| The TS-20 (Tweed Super 20 Watt). For questions, email . | ||
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This amp is completed... I've grafted two different schematics
and it worked. Yes I am relieved. The schematic below needs some
tweaks to show the final build but it is mostly accurate. This is a mod of the 5E5 and 5E5-A (Tweed Pro) designs from the 50's, mated to dual 10-inch speakers like a Tweed Super. I'm calling it a Tweed Super because the shorthand for Tweed Pro is 'TP'. I like 'TS' better. The goal was to achieve the Fender tweed tone, cathode-biased for modest modest power (I don't gig and I value my hearing). That was achieved - this amp gets great tone in a reasonable volume for a 6L6 amp - far better than my old Son of Boogie or Hot Rod Deluxe. And the volume controls are much better behaved--a nice, slow ramp rather than the knife-edge of the HRD. The genesis of this amp was my purchase on Ebay of a pair of old transformers some years back. Turns out the PT was from 1962, my birth year. The OT is paper-wound, probably later 60's, who knows. It's impedance ratio implies a 16-ohm load, so the 2 10's are run in series. (Frankly it sounds fine with an 8-ohm load as well.) Thanks to Bruce at Mission Amps for the great deal on the chassis, it's a beauty! Also his chassis bracket is rock solid, highly recommended for a Tweed Super or Pro, that is a heavy power tranny. The 5E5-A's preamp was chosen for a bit more flexibility in tone shaping, and the 5E5's power amp for that cathode mojo, and lower output. The tubes I have for this are 6L6WGB, a lower-output version of the 6L6, and noted for its 'tweed' tone. But it still is more clear and bell-like than a 6V6, and I'm looking for that sound. A NOS 5U4G provides power. |
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Here is the voltage modeling using Duncan Amp's
PSU Designer II. Here's the output
with the 5U4GB :
and with 5AR4:,
which might be better for full power with 6L6GTs. Cathode resistor is a
275-ohm. I also think I could run 6V6s in this system with the same rK, as the voltages are pretty low with a 5Y3GT: in fact the testing I did confirms this. Here is a link to my testing spreadsheet. Actual voltages in
completed amp - with strong 5U4GB |
  
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| This is the schematic. Actual voltages achieved with the stated rectifier and power transformer are shown. They were within 2-4 volts of the original Fender design, so cheers to Duncan for his excellent modeling program. The extra hole (for second speaker out) on the back is used instead for a half-power switch. This layout shows the project as built, except for the half-power switch, which is left out for clarity. | ||
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Here are a few pictures of the build so far.
the completed chassis:
And, finally (July '08, about 3 years since I bought the transformers) the amp gets a cab, a spiff tweed 'Super' cab from Mojo tone, seen in the first picture with its intended buddy, the USACG Broadcaster. Yeah they sound good together!
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| Some sound clips coming. soon. | ||
For questions please contact the
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