Output Transformer Upgrade
April 17, 2010 | Posted by Billy Penn 
I have a cool little 1980′s Fender Super Champ. It’s one of the amp models that was designed by Paul Rivera. This little guy puts out about 18 watts through a single 10″ speaker. It also features Reverb and an overdrive mode. This is a great little amp to take to jams or recording sessions. It’s an all tube design and one of the last point to point hand-wired Fender amps. A few shortcomings of this amplifer are 1- The footswitch design that engages the overdrive mode sucks….it completely changes the tone of the amp the instant you plug the footswitch in. 2- The stock 10″ speaker sucks…nothing left to say. 3- The tiny output transformer holds back this little monsters potential.
Two of the three shortcomings can be fixed pretty easily and for not too much money. The one that cannot be fixed is the footswitch circuit….I’ve tried and it’s just the design….oh well. First thing is to ditch the stock speaker and put in one that’s more efficient with more clarity and better bass response. I chose an Eminence Ragin Cajun and the amp totally came to life. You can do a gig with no problem once you install the Cajun.
If you want to take the amp up another level or two then you have to replace the puny output transformer. I removed the stock unit and replaced it with a Mercury Magnetics FBFDR-O model. This is the clone of the blackface Deluxe Reverb output transformer. It is definitely bigger and if you install in on a slight angle you can catch a mounting screw hole for a terminal strip so you do not have to drill any holes in the chassis.
The result is absolutely astounding..!! It has been a long time since I upgraded a transformer in an amp and this swap reminded me how effective upgrading an output transformer can be. The whole amp just opened up and the bottom end got much tighter and defined…almost piano like. The overall volume of the amp increased and the dynamic range was broadened. There was much more harmonic content and overall the amp sounded and felt much more solid. Besides sounding and feeling better this amp was now a lot more gig worthy. A simple transformer swap did all that and only took about an hour from the time I dropped the chassis until I hit the first note. To me that’s a total home run..!!
If you have an amp that sounds and feels good but want to take it up a level or two then let me suggest two reasonable upgrades: New speakers and a transformer swap….at least the output transformer. These two upgrades can transform your amp into something magical. Plus it is a lot less expensive than getting a whole new amp, not to mention the time you have to invest trying a bunch of them until you find one that works for you.
I am affiliated with both Eminence and Mercury Magnetics. If you have any questions and are interested in upgrades please email me and I can help make a recommendation or two on speakers and/or transformers. You will be amazed….I am every time..!!
Tags: Amp, Amplifier, Eminence, Fender, Guitar, Mercury Magnetics, Ragin Cajun, Rivera, Super Champ | 
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Hi Billy, I have a recently re-issued Fender Champ and wonder if the upgrades you made will be worthwhile for my amp. All I have done so far is swap the 6V6 for JAN- Plillips 6L6 and it seems to have increased/tightened its range and better dynamics albeit not as significant as what you`ve mentioned.
Hi Hiew- Thanks for visiting 300guitars….!!! Can you tell me which re-issued Champ you have? I can help you better if I knew the model. Thanks!! -Billy
Hi Billy, I have an original Super Champ too, so I’m stoked to hear about this upgrade!
Have you tried any other speakers in yours before the Eminence?
Thanks for the info!
Hi Loni- I have tried my Super Champ through different brand speakers in other cabinets. I did try a Weber 10A125 in the Super Champ cabinet and it sounded really good. The best so far to my ears are the Eminence Ragin Cajun and Red Fang 10. The Celestion G12H sounds really nice too but in an extension cabinet. The output transformer REALLY helped out the amp. -Billy
Hi Billy, Sorry it`s a Fender Champ 600. Thanks, Hiew.
Hiew- Did you see this article? http://www.300guitars.com/articles/diy-hot-rodding-the-new-fender-champion-600/
The good folks over at Mercury Magnetics have a cool demo video: http://www.mercurymagnetics.com/pages/mainframe.htm
Upgrading your transformers will make a big difference in your amps sound and dynamics for sure. Check out the links above and let me know what you think…!!
-Billy
Hi, Billy – I have a Fender champ II … same wattage…same 10 inch speaker…1982…has a pull out in the treble knob for mid’s. This same output transformer should work for this also??? Please let me know!! Thank you, Mickey.
Hi Mickey- Yes, the same OT I used will work and in conjunction with a really good speaker that amp will blow your mind…!! The circuit is very similar to the Super Champ in the clean mode without reverb. Please let me know if you want more info and pricing…. Email me: billy@300guitars.com
-Billy
Many Thanks, Billy. I missed your earlier article .
Hey Billy,
I have a Fender Hotrod Deluxe that I would like to upgrade and improve the tone. I’ve done as much as I could without taking the thing apart. TAD 6L6-str, Tung Sol 12ax7 and two Mullard 12at7 with Jensen P12N sitting in. They did increase the tone for the better but I’m always looking into improving the “tone”.
I’ve been researching and one that might be somewhat easy to do would be OT and PT upgrade? I read what you wrote about how OT changed the dynamics on your tone but what improvement does the PT upgrade bring? And lastly how easy are they to do?
