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Hoffman Amps Forum image Author Topic: How to wire Standard powertransformer for a Blues jrIII conversion  (Read 2544 times)

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Offline Toffe007

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How to wire Standard powertransformer for a Blues jrIII conversion
« 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.
« Last Edit: September 19, 2019, 02:11:10 am by Toffe007 »
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Offline smackoj

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Re: How to wire Standard trafo Blues jrIII conversion
« Reply #1 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

Offline Toffe007

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Re: How to wire Standard trafo Blues jrIII conversion
« Reply #2 on: September 19, 2019, 02:03:49 am »
Theres no info/schematics/pictures of the original transformer :w2:
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Offline shooter

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Re: How to wire Standard powertransformer for a Blues jrIII conversion
« Reply #3 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
Went Class C for efficiency

Offline 2deaf

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Re: How to wire Standard powertransformer for a Blues jrIII conversion
« Reply #4 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

Offline Tony Bones

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Re: How to wire Standard powertransformer for a Blues jrIII conversion
« Reply #5 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.


Offline Toffe007

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Re: How to wire Standard powertransformer for a Blues jrIII conversion
« Reply #6 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.
« Last Edit: September 25, 2019, 09:45:22 am by Toffe007 »
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Offline Tony Bones

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Re: How to wire Standard powertransformer for a Blues jrIII conversion
« Reply #7 on: September 25, 2019, 10:02:23 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.

 


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