Hi there,
I'm currently having troubles with one of my amps which I converted from an 65amps clone with 6V6 PA into a dual channel amp (tweed channel and Vox EF86 channel mixed at LTPI).
Blocking distortion occurs within the tweed channel and I guess it's due to the sloppy wiring.
Anyway I think about rewiring the whole signal path and thought why not converting the LTPI into a Paraphase PI like the 5D3 has.
As there is one triode left I would use it as a cold clipping Trainwreck kind of gain stage to increase the available distortion.
Now I'm probably running into new problems like mixing the channels via mixing resistors.
Stability could suffer when the tone stack is maxed and the pseudo "Presence" control is untested as well.
Here's a first draft and I'm curious what you people think about it?
Anyone tried something similar with success?
Hot Rodded 5D3?
Moderators: pompeiisneaks, Colossal
Hot Rodded 5D3?
You do not have the required permissions to view the files attached to this post.
Re: Hot Rodded 5D3?
Because of phase inversion, mixing the channels isn't a good idea. I should rather think about switching between them.
-
Stevem
- Posts: 5144
- Joined: Fri Jan 24, 2014 3:01 pm
- Location: 1/3rd the way out one of the arms of the Milkyway.
Re: Hot Rodded 5D3?
You have answered your own question here!
Yes, the channels are out of phase with each other so you need to just plain switch them or add a single unity gain stage after the pentode to get it right.
Yes, the channels are out of phase with each other so you need to just plain switch them or add a single unity gain stage after the pentode to get it right.
When I die, I want to go like my Grandfather did, peacefully in his sleep.
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
Re: Hot Rodded 5D3?
Yesterday I tried the paraphase inverter and I went back to the LTPI.
First I wired up the 3rd stage with 10k on the cathode but it had not enough gain to compete with the LTPI.
Then I tried different values, bypassed and unbypassed while 1k5 unbypassed gave the best result but distortion seemed to occur earlier.
What I missed most was the tighter bass I got with the LTPI. The amp just sounded bigger before although I think that the paraphase isn't bad either but needs a lot more tweaking to sound right.
If I had added global feedback, I might get away with it but I guess I would rather start a new amp from scratch around the paraphase.
First I wired up the 3rd stage with 10k on the cathode but it had not enough gain to compete with the LTPI.
Then I tried different values, bypassed and unbypassed while 1k5 unbypassed gave the best result but distortion seemed to occur earlier.
What I missed most was the tighter bass I got with the LTPI. The amp just sounded bigger before although I think that the paraphase isn't bad either but needs a lot more tweaking to sound right.
If I had added global feedback, I might get away with it but I guess I would rather start a new amp from scratch around the paraphase.