Thanks Billy,
Hi Jonathan- Thanks for visiting 300guitars..!!
As you read in my article the OT can really increase the performance of your amp overall. It can be a drastic difference for some amp models. I highly recommend this and swapping an OT is not that difficult if you have some soldering iron experience. Mercury Magnetics makes a direct replacement so you won’t have to do any “reptile dentistry” to make the transformer fit.
The power transformer can make a big difference in dynamics and will help with clarity as well as a wel defined bottom end. This is the supply for the rest of your amp. I did an interview with Sergio Hamernik at Mercury. Here is the link to a bunch of great info it has two parts: http://www.300guitars.com/articles/interview-sergio-hamernik-of-mercury-magnetics-transformers-part-1/
The PT is a little more involved but again there is a drop in replacement.
Please let me know if you have any questions or you would like to order a set for your amp. I have been affiliated with Mercury for about 8 years and their products are excellent and service second to none..!!
-Billy
Billy,
I have a Super Champ that i am in the process of getting up to speed. I have been experiencing strange and random output surges where the amp sounds fantastic and wonderful for a few minutes, than fades back into not a horrible tone, but rather bland and mediocre – nothing like when it was new, but nowhere near what it should be given what the amp is capable of. I remember A/Bing it when they first came out with the PRII and i liked the tone of the SC better -so i bought it. What you imply in your upgrade report is that really the amp was under powered by design. Nonetheless, i am a bit gun-shy of replacing the OT because i did this on a Fender Blues Junior and was underwhelmed with the improvement. The Rivera-era Super Champ is a wonderful amp in concept and features and to me is every bit as quality as any amp ever made by Fender and I don’t mind investing in it. The OT and the PT appear to be the same size as on my ’79 Princeton Reverb, and i have been told that the Vibrolux Reverb PT and OT from that amp can fit directly onto the chassis with no modification into the same holes, but the amp would run 6L6′s in lieu of 6V6′s for around 30 watts output. Could this be done on a Super Champ? Also, do you know of any sources for the odd Multi-stage Can electrolytic filter cap -the 80-40-20-20 one. My amp is nearly 30 yrs old which beyond the life expectancy of these caps. What say ye? Thanks, Keith
Hi Keith- First I would get my amp playing correctly and not fading in and out of godd/mediocre tone. Does it need new tubes? Did you use a Mercury Magnetics OT? they are really great imo. You cannot fit the Vibrolux PT in that amp. I would leave the PT alone…or upgrade to a Mercury Princeton clone that will bold right in. Also, I used a Deluxe Reverb OT so there is more core….it’s louder with better bass response…BIG difference. I believe you can get that cap can from Antique Electronic Supply. I cannot get on their site right now or I’d post a link. I believe that’s where I got mine. Let me know if you need more info..I’m a Mercury Magnetics dealer fyi in case you want to go for the iron upgrade… -Billy
Billy,
Thanks so much for your response! I have replaced tubes and caps, added a bias pot, and screen grid resistors plus a sag resistor. It is actually sounding much better, and i did have a bad guitar cable (since repaired), and cleaned all cable/jacks associated with my pedal board. It is possible that the odd surges were because of bad/dirty 1/4″ cables and jacks. Since i’ve cleaned everything the tone/output has been pretty good and consistent – i haven’t experienced any noticeable power swings yet (a couple of days anyway). I’d feel pretty stupid, but at the same time pretty happy if that’s all it was this whole time! I really want to do the Mercury Mag Deluxe Reverb OT upgrade though. My ’79 Princeton Reverb was restored after being through an apparent flood (a long and beautiful story) and nothing was done to the original trannies but it has the most wonderful full-bodied bass and blooming o’tones that makes me wonder if the spiel about certain OT’s in certain amps is the ticket. The Super Champ and my PR have the same trannies – only difference is one has been through a flood and the other hasn’t. The fact that Mercury Magnetics would seek out a Deluxe Reverb with the best tone to clone that particular OT rates pretty high in my book. The Super Champ has so much goodness in such a small package – how can ye not love the thing? My theory is that it should sound at least as good as the PR. It’s small enough, it’s loud enough, and doggonit people like it! I’ll let ye know what happens after the upgrade. Be patient with me as i have to sell some stuff on ebay in order to buy the thing. I’ll be back.
Manzano.
Keith- I use my Super Champ with the DR OT all the time. Makes people really scratch their heads….that OT really opened the amp up. Not only is it a great OT it’s bigger than the original so the amp is fuller, clearer and louder. Mine also has an Eminence Red Fang which also made a big difference… It’s more efficient (102db if I remember right) and there is plenty of bottom with nice thick mids..clear highs as well. It’s a magic combo..!!
About your bad cable….been there, done that. It happens..!!!
Let me know when you are ready and I will get your order going…..NP..!!
