Rebuilds for the Fender Pro Junior

The Fender Pro Junior can be rebuilt into a boutique quality hand wired amp! Carl's Custom Amps has been doing this for a while turning Pro Juniors into true tone machines. Lots of different style are possible. Each kind retains the original controls.  We always replace the output transformer with much better Hammond, Heyboer or custom made unit for much richer sound.  The hand wired circuits sound amazing, rich and 3-D. All you need to do is send in your chassis and we'll rebuild it and ship it back to you to re-install.  In some cases we'll recommend that you also replace the speaker the speaker for the best sound.  Contact us to get started today!

Rebuild cost vary from about $400 to $900 depending on the model. Contact for current pricing.

Note: we give you a trade in value on the parts we don’t re-use like the PCB and transformers. If the chassis is stripped of parts we will need to add those to the final cost of the conversion.

SEE BELOW for rebuild models

Rebuild Options:

Contact for current pricing

$500 and up:

5 W Tweed Champ/Princeton Style

Great gritty Tweed tones. Think Eric Clapton’s Laya and Kieth Richards and other greats! While the Pro Junior cannot fit a tube rectifier a special sag circuit is installed to retain the same feel.
Tubes: 1X 12AX7, 1x 6V6
Controls: Volume and Tone
New Handwired board, Custom Transformer Set,

Speaker Options: the stock speaker works well with this amp. If you want more vintage sound we provide a Weber 10A125 Alinco Speaker

5/10 W Tweed Champ/Princeton Style

Great gritty Tweed tones. Think Eric Clapton’s Laya and Kieth Richards and other greats! While the Pro Junior cannot fit a tube rectifier a special sag circuit is installed to retain the same feel. The amp can use a 6V6 for 5W or any 6L6 type for 10W with any changes except for swapping the tubes.  

 
Tubes: 1X 12AX7, 1x6L6
Controls: Volume and Tone
New Handwired board, Custom USA Made Transformer Set

Speaker Options: the stock speaker works well with this amp. If you want more vintage sound we provide a Weber 10A125 Alinco Speaker

5/10 W Tweed Octal Princeton Style

Great gritty early Tweed tones with great harmonics. Look at the Octal Princeton page for more into. While the Pro Junior cannot fit a tube rectifier a special sag circuit is installed to retain the same feel. The amp can use a 6V6 for 5W or any 6L6 type for 10W with any changes except for swapping the tubes.  

 
Tubes: 1X 6SL7, 1x6L6
Controls: Volume and Tone
New Handwired board, Custom USA Made Transformer Set

Speaker Options: the stock speaker works well with this amp. If you want more vintage sound we provide a Weber 10A125 Alinco Speaker

5W British Champion

My hybrid between the Tweed Champ and the Marshall Plexi sound. Uses the stock power transformer and EL-84 power tube.

Tubes: 1X 12AX7, 1xEl84
Controls: Volume and Tone
New Handwired board, Classic Tone Output Transformer

Speaker Options: the stock speaker works well with this amp. If you want more British sound we provide a Weber Silver 10.

5/10W British Champion

My hybrid between the Tweed Champ and the Marshall Plexi sound. Fitted with El-34 power tube it’s got rock n’ roll thunder. It can use most octal power tubes.

Tubes: 1X 12AX7, 1xEl-34
Controls: Volume and Tone
New Handwired board, Custom USA Made Transformer Set

Speaker Options: the stock speaker works well with this amp. If you want more British sound, we provide a Weber Silver 10.

British Royale 5 Lite (Vox Style)

Great 60’s Vox type tone. It’s crunchy and classic sounding!

Tubes: 1x12AX7 and one El-84

Controls: Volume (with push-pull FAT switch) and Tone

New Handwired board and Classic Tone Output Transformer

Speaker Options: the stock speaker works well with this amp.

 Tubes and the power transformer will be tested when the amp arrives. Depending on the speaker model you have and rebuild model you choose we may recommend a replacement speaker that can be sent back with the amp.

Customer Comments:

“Hi Carl,

The amp was delivered yesterday. I tested it in the morning just to make sure it survived shipping and played it for an hour in the afternoon. As you said, it sounds great! I'm so glad to have discovered your website. Since there was such a discount on the Pro Jr. I was considering buying one and replacing the speaker and tubes myself. When searching for info on the inside of the amp I fortunately came across a photo from one of your rebuilds. You are a gifted mechanic in the classical sense with an understanding of the physics of sound and capable of conceiving ways to amplify it and then execute the projects with your hands. Thank you!”

William O.

“Let me start by saying that I’m not an expert when it comes to the finer details of tone and amplifiers. Here’s my story.

I play guitar mostly at home because it’s good fun. I sometimes go to a local rehearsal space where I can crank an amp until my ears bleed. Sometime I get together with friends to jam on some basic blues progressions. I live in a small house, so turning up an amp beyond the volume of a normal television rarely happens at home.

I started playing in the late 1980s and I’ve always had solid state amps. Not sure why. They’ve always been plentiful, reliable, and met my needs. The last few years, older Peavey amps have been my main squawk boxes - a 1979 Backstage 30 and a 1987 Bandit 65. No complaints, great affordable amps that sound good to my ears. Then, I started to ponder the much hyped world of the vacuum tube amplifier. Yikes! So much to consider. Without getting into the weeds, I decided to purchase a used Fender Pro Junior. The reviews were favorable, it was the right size for my needs, and it was affordable. The used amp showed up in November 2019.

The Pro Jr was good and seemed to get along with my 2016 Les Paul Traditional and my pedals. But, to my ears, it wasn’t the magic tone that was supposed to blow my mind. It was just.....okay. Meh. Then, the amp started to develop a loud hum and rattle that was obnoxious and ultimately made me stop using it. A shame for sure. I started calling local shops to inquire about repairs. It quickly became apparent that it was going to cost me a few hundred dollars to fix my $325 amp. I started researching alternatives and stumbled on Carl’s Custom Amps in New Mexico (I’m in MA, so definitely not local). Carl’s website had some good information about his options for a Pro Jr rebuild/ overhaul. I sent Carl an email with some general questions and to my surprise, he responded the same day with great information. After a few more emails, I decided to bite the bullet and send my chassis to Carl for a complete rebuild into a British voiced 10 watt Fender Champ. Sounded good to me and the price was fair.

After a 3 week wait, the chassis came back to me by FedEx. I’m no electronics wiz, but everything was completely replaced with hand wired/soldered high quality components. Visually it was very obvious that the amp was assembled with care and skill. Its beautiful to look at. I quickly installed the chassis into my old Pro Jr cabinet with an 10” Eminence 1058 Speaker. The first thing I noticed was that the amp is dead quite, even at idle with the volume at 50%. The second thing I noticed WAS THE AMAZING TUBE TONE I’ve heard about! Goddamnit it’s true! This simple little amp sounds incredible- it’s super touch sensitive, it breaks up and compresses in all the right ways and it’s gritty and awesome in all the right ways. It’s has “that tone” that makes you instantly think of classic Rolling Stones. The volume and tone knobs are very interactive and sculpt the tone more than you’d expect. And it sounds amazing with pedals. Plugging a Les Paul straight in is pure rock and roll heaven. I’m pumped.

I can’t say enough good things about my experience with Carl. And no, I’m not paid by him nor do I have any vested interest beyond sharing my experience.”

—JP