Newbie needs some Dumble help?

[Wasserockinbluesman]

Gentleman,

I just signed up to this forum, guess that makes me a newbie !!!

Your tech talk is way over my head but I am lucky to have an amp-builder/tech buddy that has offered to build me a Dumble OD Clone. He currently builds Fender-type amps and lots of experience. What I need is to supply him a schematic and layout, I know this will be a baseline, I can worry about the tweaks later. So perhaps someone can point me in the right direction? here is my question ...

Can anyone point me to what I will call a "completed" schematic & layout for a Dumble OD 50W amp?

Please be specific with me, links and/or files would be wonderful. Again .. I am a newbie and this is all over my head. .

Thanks in advance, Donuts and Coffee are on me !!!

Glenn Wasserman
bluesguitar@rcn.com

[sliberty]

Welcome, newbie! I am sure that one of the gang here will help you out. Glad you could join the party

Steve

[Bob-I]

Can anyone point me to what I will call a "completed" schematic & layout for a Dumble OD 50W amp?

Glenn,

Welcome... and good luck. IMHO there's really no such thing as a "complete" Dumble schematic. Dumble's greatest asset is his ear. You'll need to use yours to tweak the amp once it's done.

That said, I posted a 90's schematic/layout here. https://tubeamparchive.com/viewtopic.php?t=1106

This one sounds great and the schem incorporates all the tweaks that I put in. It's a bit unusual in that the OT is Ultra Linear but that can be skipped, just connect the screens to the second node on the PS.

[Wasserockinbluesman]

Bob .... thanks Big Time !!!

I agree the word "complete" may not be correct, but I needed a starting point.

My friend "sliberty" told me about the forum and just by reading the posts, it's amazing how helpful you all are. I have a lot to learn but this should be a fun ride.

Thanks again !!!
Glenn

[dogears]

Glenn,

Come over, play my amps, and choose your recipe....

Best way dude.

[Wasserockinbluesman]

Hey Dogears .... looks like I'll have to bring the donuts !!

Soooooooo, where are you located?? I'm in the Lehigh Valley, PA !!

Glenn

[skyboltone]

Bob:
How do you like the OD tone stack? Is it really usefull for getting to the grail? You've built ODS's with and without them; pontificate for a bit if you will please.

Thanks
Dan

[dogears]

Cherry Hill... But you knew that........

Hey Dogears .... looks like I'll have to bring the donuts !!

Soooooooo, where are you located?? I'm in the Lehigh Valley, PA !!

Glenn

[Bob-I]

Bob:
How do you like the OD tone stack? Is it really usefull for getting to the grail? You've built ODS's with and without them; pontificate for a bit if you will please.

Thanks
Dan

I like it a lot. Not so much for adjusting the tone, but for what it does to the tone. There are some differences in how the tone is shaped through the gain stages, more bottom end on CL1, 2 and OD1, then removed at OD2 and in the Post OD TS.

I've build several Dumbles and I like the post OD TS best...... right now... that could change in a heartbeat

[Wasserockinbluesman]

Hey Dogears ..... I didn't know, but now I do since I know it is you !!

I want you to know that you are partly responsible for my "NEW" found insanity, my "old" insanity is all mine ... and yes, I will stop by soon!!

[Wasserockinbluesman]

Sorry Bob .. one more question !!

Output tranny, what do you suggest?

On the shelf we have Schuler, Kendrick, Fender, Allen .... ??? These are all 50W with 2/4/8 ohms. Also have a Bandmaster (Schuler) tranny .. 35W @ 4/8 ohms.

Or should I go out and get something specific?

I know 50W is the standard, but I was thinking maybe something a little smaller that I can push more for the output saturation?

What do you guys think ?? more to come I am sure !!

Glenn

[Bob-I]

Sorry Bob .. one more question !!

Nah, there'll be more... don't limit yourself.

Output tranny, what do you suggest?

On the shelf we have Schuler, Kendrick, Fender, Allen .... ??? These are all 50W with 2/4/8 ohms. Also have a Bandmaster (Schuler) tranny .. 35W @ 4/8 ohms.

You have all of those

I've used the Fender Bassman replacements from tubesandmore.com. I'm not sure who makes them but they seem to sound really good.

Or should I go out and get something specific?

Not that I know of, someone else might chime in though.

I know 50W is the standard, but I was thinking maybe something a little smaller that I can push more for the output saturation?

What do you guys think ?? more to come I am sure !!

