New Mesa (Studio Preamp) user

[Spiggy]

Hey! I just purchased a Mesa/Boogie Studio Pre off of Reverb. I LOVE it, but I'm sorting through some issues and had a couple of questions.

When I got it it had an AMAZING clean sound, and I got some good growling distortion on power chords but it didn't seem to have the gain it should and individual notes would kind of die... I couldn't get the singing lead I'd heard about. Plus the reverb basically didn't work, if you put it on 10 you could almost barely hear it. I swapped tubes with some JJs and the gain problem was fixed, the reverb was fixed, but I lost a lot of the warmth and harmonic lushness of the clean channel.

Questions... Tubes. It had one tube with a black plastic/rubber jacket on it that reads SPR SPAX7-A in what I believe is V1. The next one said Mesa Russian 2 and was black at the top with no jacket. Then an EHX tube. Then another Mesa Russian 2 that was silver at the top. And it had a 12AU7 in the reverb spot. What would you guys officially recommend to retube with? I was going to order Mesa tubes but I heard Mesa just puts their name on various other manufacturers tubes. Is this true? Are the JJs just harsh because they are new? Should I put a diff brand in V1? Right now I have four JJ 12AX7 short plates in 1-4 and an EHX 12AT7 in the reverb. I'm tempted to put that Mesa with the black jacket back in to 1 and see what that does. For that matter, let me make sure I have this right... Looking at the front of the amp, 1-4 are left to right and then 5 is in the back right? And V1 is the input and strongly affects the clean tone correct? It's a bit sterile and lifeless now, before it had a wet harmonic sound. What are your recommendations for tubes in which spots in the Studio Pre?? The guy I got it from said that it "kills tubes" and goes through them pretty fast, he's had a couple die. I have a feeling the reverb was out and the outputs did something flakey once where I lost a channel and had some popping due to bad tubes because the re-tube has now fixed those issues.

I've heard reference (since I bought mine) to black or gray graphic EQ versions of this preamp. Is there any difference between sound/build on these versions or is does that just show when they were made and is cosmetic only? Mine is black EQ.

I'm hoping mine doesn't have any previous mods. Can I send you guys a pic and have you tell me if it's unmodded or not? I don't want to do any mods that would be hard to undo, or have any drawbacks, such as... I've heard of a Mark IIC mod that is popular, but then I've heard that it can have a negative effect on you clean channel which I definitely do not want. I've also heard of people getting a better/brighter/more modern sound by disconnecting the recording outputs and/or reverb tank. Are there any of these mods you guys would (unofficially) recommend?

Speaking of the reverb tank... It sounds pretty good turned down to 3 or 4, but at higher settings it's pretty harsh and unusable. Is there anything you would recommend there, such as a different aftermarket reverb tank, a different tube in that spot, or as mentioned above, disconnecting it altogether to improve overall tone and stick to pedals or rack units for reverb?

That's about it... unless you have any other major tips or advice for a first time Studio Pre user. These things have an almost cult status. I read one person say he felt it was one of the best products Mesa/Boogie has made. I just want to make sure I'm getting the very most out of mine and using it to its fullest potential. I'm using a custom stereo low wattage EL84 tube power amp with this and am getting some really good sound, but I would like for the Studio to be my main tone source and want it to be set up as perfectly as it can be.

 

[mkcreel]

Hello,

I have the same questions about my Studio Preamp. Is there not anyone here who can answer or help out with these questions. I see the previous post was on 4/12/16 and there have been no replies, what gives? I know there are people here who can answer these questions or at least point us in the right direction. C'mon fella's help us out. Isn't that why this forum is here?

 

[Markedman]

When I had a studio preamp it really sounded good and had more than enough tone, I used the Sovtek 12ax7LPS tubes, from what I'm reading I think both of yours need a recap. I used the effects send as my output, try that out.

 

[IronSean]

Bunch of stuff to unpack here.

For starters, there's some general wear and tear / age related work you should do:
Replace the Caps. The large filter caps wear out and dry up over time, and since there were all late 80s/early 90s they're 30+ years old and due for replacement or failure. Should breath a lot of new life into the amp.

Replace the LRDs: These Light Dependant Resistors are used to control the channel and feature switching, activating the EQ or changing channels. They wear out over time as well, and are the cause of most weird behaviour on Studio Preamps/Quads that relate to channel switching not working, drops in volume, sapped tone or gain, etc.

Then some general amp knowledge:
Remember that the volume on the clean channel feeds into the gain on the lead channel. Usually 7-8 is where you can limit breakup on clean but still feed the lead strongly, but you'll have to tease out the balance yourself.

It sounds like some bad tubes were definitely affecting you. IF you look up the manual/schematic you can see which tube does what. V1 is largely in control of the clean, later ones do the lead channel, so replaced tube in the lead channel might give you gain back without affecting the clean. Which tubes to use is hotly contested and debated, and you'll probably jsut need to get some and try. I hear lots of good things about the new Tung Sols though. The SPR ones in the jacket are Mesa's special low noise ones designed for V1 to limit amp noise. Mesa buys tubes, tests them, then brands them. So they know they'll work, but you can save a bit of money buying directly from thetubestore or dougs tubes or something.

As for it killing tubes.. that's strange, most preamp tubes should last for a decade or more, I haven't noticed this.

can't remember if there's a difference between black and grey, but it's minor if anything.

Disconnecting the reverb is just as simple as unplugging it, and can be plugged back in. And I don't know about disconnecting the recording outputs, you could just as easily use the effects send outputs to bypass it.

 

[mkcreel]

A little late I know, been insanely busy.

I appreciate IronSean taking the time to respond and provide useful and positive info! Thank you Sir