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Author Topic: MP1 Classic Clean Issue  (Read 1212 times)

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AndiK

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MP1 Classic Clean Issue
« on: Time Format »

Hi all,

my MP1 Classic produces hiss/strange sounds in clean tube mode, when the "brown" uses both modes it is not that strong. Solid state and distortion mode are working normal. Battery and tubes are checked and ok...symtoms appear to be clearly limited to the clean mode only...
Any suggestions???

Thanks
Andi
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MarshallJMP

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Re: MP1 Classic Clean Issue
« Reply #1 on: Time Format »

Try to replace R151 and see if that works. There's some info about it on the depot, just do a search for it. You could also try to measure the resistance first, it should be 180k ohm. Sometimes these go up in value.
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AndiK

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Re: MP1 Classic Clean Issue
« Reply #2 on: Time Format »

Just measured R151 - reading 176k, so this should not be the reason for the issues. Has to be in the signal path of the clean tube mode....

Andi
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AndiK

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Re: MP1 Classic Clean Issue
« Reply #3 on: Time Format »

Just measured the testpoint voltage - reading 207 V with my good voltcraft meter....
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AndiK

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Re: MP1 Classic Clean Issue
« Reply #4 on: Time Format »

Issues are solved - changed R151 and R382. Now the voltage for TP34 is 202V....
Soldering on this PCB is a pain (at least for me).....
As stated by others before, it is really essential to desolder the components before measurement!

Due to the infos in this forum i now have also a fully functional MP1 Classic  :bow:

Thanks a lot!
Andi
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rnolan

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Re: MP1 Classic Clean Issue
« Reply #5 on: Time Format »

 :whoohoo!: :thumb-up: great news
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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

Dante

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Re: MP1 Classic Clean Issue
« Reply #6 on: Time Format »

+1! Great news!!
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ADA Gear: MP-1 Classic | MP-2 | Viper Combo | MicroTube 200 | MicroFet | MXC w/Quad Switch
Current Live Rig (wait 10 min., it'll change): Carvin V3m head into my Viper combo as a speaker cab, using my TCE G-System via 4CM.

MarshallJMP

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Re: MP1 Classic Clean Issue
« Reply #7 on: Time Format »

Classic pcb's are a pain in the ass to desolder
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