The sunn Forum
Sunn Musical Equipment => DIY => Topic started by: kleptocracy on April 15, 2009, 11:29:06 pm
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Hello everyone! I'm new to the site. I joined because I've picked up a bit of a crazy project: A Sunn Model-T.
Ok, so it's not exactly a Model-T, because I just redesigned a pre-amp a little bit. But from a power and voltage and current draw perspective, it's the same.
So, by my math what I'm looking at is a PT with a secondary in the 400-0-400 range, to get a rock solid 505V on the plates of the 6550's, which are biased to -55V. At max output I'm looking at drawing around 600mA through the PT and Choke(s). I don't know what the ratings on the two chokes are in the schematic, but I'm guessing 5H@300mA each (wired in parallel). We're also totaling 7.3A on the 6.3V heaters. And don't forget the bias tap aimed at -55VDC. (If you hadn't noticed, since these are all guesses, some specs from a real Model-T would be super useful and I would be very appreciative!)
Anybody know where I can find such a PT without breaking the bank? I think I'm going to use two Hammond 193L (5H, 300mA) chokes, which I can get on Digikey for a seemingly reasonable $44 apiece.
As for the OT, I know the Hammond 1650T claims it's a little underpowered for the 150W output of the Model-T, but I noticed those ratings are for a hi-fi amp at 1%THD. Even Dan Torres claims they can handle up to 180W (http://www.torresengineering.com/ham120180wat.html). Anyone have any thoughts on this OT for this application? I'm definitely not really a hi-fi kind of a guitarist but I do appreciate solid LOW END.
FYI - I'm currently playing a drop-tuned '79 Peavey T-60 strung with flat-wound .013's thru a Russian Big Muff and a vintage '70s Acoustic 140 solid state bass head into a 4x12 bass cab. The T will just replace the 140, so I can get the grinding lows but still manage some sharp clean highs.
Thanks for all your help in advance! :-D
Matt
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Hi, I just found this sucker: http://www.antekinc.com/AN-4T400.pdf
I've never used a Toroidal PT before. Any pitfalls I should be aware of? I'll probably hook it up center tapped. I also need to figure out what to do for the -55V bias supply.
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Did you use those 5H/300ma chokes?
Did you end up getting a PT with 8A heaters and an OT with ultra linear taps for the screen grids or figure out how to work around these issues? Curious...
I am about to start a build and was going to get the Mercury set but would like to save some $$ if possible.
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is this what yer building?
https://taweber.powweb.com/store/6s100_ad.htm
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is this what yer building?
https://taweber.powweb.com/store/6s100_ad.htm
No, I was just gonna do a 70's red knob 5 input type deal. 4x6550 with taps on the screen grids and tonestack after V2. I dont even think that Weber build is based off of a real Model T. I mean EF86 and a 12AU7??? c'mon man. I LOVE playing my amps on 10 but you might have to turn that one up to 100 to get nasty od.
Might try to install a master volume bypass switch so that I can just play the amp normal loud.
any suggestions?
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i just threw that example out there. nothing like a T...i have three of the red knobs...they kill
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Yes, they are amazing!
I'm assuming that the chokes are under the hood. Can you post a gutshot? Any porn will be totally appreciated!
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hows the build coming?