Mark IV technical wiring question

[marklyn]

I came across the Area 51 add-on tube tremolo. If I understand correctly it basically adds the tube modulation stage of the tremolo and modulates the existing power tubes for Fender Brown Face type trem. Cool!
http://www.area51tubeaudiodesigns.com/bmt60trem.htm

Does anyone who understands the Mark IV schematics and power section have any ideas if this would work? I don't know if it will work with all the various power options of the Mark IV.

 

[marklyn]

Any of you smart folks have thoughts on this?

 

[Schmoog]

should be fine with the mark IV. if in doubt, ask them, they'll tell you. dude that looks freakin awesome. maybe I'll have one put in on my mark III when I have my amp tech add the triode-pentode switches for each pair of tubes

 

[Restless Rocks]

The Area 51 Tremelo acts by modulating the negative voltage bias supply to the control grids of the output tubes. The Mark IV's simulclass arrangement (one pair of the output tubes operate in class A and the the remaining pair operates in class AB while sharing the primary coil, via ultralinear taps, of the output transformer) shows about -45 volts to the class A and about -56 volts to the class AB pairs respectively. Mesa also uses a factory fixed bias setting. By modulating the bias supply at its source these two pairs would probably see an unproportional swing in bias voltage. The AB side would most likely act as desired and produce an acceptable "brown face" tremelo. The class A bias voltage could possibly dip so low as to cause a harmful situation and a loud hum upon each negative swing of the modulation. And a resulting over heating of the tube's anodes or "plates". In the stock arrangement of the Mark IV the only choices are class A by itself, or "simulclass" the combination of both pairs of output tubes. I recall seeing the web ad for this mod and that they listed amplifiers compatible with the product But I don't remember wheather or not the Mesa Mark IV or simulclass format was recommended. I would strongly suggest a call to Mesa to hear their comments and I'm sure it would void your warranty. Hope this was of some help.

 

[Boogiebabies]

Uh, theres a pentode switch that runs them through the same primary. I still would not dick with an X371 bias modulator. It could blow up the planet.

 

[Russ]

:lol:

 

[Boogiebabies]

 

[Boogiebabies]

 

[Restless Rocks]

Uh; BB check your drawings again V8 and V9(the class A pair) share the B tap off the power supply to the screens ,when in pentode,with V6 and V7 (the A/B pair) but still maintain plate connection to their very own personnal primary taps on the output tranny.

 

[Platypus]

hahahaha that's seriously the first thing I thought of after reading your last post BB :lol:

 

[Restless Rocks]

I did forget to mention that the ceramitical dentally occlused version of the Yomama69-73A output tranny will withstand at least 40,026.7584 millivolts of static applied directly to the subatomical cheezeburger particle clinging (since may 14th, 1985) to the left Elvisalizer stabilizer sideburn hair (the graying one just by the lobe) as long as, mind you, you never reveal your true identity! :mrgreen:

 

[Russ]

http://www.gargaro.com/MaRvInWaVs/stolen.wav

http://www.gargaro.com/MaRvInWaVs/goody.wav

 

[Restless Rocks]

Hey Marklyn, I apologize if you're by now wondering what kind of loonies they turn loose with computers these days!! "Hell anybody can get hold of a set of car keys in America". BB, Russ and yus guys: thanks for having a sense of humor. Even if not everyone gets it! But that's the best part.

 

[michelj]

Uh, theres a pentode switch that runs them through the same primary. I still would not dick with an X371 bias modulator. It could blow up the planet.

Hey Boogiebabies, not the Illudium Q37 space modulator! Geez, here's a page of Marvin the Martian quotes for those of us that grew up with Bugs Bunny and all of his cohorts as baby sitters.

http://www.gargaro.com/marvinsounds.html

Enjoy,

Michel

 

[Boogiebabies]

Uh; BB check your drawings again V8 and V9(the class A pair) share the B tap off the power supply to the screens ,when in pentode,with V6 and V7 (the A/B pair) but still maintain plate connection to their very own personnal primary taps on the output tranny.

It runs through the screens !!!

Dude, I just yankin your chain. If he wants to run it, let him.
You can run cooler tubes in the outer sockets. He has the schematic and can see the jump in the outer primary on the outer sockets. The question should be how big a sweep will the unit alter the bias? I personally have no wants, needs or desire for an ancient tremolo circuit. I'd go buy a roach and use that opto circuit anyway.

 

[Schmoog]

having thought about it some more, I'd prefer to just get a pedal. the fulltone supa-trem is an AWESOME tremolo, and you dont gotta modify your amp, or worry about red plating your tubes to run it

 

[Restless Rocks]

.Dude, I just yankin your chain.


We knew that man, I was trying to have a little fun at the end of long day myself. When ever I need a bit of tremolo like at the end of a ballad I just reach down with my pinky and shake the guitar volume knob myself.
He should just get a Tremoverb if that's what gets his surf up!

Okay who's our next Victim?????

 

[Boogiebabies]

Anyone who mentions Hamsters or pretends to be Roger the Shrubber.

 

[marklyn]

Just got to say thanks here for the really good info in this thread. Looks like I'll be sticking with my Valverb in the loop for trem. I leave it on most of the time so I was looking for a permanent solution.
I just totally have a thing for that old school Fender amp trem. But it's not worth giving up the Mark IV flexibility at this point.

And I couldn't be happier that we've ended up with Marvin the Martian. I should have counted on that bringing an Area 51 question.

Good info and Loony Toons. Double Bonus! :!: