RR (Randy Rhoads) Plexi

Matthews Guitars

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The 1959RR...high gain, 2203 type preamp with no master volume control. :facepalm: Holy hell, that's gotta be loud! :cool:

I'd definitely recommend running that with a variac run down to about 90 volts. It'll definitely reduce output by enough to make a difference.

I have a big 2 KVA Powerstat variac that runs the two 1959s I currently have set up in my practice room. The volume difference
between full 120 volt line voltage and 90 volts "brownout" voltage is considerable. But it doesn't bring the 1959 down into the range of a quiet amplifier. It's still brutal. Just LESS brutal.
 

NoelH

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I see a lot of guys going into a deep dive on this. And they're probably all correct.
I really think the biggest factors are taking a metal-panel 1959 (whatever appropriate component values, etc.), running KT88's . A pedalboard in front with a script MXR Distortion+, and MXR 10-band. Then, the painful part: Run 4x12's full of Altec 417's. Yikes! I can't imagine being in the same room without military grade ear plugs! My understanding (read a Max Norman interview years ago) is that Randy ran his stage rig at full volume in the building's basement. Norman must be some kind of genius to figure out how to tame that!
 

V-man

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I see a lot of guys going into a deep dive on this. And they're probably all correct.
I really think the biggest factors are taking a metal-panel 1959 (whatever appropriate component values, etc.), running KT88's . A pedalboard in front with a script MXR Distortion+, and MXR 10-band. Then, the painful part: Run 4x12's full of Altec 417's. Yikes! I can't imagine being in the same room without military grade ear plugs! My understanding (read a Max Norman interview years ago) is that Randy ran his stage rig at full volume in the building's basement. Norman must be some kind of genius to figure out how to tame that!
one of the few acceptable necro threads given the limited number of amps made.

1. in terms of volume, people talk about how insane it is dimed, especially through 100w Altecs. That‘s a “yes, but not the whole story” assessment. I had owned a pair of 417H speakers and still own some G-12K 100s. Dimed in the next room, it sounds like you are going through security at an arena show, but that is only half the story. The volume taper is such that all usable (perceptible) volume ends around 3-4.

That is to say 4 sounds no less (perceptibly-) loud than 10, and at best, you are only getting more saturation (maybe). clean is at 0 (yes, fucking 0) to 1. Loud AF clean is at 1-2 and it will easily give full feedback at this volume if close. 3-4 is basically the rest of the amp. There is no earthly reason to put it past 6 because you may be driving the components harder and getting no (appreciable) juice for the squeeze, at least with EL-34s. IF Randy’s JMP acted like this, I am reasonably convinced the addition of the tubes and the speakers were to buy more headroom out of a “0-100 in 3“ sort of amp, because Greenbacks pretty much push every thing I said back by (at least) an increment of 1.

2. The other point (probably discussed here and discussed often enough) was that RR did not care much for the cascade side. Pictures we have show the lead running into either the hi or lo side of ch 1 typically if not exclusively. There is no appreciable volume difference between either channel and (IMO) no massive improvement in gain. Running an AB box to both channels for instant comparison shows a subtle but perceptible change in gain structure or voicing, lending to a different flavor. But given a blind shootout and I think ppl would either struggle to predict which is “high gain” side or, predicting accurately for the most part, butalso commenting they didn’t hear a seismic difference between the two in gain.

This leads me to ponder the question about the RR I have not been able to solve yet: Does the 1959RR actually have more gain (Ch1) than a 1959 SLP, or does it simply break out of the box earlier (or both)? If the latter, (gets loud way sooner) then perhaps the extra gain only comes from ch2 (subtle as it is). If the former, it’s a hard rock monster at half the dial turn a SLP would be at with the volume to match. Anyone want to ship me an SLP to find out?
 

lenheyvan

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1959RR is expensive.

However, it is possible to modify a regular 1959slp to the same condition.

The modification is called one-wire mod.

The circuit diagram of 1959RR is down on the Internet, so you can get the 1959RR sound inexpensively by modifying it while looking at it.

Please refer to the following book.

How Tube Guitar Amplifiers Work (Part 2)
- Modification Know-How -

 

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