-Billy
Hi! I got an ’83 Super Champ and I love it!! I play it at ’9′ all the time with no problems whatsoever! I put a Weber 10F150T and the amp became a bass monster! The Weber blue pup was super cool too! (Sounded like knopfler!!) The last thing i did was move the chassis to a 1×12 solid pine cab with a tone tubby 12″ in it! One word…wow!
I got a question. If i change the OT can i also change the Output tubes to 6L6s?? would it it need just a bias change or is it more complicated? thanks!
Hi Krommydas- I do not know if the power transformer can supply enough current for 2x6L6′s… I would try to check with Fender or upgrade the power transformer as well. You would also have to adjust the bias. I would change the OT and keep the 6V6′s and see where you’re at. I think you will be very surprised what a difference a Mercury Magnetics OT can do for your amp..!!! I was really knocked out..!!! I am affiliated with Mercury and can supply one for you if you like. -Billy
hi! I found this deal on ebay
http://cgi.ebay.com/Mercury-Magnetics-Deluxe-Reverb-Output-Transformer-OT-/160460687172?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item255c33c744
if you can do better i ll get the trannie from you!
Consider paypal and shipping to greece europe via airmail priority!
Thanks a million for your help!!
Billy,
I am ready for the FBFDR-O upgrade. Please email me with your price w/ shipping. Not sure if they send direct from Mercury Mag LA to me or it has to go to New Jersey first and then back across the U.S.S.A. to the Peoples Republic of Oregon, but i’ll let you work that out with the Politburo. Also, i’d like to get a 500pf cap for the o.d. channel as described in your video of your mods if you could throw it in too. Also, i’d forgot to mention to you that i upped the negative feedback resistor on my Super Champ (some recommend removing entirely) and this also improved the tone. Stock it is a 2.7k and I changed it to a 4.7k – gave the amp a looser feel with a tad more gain. There is a slight difference between no resistor and the 4.7k, but figured some negative feedback would be good so l left the 4.7k in, per my amp guru’s suggestion. Anyway, i’m hoping you can come close to the Ebay price as Krommy from Greece has noted above. Let me know. Thanks. I dig your guitar playing! I checked you out on youtube – very inspiring. What is that amp that looks a lot like an electric cooling fan behind your bass player?
Billy,
Thanks for the great experience with the Mercury OT order – great price and they did ship it from California which was most efficient! The 500pf cap arrived in the mail, and I really appreciate the rapid response time on communications given the east coast / west coast time zone difference. It was a tight fit with the OT but managed to use existing hole locations to avoid drilling. Wiring it up was easy once it was mounted securely. It was not an overwhelming improvement, but it did eliminate much of the boxy-sound of the small cabinet, and there is now better note-definition and clarity with chording and a noticeable pleasant chimey-ness that wasn’t there before. It sounds like a blackface Fender amp should, with a tad more punch than it had before. I still feel there is something off with my particular amp – it is not pushing out the sound that it is capable of. It could have something to do with the footswitch circuitry / pull pot switching that is not functioning as it should and zapping some gain. If anyone out there has any ideas let me know. My Princeton Reverb has way more clean gain than the Super Champ, but in theory it should be the other way around, especially now with the beefier OT. Anyway, thanks again Billy for all you done did!
Hi again! Thanks for the excellent communication and service! I installed the transformer today (that was WAY easier than I thought although I had to solder it to place ’cause it wouldn’t fit in the existing chassis screws)
Anyway, the amp sounds…more ‘alive’ .Like its frequency responce was broadened. Can’t say it;s louder or bassier but it sure sounds better than before ! I loved this amp before ,I sure love it now even more!
All in all a great tip from the Pennalizer! Thanks again so much!
Argy
Thanks for the kind words Argy..!!! I’m glad it all worked out and that you are happy with the results. Please let me know if you ever have any questions….I am happy to answer them for you..!! -Billy
Hi again!!
Got some more questions!
I swapped the 6V6s the other day with NOS 5881s and was amazed by the improved bass/punch. I already see that my amp has a trim pot for bias. Qs are:
1.Can I get a 220VAC Power Tranny that would be a direct replacement for the Super Champ only bulkier to handle 6L6 tubes heat/current draw?
2.How much would it cost?
3.Is this amp cathode biased?
4.What bias current is ‘right’ for 6L6 for this amp?
thanks!!
Hey thanks for the thorough answer!! I appreciate it!!
It seems quite some trouble though and I don’t want to make permanent changes to the vintage amp ,so I ‘ll just keep the new trannie and the 1×12 cab! (it already sounds sweet and is loud enough for most miked gigs!)
Dude you rock !! Thanks!!
I am upgrading an upgrade. A Tweed Hot Rod Deluxe was purchased for $750.00. I sounded great, but took a dump in a year. New tubes bias etc. Same thing in 6 mos. I sent the chassis to Torres Engineering for a complete upgrade.. $800.00 and 6 weeks later It came back working but sounded like crap! I changed the pots, moved ground wire from the treble to the mid pot and it sounded better. Pilot lite flikers on and off, the whole thing hums. Now I am putting a Cannabis Rex, and thinking I should upgrade the OT? any suggesstions?