Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => PC Express and JSchem - Schematics and Layout diagrams => Topic started by: tubenit on December 21, 2008, 09:10:25 am
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I wanted to try an experiment, so I converted my Little Wing Reverb to a Carolina Blues Rocket Jr.
(gasp!) The Little Wing is a fantastic amp and I have probably gotten more compliments from people playing it than any amp I've done. It looks the same with the exception of a mid pot added and the middle of the layout board rewired.
http://s28.photobucket.com/albums/c216/tubenit/?action=view¤t=LittleWingReverbcombopic.jpg
http://s28.photobucket.com/albums/c216/tubenit/?action=view¤t=cabopenchassisbackspeakerreverbtank.jpg
http://s28.photobucket.com/albums/c216/tubenit/?action=view¤t=LittleWingReverbchassisrearpanel.jpg
However, I have been enjoying playing my Carolina Blues Rocket quite a bit so I thought I'd try a 7.5 watt version of it by converting the Little Wing. It was something of a challenge to do because initially it would oscillate using a 12AX7 in the V3 position (2nd & 3rd gain stage). Carolina Blues Rocket (w/5881's):
http://www.el34world.com/Forum/index.php?topic=3947.0
http://s28.photobucket.com/albums/c216/tubenit/?action=view¤t=CarolinaBluesRocketcab.jpg
However, I resolved that. I'm using a 12AU7 as V3 because it sounded best to my ears. I found I could use a 12AT7 without oscillation. There is an internal 100k trimmer inside the chassis. I have 37k going to ground on the trimmer. I recommend using a trimmer inside the chassis and setting and forgetting it instead of using another gain pot.
The amp does not have as much of a Dumblish tone as the CBR which uses 5881 or 6V6 tubes. Instead it sounds more like a really cranked Blackface fender to me. If you are familiar with Smokin Joe Kubeck, it's closer to that tone.
The amp is very very touch sensitive in the playing. The harmonics are excellent. I can sustain til the note feeds back if I want to. Yet the amp has a very clear tone that is brighter than the Little Wing but with more sustain. All the notes articulate well with no mud.
It has a preamp boost (PAB), a NFB switch (I usually play w/o NFB), and a DPDT that allows the overdrive gain stage to be engaged or not. With all that I can get a plethora of tones from it anywhere from country clean to cranked overdrive. The amp is as quiet at idle as the Little Wing was. I also tried a couple of tweaks if you want less gain. I used a 5Y3 instead of the 5V4. And changed the cathode resistor/cap values on the V3 (12AU7). See modified schematic below.
Thought I'd share this as another idea for others to ponder.
EDIT:
after hrs of trying this amp ........... I rewired it back into the Little Wing Reverb but lowered the voltage on V1 on the
LWR. I can't say one amp is better than the other ........ they're just different. My other two amps cover the CBR tone
just fine, so I thought I'd go back and get the LWR "Marshall-y crunch" back .
With respect, Tubenit