm

Hi; are you asking about the power transformer wiring?  If so go to this link and there is plenty of info with pictures.


https://el34world.com/schematics.htm#Hoffman_Blues_Junior_Conversion

Title: Re: How to wire Standard trafo Blues jrIII conversion
Post by: Toffe007 on September 19, 2019, 02:03:49 am

Theres no info/schematics/pictures of the original transformer :w2:

Title: Re: How to wire Standard powertransformer for a Blues jrIII conversion
Post by: shooter on September 19, 2019, 09:04:27 am

Quote

I have the orignal schematics.

then draw lines from all the "CP" connections in your partial schematic of the PT.  from there look at your new PT and draw up the "translation" CP4 is now New Black kinda thing

Title: Re: How to wire Standard powertransformer for a Blues jrIII conversion
Post by: 2deaf on September 19, 2019, 09:39:31 am

VIO:  One lug of ON/OFF switch on Hoffman drawing
BLK:  Other lug of ON/OFF switch on Hoffman drawing
BLK/YEL connected to BLK/GRN
BLK/RED:  capped-off
WHT:  capped-off
WHT/BLK:  capped-off

Title: Re: How to wire Standard powertransformer for a Blues jrIII conversion
Post by: Tony Bones on September 21, 2019, 09:15:03 am

As shooter (and 2deaf) said, connect the CP's on the PT as suggested by the schematic. Notice the jumpers that were on the PCB of the original amp. You'll need to reproduce those, either on terminal strips or just solder and shrink tube.

Title: Re: How to wire Standard powertransformer for a Blues jrIII conversion
Post by: Toffe007 on September 25, 2019, 08:52:09 am

Thank ýou - problem solved!
Primary side on PT for 240v should be white/black and violett and black/green and black/yellow should be wired together.

Title: Re: How to wire Standard powertransformer for a Blues jrIII conversion
Post by: Tony Bones on September 25, 2019, 10:02:23 am

Quote from: Toffe007 on September 25, 2019, 08:52:09 am

Thank ýou - problem solved!
Primary side on PT for 240v should be white/black and violett and black/green and black/yellow should be wired together.

According to the schematic, that's the 230V connection, but it'll probably work fine on 240V.