Glenn

50 watt seems to be the most common, but I have a 15 watter using 6V6's and a Bassman OT and another in the works using a Deluxe OT. I'm not a huge fan of output saturation, but Robbin Ford and Sonny Landreth both push their 100 watt Dumble's into pure output tube saturation. Your choice.

[Wasserockinbluesman]

Thanks Bob and you're right ... there wil be more questions, lol.

Well, *I* don;t have all those tranny's ... my tech buddy does. He builds a Fender knock-off so he tends to stock parts. (He's a good friend to have)

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I do tend to prefer out-put to pre-amp overdrive ... it seems the Dumble however has a interesting circuit at the front end / driver but as a general rule (most lesser amps) tend to get harsh and shrill at the front end. Pre-amp distortion is also the source of ear fatigue where as on the output side, it seems much smoother, thicker ... at least from my ears perspective.

Anyway, my amp tech tossed out a 40W option in the power section using 4 x el84's. At this point, I do not want to get too far out of the box so will likely use the bassman trannys he has in stock.

Dogear ... was kind enough to invite me over to try his toys and I know he has lots of experience in this arena so once I try his amp, and assuming I do not need to push it too hard to get what I like, I will know how much power is right. However in general, I play small clubs and tend to use my 20 watters and watch the bigger guys get dusty.

Thanks again Bob .. and all !!!

[Bob-I]

Thanks Bob and you're right ... there wil be more questions, lol.

Well, *I* don;t have all those tranny's ... my tech buddy does. He builds a Fender knock-off so he tends to stock parts. (He's a good friend to have)

Since Dumble started with Fender mods, Fender parts are good to have.

______________________________________________

I do tend to prefer out-put to pre-amp overdrive ... it seems the Dumble however has a interesting circuit at the front end / driver but as a general rule (most lesser amps) tend to get harsh and shrill at the front end. Pre-amp distortion is also the source of ear fatigue where as on the output side, it seems much smoother, thicker ... at least from my ears perspective.

You'll be pleasently supprised at the Dumble. There's a ton of engineering in this thing to smooth out the preamp OD. The typical harsh brittle Fender/Marshall preamp OD is non-existant, replaced by smooth singing OD, so smooth it almost sounds clean through the OD. It's a unique tone and not for everyone, but I love it.

Anyway, my amp tech tossed out a 40W option in the power section using 4 x el84's. At this point, I do not want to get too far out of the box so will likely use the bassman trannys he has in stock.

You might want to make a 36 watt Marshall from that 4xEL-84. It will NOT do Dumble!!

Dogear ... was kind enough to invite me over to try his toys and I know he has lots of experience in this arena so once I try his amp, and assuming I do not need to push it too hard to get what I like, I will know how much power is right. However in general, I play small clubs and tend to use my 20 watters and watch the bigger guys get dusty.

Thanks again Bob .. and all !!!

Cool, I've been talking to Dogears about getting together but with my travel schedule we've never nailed down a date. Let's make it a 3 some!!

Where do you live? I'm in Central NJ near Somerville.

[Wasserockinbluesman]

Ok, I hope I got this "quote" thing right ... lol
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You'll be pleasently supprised at the Dumble. There's a ton of engineering in this thing to smooth out the preamp OD. The typical harsh brittle Fender/Marshall preamp OD is non-existant, replaced by smooth singing OD, so smooth it almost sounds clean through the OD. It's a unique tone and not for everyone, but I love it.

Yes, I know for the "D" it is all in the design and is maily in the front end. I guess I need to stop thinking in the way I am used to when it comes to this amp.

You might want to make a 36 watt Marshall from that 4xEL-84. It will NOT do Dumble!!

Interesting comment on the 4 x el84, ok then ... 2 valves it is !!!

However, my amy tech showed me an interesting amp he built, it had two seperate output sections, one being switchable. He used 2 OT's, each feeding 2 x 6v6's (4 total). Basicially, the same front end fed one amp (20 watts) and flick a switch and the 2md amp kicked with the other two tubes. This "Double Deluxe" seemed like a cool idea to me, at least in theory.

Cool, I've been talking to Dogears about getting together but with my travel schedule we've never nailed down a date. Let's make it a 3 some!!

Where do you live? I'm in Central NJ near Somerville.

Bob, I am in the Lehigh Valley, PA right off 78 near Dorney Park ... 78/287 interchange is approx. 1 hr east for me, (Philly is an hr south). I am chomping at the bit to start this project and so I will corner Scott as soon as I can. If we can't do a threesome now due to the timing, I know I will be going back to tweak the beast *wink*