Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: LooseChange on July 03, 2010, 11:31:23 am
-
I Just completed another Champ.
-
It sounds crazy good... Warm and creamy and I have yet to do the 30 hour burn in.
GUT SHOT...
-
Nice build :grin:
Rock On
-
Yeah when you dial them in and use a good speaker they sound great. I see you used the Jupiter caps, do you like them? Have you noticed a tone/sound difference?
What power tube are you using? My next build is a Big Daddy Champ but with a 6G6G then another with a 6AK6 and under 300V on the plates and around 250v on the screens. I changed over one to 6K6GTs and it was pretty loud but nowhere near as loud as a 6V6 or 6L6.
-
The Jupiter's ssound good... I used sozo's too.
The power tube is your basic 6V6.
-
Have you tried the SOZO blues? Despite what some people say I think there is a difference and they sound better, the Jupiters and the SOZOs. I hope that discussion doesn't start again.
Anyway, great looking amp!!! I bet is sounds awesome.
-
Very fine! The Champ with the most modern appointments. I sure would like to see the schematic.
Plate
-
I'll second that!
-
REALLY nice amp all the way around! :grin:
I've never tried triode mode on a power tube. How does it sound and what's different tone-wise?
Does the Tweed switch lift the ground of the TMB tone stack or is the TMB stack still in the circuit?
From the front shot, it looks like you might have a progressive off/on/on power switch for standby. The schematic shows the fuse on the hot side and switch on the neutral (or vice versa). Can't tell if it's wired that way from the gut shot. Just curious.
Happy Indepence Day!
Chip
-
Thanks Chip.
The triode mode on the Champ makes a big difference in output volume. It is a bit darker but that one reason to add the Tweed control.
The Tweed switch does not lift the ground. With thee Tweed switch engaged it bypasses the tone stack. The tone stack has no effect in this mode.
Yes, I am using the progressive off/standby/on switch.
I'll check the fuse and hot side. I think it's good to go.
-
These are so cool.
Beautiful.
Gonna do one with another preamp tube sometime?
-
I've done a Single Ended Silver Jubilee and a SE Dumble... There's an extra preamp tube in each one of them.
-
Hi Loose Change, Sounds like you have these amps nailed. I'm looking for something low watt for my next build and the Champs keep coming up. I posted this http://www.el34world.com/Forum/index.php?topic=9600.msg87096#msg87096 but yet to get a responce so i'm thinking the Champ is the way to go. In the parts department i have 5881,5879 12ax7 ,12ay7,ez81,el84 and two 125se but no trany.Would you have any ideas for a build. Thanks
-
Thanks for the schematic. All these controls should make a Champ as flexible as you can get. I can't help but wonder how well the tone stack works and how much it pulls the output down as compared to a tweed tone control? The only other thing I could think of to make it a little sweeter is have it set up to run 6V6 or 6L6. Plate
-
The volume does increase a lot with the tweed control engaged. This amp is designed to run any octal power tube. It's sister has been running a 5881 for months.
-
Loosechange, I am so impressed by these small amps.
I remember those threads on the desktop dumble and jubilee, and some serious covet set in instantly!......
Couple questions:
How do you like that implementation of the effects loop?
Is it happy with all fx devices? Some loops aren't friendly towards rack gear but love pedals, and vice/versa.
Have you ever tried the simple preamp out/power amp in - "interupt" style loop in this amp?
-
Sorry I missed this back then.
The loop works perfectly with pedals. I never tested it with rack gear (haven't owned any since the 90's) but I've been told it works just as well. I placed the loop after the volume pot and in front of the second gain stage so that the return can be used as a power amp in. This way you can plug your fancy guitar preamp in and use the Champ as a power amp. Works VERY well.
-
I was curious about that loop as well. Then forgot.
thanks for the info.
-
Nice build looseChange I really like having the ability to use it as a power amp for another preamp section. that is a very usefull addition on your part. some day I want to build an SE type amp just never got around to it yet. Bill
-
The Tweed switch does not lift the ground. With thee Tweed switch engaged it bypasses the tone stack. The tone stack has no effect in this mode.
I respectfully disagree with this. With a SPST arrangement like that in your schematic even with the switch engaged the signal still has a path to ground through the tone stack and some of the signal is going to be shunted there. When I had my tone stack bypass in my Vibro Champ I wired it with a DPDT (see attachment) to totally remove the tone stack from the circuit. That's the only way to make it have no effect.
Having said that, I'll bet I would like the way it is wired in your schematic better. Totally removing the tone stack really adds a ton of gain to the circuit and I didn't find it to be terribly musical gain so I removed the mod. I may try it the way it is in your schematic.