Chump Turns Into a Real Champ

Not to digress too far from the Surfcaster, I wanted to get with the program and write up my Champion 600 to 5F1 conversion.

About a year and a half ago, I picked up a used Champ 600 off e*ay. I had seen one in the flesh in my local huge independent music store (still haven't gone into a Guitar Center...) and thought it was cute and might make a neat practice amp. I wasn't going to spring for $200 for a new one, but I started watching online to see what a used one could be had for.

Long story short, I snagged one in virtually as-new but "not working" condition for $105 plus shipping. It even came with all the factory paperwork and the original box.

Turns out the Chinese-made 6V6 went belly up and took a couple of resistors with it. I replaced them (remembering in the process how much I HATE PC boards...) put in an old RCA 6V6 and the little puppy was back in business. This was good.

Well, not so good. The amp had an awful, unacceptable hum, had virtually no high end, and sounded really dull to me. I have an original '56 Princeton and just finished building a 5F11 Vibrolux clone, and they both sound great. I didn't expect the Champ to be exactly like them, but on the other hand, given the circuit, I expected a lot more.

So...I went on a mini-quest to mod the Champ as it was. I replaced all the Chinese electrolytics with better quality Nichicons, and upped the value of the first filter from 22 uF to 47. Some improvement on the hum, but it was still bothersome. I also replaced the original speaker with a Weber, and added a circuit to switch a cathode bias cap in and out of the first gain stage to get a little more grit.

It was better, but still lacking.

So after letting the cute little amp serve as my workbench/test amp for a while, I got an idea: why not ditch the modern guts and build the thing into a tweed? I did some measurements and it looked feasible. I figured I could use some old parts I have on hand to give it some vintage vibe.

So with that background...

Here's the chassis still in the amp:




Here's the chassis and cab:



It sure is a cute little thing. Maybe we can make it sound as good as it looks, yes?

At least it passed QC, whatever that was.

You can see my goofy mods:



The arrows point to the 47uF cap (had to mount sideways due to its height), a couple Orange Drops and the gain switch.

First order of business is to strip the chassis:



Labelling a few things for future reference...you never know when those bits might come in handy!