My first build from scratch...an Express

[donzoid]

I have lurked on this forum for almost two years studying the works of all you Zen Masters. During that time I've built an Airbrake, troubleshot my 50w JMP Mk2 to success, and corrected a ton of previously "aquired" mistakes done to my 100w. Well I finally decided to take a serious plunge. Here is the start of my first Wreck build and thanks to RJ for many of the parts. Some I had here, but mostly his. I'm on a super tight budget, so since I am probably going to gig this amp extensively I may go with an "Industrial" looking cab to start out. I know...a wreck for the first build. Ambitious, aren't I?

[donzoid]

I noticed that Francesca and I think Ingrid have these two resistors at 1 watt instead of half watt. But it looks like they are half-watt on the Ceriatone layout (though not specified). Also listed as 1 watt on RLW's diagram. Should I swap these for 1 watt value? (they are half watt now).

[RJ Guitars]

Congrats! That looks like a great start. You have arrived at the hangout of the finest group amp building folks on the planet... with 24/7 access to more wisdom and info than any tech support office can offer.

If you'll make those two 1/2 watt resistors easy to remove I'll make an effort to put a couple in an envelope for you.

The photos are really helpful, keep up the good work.

rj

[donzoid]

Fair enough, thanks RJ...I was kind hoping someone would just say "fuggettaboutit" but I will leave them accessible for now.

Did I mention this guy's customer service is stellar?

;>

[donzoid]

Bias Board...I found a 30K locking-shaft pot and I'm going to mount the adjuster on the back panel.

[KellyBass]

A back panel bias pot will be a nice feature...especially on an express! It will great finding that "sweet spot" with the amp in it's cabinet...very sensitive. Not to mention 6v6 swaps.

Excellent start, BTW!

[sliberty]

Other than power supply resistors, 1/2 watt is fine. But many of us build with 1 watt anyway, because we can.

[Reeltarded]

It's looking very nice!

[donzoid]

Thanks all! Got a little more done last night. Reflowed the power board, built the cap stack (used some Fiberglas board to make it all sorta self-contained then I can just glue the whole mountain down at once. God I hate that silicone adhesive. Then I started working on the chassis - added two holes front and back and opened up the power indicator to 5/8" to take a replaceable jewell type. WAS going to start assembling the chassis this morning when I realized...OH...I need a front wood panel. So, it's out to the shop at lunchtime to search for a suitable piece of 1/8" material, hopefully I can find something lurking below the bench (other than the spiders).

[cap217]

Good luck. I am trying to learn here as well and ask a lot of questions. It looks simple but we all know its not.


Looks good so far.

[donzoid]

This could work...IF I can figure out how to run the planer (I inherited) out in the shop because it's 3/16" instead of 1/8". I don't think I can stand this up in the table saw and shave it without breaking it, or having it kick back and impale me. Oh yeah. Here comes another monkey bump.

[RJ Guitars]

Have you measured the height of that cap stack? I know on the old Mallory caps they got pretty close to that 2" chassis depth.

Looks like you are doing a good job...

[donzoid]

Thanks RJ! I want it right, and I need it cheap. So I'm not rushing!

It's actually LESS room than 2" on the internal measurement after we allow the thickness of the top plate. Closer to 1 -7/8. But these are the kind of things I tend to shoot myself in the foot with....so I appreciate that wisdom. I measured the stack before I glued the top three on there. I have 3/16" left....just enough for a piece of weatherstrip on the bottom plate to make them snug. But that's not counting the adhesive that will take up 1/16" or so when I glue it to chassis so I am still good....snug...but good.

A friend whose much better at woodwork than I surrendered (and even milled) a piece of striped mahogany for my face plate. I'll stain it tonight and hopefully get started on the hard part (lead dress) in a day. I guess he didn't want me hurting myself...

[donzoid]

OK couple of questions for the more experienced builders. I am test fitting the faceplate and it's "just not quite" enough thread to start or catch the pots without leaving off the washers altogether, and that will likely scar the wood tightening them. I think this is too thin at 1/8" to try to countersink. Grind 'er (the wood, with a sander) down from the backside? Is that what you guys normally do?

Also, is it allowable to use a Marshall-style jack as an input, because it is not directly grounded to chassis the way a switchcraft would be.

[donzoid]

OK couple of questions for the more experienced builders. I am test fitting the faceplate and it's "just not quite" enough thread to start or catch the pots without leaving off the washers altogether, and that will likely scar the wood tightening them. I think this is too thin at 1/8" to try to countersink. Grind 'er (the wood, with a sander) down from the backside? Is that what you guys normally do?

Also, is it allowable to use a Marshall-style jack as an input, because it is not directly grounded to chassis the way a switchcraft would be.