Hi all, would it be possible to incorporate RJ's Rocket Booster to the phase inverter arrangement on a Hiwatt build? http://rjguitars.net/Rocket_Booster.html
http://hiwatt.org/Schematics/DR_PreLinkedInput_v1.gif
Thanks for any advice.
rocket booster + Hiwatt
Moderators: pompeiisneaks, Colossal
Re: rocket booster + Hiwatt
Rj's plan brings a parallel gain stage into the "other" input of a LTPI.
That is where most amps bring back the negative feedback/presence signal.
So...my guess is that what ever Hiwatt design you are eyeing would need to use a LTPI but no feedback.
There are other ways, of course, but it would be a divergence from Rj's design.
Dave O.
That is where most amps bring back the negative feedback/presence signal.
So...my guess is that what ever Hiwatt design you are eyeing would need to use a LTPI but no feedback.
There are other ways, of course, but it would be a divergence from Rj's design.
Dave O.
Re: rocket booster + Hiwatt
Thanks Dave, I thought about adding a casacded stage like the OL or Lead models but I think it would add too much overdrive. I like RJ's idea because it added just a little more push. I would like to keep the Hiwatt PI setup though
and I would like to add that I am going to install a PPIMM instead of the traditional MV. I'm open to any other ways though. Thanks again.
and I would like to add that I am going to install a PPIMM instead of the traditional MV. I'm open to any other ways though. Thanks again.
Re: rocket booster + Hiwatt
My pleasure Andrew!
Paralleling gain stages isn't at all difficult if you have adequate filament supply and the extra triode is already installed.
The signal path location will most likely be influenced by the location of the extra triode...but not necessarily.
If you are starting from scratch including building your own board...the world is your oyster!
What are you contemplating at the moment?
Cheers,
Dave O.
Paralleling gain stages isn't at all difficult if you have adequate filament supply and the extra triode is already installed.
The signal path location will most likely be influenced by the location of the extra triode...but not necessarily.
If you are starting from scratch including building your own board...the world is your oyster!
What are you contemplating at the moment?
Cheers,
Dave O.
Re: rocket booster + Hiwatt
Dave, I'm building it from an existing Express build (I couldn't get it right!)
I have a blank turret board to work with. I am only going to use the Hiwatt Normal channel. There is room for an additional socket between V2 and V3. I would use the new socket for the CF tube. Thanks again.
I have a blank turret board to work with. I am only going to use the Hiwatt Normal channel. There is room for an additional socket between V2 and V3. I would use the new socket for the CF tube. Thanks again.
Re: rocket booster + Hiwatt
I forgot to add that it is a Toneslut with 300ma. 300vt taps
Re: rocket booster + Hiwatt
Yep....those Express builds can make even a strong man cry!
I have to admit that this is my first forray into HiWatt architectures.
Do you have a schematic of the plan that you want to emulate that can be shared? I understand that you will be excluding the high-gain channel.
Cheers,
Dave O.
I have to admit that this is my first forray into HiWatt architectures.
Do you have a schematic of the plan that you want to emulate that can be shared? I understand that you will be excluding the high-gain channel.
Cheers,
Dave O.
Re: rocket booster + Hiwatt
the schematic is on the original post. I drew an actual sized layout with components and even with a few parts PTP on a couple of tubes there is no room to spare on the 8" board. There is room though for an off board if needed. Thanks for your time on this project. Andrew
Re: rocket booster + Hiwatt
My bad Andrew! I missed the link in the first post. My eyes thought that it was all a single link and my head didn't dissect it into two.
Ok...at first blush I would try to keep the cathode follower (CF)/PI intact as I believe that is a fairly important part of the HiWatt sound. This was your original sense I think. But again, I have no practical experience with these plans unfortunately.
I would also try to keep everything upstream of the tone stack consistent with the schematic for the same reason.
So...if it were me...I would try slipping in a parallel stage just down stream of the master volume pot for starters. This will "fatten up" the signal hitting the CF and give a little boost in gain. CF's can produce some nice sounding, "soft" clipping when leaned upon.
I would initially set the parallel stage up exactly like the one it is linked with and tweak plate load/cathode resistors and cathode bypass cap to taste. B+ source and cathode ground, likewise, at the same locations as the stage it is paralleled with.
Do double check your PT's filament current capacity before punching any additional holes in the chassis just to be sure. I have to believe that it's HT secondary won't notice the additional 2-3 ma that the additional triode will draw.
A small, secondary turret/eyelet board would be great. However, there is no reason why you couldn't add the components on properly insulated (heat shrink where needed) flying leads. I have successfully done a lot worse!
It will look kind of funky...but..who the eff cares!
Cheers,
Dave O.
Ok...at first blush I would try to keep the cathode follower (CF)/PI intact as I believe that is a fairly important part of the HiWatt sound. This was your original sense I think. But again, I have no practical experience with these plans unfortunately.
I would also try to keep everything upstream of the tone stack consistent with the schematic for the same reason.
So...if it were me...I would try slipping in a parallel stage just down stream of the master volume pot for starters. This will "fatten up" the signal hitting the CF and give a little boost in gain. CF's can produce some nice sounding, "soft" clipping when leaned upon.
I would initially set the parallel stage up exactly like the one it is linked with and tweak plate load/cathode resistors and cathode bypass cap to taste. B+ source and cathode ground, likewise, at the same locations as the stage it is paralleled with.
Do double check your PT's filament current capacity before punching any additional holes in the chassis just to be sure. I have to believe that it's HT secondary won't notice the additional 2-3 ma that the additional triode will draw.
A small, secondary turret/eyelet board would be great. However, there is no reason why you couldn't add the components on properly insulated (heat shrink where needed) flying leads. I have successfully done a lot worse!
It will look kind of funky...but..who the eff cares!Cheers,
Dave O.
Re: rocket booster + Hiwatt
Thanks Dave O, it looks like a good fit. This is going to be fun. Now it's time to place an order. I'll get back with an update. Thanks again for the help, Andrew