What iron for RXES?

[azatplayer]

Hey Mark, im kicking myself for not documenting the RX when i had it!

I have pics of it inside, that the new owner sent me, but cant work out the boost switching.
Do you have a handle on it?
I ended up scrapping the rt 66 and using that amp, same but new board and tube holes, as a base for an ampeg B15N, and what an amp! Octal pres are amazing!
Had it that way for months, built it for my bassist, actually jag baritoneist, and its great but he bought a JCM800 superbass which kills.
I can get amazing tones with the ampeg with the bass dialed out and bright switch in and trebs right up, which led me to start modding it. Ive changed the bax stack values and load R's and pre cathodes, getting really close to something great, just gotta dial out some volume, change pot values maybe.
Was wondering how the boost was wired, thought it could be cool.
As its fixed biased and cathodyne phase inverted, im thinking of the finished product having a bias wiggler trem in it too.
Then i see this thread again and think, wonder what a stangray would sound like, and i do have trannies for a 4 el84 build...
Cheers dude, Don

[Colossal]

I have pics of it inside, that the new owner sent me, but cant work out the boost switching. Do you have a handle on it?

Hi Don,

Did you have the Prescription or the Prescription Extra Strength?
Footswitched Overdose or Toggle Switch version? The footswitched version uses an optoisolator (triggered by the footswitch) to switch a cathode bypass cap in and out of the EF86 circuit. This gives a 3dB boost with no change in EQ. B+ is tapped off the main supply and lowered to provide the correct current for the LED in the optoisolator. An LED on the front panel just indicates when the cap is switched in.

[M Fowler]

And this is such a funky looking circuit I initially was thinking the LED was being used as a diode but as Colossal said its the optoisolator. Like the idea of toggle switched as well as foot switch.

[M Fowler]

Dr Z's new video is pretty good and he says the Zwreck is a Rocket that Z built and Ken F tweaked for Brad P.

[cap217]

Are the voltages high in the RXES? I am going to swap tubes and want to know if I should go with some military grade tubes or if JJ's would work fine.

[M Fowler]

Are the voltages high in the RXES? I am going to swap tubes and want to know if I should go with some military grade tubes or if JJ's would work fine.

I have a note that the plate voltage was around 347v to 350v.

Mark

[M Fowler]

Anyone heard from Don - azatplayer lately? He hasn't posted since January 2013 and no emails from him.

[cap217]

I have a note that the plate voltage was around 347v to 350v.

Mark

Should I be using EL84M or 7189's in this amp then? Isnt the normal EL84 range 275v?

[Colossal]

Anyone heard from Don - azatplayer lately? He hasn't posted since January 2013 and no emails from him.

Nope. I spoke to him last around then too, IIRC. I think he was dabbling in Hi Fi so might have been swayed by the Dark Side for a while.

[M Fowler]

I have a note that the plate voltage was around 347v to 350v.

Mark

Should I be using EL84M or 7189's in this amp then? Isnt the normal EL84 range 275v?

I use JJ's myself at very high voltages probably a little excessive voltage but that's where they sound good.

You should always try different tubes to see what you like best but many EL84 amps are running plate voltage of 350.

[M Fowler]

Anyone heard from Don - azatplayer lately? He hasn't posted since January 2013 and no emails from him.

Nope. I spoke to him last around then too, IIRC. I think he was dabbling in Hi Fi so might have been swayed by the Dark Side for a while.

I sent Don a PM maybe he'll respond.

[cap217]

Another RXES question here.... I talked to the old head tech from DR Z and he said that he could change the tone stack in the es and it would be more scooped in sound and would bring it close to a Z Wreck sound.

I have to believe him but would like some quick input as to what this would do. I want more bass and more highs and less mids from this amp. It makes me think I should just get a StangRay but I have this and it might work out.