View Full Version : Pro Jr. to 18W lite conversion?
07-18-2011, 02:57 PM
Does anybody know of anyone or company that is doing Pro Jr. to 18 Watt Lite conversions? The 18 Watt website seems to be gone and I've googled with little/no results. My input jack is getting pretty loose, so I thought now might be a good time to do this, but now I can't find any sources. Weird... Any help appreciated!
07-18-2011, 03:29 PM
I've done it! Make sure to check out 18watt.com, as there's a few people who've done that before. Their main page doesn't seem to work, but go somewhere like this:
and you'll be able to sign-up, join and be a part of the group!
It takes some work... there were some people selling PCBs to do it, but I haven't followed those threads since they came after I did mine. I used a turret board from turretboards.com and ordered all of the needed parts from tubesandmore.com.
That said, I've actually come to really like the sound of the Pro Jr amps as they are. Though lots of people will rave about the sound of those 1974x amps, it isn't a necessary conversion... and a loose input jack is hardly a difficult fix in contrast to gutting the who amp and rebuilding!
Have you built an amp before? There can be a LOT of trouble shooting to get an amp up and running. It's also lots of fun, but take your time and do your research.
Lastly - my personal take on the conversion - while you CAN use the same transformers, they really are the weak link. You can get the amp running with the stock PT if you use diodes for the rectifier & a sag resistor to get it to act like a tube rectifier. But the OT is the weak link. Heck - I think fender even knows that, seeing as they put a conjunctive filter on the OT primaries to smooth out it's frequency response. So I'd suggest getting a proper 18 watt OT if you want it to sound like an 18watt amp, or, at the very least you'll want to use a conjunctive filter to sort of "fix" the poor sounding OT. Additionally, with the scope of this project, most people prefer getting a better speaker...
By the time you've done all of that, you could have sold your amp and used the money to buy a better amp than you currently have (or bought all of the parts to build an amp from scratch/kit). Plus, a hacked up conversion amp doesn't have much resale value, so you better hope you like the end product. If your goal is to learn about amp building, this can be a fun project, but if your goal is the ultimate tone, this may or may not get you closer to what you want.
My pro junior was completely toast, so it was worthwhile for me as I didn't have much to loose. It really does sound great after some tweaking, but I've got new transformers, a new speaker, bigger cab.... not really a conversion by the end of it (the only thing original, now is the chassis and PT!) Not sure I would do it to a working amp, though.
07-18-2011, 03:41 PM
Wow! Thanks for the in-depth answer HughesP!
Yeah, I really like the Pro Jr. as-is soundwise also. I just thought it would be cool to have a hand-wired version. Are the 18 watters not that close in sound?
No, I haven't built an amp before and not completely sure I'm up to it. That's why I'm wondering if there are still individuals or companies that will still do the mod.
Maybe I need to re-evaluate...
07-18-2011, 05:39 PM
i love the pro jr. eventually plan to pick one up as i think it's a great amp as is.
i did do a blues jr conversion myself and while im not 100% on it, i think it was well worth it. i bought the blues jr from someone who fried the board so it was a lot better. i plan to upgrade the OT and add power scaling but i say go for it if you want.
07-18-2011, 05:55 PM
i sent a pro jr. to steve @ S2 amps a few years ago and he did an 18w lite and it was a fire breather! i dont know if hes still doing these conversions, but he did a great job on mine!
07-18-2011, 06:55 PM
Thanks for the input, guys. S2 recently went out of business, so they're no longer an option.
That's what has surprised me. This seemed to be very common and all over the place a year or 2 ago and now I can't seem to find anyone doing them.
07-19-2011, 04:33 AM
by the time u get the board, transformers,etc, u may as well just order a 18watt kit and start over from new. Check out trinity amps for some cool takes on lower watt amps, they are top notch.
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