Madison PA-A203 amplifier

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Hazardsneon

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I have been searching all over trying to find out anything about this Madison PA-A203 amplifier that I have. I picked it up with a blown channel. I can fix it and keep it or I might sell it. The problem is that the person I bought it from didn't know a thing about it and didn't have any information on it. I have been looking for months now and I just did a search today and found back in 2004 someone mentioned having a couple of these amplifiers on this forum. If anyone could give me any information on this amplifier it would be AMAZING! A pdf manual would be incredible.
 
Yeah, not much info on it- first four returns from a google search are your posts, here and elsewhere, asking for info on it! :) Did you send a PM and/or email to the fourmite who had those amps?

Did you see this ebay search?:
madison amps | eBay
If it's a Madison-Fielding, I don't think you have much, there, although if it's a tube amp, guitarist sometimes like to convert those older tube PA amps into guitar amps.
 
I know that I'm littered all over but I can't seem to find anyone who has one or even knows anything about it. It is definately not a Madison-Fielding nor is it a tube amp. The guy I bought it from was not technically savy, he was just clearing out equipment that had been sitting broken for a year or two. He didn't have any more information than I could find searching via google. I believe it is made by the same company that made the amp in the ebay search. Here is a poor picture of the face of it:
0719111052.webp
 
Madison is cheap stuff. It would most likely cost more to fix it than it's worth and then it may not be that reliable.
 
I can fix it for $8. I found the faulty transistors already and I just need to purchase them. I didn't pay much for it so it wouldn't be difficult for me to get rid of it for more than I paid for it. Otherwise I wouldn't mind keeping it but I don't know a single thing about it other than it is a Madison amp probably from 2003 and it exists. Another concern of mine is that there is no fuse currently in the holder and I wouldn't know what an appropriate fuse would be. Here are some pictures of the back. Notice that there is a silk screen for all the ratings but not populated. 1317749955101.webp1317749933072.webp
 
Fuse size isn't stated on the inside where it connects?
 
No such luck. I emailed the previous owner to see if there might be any manual still lying around but I'm not too optomistic about it.
 
Doing a quick calculation working from what I believe the amps output is (about 200 watts channel unless it says otherwise on the fuzzy photo), I would guess the fuse should be 4 to 6 amps, however just to protect the amp when you fire it up, put say a 3 amp fuse in first and turn it on with the volume down. With the volume down the amplifier won't pull full load and if there is a short the 3 amp fuse will blow.

When you ensure that the amp is working properly if the 5 or 6 amp fuse blows when the amp is working hard, up the fuse size a little and try again.

The logic behind this is that the fuse is there to do 2 things, protect the components if there is a short and to protect the amp if it is working too hard.

Alan.
 
What did you see that I didn't to be able to make power calculations?
 
Hazardsneon said:
What did you see that I didn't to be able to make power calculations?
Click to expand...

A bit of guess work, but I had a look on the net for various power amp fuse ratings and power consumptions, I guessed that the amp you had was about 200 watts a channel, a typical power consumption for a 400 watt amp (total) is about 700 watts, watts divided by volts = amps, 700/110 = 6 amps.

I downsized the fuse size I recommended as I did not know for sure that the amp was 200watts a channel and I did not want you to fry anything, using a smaller fuse first up won't hurt anything only blow the fuse when you crank it up.

Sorry I just did an edit as I put the wrong numbers in my explanation.

Alan.
 
Geez, if it's only gonna cost $8 to fix, you didn't pay much for it, and you already know what to do to fix it, just FIX IT.
 
It has nothing to do with fixing it. You are missing the point. If I were to fix it and sell it I would need to know specs. I don't have any specs on it. The fuse "issue" clouded the issue that I initially proposed. I would have no issue putting in an appropriate fuse. I just used that as an example that I don't have any information on this amp. If I needed help or questions on fixing it, I would have asked different questions. All that I want are the manufacturer specs.
 
Hey, man, calm down, I was not ragging on you. Sometimes internet communication can be difficult to follow, esp. the intent, because it's so one-dimensional.

The amp has two channels- can you compare component test readings on the good side with the same on the bad side, to close in on what might be bad? Most components are standard issue, and probably fairly readily available.

And if I am stepping on your toes, again, I apologize. But really, dude, don't be so touchy.
 
Hazardsneon said:
It has nothing to do with fixing it. You are missing the point. If I were to fix it and sell it I would need to know specs. I don't have any specs on it. The fuse "issue" clouded the issue that I initially proposed. I would have no issue putting in an appropriate fuse. I just used that as an example that I don't have any information on this amp. If I needed help or questions on fixing it, I would have asked different questions. All that I want are the manufacturer specs.
Click to expand...

doesn't look like you're gonna have them at this point.
As for selling it ..... you can still sell it for a profit over 8 dollars.
If you feel like you have to know it's output you can take it to a good tech and he can put it on a scope and figure our roughly what it puts out.

Or you can do nothing and sell it "as is".
 
Lt. Bob, what is involved in measuring the power output? I have an o-scope on my bench.

In addition, I take all caps as yelling and I take it offensively. Also, stevieb, I didn't say anything malicious so I don't know why you assume that I need to calm down. All that I was saying is that I wanted the focus to be on my original question. If you think that you said something that should bother me then that's on you.
 
Hazardsneon said:
Lt. Bob, what is involved in measuring the power output? I have an o-scope on my bench.

.
Click to expand...
I don't remember the specifics since it's been maybe 30 years but I've seen it done several times when checking hi-fi amps for output.
McIntosh used to have a guy that went around with a scope for clinics and he'd check your amp for you. It was quick enough that he'd do dozens of them in an afternoon.


I would think they run it into a dummy load so they can crank it and I usually see amps rated at 1000hz/1 volt input so you'd put in a 1v 1000 hz signal.
But I'm not sure how you read the scope to determine what it's putting out. Sorry.
But if you have a scope .... I'm positive it's an easy procedure. I'm sure there's gotta be a lotta places on the 'net that detail how to do it.
 
Just for the sake of information sharing, here are the results that I came to:

I used a large adjustable resistor as a dummy load, a signal generator, a scope, and a true RMS DMM. I used the DMM to measure the voltage across the load to measure the power and I used the scope to make sure I measured before the output started clipping.

Stereo:
749Wrms per channel
Measured: 54.76Vrms with 4ohms - input of 1.7Vp-p at 1kHz

520Wrms per channel
Measured: 64.54Vrms with 8ohms - input of 1.9Vp-p at 1kHz

Bridged:
1318Wrms
Measured: 102.7Vrms with 8ohms - input of 1.6Vp-p at 1kHz

I also ended up using a 15A fast blow fuse.
 
Hazardsneon said:
Just for the sake of information sharing, here are the results that I came to:

I used a large adjustable resistor as a dummy load, a signal generator, a scope, and a true RMS DMM. I used the DMM to measure the voltage across the load to measure the power and I used the scope to make sure I measured before the output started clipping.

Stereo:
749Wrms per channel
Measured: 54.76Vrms with 4ohms - input of 1.7Vp-p at 1kHz

520Wrms per channel
Measured: 64.54Vrms with 8ohms - input of 1.9Vp-p at 1kHz

Bridged:
1318Wrms
Measured: 102.7Vrms with 8ohms - input of 1.6Vp-p at 1kHz

I also ended up using a 15A fast blow fuse.
Click to expand...

wow ..... :eek: ..... I'm guessing you've decided to fix it.

That's a lot more power than we were thinking it'd be.

And now you have a new skill!

:)
 
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