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:

Need a Schematic? Check the Vault *MP-1 Classic Schematics Just Added!!

Pages: [1]   Go Down

Author Topic: ADA MP-1 v1.36 Switches on! Normal background noise there, but no Output!!!!  (Read 380 times)

0 Members and 1 Guest are viewing this topic.

Pedro

  • Newbie
  • *
  • Offline Offline
  • Posts: 6

Greetings,

I am new in the ADA Depot.

I have just acquired a ADA MP-1 on Catawiki. Unfortunately it arrived not working.
The unit turns on and appears ok after the diagnostic. Its a firmware 1.36.
You can also hear a background noise in the distortion channels, which is not there in the clean channel.
No sound comes from the input (tried both front and rear).

Can anyone help me to pin point the problem?

Here is a video with the problem.
https://www.youtube.com/watch?v=Mt4MzFgl4AA

Thanks in advance for any help you can give me.

Cheers!
Logged

rnolan

  • Administrator
  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 5124

Hey Pedro, welcome to the depot.  Do you get any output from the Fx send or the headphone out?
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

Pedro

  • Newbie
  • *
  • Offline Offline
  • Posts: 6

Hi rnolan,

No output from the headphone out (besides that standby noise), FX I havent checked but i will check this afternoon.
Thanks!
Pedro
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4117
    • marshalljmpmodshop.net

Hey Pedro

From looking at your video it seems that the front jack has been replaced, can you take a few pics of the inside of the unit so I can have a look?
The unit seems to work so my first guess would be to check that input. BTW the rear input is line level in, not instrument and is normally switched on if nothing is plugged in in the front. But if they replaced the front jack it could be it doesn't work anymore. So first let's start out with some pics.
Logged

Pedro

  • Newbie
  • *
  • Offline Offline
  • Posts: 6

Thanks for your fast answer guys!!
Much appreciated.

First to rnolan, i did try the FX send output and again noise comes but no output. The noise level does increase if i turn the fx level up.

In Answer to MJMP, i did not notice any volume difference when changing from OD1 to OD2.
Here are a few photos from the inside in zip file attached.

I did notice when comparing with other photos for MP-1 insides, that the capacitors are not original (makes sense after all this time), no cable tie around them and it was not used axial capacitor but a radial one. A bit sloppy work maybe.
Also i i measured the battery which seems also not the original system (maybe battery mod?!?!) but measures above 3v so that seems good (also no error during start up).

Again thanks for your help.
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4117
    • marshalljmpmodshop.net

I mean when you change the OD1 or OD2 controls, do you  hear more or less noise?

Now from what I can see in the pics someone did a very poor job on some things. Those caps in the power supply are no good, they need to axial types secured to the pcb, not flapping around in the breeze like this. It seems the front jack is replaced although it looks like the correct type. Can you take a pic of the underside of the pcb near that front jack?

Also I think it's modded with a 3.666 or a 3.1 mod (as far as I can see). I see the bass trimpot in the tonesection.

It has the battery mod.

Also has the MDRT transformer in it. So that's a good thing  :thumb-up:

If the serial number is 800083 than this is a very old unit, number 83 out of 25000 made.
Logged

Pedro

  • Newbie
  • *
  • Offline Offline
  • Posts: 6

Wow Great info MJMP!!
Same noise from both ODs
Attached some pictures from bottom of the unit.

I am bit worried with these mods, I would prefer to have the original unit.
Based on your experience can these mods be reversed?
Of course if there is a modification based on the ADA specs like that letter from 92 where ADA recommends some modifications for older units. I guess this one is applicable.
Glad to see its from the first 100 batch!! Thats quite cool.

I am indeed worried with the poor job done. If you see some pictures some solder is very poorly done and there are cables with wires not included in the solder joint which look dangerous...
I would be interested in putting this unit beck to stock, however i would like to keep what you think should be kept. For sure the transformer as you mentioned.

But regarding these mods... I am not sure. I have to listen to it. I really like the Nuno Bettencourt, Vitto Bratta sound and not so much Paul Gilbert. Not sure if these mods change the unit sould a lot. I will investigate and hear some demos on you tube.
There is also the noise mod, maybe that is beneficial. Do you advise this one?

I think i will start by checking that input jack, if you agree, and then move on the check the capacitors and replace the inadequate ones. I will have a look at the mods schematics to see what was modified.
Another option is also to send it to you for repair, if you would be available for that. But i would like to first have a shot at understanding whats wrong with unit, with your help.
I noticed also the volume knobs should be blue in the original? but these are all black. Could be that some units came like this?
Thanks again for help and sharing your knowledge!
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4117
    • marshalljmpmodshop.net

Does the master volume do anything noise wise (I mean the pushbutton, not the volume pot).
Logged

Pedro

  • Newbie
  • *
  • Offline Offline
  • Posts: 6

The master volume affects the 'noise' volume, also Eq (mid bass,treble and presence) also affect it.
Checked continuity from the cable on the input to the traces of the PCB and appears input jack is good!
Will check the capacitors now.

Cheers,
Pedro
Logged

Pedro

  • Newbie
  • *
  • Offline Offline
  • Posts: 6

I guess i cant figure this one out.
I will send this one out to you for fixing MJMP, is thats ok with you.

Regards,
Pedro
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4117
    • marshalljmpmodshop.net

No problem, already send you an email about it.
Logged

MarshallJMP

  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 4117
    • marshalljmpmodshop.net

For anyone that is interested. Pedro shipped it to me and the problem here was that one of the digital pots (U14,TC9176) was bad. this one controls the OD1 and OD2 settings. Put in a NOS and it works again.
Logged

rnolan

  • Administrator
  • Superhero Member
  • ******
  • Offline Offline
  • Posts: 5124

Great news  :thumb-up: , thanks for letting us know.
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
Pages: [1]   Go Up