Unit inspection

[Rawk777]

I just got a MP1.

Looks like it's been modded. The red wires all seems to be cut. Inside the brown wire, connected to the tube board, the one nearer the front volume pot, the black wire is also cut.

What can you tell me about this unit?

[Rawk777]

Images

[rnolan]

Others will no doubt throw more light on it, it's a early MP-1 (with top switch) and it's got the older v1.38 EPROM and is probably due for a new battery.  Does it work ? how does it sound ?

[Rawk777]

It will need a noise gate, but I would no define the unit as being noisy. In fact I thought it was going to be much more noisy than this!

I would not say it sounded bad. I don't know what the tubes really are, but they are branded marshall. I had the impression the sound was  more dynamic than the mp2 and that it sounded more "raw", but what I perceived might have been biased by what I expected of the unit. Time will tell :) .

I'm a bit worryed about those disconnected red wires.

[Kim]

Those removed and wrapped red wires were part of a revision ADA did during production.   I don't remember the specifics of how and why that came about, but it's normal to have those wires like that in the early versions.

[MarshallJMP]

From what I can see this is and old rev (B I guess).What serial nr does it have (starts with 8xxxxx)?

[Rawk777]

Thanks Kim, I'm glad to know those red wires are normal.

The serial is 800562.

Does it look stock?

[MarshallJMP]

Okay that a really low serial nr, so it's stock. There some changes you could do if you want. I have a paper for that.

[Rawk777]

Well, I think I'm going to update the eprom, do the battery mod and replace the rear input jack (it's broken).

What are the other changes you'd suggest?

[vansinn]

Replace all electrolytic capacitors..

[DannyjoeCarter]

Replace all electrolytic capacitors..

Hey van sinn just curious, how much different will the unit sound with the caps replaced? Night and day or more subtle?
Share you thoughts  :D

[vansinn]

That will be impossible to judge up front. I had a look at Rawk's most telling picture, and see no caps bulging out, which is a good sign.
Now, electrolytic caps all loose some of their capacitance over the years due to the electrolyte gradually drying out; how fast this takes place is in part stated by the manufacturer and in part depends on their use and how lucky we were with the production..

The reason I always say replace them is that electronics as old as our ADA's will have a number of e-caps in less than optimum shape.
Not only can this create hum, but i.e. a cathode resistor with a bypass cap that's down in value will result in different transfer characteristics / different frequency response than was intended by ADA when they designed it.
As such,, I see no reason not to replace all e-caps when about to do the basic sanity scoop-up's anyways..
You know, it's commonly said that our ADA's all sound a Bit different, and I think components going off factory specs could well play a role here.

[DannyjoeCarter]

That will be impossible to judge up front. I had a look at Rawk's most telling picture, and see no caps bulging out, which is a good sign.
Now, electrolytic caps all loose some of their capacitance over the years due to the electrolyte gradually drying out; how fast this takes place is in part stated by the manufacturer and in part depends on their use and how lucky we were with the production..

The reason I always say replace them is that electronics as old as our ADA's will have a number of e-caps in less than optimum shape.
Not only can this create hum, but i.e. a cathode resistor with a bypass cap that's down in value will result in different transfer characteristics / different frequency response than was intended by ADA when they designed it.
As such,, I see no reason not to replace all e-caps when about to do the basic sanity scoop-up's anyways..
You know, it's commonly said that our ADA's all sound a Bit different, and I think components going off factory specs could well play a role here.

Wow this is really good info here! I would not have thought of looking for bulging caps, thanks for that tip Brother!

[Iperfungus]

That will be impossible to judge up front. I had a look at Rawk's most telling picture, and see no caps bulging out, which is a good sign.
Now, electrolytic caps all loose some of their capacitance over the years due to the electrolyte gradually drying out; how fast this takes place is in part stated by the manufacturer and in part depends on their use and how lucky we were with the production..

The reason I always say replace them is that electronics as old as our ADA's will have a number of e-caps in less than optimum shape.
Not only can this create hum, but i.e. a cathode resistor with a bypass cap that's down in value will result in different transfer characteristics / different frequency response than was intended by ADA when they designed it.
As such,, I see no reason not to replace all e-caps when about to do the basic sanity scoop-up's anyways..
You know, it's commonly said that our ADA's all sound a Bit different, and I think components going off factory specs could well play a role here.

Wow this is really good info here! I would not have thought of looking for bulging caps, thanks for that tip Brother!

Hey Dan!

How many MP-1s you and your buddy have picked up so far???  :metal:

[DannyjoeCarter]

That will be impossible to judge up front. I had a look at Rawk's most telling picture, and see no caps bulging out, which is a good sign.
Now, electrolytic caps all loose some of their capacitance over the years due to the electrolyte gradually drying out; how fast this takes place is in part stated by the manufacturer and in part depends on their use and how lucky we were with the production..

The reason I always say replace them is that electronics as old as our ADA's will have a number of e-caps in less than optimum shape.
Not only can this create hum, but i.e. a cathode resistor with a bypass cap that's down in value will result in different transfer characteristics / different frequency response than was intended by ADA when they designed it.
As such,, I see no reason not to replace all e-caps when about to do the basic sanity scoop-up's anyways..
You know, it's commonly said that our ADA's all sound a Bit different, and I think components going off factory specs could well play a role here.

Wow this is really good info here! I would not have thought of looking for bulging caps, thanks for that tip Brother!

Hey Dan!

How many MP-1s you and your buddy have picked up so far???  :metal:

We have four right now and one of them I really don't like the voicing of, but I will keep it for parts. My buddy Jason has a 1.38 that we have retired and will also use that for parts. The chorus went out plus compared to my new main one, it really sounds terrible.

Also I know for certain we have purchased at least two MP-1s from forum members on here  ;D And they were good to us and very professional  :thumb-up:
That's the thing, I'm not buying them to collect but rather I'm trying to build a back up rig and one for my buddy as well. And like it has been mentioned before Iperfungus, so far none of these units sounded ANY alike! Not even in the same ball park but I'm just trying to get one more similar to my Holy Grail one that the battery/eprom error when I first got it.
Then I'll be happy - for awhile  :lol: