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Author Topic: My MP1 arrived! Time to modify it!  (Read 1194 times)

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rnolan

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Re: My MP1 arrived! Time to modify it!
« Reply #15 on: Time Format »

Hey Tommy, the output level of the tube voicings (clean or dist) should not be lower than the SS, if anything it should be the other way round.  Something isn't quite right.  I'd send it to MJMP :thumb-up:
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Studio Rig: MP2/MB1 > Eurorack UB2442FX-Pro > TC M-One XL > Behringer Truths (with Truth Sub) / QUAD ESL 63s
Live Rig: MP2/MB1 > Alesis Quadverb > Alesis Midiverb 4 > Yamaha AM802 > B200s/Carvin TS100/DCM200L > ADA Split Stacks/Mesa P112s

Harley Hexxe

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Re: My MP1 arrived! Time to modify it!
« Reply #16 on: Time Format »

Hey Tommy,

       If the MP-1 was having issues before you installed the mods, then more than likely, the issue is still there. It was never addressed before you installed the mods, so it still goes on even with your hard work. I wished I had known that before you went to all the trouble you did to install these mods.
       Even a stock MP-1 operating like it was originally meant to does not sound thin in any way, unless you dial it in that way, and you pretty much have to turn everything almost all the way down to get it like that. It's a robust and full-bodied preamp that was powerful enough to turn the entire amplifier industry on it's ear when it was introduced in 1987. (As was evident in 1988 when all the other single space rack preamps began to show up on the market).
      There is something in the un-modded circuitry that is already goofy with that preamp. Perhaps you might be able to get MJMP to help walk you through some checks with that preamp to try to figure out what it might be. I'm pretty sure this issue has come up in the past with stock MP-1's and it's been addressed here on the Forum. You might be able to find it in some old posts, but I would run this by MJMP regardless, and let him point you in what might be the best direction to figure this out. The only thing I can say at this point, is that you have already narrowed it down to an issue with the tube voicings, since you said the SS voicing sounded very good, that takes that part of it out of the equation. That also means the issue is common to both clean and distortion tube voices, if they sounded thin before the mods. I don't know this for a fact, but I'm going to guess that it's somewhere in the power to the tubes circuit. I would start with a meter on the tube filament voltage to see if you've brought it up with the transformer mod. The stock MP-1 ran the tube filaments at a lower voltage to begin with, around 6.3 volts if I recall correctly. So I would check the filament voltages at all 3 tubes, and also, check your grounds to both circuitry and chassis for cold or incomplete solder joints. Weak tubes sound like dogshit on razor blades. I would also check the output voltages at the transformer to be sure it's not damaged in any way.

Harley 8)
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I used to be ambivalent. Now, I'm just not sure...

TommyVonVoigt

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Re: My MP1 arrived! Time to modify it!
« Reply #17 on: Time Format »

Thank you :)

I emailed MJMP directly about this. I do hope I can get to the bottom of things!
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MarshallJMP

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Re: My MP1 arrived! Time to modify it!
« Reply #18 on: Time Format »

Hey Tommy, sorry for the late reply, (was pretty busy yesterday) but I just send you an email with things to do. So let me know.
BTW do you have a multimeter, scope ? Just to know what we can do.
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tnipe

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Re: My MP1 arrived! Time to modify it!
« Reply #19 on: Time Format »

When I got my unmodded unit it sounded pretty good. And then I got the noise mod and others installed, and I have this same issue (not 3TM). There must have been something gone wrong in the modding process. Let me know what you find out!
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TommyVonVoigt

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Re: My MP1 arrived! Time to modify it!
« Reply #20 on: Time Format »

We’re still working through it. MJMP has had me do several measurements, and so far, everything totally checks out.
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TommyVonVoigt

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Re: My MP1 arrived! Time to modify it!
« Reply #21 on: Time Format »

I've decided to move it on, guys. Kind of a bummer, but I can't find anything wrong with it, everything works as it should, and I just don't like the way it sounds. I made a post in the for sale section, if anyone is interested.

But hey, like  was saying, the cool thing is I discovered the Rane EQs because of this site! So, honestly, I consider this a huge win, still!
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Harley Hexxe

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Re: My MP1 arrived! Time to modify it!
« Reply #22 on: Time Format »

Hey Tommy,

       That IS a bummer. Sorry you didn't find out what's keeping a lid on the beast.

       The transformer mod you did, is that the MDRT?

Harley 8)
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I used to be ambivalent. Now, I'm just not sure...

TommyVonVoigt

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Re: My MP1 arrived! Time to modify it!
« Reply #23 on: Time Format »

Yep, the MDRP. I bought all the best stuff. I wanted to have it be the best MP-1 possible.

I really am bummed out. If I'm right, and this is simply a case of me not being a good match for an MP-1, that is super disappointing. All signs pointed to this being the perfect preamp for me. Like, it's made for exactly what I like and what I want to do. But, I also realize that sometimes the gear and the player just aren't a good match, and it's no knock against either. For example there are some Synergy modules that have near universal praise, that I just couldn't get a sound I liked out of. It wasn't the modules...it just wasn't the right match.
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Harley Hexxe

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Re: My MP1 arrived! Time to modify it!
« Reply #24 on: Time Format »

Hey Tommy,

      Yeah, I get that. I've always said taste is subjective because it's true. No harm no foul. For all you've put into it, you're asking a very reasonable price IMHO.

Harley 8)
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I used to be ambivalent. Now, I'm just not sure...

TommyVonVoigt

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Re: My MP1 arrived! Time to modify it!
« Reply #25 on: Time Format »

Just throwing this idea out there, and I posted in my for sale thread as well - if any of you happen to have a spare, stock MP-1, that you know for sure is in perfect working order and sounds the way these things should sound, I would totally swap straight up. A stock unit, assessed by one of you guys that is actually familiar with these, for this modded unit, and all the parts I list in my for sale post.

I think I am always going to be wondering, otherwise.
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