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Studio Premp w/ MKIIc+ mod

Posted: Fri Nov 04, 2011 8:15 am
by mboogman
Posted this in the announcements section, but I figure it should be in here too, since, it's about a rack piece, so here ya go.

I just got done doing a little work on my Mesa Studio Preamp. When I bought it, the reverb tank was not working, so I replaced it with a tank from MojoTone. Sounds great! While I was at it, I went ahead and set it up for the MKIIc+ tone stack. I think it made a huge difference in the overall feel of the lead channel.

Here's a quick recording I did one morning before heading off to work.

http://soundclick.com/share.cfm?id=11184795

I normally would have an SM57 on the cabinet, but all I had on hand at the time was one of my AT4040's. No FX, just straight into the preamp, then into my VHT 2:Ninety:2 power amp, into my Peavey JSX cab, which is less than ideal, but you'll get the idea.

Re: Studio Premp w/ MKIIc+ mod

Posted: Fri Nov 04, 2011 5:44 pm
by dbone
The link brings me to soundclic but not right to the clip
At least on my iPhone

Re: Studio Premp w/ MKIIc+ mod

Posted: Sat Nov 05, 2011 8:40 am
by mboogman
Fixed link ... Maybe? :)

Re: Studio Premp w/ MKIIc+ mod

Posted: Sun Nov 06, 2011 12:36 pm
by Whoopysnorp
Sounds awesome, though without a 'before' clip to hear how the stock version sounded on your particular setup, it's difficult to know exactly how much of the sound to attribute to the mod.

I have a couple of schematic images regarding a IIC+ mod to the Studio Preamp, one of which is apparently just for the lead circuit and involves changing some resistor and cap value, and the other of which is for bass shift and deep modes. Did you do just the lead mod, or the others as well? Or is it a different mod you worked from?

Re: Studio Premp w/ MKIIc+ mod

Posted: Mon Nov 07, 2011 9:31 am
by mboogman
Whoopysnorp wrote:Sounds awesome, though without a 'before' clip to hear how the stock version sounded on your particular setup, it's difficult to know exactly how much of the sound to attribute to the mod.

I have a couple of schematic images regarding a IIC+ mod to the Studio Preamp, one of which is apparently just for the lead circuit and involves changing some resistor and cap value, and the other of which is for bass shift and deep modes. Did you do just the lead mod, or the others as well? Or is it a different mod you worked from?
It was just the Lead mod. I'd be interested in seeing your schems for the bass shift and deep mode too though.

I agree that I should have done a before clip. I just got excited to get the mod done, and jumped the gun a little.

Re: Studio Premp w/ MKIIc+ mod

Posted: Thu Nov 24, 2011 9:00 am
by toolshed
my studio pre never get that clean, if i do get it that clean, i sacrifice the lead channel. I havent changed tubes and i bought it used so there is a good chance that the tubes are all stock. what would you suggest to be able to get my stupre sounding like that? oh, and was the mod hard to do?

Re: Studio Premp w/ MKIIc+ mod

Posted: Thu Nov 24, 2011 4:25 pm
by dbone
toolshed wrote:my studio pre never get that clean, if i do get it that clean, i sacrifice the lead channel. I havent changed tubes and i bought it used so there is a good chance that the tubes are all stock. what would you suggest to be able to get my stupre sounding like that? oh, and was the mod hard to do?
New tubes would allow you to determine if the old ones sound.... old.
If they sound fine then you have backups : )
What are your current tone settings?

Re: Studio Premp w/ MKIIc+ mod

Posted: Thu Nov 24, 2011 7:12 pm
by toolshed
Image

as far as old tubes, I have changed them in other amps and it's made a world of difference, as far as the setting
here is an awful pic of the rig but you get the idea. the settings are
gain4.5,volume 2,high 9,low 1,mid 7.5, reverb 1,gain9, 4lead volume all switches are up except the bright rhythm channel
i'm running a eq pedal on the lead channel via switcher but the clean is breaking up even with the settings like 2 on the gain and almost all the way up on the volume. then the lead channel needs more gain...

Re: Studio Premp w/ MKIIc+ mod

Posted: Fri Nov 25, 2011 1:52 pm
by Whoopysnorp
mboogman wrote: It was just the Lead mod. I'd be interested in seeing your schems for the bass shift and deep mode too though.

