TW out of a Pro Jr?

[JJGross]

Hi,
Kind of a noob but I've done several repairs and upgrades on amps. Just getting into builds and some serious conversions now.

I have a pair of Fender Pro Jrs that I gig with and one is getting a complete terminal board conversion rather that screw with chasing a repeatedly popping power resistor. I gig with these things and reliability is paramount so the PCB is going bye-bye.

Here's what I'm after:
A buddy of mine has a real Trainwreck and after allowing me a brief look inside for all of about 30 seconds & a brief orgasmic experience wanking away though it, I'm thinking maybe one of my Pro Jrs could be used for a TW conversion. Obviously not a real one or even all that correct, but a "good enough for rock & roll in biker bars" kind of conversion. I build all my own effects and already have guitarists at nearly every gig doing the WTF?! look at my PJs. I'm looking to take that to the next level of minimizing the effects I use to get my sound. Since most of my overdrive is amp + Bluesbreaker style clone pedals rather than Rat/TS fizz, I'm looking to do more on the ampside than floorboard side if you know what I mean.

Would a tweak-type of modification of the original PCB work, or would it just make more sense to make a complete terminal board myself (I've done several in the past) to get the TW vibe going on in a Pro Jr? Is the iron in a PJ even up to the task?

I'm open to any suggestions from anyone but particularly from anyone using the venerable Fender Pro Jr. as the basis for the build. Something about the simplicity of that little snot-box that appeals to me like no other amp I've ever owned - and there have been dozens over the last 35 years. One volume and one tone control means more if they really do what they're labeled for than a multi-channel science project at this point in my playing career. This is not a business proposal, just a player and builder looking for onstage-gear options.

I know about HV safety and own a drill press as well as several linear feet of Garolite & boxes of other ingredient-stage goodies.

Any help is appreciated.

Cheers,
- JJ

[Cygnus X1]

Welcome to the board, JJ!
I recognize you from another place.

Not sure about the iron. I'm thinking about the AX84 mini wreck, (4-4-0).
There are posts about it in the Trainwreck section.
Here's a link to a good discussion about the 4-4-0:
https://tubeamparchive.com/viewtopic.php?t=5504

Best of luck on the amp building!

[Tubetwang]

i like your web site JJ...well done...

i would also go for a mini Liverpool type amp...

i will let the guys that know what there doing speak to you...

[M Fowler]

Just a thought, why not go with a 50 watt Fender circuit using 6L6s with high gain preamp rather than the Trainwreck thing?

I started out by building the TW liverpool, then the Rocket, then the Matchless Spitfire. Now I will be building a new chassis and circuit to replace the crappy transistor amp in my Fender Deluxe 90. The reason for this is it has a great mid sized cab with a new 4 ohm celestion 100 speaker. The chassis is not suitable for my build so I will replace that with a custom chassis since the combo takes a 19 inch wide x 8 chassis. So far I haven't seen anything that will work. Also I want the chassis undrilled so I can decide what holes I need. Single channel TMB, 3 12ax7 and 2 6L6 with SS rectifier/GZ34 switched.

Mark

[RevD]

The 18 watt derivatives are also a great way to go. A lite IIb 18 watter in the pro jr would work cool, iron probably would work same tube complement, but I'd change the Output Transformer for something a bit better sounding. I built one in a old Peavey combo and even using a deluxe reverb tranny that isn't optimized for EL84's its one bad ass little combo. Has all the crunch and mini marshall sound you could want once its past about 5/8's on the volume knob. As mentioned the Ax84 idea might be more what your looking for, but I thought I'd mentioned the 18 watter (inspired from the Marshall 18watter) as a alternative. I know one of the companies makes conversions of the blues jr and pro jr's as well offering a bunch of possibilities. http://www.s2amps.com/bluesjr.html (look down about half page for Pro Jr. possibilities (you may know this already but thought I'd pass on the link.)

Regards,

Rev D

[RJ Guitars]

JJ,

imho - The Pro Junior is probably the best bargain for tone you can get. I've even had that confirmed for me by Derek Ferwerda, friend of Ken Fischer and owner of Trainwreck Rocket #1 - Amanda. (His approval is worth 1000X of my own).

As a donor for a Trainwreck, its a tube short for either the Express or Liverpool, and two tubes short for a Rocket. I myself have two of them in various states of rebuild on my workbench, but I was going for a Carmen Ghia, which has the same tube compliment as the as the Pro Junior.

There is a pretty knowledgeable contingent here on the forum that believe the smaller chassis of the Pro Junior will disturb the mojo of the amp to the point that it is really not the same amp. So even if you could cram another tube in there, making it sound a wreck could be challenging.

I do think the Pro Junior is an awesome little package and I think you can do better than the printed circuit board and robot built amp as it comes from the vendor. For sure the output transformer can be approved upon. Curiously the power transformer voltage is pretty similar to the El-84 Trainwrecks.

Send us a look at what you build, we can all learn something.

rj