New ODS 100W build with pictures...

[ic-racer]

Background: I have know about Dumble amps for many years. I still have my "David Lindley Cover" Guitar player from the eighties and the one with the Dumble interview. For all these years I thought the Dumbles were CLEAN amps! I must have been mislead by some descriptions of SRV using the Slinger and EJ (who did NON use the Dumble for his lead tone).

I first heard Robbin Ford when a friend played me a CD of his. I was impressed by the 'up front' tone. No question the 'casual listener' was being fed an awesome, almost raw, guitar sound. The tone was grittier than the usual 'processed' guitar sound of many 'popular' CDs. But I had always thought his tone was from some distortion pedal in front of the Dumble.

It was not until I got RF's Latest, and was trying to find clips of RF playing on YouTube. I ran into the one where he shows his rig and then it hit me that the Dumble alone WAS the sound.

Well, I just went back to check that David Lindley article (GP April 1982) and I must have just skimmed over this back then. It says "Do you use any Distortion Effects?" DL: "No, thats just the Howard Dumble amp. It sounds like that naturally..."

Anyway, the Dumble is on the 'must have' list so here is the description of my ODS 100W clone build. It may be of interest to those who have not built one yet and want to see how hard or easy it is.

In preparation for this clone project I studied the pictures of #124 and the schematic of #124. Also, I traced the circuit on the Ceriatone Overtone layout and compared all the values to the ODS-101 and the #124 schematic. I also read a lot of the other posts on this board, paying attention to old posts, because sometimes info becomes 'common knowledge' and isn't fully repeated.

After analyzing the schematics and reading the critiques I thought I would get the pre-made boards from Ceriatone.

I ordered Hammond "Fender Twin" replacement transformers for Power, Output and Choke. I ordered a 6.3V transformer for the relays and LEDs (the Ceriatone boards have the doubling circuit)

Since I don't have time for curious oscillations and noise, I wanted to follow the lead dress of #124 as close as I could. So, for me that means nothing missing from the circuit (ie FET input and 50/100 switching etc) and nothing added (like Reverb or built-in Dumbleator, bias checkers, variable output impedance etc.).

The boards from Ceriatone and the Ceriatone Layout give me just about all I need to start building. I just added the 50/100 switching to the schematic and will use a separate transformer for the relays (rather than bringing 6v off the PT, as the Ceriatone layout shows)

I have been tracking down the little stuff too:
Mouser has a chrome trim for the Led under the 50/100 switch that looks close (#351-1001).
The Female connector for the footswitch is a Switchcraft part (502-C5F)($25.00!!)
Funk has the weld nuts for the frame mounting.
More to come as things progress.

[ic-racer]

Just started installing miscellaneous components on the chassis. Transformers should be the next to arrive.

[roadkingbluzs]

Very Cool. Great Happy New Years start!

[ic-racer]

Just got an e-mail that the transformers shipped...so they should be the next to arrive.

[ic-racer]

Well, this is a pretty boring thread... I have no parts yet except the chassis. Package tracking says the transformers arrive tomorrow.

In the mean time I put together a 'tone baseline' of some MP3s made with my current amp lineup (which has been stable for 10 years now! Certainly time for a new amp!)

A few of these MP3 are actually from 10 years ago from a CD I did in 1998! The current tunes are all Blues oriented, I think my taste in music is changing a little.

Tremoverb: http://soundclick.com/share?songid=6147741
Marshall: http://soundclick.com/share?songid=6147864
Maverick: http://soundclick.com/share?songid=6147834
Tremoverb: http://soundclick.com/share?songid=6147891

[Bob-I]

Well, this is a pretty boring thread... I have no parts yet except the chassis. Package tracking says the transformers arrive tomorrow.

Nah, really cool to see an amp come together. Keep posting updates as they come.

[Alpedra]

Well, this is a pretty boring thread... I have no parts yet except the chassis. Package tracking says the transformers arrive tomorrow.

Nah, really cool to see an amp come together. Keep posting updates as they come.

+1

[BobW]

double post,

[BobW]

ic-racer

Where did you purchase your chassis?

