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

Please login or register.

Login with username, password and session length
Advanced search  

News:

Lets get Technical > All Things Tube All about preamp and power amp Tubes.

Pages: [1]   Go Down

Author Topic: Need Help from my forum Brothers  (Read 1888 times)

0 Members and 1 Guest are viewing this topic.

DannyjoeCarter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 282
    • View Profile
    • Dannyjoe Carter
Need Help from my forum Brothers
« on: Time Format »

Well Folks one of my MP-1s came into today, incredibly clean condition and without a doubt this is the most ballsy MP-1 I have ever heard! However it has less gain than ANY ADA I have ever heard!!!!! I'm talking Angus and Malcom dry AC /DC Highway to Hell tone with both gains at 10 and I need way more than that!

 So I put in a brand new set of JJ 12Ax7s and full adjusted the gain trim pots both clockwise and counter and only heard a slight different. Both full clockwise I can see the subtle clipping light on the front panel light up and counter it stops.
 I have included pics so have a look - I have never seen ( or noticed ) these two long red leads floating around the tubes on an MP-1 - could this be some sort of lower gain mod?

Let me know your thoughts guys!
« Last Edit: Time Format by DannyjoeCarter »
Logged
Owner of DeJayce Guitars
www.dejayceguitars.com
www.youtube.com/dannyjoecarter
www.facebook.com/dannyjoe.carter

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 3626
    • View Profile
    • marshalljmpmodshop.net
Re: Need Help from my forum Brothers
« Reply #1 on: Time Format »

Those red wires are normal, is on of them loose? Looks all attached to me.

Now if you set T2 full clockwise and OD1 on 10 the OD1 led should go on a lot. So it seems to me a problem in the preamp section before the tubes. Do you use the front or rear input? or doesn't it matter which one you use?
Logged

DannyjoeCarter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 282
    • View Profile
    • Dannyjoe Carter
Re: Need Help from my forum Brothers
« Reply #2 on: Time Format »

Those red wires are normal, is on of them loose? Looks all attached to me.

Now if you set T2 full clockwise and OD1 on 10 the OD1 led should go on a lot. So it seems to me a problem in the preamp section before the tubes. Do you use the front or rear input? or doesn't it matter which one you use?

 Yes either full clockwise barely clipping on the front. And the signal seems just very slightly hotter using the rear input.
Normally on the MP-1  with OD1 and 2 at 5.0 and 5.0 it's very hot and juicy like the ultimate hotrod Marshall but on 5.0 it's as if you are cranking up a clean Fender and you get a little bark. With both on 10 it sounds just like the intro to Highway to Hell.
Logged
Owner of DeJayce Guitars
www.dejayceguitars.com
www.youtube.com/dannyjoecarter
www.facebook.com/dannyjoe.carter

rnolan

  • Administrator
  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4667
    • View Profile
Re: Need Help from my forum Brothers
« Reply #3 on: Time Format »

I think MJMP is on the money here, seems something before the tubes.  I assume you have known good guitar signal and guitar lead, worth checking just to rule it out.
From your last pic, seems someone has worked on the rear jack (rear jack mod?).  Could be a problem with signal from the jacks not getting into the board optimally (or the mod not being done quite right ?). Can you take a pic (or 2) of the cables from the front jack where they attach (an underneath pic would be handy).
« Last Edit: Time Format by rnolan »
Logged
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

DannyjoeCarter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 282
    • View Profile
    • Dannyjoe Carter
Re: Need Help from my forum Brothers
« Reply #4 on: Time Format »

I think MJMP is on the money here, seems something before the tubes.  I assume you have known good guitar signal and guitar lead, worth checking just to rule it out.
From your last pic, seems someone has worked on the rear jack (rear jack mod?).  Could be a problem with signal from the jacks not getting into the board optimally (or the mod not being done quite right ?). Can you take a pic (or 2) of the cables from the front jack where they attach (an underneath pic would be handy).

OK here's a few more pics
 (and even a pic of me ;D my Buddy in England did not believe I was on this board and playing MP-1s again )

See if you guys can spot anything - I am beginning to suspect this may have been a 1.38 that was updated? Share your thoughts gentleman.  :)
Logged
Owner of DeJayce Guitars
www.dejayceguitars.com
www.youtube.com/dannyjoecarter
www.facebook.com/dannyjoe.carter

rnolan

  • Administrator
  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4667
    • View Profile
Re: Need Help from my forum Brothers
« Reply #5 on: Time Format »

MJMP will know better than me, but that rear jack doesn't look right  :dunno: .  And the front jack I'd replace as it's looking quite tarnished.  My guess is this is a rear jack mod that hasn't gone quite right.  And now you are not getting a full signal into the tube stage.
Logged
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

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 3626
    • View Profile
    • marshalljmpmodshop.net
Re: Need Help from my forum Brothers
« Reply #6 on: Time Format »

This is a original V2 unit, input jacks look okay to me (there is no rear jack mod done to it).

The only thing that seems to be changed are the output jacks and the front pot, the rest is as far as I can see all stock.

Hey Danny, do you happen to have a scoope?
« Last Edit: Time Format by MarshallJMP »
Logged

van Sinn

  • Hero Member
  • *****
  • Offline Offline
  • Posts: 534
  • Know Thy Law
    • View Profile
Re: Need Help from my forum Brothers
« Reply #7 on: Time Format »

Well, he did notice a slight change in gain between front and rear inputs, which suggest the switch in the jack could be oxidized.
Try cleaning that switch using very fine emerald cloth (paper?) - but make sure to polish two pieces against one another to make sure it doesn't grind the contacts, but merely polish.

I don't remember the MP-1 (late 80's for me). Could it be not-so-good potentiometers causing gain loss?  - I've experienced this a--lot, both on an MP-2, my ADR compressor, a Lexicon LXP-15, and on a hifi preamp.
« Last Edit: Time Format by van Sinn »
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 3626
    • View Profile
    • marshalljmpmodshop.net
Re: Need Help from my forum Brothers
« Reply #8 on: Time Format »

No don't think that is the problem here, in that case the rear would work worse then the front. The pot is after the tubeboard so that won't be the problem either.

Maybe the wires on the front jack. I attached a pic and I put a circle around the shield of both cables, make sure it doesn't touch anything on the jack.Can't see it so good but I feel it's quite close.
Logged

DannyjoeCarter

  • Sr. Member
  • ****
  • Offline Offline
  • Posts: 282
    • View Profile
    • Dannyjoe Carter
Re: Need Help from my forum Brothers
« Reply #9 on: Time Format »

OK guys thanks again for all the help; I did contact the seller and they are giving a full refund. Supposedly he had since it was new however now he has confessed that he bought it two years ago used and actually doesn't know the full history of it.  :poop:
But the info you all have shared will come in for future use for sure - thank you!
 
 I just put up a post about these kind of things last night! Buying things that are supposed to be "MINT" and "Perfect Condition" as well as "I bought it brand new and have had it all this time". And they don't work.  :facepalm:
 So yet another one is going to be delivered today so I'm keeping my fingers crossed that this one works!!!
I will keep you all posted!
Logged
Owner of DeJayce Guitars
www.dejayceguitars.com
www.youtube.com/dannyjoecarter
www.facebook.com/dannyjoe.carter
Pages: [1]   Go Up