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Author Topic: MP-2 After the noise mod - Spanky Clean is distored . . .  (Read 11320 times)

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W.Laturno

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I've finished swapping out the R913 and capacitors - no more motorboating -

now it's like the clean voicings 1-6 are super overloaded - the RED LEDS light up like a Christmas tree.....

I started replacing the original caps back ( all the polarities were correct BTW ) and was about 95% done ( testing each time before moving on to the next one ) when C907 blew up !   

 :hair-out:

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W.Laturno

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Picture added ....for effect,,,
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rnolan

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Hi Will, it made a bit of a mess :-\
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W.Laturno

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Gents - If possible, please reply -

What is your drive setting on voicing number 1 Sparkly Clean ?

Right now, when I goto the preset channel 12, it is very very loud and distorts if I hit a full chord....
It is not quite so bad if I lower the DRIVE to about 0.....but this does not seem right

thanks -
« Last Edit: Time Format by W.Laturno »
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rnolan

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Hi Will, this is Patch 12 in my spare MP2 so the previous owner may have changed it from factory  :dunno: , my other MP2 (which I know is factory as I never changed any of the default patches) is 2 hours away and I wont get to it for a few weeks. I'll do a factory restore later when I get some time and compare.  BTW what are the EQ settings on your patch, The EQ can add/subtract a lot of gain.

Voice -> 1 Crystal clean
Drive -> 50
Master -> 50
Comp -> out
Lo: 0
Mid: 0
Hi: 0
Pres: 0
Graphic (all flat (0))
Wah -> out
Trem -> out
NR -> out
Ch -> out
Loop -> in (mix A 25% mix B25%)
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W.Laturno

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OK - Update ( 02-06-2014 ) - After (MANY) e-mails and such to MarshallJMP, I've come to the concluesion that when I did the noise mod I simply did not have both sides of the printed circut board (PCB) 2-layer solder 100% since when I pushed the caps all the way down there was no way for me to insure that the top layer was making great contact....sounds lame I know, but what can I say...the whole MP-2 is  seems to be working very well now....after re-doing the mod with longer cap leads so I could solder both sides...

the clean issue I seem to be having is still strange....in order to keep the voicing one super clean, I have to lower the drive ( to about 0-15 ), I just don't remember it being that sensitive before....but I can get by for now.

  :metal:
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Dante

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Once again, MJMP saves the day

Thanks!

rnolan

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the clean issue I seem to be having is still strange....in order to keep the voicing one super clean, I have to lower the drive ( to about 0-15 ), I just don't remember it being that sensitive before....but I can get by for now.

  :metal:
Seems very strange, what are your MP2 eq settings (including graphic) ?
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W.Laturno

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Sorry for falling off the grid,  rnolan- eq settings are all flat....I've been jsut trying to get as clean a sound a possible...So, since Feb I guess, the MP2 has been good - but at practice last night, , , , it went south again...

I'm going to have to plunge back into it and recheck if I used any of the original caps as well as check the voltages at the test points.....sigh.....makes me wonder....

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rnolan

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Bummer, I feel your pain/frustration.  Are you using the compressor in the clean patch and if so what's it set to, it also can add quite a bit of gain ? drive 0-15 is very low, particularly when mine is 50  :???: for that patch, and my clean stage patch (see MP2 patches) is 37 but that's with compressor gain at 50.  Also what's the input chain into the MP2 ? guit > MP2 ? and what pickups. Or are you running other gadgets before it as well ??
Cheers Richard
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MarshallJMP

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What seems to be the problem?
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W.Laturno

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Seems ANY channels that had the compression ON - are now a complete waste ( 100% garble and muck sounds )....even the preset 12 which was suppose to be Compressed Clean.   If I take and shut the compression off - - it cleans right up . . . amazingly too....

There (seems to me ) to be a lot of humm now.....

To appease, I'll go to a clean channel and keep the tone and eq at 0 ( flat )  - no chorus, no effects loop, no noise reduction, no wah, no compression  - Voice 1 Crystal Clean, drive 15, master 79....nothing plugged into the unit ( no guitar cord) just one cable to my ADA microtube 200 and a single 30W celestion . . . audiable hummmmmm

Plug in my guitar ( Les Paul Shred stock pickups ) - and it's nice, clean and loud...but...hummming...

Change to voice 2 Spanky Clean - - same thing, with a bit, less hummm, but still there...

Voice 3 Fat Clean - nice - ....with hummmmmm

Voice 4 Vintage Brown and 5 - I hear no humm a lot less volume though...a lot . .

Voice 6 hummm is faint...

Voice 7 brings in the OD - I played with it . . even at 0 and the drive at 0 ( Master at 79 ) - it's garbage....worse sound ever...
 8 - same . .  .not even playing any notes, nothing plunged into the input, the green light stays lite on the Graphic EQ and Chorus . . . hummmmmmm

I can probaly re-work all my patches and live with this - I'll have to use the Noise Reduction for sure.....

but by no means can I turn on the Compression anymore....it just is a loud obnoxious bunch of garbled feedback...ughhh

So - having been schooled a bit by M_JMP - the first thing I did was measure the test point - 193.9 vdc   ( a hair high...)

then I started to check my caps since I did the noise mod in March. ..  I swapped out a few, but no real difference....

I am going to probably try some new tubes just to rule that out....it would surprise me ( though I haven't a lot of experience) if the new caps I installed a few months ago were to already be shot....

VCC1 = 5.09vdc
VCC2 = 15.24vdc
VCC3 = -15.49vdc

uh-oh.....suppose to 24vdc at pin three of  U 906 (LM317T) . .  .I measure 38.2vdc 

U 901 (LM337T) @ pin three is suppose to be -24vdc I measure -38vdc

Filliment U 904 should be 12vdc - I get 11.8

sooooo - something is messing up the 24 vdc . . .    feedback ( no pun intended ) . . . .


« Last Edit: Time Format by W.Laturno »
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MarshallJMP

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U906 (LM317) pin 3 is the input and pin 2 is the output,so it's normall you measure +38V,measure on pin 2 what's the voltage there?
U901 (LM337) here is pin 3 the output and pin 2 the input,what voltages you have here?
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W.Laturno

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Across U 901 ( LM337T ) pin three I was getting -38vdc
I'll check back tonight when I am able to get a level on pin 2 ( input )

as well as re-check U 906 (LM317T) . . I had not paid attention to the schematic and noticed pin three was input...grrrrr :crazy:

« Last Edit: Time Format by W.Laturno »
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rnolan

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Hey Will, you'll get it sorted, new tubes can't hurt but your issues seem a bit more than that unfortunately.  Between you and MJMP I'm confident you'll get it sorted.
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