ADA Depot - A Forum To Support Users of ADA Amplification Gear

Please login or register.

Login with username, password and session length
Advanced search  

News:

Temp "Time Format" issue Fix in Discussions

Pages: [1]   Go Down

Author Topic: MP1 Classic Clean Issue  (Read 3990 times)

0 Members and 1 Guest are viewing this topic.

AndiK

  • Newbie
  • *
  • Offline Offline
  • Posts: 7
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
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4702
    • marshalljmpmodshop.net
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.
Logged

AndiK

  • Newbie
  • *
  • Offline Offline
  • Posts: 7
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
Logged

AndiK

  • Newbie
  • *
  • Offline Offline
  • Posts: 7
Re: MP1 Classic Clean Issue
« Reply #3 on: Time Format »

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

AndiK

  • Newbie
  • *
  • Offline Offline
  • Posts: 7
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
Logged

rnolan

  • Administrator
  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 5998
Re: MP1 Classic Clean Issue
« Reply #5 on: Time Format »

 :whoohoo!: :thumb-up: great news
Logged
Studio Rig: Stuff; Live Rig: More Stuff; Guitars: A few

Dante

  • Administrator
  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 2124
  • Nothing more uncommon than common sense
    • The Best Cover Band In Sacramento
Re: MP1 Classic Clean Issue
« Reply #6 on: Time Format »

+1! Great news!!

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4702
    • marshalljmpmodshop.net
Re: MP1 Classic Clean Issue
« Reply #7 on: Time Format »

Classic pcb's are a pain in the ass to desolder
Logged
Pages: [1]   Go Up