Champ Amp Modified Clone 180519

Inspiration 

This is the piece which started my Butterscotch Series of builds.
Over 10 years ago I had this Fender Champ clone, modified 5F1 amp built by the owner of one of the main amp and guitar parts suppliers. I asked him if he could make me a Champ with more gain. He said he could and I got a modified 5F1 circuit, the nature of which he did not disclose to me in terms of the circuit mods. I could see several additional resistors on the preamp 12AX7 tube and some modification to the wiring. Regardless, I had great hope for this amp. I plugged it into a speaker cab and it was terribly noisy. It had the high gain but was unusable. I assumed that this was the byproduct and the result of the high gain modification done to the circuit. Well, the whole thing was an unknown and I took a gamble. So disappointed I just put the chassis on the shelf, where it sat untouched for over 10 years.

At the same time I met a guy online who specialized in cabinet building. I commissioned him to make me several cabinets, one of them was meant to be for this Champ amp. He did a very nice Job on the cabinet. Much nicer than the original Fender cabs, which were rough underneath but then covered in either Tweed or Tolex. I first wanted him to make me the cabinet from the same Pine that Fender used but he told me that if I will keep this cabinet uncovered, it would not look very good with the knots and voids that Pine is known for. So he suggested we go with Aspen. Good advice. Aspen is a much cleaner wood and this has no knots or voids and is smooth everywhere. This was an unfinished cabinet with no grill cloth, no feet, and no handle. The cabinet also sat on my shelf for over 10 years. 

I finally got sick of looking at these pieces going to waste on my shelf and this year I decided to do something about it. It was to be a revisited project. 
I know more about electronics now than I did years ago, so I analyzed the circuit diagram and realized that the first thing I should do was to return this amp to the stock specifications of the 5F1 Champ circuit. I removed all the modified components and returned it to stock. 

I plugged it in again and the amp worked well but was still very noisy. It was buzzing loudly at all volumes. So, I looked at the circuit again and finally found what was going on. One wire was missing, It was a grounding wire, which grounded the circuit to the chassis. This is all that it was. The original builder had missed adding this wire and did not ground the amp. All problems solved. 

The amp was now completely stock but I needed to do something with the hole in the faceplate where the original mini-switch was before, which turned the high-gain circuit on and off. What I decided to do is to add a Negative Feedback control but instead of a switch I wanted a potentiometer in order to make the negative feedback control variable. This way I can dial in the exact amount of Negative Feedback I want for any playing situation.

To my surprise this pot acts like a quasi master volume. Not quite but similar in function at least. It comes in very handy when one wants to turn the amp down to bedroom noodling volumes, while watching TV, whereas I was not able to achieve such low volumes from a stock Champ. This way I set my minimum usable volume, in order to have the tubes still work at a proper level, then simply activate the negative feedback, as needed to bring the overall volume of the amp down even lower. Its similar to a master volume control in this regard.

Aside from lowering the volume, the negative feedback control also attenuates the high end of the amp, so it also works as a quasi tone control on an amp which does not have a tone control.

After taking care of the electronics part of the amp. I had the idea of doing something unique with the cabinet. I did not want to cover the nice wood and joinery with any material. That is too common. I decided to paint it, but that had to be unique also. I wondered why Fender never pained their amp cabinets, realizing that they could not, given the nature of knotty pine they used for the wood. So I decided to give it the same finish as the period-correct Butterscotch Blond Telecasters. I used real Nitrocellulose Lacquer to paint it this iconic Telecaster color. It just begged for antiquing, in order to have it look right. I reliced the entire amp, grill cloth, leather handle and all metal parts and knobs. I liked the way it turned out so much that this amp started the butterscotch series and inspired two other instrument. You will see these instruments cataloged on this site, consisting of Zachary ZT Telecaster Guitar 202-060619 and Zachary Telecaster Bass 204-170819. 

So there you have it, it worked out well in the end. Its a killer little amp, with a very unique finish.