Just a few quick comments on this amp now that I've been running it for awhile:

Great Tweed-era Fender sounds, with a round, mid-heavy tone and not much headroom. That's a good thing, if you're going for that Tweed break-up tone and want to be able to achieve it without too much volume. The bass tends to be on the loose side, so not a good amp if you need a tight bottom end. But for blues & late '60s/early '70s style rock, it's pretty much perfect. I prefer single coil guitars to humbuckers through it--not surprising, since when the Tweed amps were being made, single coils were all Fender made, and the amps were designed to compliment them. Humbucker guitars sound fine through it--and distort quickly--but you just have to watch that the bass doesn't get too loose & woofy.

The thing that the TR offers that you won't get from a Tweed Champ or Deluxe is all of the "in between" tones that can be achieved with this amp, with the tone control, cut control (actually a negative feedback control) and choice of single-ended or push-pull output modes. At one extreme, you can mimic a 5F1 Champ by running single-ended, full on the cut control, and tone control bypassed. At the other, push-pull mode with the cut control off and the tone control turned to taste gives you the classic 5E3 Deluxe set-up. But you can mix & match those three parameters to give you all kinds of in-between shadings. Running in Champ mode but want more grit? Dial the Cut (NFB) down. Running in Deluxe mode and need a bit more headroom? Do the opposite and roll on some Cut. The possibilities go on...

Of course, I couldn't leave the amp stock and added a couple of switches to the front panel. One changes the V1 cathode resistor and the second selects different bypass capacitors around that resistor. Both affect the preamp gain, and the caps also alter the bass response profile. Gory details here: http://buildyourownclone.com/board/v...p?f=49&t=41943

Another thing I've tried is a different V1 tube type to alter gain & headroom characteristics. I have a NOS JAN 5751 in there now, which runs about 70% of the gain of a 12AX7, and seems to be a nice compromise for the amp, since the original 5F1 Champ used a 12AX7 and the 5E3 Deluxe had a 12AY7 (~45% of AX7 gain) in that position.

Things that could be improved in the Tweed Royal? It hums a bit--not bad, but noticeable when cranked up--which I think is just a reflection of the vintage Tweed chassis & wiring layout. If I was building another, I would change a couple of things that should help that. First, I would forego the heavy cloth-covered wire for the filament heater runs, since the thickness/stiffness of the insulation keeps you from getting the nice, tight spiral winding that helps minimize 60Hz hum. It would also be easier to route it along the chassis and away from the other wiring. I'd also look into shielded cable for the input connections and maybe a couple of the long runs to the pots.

The other thing--and I've got the parts on order to do this--is to build it with a voltage regulator module (VRM) to be able to run the amp cranked up without endangering my marital status. If you're a home player like me, even at about 12W max, this is still one LOUD little amp. I run it through a Weber MicroMASS attenuator most of the time now, but an integrated VRM to reduce the DC voltages does this more effectively & conveniently, not to mention with less tonal loss than even a good attenuator like the Weber will do. I have a Mini-Watt from Skipz Circuits on order for this purpose. I like their design because it uses a switched pot for the voltage control, so you can install it in place of the power toggle switch and avoid having to drill another hole in the chassis.

Now let me get back to jamming with my new American Standard Strat through this little beast....