Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: soeves on December 04, 2017, 08:21:03 am
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Dear all!
Just bought a cheap Pro Junior. Lots of hum, and a bit messy inside. Did a 5e3 contstruction a few years ago, and I am considering to do a point to point job on the Pro Junior, that is throw out the printboard and redo the amp point to point.
Saw an earlier post on the subject, but would like to hear, if anyone has new experiences with layout for a point to point Pro Junior. I would like to continue with the original transformers!!
Hope for som advice;-))) :help: :help:
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Doug was working on a turret board replacement for the Pro Jr. But I don't know where it is in final development. Could be coming down the road.
http://el34world.com/Forum/index.php?topic=19657.0 (http://el34world.com/Forum/index.php?topic=19657.0)
Then there's this thread on the Pro Jr. - I think it wouldn't be too hard at all to get some FR4/g10 board material (sold here) and some turrets and make a board yourself.
http://el34world.com/Forum/index.php?topic=21975.0 (http://el34world.com/Forum/index.php?topic=21975.0)
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If you do design a board you can buy a custom-made one on this site too!
You could also build a different amp with the same number of tubes, if you're not set on the Pro Jr. For example, one channel of a Twin Reverb preamp plus PI would use 3 preamp tubes.
The Pro Junior drives its reverb with a solid state opamp. That's harder to work into point-to-point wiring and the low voltage power supply increases parts count.
^ edit: you can still do something like that, but I was looking at the wrong schematic.
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For example, one channel of a Twin Reverb preamp plus PI would use 3 preamp tubes.
The normal preamp plus PI only uses 2 little tubes.
The Pro Junior drives its reverb with a solid state opamp.
There is no reverb on the pro jr.
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For example, one channel of a Twin Reverb preamp plus PI would use 3 preamp tubes.
The normal preamp plus PI only uses 2 little tubes.
The Pro Junior drives its reverb with a solid state opamp.
There is no reverb on the pro jr.
Good catch. I figured the vibrato channel would fully use all 3 available tubes, but I was looking at a Blues Deluxe schematic! The Pro Junior only has 2 preamp tubes, and no reverb.