[ic-racer]

I got some Garolite in the mail today. This came from McMaster Carr.

The large piece is 1/16" "XX" in Brown and the smaller piece I got just to see what it is like. The smaller piece is G10/FR4 in Tan. I'm going to use the one that is closest to the pictures of #124, so I will use the "XX."

I am supposedly getting Ceriatone boards (if he is still going to make them) but I know I will need to re-do the main cap. board to fit my 300uf/350v caps. I have enough to do the rest of the amp, should I need to...

I have estimated the size of the cap board to be about 4.5 x 5 inches.

[odourboy]

I am supposedly getting Ceriatone boards (if he is still going to make them) but I know I will need to re-do the main cap. board to fit my 300uf/350v caps. I have enough to do the rest of the amp, should I need to...

IC,

I have a complete set of Ceriatone dumble boards available. PM me if interested. I bought a chassis. panels and boards from Nik but ended up making my own boards for my build because I decided to do a built in loop, already had relay PCBs, wasn't bothering with the FET board.... I'm sure you get the picture.

Brian

[ic-racer]

ic-racer

Where did you purchase your chassis?

Actually I am a little embaressed about that. I got it at a swap meet under the impression that it was a 'real' one (iI probably paid too much for it ) I just got it as a 'collector's item,' with no real plans to build anything with it back then.

When I bought it I thought it could be concievable that one chassis slipped out from the person building the chassis for HAD.

However, now that I am more savvy, I can see that this chassis is clearly a reproduction, and here is why:

A) it is obviously CNC machined. I don't recall that in the early 80's this would be a standard way to make this.
B) The end plates of the chassis are welded to the rest, therefore it would not be a good idea to support the whole thing from these chassis endplates. If you look at the "ODS Spotter's Guide" you can see that in the early 80s the chassis WERE mounted from the end plates, suggesting a different construction.

It is a REAL NICE repo, though, and I am planning my build around the chassis. So, my plan is to build a 'Vintage Dumble' from the 80s. Kind of like if one had a cabinet and chassis from a tweed Fender amp. You would probably want to put a 'tweed' circuit in that chassis, rather than a Prosonic circuit.

If I feel the need for a more modern 90's Dumble sound, I will build another amp around one of the more modern styled chassis, like Funk's.
I'm already kind of planning my next build, but I am in no big hurry as I am thinking that in the next few years someone is going to de-goop one of these later amps and we will have a better idea of what is inside.

[ic-racer]

Here is a shot with a test-fit of the transformers. They are pretty bulky, so I may have to take them off while I work on the innards of the chassis.

The holes drilled in this chassis fit the transformers perfectly. (Same with the switches and hardware on the back panel.) The choke and OT are away from the PT more so than on #124 (where they are all close together). I suspect this will make it easier to carry with a better weight distribution. I am familiar with heavy amps (I have a massive Fender Super Twin Reverb and a Mesa Trem-o-verb) but I am always surprised at how heavy these transformers are.

These are Hammond made 'Fender Twin Replacements.' I got them from Antique Radio Supply. They were running a 'Free Shipping' special the first week of Jan. (They were probably not expecting someone to order 25 lbs of Iron with free shipping )

[ic-racer]

Now starting to work on the inside...

[ic-racer]

The parts are slowly rolling in.

Here is the capacitor board. I have always wondered what would happen if one were to put 'big mother' capacitors on the first filter stage of an amp. Well, now I am going to find out, this puppy is being set up to take two of the 300uf/350v caps . Gil once posted that the best Dumble he played had the 300uf caps. Of course Mr. D abandon this setup...

So, with the two 300uf caps on the board there is no room for the last two 20uf caps in the chain. One will be on the side of the chassis and the other will be a 10ufx2 can up with the tubes and trannys.

My mantra for this build is going to be "I don't claim to know more than Mr. D about this...."

In the picture I have the two 'smaller' capacitors. I had these two left over from a re-cap...they were to big, so I had to go with Illinois wiich are a little smaller.

The board is not perfectly square and the holes positiions are just 'eyeballed,' all in keeping with the handmade jive of the originals. ("This aint no Hiwatt...")