Studio preamp questions

[masher]

Since I got my studio preamp a few weeks ago, I just can't seem to get enough info on the unit. Unfortunately there's just not that much info on these older units, alot of threads, but they all seem to go in the same direction.Since most of us newer owners are getting these units second hand, and who knows what the previous owners have changed over the years, I'm wondering if some users could shed a little light on these gems.
I know there were 2 revisions, I've seen 1 with a blue grey eq(with toggle on rear), and the other with the black eq(with switch). I've also seen ones that have no front inputs at all.I've also read they switched to a 12ax7 for reverb at some time.
Any known difference between revisions?, any way to tell what revision a unit is?
Does anybody know what years the studio pre ran?, mine is a 93 with a 12at7 reverb tube, I wondering if it came with a 12ax7.When did they switch to the 12ax7?
Here's one I just picked up tonight here on around pg 38."MB said to run the send from the Quad into a 50/50 to get the same sound as the 2C+" has anyone else heard this?, or tried it?. I've never heard a IIC+ up close so I can't say, I would also imagine the studio would work the same as the quad since from what I've read they have almost the same lead 1 section, right?.

 

[r_cod_81]

I'd contact your local MESA distributor. I've done that a few times and received very quick and informative responses, interestingly enough about some similar things to that which you ask.

My Studio Preamp was built in March and April 1990 (should really have had a 22nd birthday for it ) judging by the dates on the main and EQ circuit boards. It has the black plastic switches rather than the metal toggle ones so I believe it's the 2nd 'version'? I also believe that this was the only difference between the two versions; the circuiry is identical.

1) You can run the signal to a power amp from the effects send - some people prefer this so experiment with the effects send, main out and recording outs depedning on your tone/ effects requirements (rec. outs are darker, main outs will give you another tube stage etc.)

2) The lead circuit is based on a generic MkII. There is a mod to MkIIC+ but it is not an 'official' mod. I have no idea whether mine has had this mod done, it certainly has a lot of gain and there are a couple of places on the circuit board where soldering has been performed. I guess this is what you mean by "not so much info about old units"...?

3) I too asked about the reverb tube. Mine was wimpy (read 'barely audible') and was driven by a 12AT7. I asked about upgrading it to a 12AX7 and was advised against it as, according to my local distributor, it was designed for a 12AT7. I replaced the tube (the old one was ancient, probably original, and the pins were hugely corroded. A new tube made the reverb positively cavernous! I scraped all the crap off the pins and it works fine...

Have fun with this awesome piece of kit, I actually had a good fiddle with the settings of mine last night, it's incredible the range of tones possible from it!