# 2 in on Modding/repairing a Mcintosh or building a Monoblock Help.



## Redman (Apr 30, 2018)

So I just bid 50$ on an MC431. If I get it wahoo. it may be broken. 

I am not rich but I live in Japan. Where mosfets and good caps are made. I was thinking that I could repair this amp if I bought a cheap scope or multimeter... if its broken. If not there is an MC430 for cheap that may be broken as well. 
I figure that I could check the circuits and replace blown components. 

But if I get a 430 I would like to upgrade it so that it can safely produce 100W without melting down.

Failing these above tasks.... 

EDIT: I need to specify clean high quality. My friend builds tubes but I dunno what he knows about class D and he has never built a car amp.

Isnt there a badass 100W (HIFI) mono block schematic out there? I have heatsinks soldering equipment and a friend who builds home amps. But he builds tube amps. I think together we could build a 4x100 quad mono design that would be much higher quality than I could afford to just pay for. I also love a challenge. 

I hope this is the right thread as I didnt feel it to be a general question. It is advanced but I figure users of this sub forum would be the best people to ask about these particular questions.

Also if you can answer these questions please advise me on who makes the best fets and caps in Japan.


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## Holmz (Jul 12, 2017)

Redman said:


> So I just bid 50$ on an MC431. If I get it wahoo. it may be broken.
> 
> I am not rich but I live in Japan. Where mosfets and good caps are made. I was thinking that I could repair this amp if I bought a cheap scope or multimeter... if its broken. If not there is an MC430 for cheap that may be broken as well.
> I figure that I could check the circuits and replace blown components.
> ...


The best FETs and the best Caps have little to do with it.
Just put it back together with new caps of the same type/brand.

I did not know a 430 was a class-D... so I guess I do like class-D amps, but never realised that I did.


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## Redman (Apr 30, 2018)

I might not know what the he** I am talkong about. A/B, D.... A is there a B or a C class. Idk... 
But What I am talking about is modification especially if I get a 50x 4 amp then making that into something that can safely throw. I imagine sizing up all of the components minus the actual drive circut should do fine as the body looks like its big enough to take the heat and I imagine the smaller amp has the same layout. But its a guess so thats why I made the thread to get more light on modding a McIntosh or building a small footprint monoblock of good quality from scratch. I could be in the wrong sub forum..... Im new to poking around inside amps. Its my buddy who knows more but hes a professor and real busy mostly.


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## Holmz (Jul 12, 2017)

The main question may be do we need more than 50W/channel these days? Or is 50W/ch enough?
And if it is enough, then just have the amp brought back to origional specs.

If not.. then you will need rails that are higher voltage, not just new FETs.


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## Redman (Apr 30, 2018)

I didnt get it anyways.... The bids went way too high for something that was " Untested" .

I want to find a good 100W monoblock design and I just happened to come across a bunch of heat sinks!! So I think it could be fun.

Anyone done this with great results?


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