Tweedle dee 5f1 build.

[Mark]

Marcus, a 5F1 Champ only has one channel, with two inputs. In my amp I reduced the first cathode bypass cap to 5uF, this value still has the bass response I want and sounds very similar to the stock 20uF. I don't waste power trying to reproduce very deep lows. The cathode bypass on the output stage is also an area to adjust tone, I've found the 22uF cap works well in this position. I've tried larger caps (100uF) in one amp and the amp sounded pretty dead.

[norburybrook]

Marcus, a 5F1 Champ only has one channel, with two inputs. In my amp I reduced the first cathode bypass cap to 5uF, this value still has the bass response I want and sounds very similar to the stock 20uF. I don't waste power trying to reproduce very deep lows. The cathode bypass on the output stage is also an area to adjust tone, I've found the 22uF cap works well in this position. I've tried larger caps (100uF) in one amp and the amp sounded pretty dead.

Doh.….


Sorry I didn't realise you were talking about a champ..just saw Tweedle Dee ignore my comments


Marcus

[Ridetheglide]

So, based on the recommendation of engineers at Eminence, I ended up trying a Eminence Tomo Fujita 12" (TF-1250). It's a very clean, bright speaker with tight low end. What was a dark 5F1 circuit is brightened up substantially. Humbuckers sound good. The amp breaks up around 7ish (6v6/5Y3) and 10ish (6L6/GZ34). I have an ES330 with Gibson PAF style pickups which sounds quite chimey but my budget J.Mascis jazzmaster with Chinese P90's sounds perfectly balanced using input 2. Go figure. I would consider this a bright amp compared to my last build.
I'll give the TF-1250 some time to break in, try and get my hands on a few more guitars and see where it leads me before I start making tweaks. However, the TF is a bright speaker and I would not go with a brighter option.

Regarding tubes, I started with a Westinghouse 5Y3, JJ 6V6 and an NOS RCA 12AX7. To me it sounded to be warmer, lower volume, earlier breakup and a looser bottom end. I then swapped in a Sovtek GZ34, Sovtek 6L6WXT and kept the RCA12AX7. This gave quite a bit more volume, tighter low end, later breakup and brighter overall. The one thing I like about the 6L6WXT is that there is no audible tube rattle which has been a problem in my other amps with 6L6 tubes.
It could be that I'm using bright tubes with a bright speaker? I haven't experimented with many tubes.
If anyone has tube recommendations, please feel free to share them..

The cabinet is pine which is stained varathane ebony with a finish coat of satin lacquer with black leather corners and handle. The grillcloth is gold sparkle. Looks pretty sharp in person. I'm stoked with it came out.

There is a faint 60 cycle hum which does not increase with the volume so I'll need to check my ground connections.

Update: I refitted the the 5Y3 to reduce output from 22watts to 17watts. The bias falls in the kiddle for a 6l6 however the classictone 40-18031 is rated for only 15watts.
I reduced hum by connecting 150ohm resistors from the pilot light to the speaker ground.