Dumble Lite? - Update, Finished!!!

[Luthierwnc]

I think it sounds like a fun project. Do a really stripped down version as far as features go. Keep the components good quality. I'll be interested in what you come up with but I expect it will be a nice amp.

As far as helping newbies, I'll throw in with jaysg. There are a lot of beginner amps out there that will give someone a solid experience building a playable rig. At this level of the game, you should have your lower division classes done. You also ought to be prepared to make the best version of this build you can. Footswitches, good speakers, good iron, tubes, whatever it takes. I don't see any way to keep the cost under $600. Cabs, speakers, chassis, iron, shipping, etc. That and all the things we take for granted like soldering irons, DVMs, variac, wire, specialized tools and all those extra parts we over-ordered from the last six builds.

I'm looking forward to seeing your schematic and layout!

Skip

[Normster]

Agreed, a newbie should have a simple build under their belt before attempting ANY version of a Dumble. Also, I'm thinking just the bare amp for $300, not including cab, speakers, tools, etc. (Although a homemade head cab is not that expensive to build.)

As for parts quality, I'm going to build the prototype with very cheap iron. If it sounds like crap, I'll upgrade to something better. The rest of the components are relatively cheap anyway. Alpha pots are only $1.25 each. Xicon 1 watters are only $1.40 for 10. I'm also going to give the Xicon electrolytics a try.

I know $300 doesn't sound like enough to get an amp off the ground, but that's about what it cost me to build my Trainwreck (sans head cab). Yes, the Dumble has a few more switches and caps, but that really doesn't add that much to the cost of parts.

Anyway, the proof will be in the pudding. If the prototype comes out sounding like crap, I'll convert it to a Deluxe.

[Luthierwnc]

If it doesn't work out, look at a Z-28. Very cool and I bet you don't already have one. sh

[Normster]

If it doesn't work out, look at a Z-28. Very cool and I bet you don't already have one. sh

I've been tempted.
I modeled my 6V6/5AR4 ODS Reverb output section after the Z-28. I added NFB and changed the bias splitters to 220k, but still pretty close. Mated to a #124 preamp it's a killer amp!

[Icetech]

Norm, sounds like a killer idea.. for me i have found a few pots useless... like OD drive.. i tend to keep it on 10 anyway and plan to remove it totally if i do a princeton build to save space:)

[SonicCanvas]

Hello to everyone, I am new to the group, I found the site today!

I have never built an amp but have completed other electronics projects in the past.

I would very much like to join you guys in this project.

Looking forward to soaking up some of the vast knowledge on this board...

Todd

[Normster]

Welcome, Todd! Warm up your soldering iron...my trannys will be here in a week.

[swt]

i'm curious about that Z28...anyone can send me a schem??. Thanks a lot!
swtnqn@yahoo.com.ar

[tictac]

What about not using a relay? Y

ou can get a pretty decent clean tone in OD mode by turning the drive down and the master up. This would make for an easy build for a newbie. Of course you really need to use an audio taper pot for the drive control to do this. Much easier to dial in the correct gain level.

TT

[Normster]

I made some progress on the Dumble Lite tonight. Chassis is drilled, hardware mounted, and preamp board assembled. Tomorrow I'll build the power board and rectifier and then start soldering. Hopefully by Sunday I'll be hearing some lightweight Dumble tones.

BTW, inspired by Bob's Princeton, I stuffed everything into a Hammond 16x8x2 chassis. Not bad for $21.

[Normster]

What about not using a relay? Y

ou can get a pretty decent clean tone in OD mode by turning the drive down and the master up. This would make for an easy build for a newbie. Of course you really need to use an audio taper pot for the drive control to do this. Much easier to dial in the correct gain level.

TT

My thoughts exactly!

[Bob-I]

What about not using a relay?

Why not use a Weber relay board. $8 and they work off the heaters. That'll keep the price and simplicity down.

[Normster]

For the first iteration, I only put in the bare essentials. The second phase of the build would move the PAB and OD switches to the back of the chassis and add a relay board. The front switches would then be converted to Jazz/Rock and Mid Boost. (Or maybe only move the OD switch and forget about the J/R?)

As for the Weber board, I've never used one. Is it small enough to put between the preamp board and control pots (ala Dumble)? If not, my concern would be all of the extra wire added to the tone circuit.

[Bob-I]

As for the Weber board, I've never used one. Is it small enough to put between the preamp board and control pots (ala Dumble)? If not, my concern would be all of the extra wire added to the tone circuit.

The Weber board is 2"x2 1/4" so you can measure. I mounted one on the side of a 3" tall chassis once, like the FET board.

I'm mostly interested in how the xformers sound. The rest is easy.

[Normster]

Finished it up a few hours ago and have been playing it non-stop since. I still have to add the OD snubbers and make some adjustments to the dropping string, but it's a pretty decent sounding amp as is...especially for $300!

[img:960:531]http://bad-domain/DumbleLite/DSC02337.JPG[/img]
[img599]http://bad-domain/DumbleLite/DSC02338.JPG[/img]
[img:971:558]http://bad-domain/DumbleLite/DSC02339.JPG[/img]

And yes, I know this thread is worthless without clips.