Chassis dimensions and board dimensions?

[Mark]

I was wondering if anyone had posted up this information?

This would make it much easier for some of the guys here to build the amp.

I can try to have a look at a few photo's and draw up something thats looks similar to me, but if someone has already done this work it would a waste of time to do it all over again.

It's all looking interesting so far.

Yours Sincerely

Mark Abbott

[pedro]

I'd be happy to draw mine up and send you a photo along with internal shot of my board if it helps.

PS - my layout is based on a variation ofb th edifferent schems so you'd have to decide which circuit variation your going with.

cheers
Pete

[Bennypapa]

I am going through this very struggle as we speak.

I have settled on a schematic and I am doing the layout now. But there are other issues to consider.

You have to keep in mind the chassis size that you have to work with. This could greatly alter your layout.
As mentioned you have to decide what schematic you want to use.

I am going to incorporate footswitching for the OD channel and boost circuit, an fx loop, and footswitch for the boost. I don't want bright switches or the deep or the jazz switches.(personal choice due to limited panel space) I have limited chassis space due to the fact that I am building in a hacked up Fender bassman.

All these things dictate the layout. My layout may be very different from the layout that someone uses to build their amp in a 12" x 18" x 2-1/2" chassis.

SO,

What schematic do you want to use and how big is your chassis?

Knowing that maybe someone with a similar setup can hook you up with their layout. I haven't found anyone that has built the exact amp that I am building but I have found some of the nicest, most helpful folks here.

Bennypapa

[Robert]

Hi Mark,

Attached you will find my build layouts for the preamp and power supply to my Dumble build. You can see the pictures of them in the other thread. I followed as close as I could the available pics and created this composite. It will at least get you started and save you considerable time. I recommend you use it for what you can and adapt it to your needs. I have changed many of the values for the resistors and caps from these layouts to better suit my taste. You will need to do the same depending on your guitars, transformers, tubes,speakers and style of music. The dumble amp really does vary considerably over time and between amps, unlike the Express which seems very consistent. There are of course a couple errors which I corrected as I built the amp. I also included a footswitch to activate the boost and channel switching. The preamp board I used fit the excellent chassis from Funk, which I would recommend to everyone. Its dimensions are 24x5 1/2 cm. The PS board is 11x13 1/2 cm. Hope this helps.

Will someone tell me how the hell you add an attachment as a file and not display it as a large image.

[pedro]

Mark,

if its any use here is my layout and board - you'll be able to see the relationship between the two I think. Hand-drawn shows board layouy only without external connections but you'll figure it I think.

let me know if you have a private e-mail and I'll shoot you a schematic for this. I was given the schem by someone so I dont want to post it without their prior permission really. Its a slight variation on many of the published schems.

NB - this layout is still being built so dont shoot me if its not bug free just yet - but looks OK. If anyone can see any errors let me know !


cheers
Pete

hope the files are'nt too big !

[Normster]

The chassis I used was 19.25" x 8.25" x 2.5". Preamp board was 8" x 2.75". Power supply was 3.5" x 5". Bias/FET/Relay boards were 1.75" x 3".

[BobW]

Normster, Excellent craftmanship! Congrats. I'll bet it sounds wonderful! Any chance you are willing to offer suggestions on the grid stopper ckt at OD1? The clean channel sounds great except for a little too much bass, and the OD sounds gritty w/220pf in the stopper ckt. Changing to a .01 sounds better but is still not THE tone. Was referencing my posted my layout in the bassman area.

[Normster]

Thanks, Bob! I tried the network but didn't like it as much as the 220k w/100k trim. I'm actually wrestling with the same problem you have on a '71 SF Bassman Dclone I built for a friend. Oddly enough, I built his amp identical to my '69 Bassman and yet my Bassman is clear with a tight bottom and his is flabby but has more gain.

Ol' Dogears has suggested that I up the primary filter caps to 220uF to tighten the bass. Also, I hate the response of the .02uF/.01uF mid cap values. If that's what you're using, try a .05uF. You just might like it.

To smooth the OD, you might try 500pF snubbers on OD1/OD2 but until you get the bass problem solved it'll probably just sound woofy. I used 270pF snubbers because I like the extra grit. I'm also a low gain player. The last thing is to maybe try a .005uF coupling cap on OD2 instead of the .01uF.

I'll be working on my friend's SFBM this weekend so if I find a magic formula I'll let you know. (Please do the same if you figure it out. )

[Omar]

Will someone tell me how the hell you add an attachment as a file and not display it as a large image.

Showing a file as an attachment is a forum setting based on file extension. I have set all attachments now show as a file.

See http://www.maximoaudio.com/forum/viewtopic.php?t=422

Omar

[dogears]

First thing to try IMO......

Then the .01 or .02 midcap works better?? No?

Don't use the .02 in OD1 either.

The last thing is to maybe try a .005uF coupling cap on OD2 instead of the .01uF.

[Normster]

First thing to try IMO......

Then the .01 or .02 midcap works better?? No?

Don't use the .02 in OD1 either.

The last thing is to maybe try a .005uF coupling cap on OD2 instead of the .01uF.

Just to be clear, Dogears is my mentor so if he says try the .005uF cap first, I have to agree. FWIW, I haven't tried the .02uF mid cap with a 250kA mid pot so that may in fact work out well.

[mlp-mx6]

I think dogears is nearly EVERYONE's mentor - myself included, most definitely. Have you been to his web site and heard his clips? Monster player.

I've never chatted with a less selfish person when it comes to amp info. He's DA MAN!

[dogears]

Shhh......

So the real secret is the sfetzer valve and ball bearings.... It's all the ball bearings! LOL

[Chad]

I've already learned alot from a few here (Dogears, Funk, Bob, Normster) in the last few weeks. You all are a wealth of knowledge. And again Thank's. I don't believe I've seen dogears's website before,were can I find it. Chad

[Normster]

I've already learned alot from a few here (Dogears, Funk, Bob, Normster) in the last few weeks. You all are a wealth of knowledge. And again Thank's. I don't believe I've seen dogears's website before,were can I find it. Chad

You're in for a scary treat
Ol' Dogears Doghouse