New Rocket Build - Mix of modern and traditional

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Mark
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Re: New Rocket Build - Mix of modern and traditional

Post by Mark »

It looks good but I suspect you will have to use the James tone controls to minimise interaction, failing that you'll need active tone controls. Active tone controls are a lot of work, but I'm surprised we haven't seen more of them in guitar amps other than Ampeg amps.
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Mark Abbott
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RJ Guitars
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Re: New Rocket Build - Mix of modern and traditional

Post by RJ Guitars »

Thanks Mark, Even though I said I was done, I played with things a bit more and finally found that I was also getting some sort of interaction between the tonestack and the MV that I added. Something about this was bugging me since I've had Fender and Marshall amps with similar tonestacks and they didn't behave this way... Eventually I found That with the MV disabled I did not hear the extreme drop in the low frequencies while dialing up the treble control. So I starting looking at everything I had done a little closer. After I slept on it last night I went back to the Trainwreck pages and found MV #4 and sure enough, I had my signal wires switched on the MV pot. The MV worked but in my configuration it was robbing some of the signal that was meant to go to the bass and mid controls and sending it to ground as the MV squeezed down the signal going into the PI. When I switched those wires to the proper terminals on the MV pot, all the tone controls worked as they should.... best variable mid control I've implemented so far in a Rocket build.

Ultimately I went with my own version of the Blackface tonestack although I added a 2.5K tail resistor to ground from the mid pot so that the total volume never goes to zero when you have all the tone controls at zero. This agrees better with my intuition of how things ought to work even though I know I am just sorta tricking myself in having the knobs all the way down and can still hear a small signal.

This afternoon I cleaned up the wiring on the MV pot with some shielded cable and then added the labels to the back panel... now I think it's done.

Really this time I mean it...

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Last edited by RJ Guitars on Sat Sep 16, 2017 9:35 pm, edited 1 time in total.
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joeboo88
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Re: New Rocket Build - Mix of modern and traditional

Post by joeboo88 »

that's nice, and I like the labeling.
Glad you figured it out, so we can learn from you.
Mark
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Joined: Sat Jan 15, 2005 8:10 am
Location: Sydney Australia

Re: New Rocket Build - Mix of modern and traditional

Post by Mark »

Did you try the Kevin O'Conner mod where you have a 100K resistor in series with the MV wiper to the PI?
It seems to make a difference to Marshall amps but Dumble amps don't seem to need it which is weird.
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Mark Abbott
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Winder
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Re: New Rocket Build - Mix of modern and traditional

Post by Winder »

Nice, clean build. I like that wood too. Sweet stuff.
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