100 Watt Master Volume Conversion

[sechfl]

Hi All,

Great forum. I'm kind of new to this, but here goes. I have a 100 watt Master Volume head from 1979. I'm wondering how much work and money would be involved to convert it to mid-70's metal panel
non-master volume specs. I'm assuming I would need a point to point board, and to add two more input jacks, but other that that, is there much else involved?

I'm a bit of a novice, and I don't necessarilly want do the work myself. Any info. would be great.

Thanks.

[Flames1950]

That's exactly what I did to my '78 50w MV. Get George's board, and he has the input jacks. I think my total cost was around $110 for mine.
Read over all the instructions that George sends, front and back. I missed some instructions he had written in specifically for my amp, and instead spent a bunch of time going through the schematics to determine where a couple of wires went on the older style board. The whole project took me a couple of days, and it's now one of my favorite amps again.

[sechfl]

Thanks for the info., Flames. I think I'm going to do it, just not sure when...have to get the funds together. I find the MV to be a bit shrill, but that not bad. I'm assuming the sound quality after the conversion will be much better. Also, could I convert it to a 50 watt, and still use the existing transformers?

I have decent soldering skills; not horrible, but not the best either. Is this a job I could do myself? Also, I am probably going to replace all of the pots with George's pre-wired assembly, as the ones that are on my head are a liitle worn out. Would this make the job easier?

[flemingmras]

Hey dude welcome to the board!

I am a local amp builder in the Detroit area and I have built 4 of George's full blown amp kits and am working on a 5th. I sell them to customers that order them, except I have different panels on mine than George does on his(mine go up to 11...literally)!

Now to agree with you about your opinion of the MV Marshalls...those are what I like to call a "one trick pony". They don't sound good at low volumes and even with a pedal thay sound like shit as you have to fight the amp to get any false harmonics. But they sound GREAT cranked. And that's about all they can do. Wheras the NMV circuit is VERY pedal friendly and has a great clean tone, but I love them CRANKED!!!!!!

To answer your questions, this is TOTALLY a job you can do yourself! Follow George's instructions just as Flames mentioned above and you will be fine. I believe on yours though on the inside of the chassis, the chassis itself is already drilled for 4 inputs, but the panel isn't, so all you have to do is drill the panel itself where they already have the holes in the chassis and PRESTO! You now have a 4 inputter!

As far as the pot goes, George sells the best pot.....uh...err...uh...OOPS! I mean, George's potS are great pots. And if yours are scratchy, get his prewired ones. This will make it much easier to change them since you have to get the back of them really hot to solder that ground buss onto the back of them. This way that will already be done and you won't have to worry about it.

If you need ANY assistance whatsoever, feel free to give me a call at (734)777-1486.

Jon

[Flames1950]

Jon's correct, the input holes are already there in the chassis, measure carefully and lightly centerpunch them into the faceplate, double check location and re-punch if needed before taking the drill to it. I don't remember the metal faceplate being aluminum, seemed to drill a little tougher than aluminum would, so a strong magnet behind the holes may catch the metal shavings and save you some cleanup time and worries from metal shavings.

[joshwilson3]

So, you guys like the NMV better than the MV? Is this because of the circuit, or because of the Master volume?

Could a NMV circuit be wired up as a Master volume, or is this something totally different?

thanks

[Dai H.]

2203/4 and 1987/59 are very very similar. A pretty simple job, but it does involve defacing the front panel when you poke the holes (which may already be in the steel part of the chassis but not the front panel). Could reduce value if and when you decide to sell it. Personally I would not do it if the amp is pristine condition, but be less apprehensive if previously modded/hacked. May be better to sell to someone who wants one and get an actual non-MV lead. But it's your amp--do what's best for you.

[Dax]

I did it, the best thing i ever did for the amp, sounds awesome! Dropped in two extra inputs, rewired the tones and installed the Metro PTP, sounds beautiful.

Dax