I agree that I should have done a before clip. I just got excited to get the mod done, and jumped the gun a little.
Just realized I never posted my schematics. Here are both:

http://maxcrowe.co/img/lead_C+mod.jpg
http://maxcrowe.co/img/bass_shift_&_deep_MOD.jpg

Re: Studio Premp w/ MKIIc+ mod

Posted: Wed Nov 30, 2011 5:33 am
by Shane C
Hi mboogman,

Can you please describe the tonal difference's you noticed after doing the mod?


Thanks!

Shane

Re: Studio Premp w/ MKIIc+ mod

Posted: Wed Dec 21, 2011 3:28 pm
by mboogman
Shane C wrote:Hi mboogman,

Can you please describe the tonal difference's you noticed after doing the mod?


Thanks!

Shane
Before the mod, I had a hard time getting a nice, round clean sound while also getting a cutting, tight rhythm/lead sound. Now, the upper mids cut a little better, some of the bottom end flub has been trimmed out of the lead mode, and the useable gain increased just a hair. The graphic EQ also seems to complement the lead channel a little better without having to use the typical "V" settings.

Re: Studio Premp w/ MKIIc+ mod

Posted: Thu Dec 22, 2011 4:30 am
by A_Ryder
mboogman wrote: Before the mod, I had a hard time getting a nice, round clean sound while also getting a cutting, tight rhythm/lead sound. Now, the upper mids cut a little better, some of the bottom end flub has been trimmed out of the lead mode, and the useable gain increased just a hair. The graphic EQ also seems to complement the lead channel a little better without having to use the typical "V" settings.
Hey great work man, my vote for post of the year. The circuit diagrams, tone samples, it's all good and the Studio sounds great.

This very week I was thinking, "hmm, it's amazing how my C+ just hangs together and both channels 'just work' even though there's all the shared dials "...

And to be honest I never understood what the + mod was really all about, I've never had IIC so I couldn't work it out for myself but I'm guessing the motivation was to make both channels happy and work better together. Maybe gain, the loop or something else changed in the process but I'll bet that's what it was mainly all about.

Cheers.

Re: Studio Premp w/ MKIIc+ mod

Posted: Thu Dec 22, 2011 7:16 am
by Shane C
mboogman,

I want to do the C+ mod on my Quad. Im just in the planning stage, I have figured out most of it but I need a little help please:

1m = the lead drive pot correct? The only part I cant figure out is where to put the 680k before the 1M/lead drive, I could post some close-up shots of my Quad's board and label everything I can see for the mod if you or anybody can help me out?


Any info would be greatly appreciated.


Shane

Re: Studio Premp w/ MKIIc+ mod

Posted: Thu Dec 22, 2011 8:24 am
by mboogman
A_Ryder wrote:
mboogman wrote: Before the mod, I had a hard time getting a nice, round clean sound while also getting a cutting, tight rhythm/lead sound. Now, the upper mids cut a little better, some of the bottom end flub has been trimmed out of the lead mode, and the useable gain increased just a hair. The graphic EQ also seems to complement the lead channel a little better without having to use the typical "V" settings.
Hey great work man, my vote for post of the year. The circuit diagrams, tone samples, it's all good and the Studio sounds great.

This very week I was thinking, "hmm, it's amazing how my C+ just hangs together and both channels 'just work' even though there's all the shared dials "...

And to be honest I never understood what the + mod was really all about, I've never had IIC so I couldn't work it out for myself but I'm guessing the motivation was to make both channels happy and work better together. Maybe gain, the loop or something else changed in the process but I'll bet that's what it was mainly all about.

Cheers.
Those are very kind words. The more time I get to spend with the SP, the more I'm loving it these days. In fact, last night, I was mentioning to the other guitar player in my band that I was really missing the "idling diesel engine" clean sound you hear on a bunch of recordings, and then I simply flipped over to the Studio clean side, no comp, no effects, just clean, and wow! There it was! I didn't need change a thing on the front panel to get there either. Win-win!

Re: Studio Premp w/ MKIIc+ mod

Posted: Thu Dec 22, 2011 8:28 am
by mboogman
Shane C wrote:mboogman,

I want to do the C+ mod on my Quad. Im just in the planning stage, I have figured out most of it but I need a little help please:

1m = the lead drive pot correct? The only part I cant figure out is where to put the 680k before the 1M/lead drive, I could post some close-up shots of my Quad's board and label everything I can see for the mod if you or anybody can help me out?


Any info would be greatly appreciated.


Shane
I'd be glad to help any I can. I haven't seen the insides of a quad before though. I can send you some pics of the inside of my Pre after the mods if you like.