cbass wrote:. I tried the 6g3 term on a rocket once.it worked but my other amps (fixed bias)had much better sounding tremolo.preamp wiggle may be the way to go
Hi,
cathode second stage instaed of the neg. voltage from Bias circuit?
cbass wrote:. I tried the 6g3 term on a rocket once.it worked but my other amps (fixed bias)had much better sounding tremolo.preamp wiggle may be the way to go
Hi,
cathode second stage instaed of the neg. voltage from Bias circuit?
Hans-Jörg
Well I tried it on the power tube grids.Basically it hooks up the same as fenders but instead of connecting to negative voltage bias supply it goes to ground.
I didn't try to wiggle the preamp tube bias but I think that would be the way to go on cathode biased amps.perhaps something like the Kalamazoo s and univoxes did.
I hope that made sense.
Oops I just saw you are wanting to try this on the express .I would just try the trem from the 6g3 which is very similar to the layout posted at the beginning of this thread.
I don't no if it will have enough voltage swing for el34 s though.
Last edited by cbass on Wed Jun 18, 2014 1:18 pm, edited 1 time in total.
I see,
first triode cathode, but it differs because of two triodes.
What I´m curious is how the schem can work (the first hand drawn in this thread) - I tried it and it does not work. Than I compared it to the Fender Reverb one, and its very similar but 2 small mistakes (Footsitch at wrong place ???). If I change it, it should work. At least as I can understand the schem. We will see.
Best
Hans-Jörg
Last edited by hans-jörg on Thu Jun 19, 2014 6:34 am, edited 1 time in total.
cbass wrote:Oops I just saw you are wanting to try this on the express .I would just try the trem from the 6g3 which is very similar to the layout posted at the beginning of this thread.
I don't no if it will have enough voltage swing for el34 s though.
Yes , it´s very close to the Princeton one.
What is the propper swing? Express has around -33V at bias. The cathode of the circuit (Tremolo) has around 2.7VDC. Which the right parameter for the right voltage swing?
The layout works. The particular amp I based it on was one of the Thomas Organ voxes, the 2 el84 one, which I thought had an outstanding tremolo. I think that amp was on Ken's list of top 10 sleeper amps.
Usually with modulating a preamp tube, you see another triode as a cathode follower for impedance matching. I don't know how necessary it is.
Hi
the cathode follower could be necessary to bring up the voltage for bigger voltage swing. The 1-2 Volt at the preamp cathode is roughly same like Tremo cathode. There swings nothing if only one triode - I guess (as Tremolo newby).
Could somebody clear out what size of swing there should be?
Jackie Treehorn wrote:The layout works. The particular amp I based it on was one of the Thomas Organ voxes, the 2 el84 one, which I thought had an outstanding tremolo. I think that amp was on Ken's list of top 10 sleeper amps.
Usually with modulating a preamp tube, you see another triode as a cathode follower for impedance matching. I don't know how necessary it is.
Hi Jacky,
please dont misunderstand, but could there be a small mistake with the painted layout you posted. Especialy the place where the FS is located. As I wrote: if I disconnect the cathode via FS from ground - there is aalmost plate voltage at the cathode. From 2.5 V (grounded) to 300 VDC (lifted from ground) - and that is almost normal, when you have, let´s say a bad grounding at a preamp cathode.
Wait! You're right, the footswitch should be connected to the turret next to it and the turret with the footswitch now, should just be ground. Sorry, folks!
If you look at it, there, the black wire goes to the footswitch and the blue wire is ground.
The cathode follower will not add any voltage gain. I'm not exactly sure of the signal swing requirements to turn off a power tube or preamp tube. I would think it would take a lot less to modulate the preamp tubes, though.
Although I doubt we've seen any gut shots of a real trem rocket, I kind of have it in my head that Ken did it with just the unused triode for some reason. Bias wiggle of the power tubes seemed like the most obvious solution.