Developing the DIY "Champ" for first time builders

[statorvane]

Will a step bit going up to 7/8" handle all the holes that are needed.

I used a hole saw for the octal sockets on my most recent amp, aluminum chassis - 1/16" thick. Worked better than a spade bit, which I had previously used. Bore a pilot hole, then slip the hole saw arbor in there. Presto.

[RJ Guitars]

I have been using step drills for the past few years and find them to be the best tool for me. I have a complete assortment of chassis punches but with the exception of the IEC punch, they are rarely used. When you get to the bigger holes like the Octal socket it helps to use some cutting fluid. Also, the step drill I use for the Octals is actually a Metric step drill. Large step drills also work best if you have a stout drill press and run them at a slow speed. You can buy them pretty cheap from Harbor freight or off of EBAY. You get what you pay for but unless you make more than 20 chassis a year you won't need the premium grade tool.

rj

[TheGimp]

I made a drill jig to allow me to drill all holes including vent holes around the socket. Then I use a GreenLee punch to open it up for the socket.

http://www.diyaudio.com/forums/equipmen ... g-jig.html

[angelodp]

rj, why the metric. snug fit?

a

[telentubes]

I'm fine with a blank chassis. I have all the gear for cutting holes. Thanks RJ for all your effort.

[TheGimp]

Tip for punching and cutting aluminium/aluminum Use WD-40 as a cutting fluid.

It is the ONLY good use for the stuff, other than as a cutting fluid for Plexiglas and lexan.

[RJ Guitars]

rj, why the metric. snug fit?

a

If I recall correctly it was that the US version went from 1-1/8" to 1-1/4" and as mentioned the Belton sockets need a 1-3/16" step. By coincidence the large metric step drill worked out perfect for those sockets. I use the US version and make a 3/4" hole for the 9 pin Beltons.

I'll plan on sending out some chassis with holes for those that don't have the tools. We want to make it not only affordable but possible for anybody that wants to build one of these to do it without the added cost of more tools.

Tip for punching and cutting aluminium/aluminum Use WD-40 as a cutting fluid....It is the ONLY good use for the stuff....

does the trick for squeaky door hinges at my house.

rj

[angelodp]

rj, have you the developed layout available yet? Will this include...

1. Chassis and all components
2. Cab & speaker
3. Tubes

best Ange

[RJ Guitars]

rj, have you the developed layout available yet? Will this include...

1. Chassis and all components
2. Cab & speaker
3. Tubes

best Ange

Ange,

A chassis, faceplate, transformers, and all the internal components will be referred to as a "bare bones parts package" and it will cost less than $100 for the works. I will label this as the "Eagle 100" DIY amp. That is the primary offering I plan to make. I'm still sorting out how far under $100 the final cost will be. I have bought enough parts to build a dozen basic units and we'll see how long they last. I've also got a few upgraded tranny sets coming in to look at a premium version which I'll label as the "Eagle Premium" amp.

I am working on the BOM and layout this week and will post it when I have it finished. If a person prefers, they can source all the parts for themselves and build from those.

I will make head and combo cabinets available on request and maybe Russian tubes, but probably not speakers. I haven't sorted out pricing on any of those things yet.

That is the story.... for now anyway.

rj

[M Fowler]

rj I was assuming this was going to be a blackface Champ but perhaps you were intending to build a tweed version? 5F1?

[angelodp]

This one will be for my grandson Marco. Looking forward to the build.

Cheers Ange

PS was their a reverb version lurking in the wings

[RJ Guitars]

rj I was assuming this was going to be a blackface Champ but perhaps you were intending to build a tweed version? 5F1?

Yes that's right, the 5F1 schematic but my own take on the layout. I am after the simplicity and very low parts count for that circuit. I do expect to morph future versions into more advanced forms of the Champ for myself. However #1 will be the simplest quality amp that can be built for under $100 and that will be the first offering.

I am currently in sunny Cleveland attending a training class for my day job... which should allow me some after working hours time here at the hotel to finish up the layout drawing for this project. I also brought the #1 chassis and parts with me so that if I don't spend too much time enjoying the evenings otherwise I can wire it up one of these nights.

I brought the Russian 6P6S output tube and a 6H2n-EB preamp tube with me. I don't know if these are going to sound good or not but they are certainly easy on the wallet.

The 6H2n looks like it requires that I wire up the heaters a little different than the 12AX7, but won't take much work to swap it out if it doesn't sound adequate. The 6P6S looks like a direct swap for the 6V6gt, although the voltage rating is quite bit less than the 6V6gt.

enjoy,

rj

http://ussr-tubes.com/index.php?main_pa ... cts_id=279
http://cgi.ebay.com/4-x-6N2P-12AX7-ECC8 ... 3f067f5730

[RJ Guitars]

Well,

This took a lot longer than it needed to but I'm in Cleveland in January and was kinda pleased to have a reason to stay indoors... wow it's cold here!!

Please take a look and see if I have all the right pieces going to the right places etc.. I can't seem to build anything that doesn't look like a Trainwreck layout these days, but I suppose there are worse amps to be influenced by.

Right now I am looking at something just over $90 if I include tubes (Russian NOS) and wire... and every screw, nut, and terminal. With a bit of effort I think a guy could put one of these together for quite a bit less.

There isn't much required to make this fly with US tubes but I'll save that for later.

rj

Edited 3/25/10 -- removed the layout posted here. Go to page 16 for the most recent version

[ChrisM]

Looks good,
You could get away with only two diodes if your looking to cut costs a tiny bit.

[M Fowler]

rj looks good and should be a fun build