champ in a box

[jjac7212]

Hey guys
sorry about the non stompbox related post
but im trying to build a fender champ amp and i know you guys are very knowledgable!!

ive built a few pedals from schematics and have grown a likening for it
iv found this schem  http://www.drtube.com/schematics/fender/champ-5c1-schem.gif  and want to build it
but there are a few things i cant work out.

1) the capacitor values are written differently to the way we all commonly know, how do they translate into uF values?
2) the heater filaments are a certain pin on each tube, right? does that leg of the transformer connect to each tubes heater?
3) these tubes are a tad hard to find, are there any good common replacements for them?

[ambulancevoice]

3) these tubes are a tad hard to find, are there any good common replacements for them?

hard to find!? there all over ebay, except for the rectifier tube
that can be substituted with any 5---- rectifier tube

[The Tone God]

1) the capacitor values are written differently to the way we all commonly know, how do they translate into uF values?
2) the heater filaments are a certain pin on each tube, right? does that leg of the transformer connect to each tubes heater?
3) these tubes are a tad hard to find, are there any good common replacements for them?

1. All values are in uF. ".02" is 0.02uF, "8" is 8uF, and so on. The second number is the voltage rating.

2. There will be two pins for the heater of each tube. One leg of the transformer connects to one of those pins. The order does not matter. Usually you hook up to the first tube then daisy chain the wires to each set of tubes. I suggest looking at pictures of other tube amp's wiring to get the idea.

3. I would not use that champ version personally. Use the 5F1 version. Classic sound, easier to find parts, and better design overall.

Andrew

[ambulancevoice]

here is the schem and layout for the 5f1

[jjac7212]

thanks very much guys, now all i need to do is switch the power transformer for something to step down australian power.
ours is 240v, does anyone know a particular model that would substitute this one?

[Krinor]

I've built a 5F1 using a Hammond power transformer.
PM me and I can send you gut shots etc. on mail.

[newfish]

Since you've got 240v (ish) to hand already, could you use a 12v step-down trannie from an old radio etc for the heaters?

By the time your 240v are rectified and smoothed (caps have a factor of 1.3 I think...), they'll still be use-able for a small valve am, won't they?

...although definately use an isolating transformer and all the usual fuse / double pole / earthing safety features.

A while ago, I built a simple 12AX7 pre-amp using plain old rectified 240v - and it *does* work.

[bancika]

A while ago, I built a simple 12AX7 pre-amp using plain old rectified 240v - and it *does* work.

That works but is not safe for you, please do not try to do that. I built 5f2-a princeton which is very similar to that champ only it has tone control. I recommend making it because it offers additional tone shaping. I also included few more mods (see my page for more infohttp://storm-software.co.yu/diy/index.php?project=princeton) which are really nice. Make sure to read it...

Cheers,
Bane