Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: sdp1234 on June 27, 2012, 04:22:11 pm
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I've build several 2 channel SE amps and a couple AC30\Rocket type amps along with a couple modded champ types. What I really want is something similar to a Dumble sound. Understand that I have never heard a real dumble live but I'm looking for something with that smooth vibe but I don't need ear shattering volume. Looking for those cool jazz cleans and that smoooth almost flute or Sax type overdrive tones.
My understanding is that the tone is mostly generated in the preamp therefore the master works fairly well in these type amps. It will almost always be played in a house or Mic'ed environment so I don't really need 100 amps or even 50 watts. Most everything I build has been in the 3-20 watt range. Initially I was looking at some of the SE type amps that folks have done and I'll probably do a carolina songbird but I'm thinking that may be a bit under powered?
I'm not looking to build to exact specs or even have it look like a dumble just want something with reasonable volume that will provide that smooth sound. Any suggestions where I should start?
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You've come to the right place for advice :icon_biggrin: You say dumble style. TOS is your next build. Tubenit has plenty sound clips posted for your pleasure.
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Re: Dumble, you may find some useful stuff here too. (This is not a competitor site is it Doug?)
http://ampgarage.com/forum/viewforum.php?f=5 (http://ampgarage.com/forum/viewforum.php?f=5)
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The Tweed Overdrive Special (23watts) ............ OR the Tweed BluezMeister (14watts & perhaps easier to build) would be reasonable choices for something Dumblish without being ear splitting. There are schematics and layouts in the ExpressSCH library of schematics.
You could also just build a Dumble clone with 6V6's. There is alot of information about those on the AmpGarage forum.
Here is a brief soundclip of the TOS with 6K6 tubes in it. I ususally have 5881's.
http://www.soundclick.com/player/single_player.cfm?songid=11527276&q=hi&newref=1 (http://www.soundclick.com/player/single_player.cfm?songid=11527276&q=hi&newref=1)
If you scroll down and look, there are some different soundclips of the TOS and TBM on this website:
http://www.soundclick.com/bands/default.cfm?bandID=860798&content=music (http://www.soundclick.com/bands/default.cfm?bandID=860798&content=music)
With respect, Tubenit
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Geezer also has a GREAT amp design in his HoSo56 & I know he has tweaked it and reports getting Dumblish tones out of it. His amp design is a very very versatile one to get different tones and overdrives. It is a really nice build!
See quote from Geezer:
Finally found the "Dumble-type" tone & built my own version, the Maxim Triple Drive (HoSo 5879 Pentode front end, 3x channels, 6AQ5 outputs) and haven't been inspired to build anything else since, those amps (2x) sound so perfect to me.
You'll need to PM him about it because I am not certain what his latest/current revision is? It might be a version of this?
http://www.el34world.com/Forum/index.php?topic=10999.0 (http://www.el34world.com/Forum/index.php?topic=10999.0)
If you ask him for soundclips, post a link for them here, please. His old soundclip links have expired. I enjoyed them enough that I'd periodically go back and listen to them to hear his playing and tone again.
:icon_biggrin:
With respect, Tubenit
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TOS it will be. I actually started laying out a TOS build over a year ago and then I started a other projects. Lately a home kitchen project has stopped all amp building. The kitchen will be done soon and I'm going to build a Carolina Songbird and A TOS. I have to try to keep the TOS from getting crazy with options. I see the fatness and other things that folks have done. Often I spend more time trying to figure and add options and the project never gets off the ground. This time it will be as basic as I can (of course VVR will be necessary ;) ) Thanks for all the information and inspiration.
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This time it will be as basic as I can (of course VVR will be necessary)
I actually removed my VVR & replaced it with a PPIMV which I like better at the volumes I usually play at.
I found changing the triode used for the "fat control" into a cathode follower behind the 5879 to be a good choice for me. It made the 5879 overdrive smoother in my opinion. The two most important changes to me are the CF following the 5879 & the smoothing cap across the LTPI plate resistor.
I've attached a schematic showing the minimum changes that I would make from the original design with the goal of keeping it "simple". I think you can still use the Hoffman TOS layout board for it. You may need a 4 post terminal strip to help with the CF addition. That would be very very easy to do.
With respect, Tubenit
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I'll second the PPIMV. It's pretty transparent, and dead simple.