Metropoulos Forum

Sorry if this is already posted, I couldn't find anything about how to do the one wire mod. I just want to try a master volume mod on my 1959 super lead, and if I don't like it, I want to be able to just take it out real quick. That's why I want to try the one wire mod first.

Could anybody help me out with how to do it? Like I said, I searched etc. and could not find anything about how to do it.

Thanks.

Have a look here:http://home.comcast.net/~mamp17/Misc%20 ... 0Info.html

There are different versions.

For simplicity the RR mod on the same site is quite good too.

Thanks. I'm actually thinking about the PPIMV mod.
And also, I don't know if I should try to do it myself, or take it to a professional. Is it difficult to do? I know how to solder, etc. but I don't want to destroy my amp haha.

Also, with this mod, if you just crank the master volume all the way up and put the volume down, would the amp sound and function as if there's no master volume there?

yep, the Lar/Mar version (ppimv) when dimed,is out of the circuit essentially. Hang out here at Metro a bit more and soak up some more info (print out layouts,analyze, etc). Get a 24" insulated test/jumper lead (with mini alligator clip on each end), clip one end on pin 1 on v1 (the first preamp tube) and the other on the chassis. This drains the voltages in your amp. That is one of the first and most important things your gonna want to do when servicing your own tube amp. Believe me, you can save lots of do-ray-mee by doing the work yourself. Most techs would charge you an hours rate ($75 to $100) up front, regardless of what they do. So just to install a PPIMV, your probably looking at around $100 (they would probably charge more though). Give yourself a couple weeks of studying and soaking up stuff (learn ALL the dangers), then have some fun

Yes, hang around for a bit and read, you asked one question but meant another! Keep asking tho' we all learn all the time

Thanks guys.
So upon more searching, I came across the PPIMV Step by step on the bottom of this page: http://home.comcast.net/~mamp17/Unsorted%20Pics.html" onclick="window.open(this.href);return false;

Is that the same way I would do it to a 1959 Super lead?
It seems really simple actually.

nickguz wrote:Thanks guys.
So upon more searching, I came across the PPIMV Step by step on the bottom of this page: http://home.comcast.net/~mamp17/Unsorted%20Pics.html" onclick="window.open(this.href);return false;

Is that the same way I would do it to a 1959 Super lead?
It seems really simple actually.

Yes that is a post phase inverter master volume (PPIMV). The one-wire mod you asked about initially is a pre- phase inverter master volume and is used typically in master volume amps although you can use both/either!

neikeel wrote:

nickguz wrote:Thanks guys.
So upon more searching, I came across the PPIMV Step by step on the bottom of this page: http://home.comcast.net/~mamp17/Unsorted%20Pics.html" onclick="window.open(this.href);return false;

Is that the same way I would do it to a 1959 Super lead?
It seems really simple actually.

Yes that is a post phase inverter master volume (PPIMV). The one-wire mod you asked about initially is a pre- phase inverter master volume and is used typically in master volume amps although you can use both/either!

So which mod would have more gain?

If you use a PPIMV on a well set up amp and use the volume 1 and volume 2 knobs as gain controls (ie turn them up!) you
simply limit the overall volume with the PPIMV. You drive the PI tube hard and the output valves do not work quite so hard. It does give a satisfying distortion but not the same as cranking the power valves hard. This can sound really good at moderate attenuation although some amps start to flub out on 10 on the preamp settings and you do lose the effect of the presence control as you dial down the volume with PPIMV.

When you use a 1-wire mod you are cascading the signal from one half of V1 into the other half of V1 (called a cascade) that gives you an extra gain stage. This works well to give more gain at lower volumes but to get the best out of it some of the caps and resistor combinations need experimenting with to get the desired tones, hence the switching or RR mods. I am biased but I think the 2 in1 mod on SDMs site wrks really well

Well actually, my original intent was to get a Jcm800, and use no pedals or anything. But then I figured I'd try this, since I already have this amp and it'd save me about $1000. Would this mod match up to a jcm800 at all? Not tone-wise, but amount of gain?

Edit: Basically, if I'm looking for gain similar to a Jcm800, will I be disappointed?

Edit again: Actually just went and cranked the amp to about 7, and (despite it being quite bassy for some reason, didn't bother to mess with the settings) I was quite satisfied with the sound.

Do the 2 in 1 mod (with my name attached - still Steve's basic idea) but mine is simple to do and will give you 2203 (JCM800 and 1959 in one box

neikeel wrote:Do the 2 in 1 mod (with my name attached - still Steve's basic idea) but mine is simple to do and will give you 2203 (JCM800 and 1959 in one box

Is there anywhere that tells how to do it step by step? Those schematics are a little overwhelming
And would that mod be easy to revert?

That link seems to be dead, is that schematic posted anywhere else?

Ray Barbee wrote:That link seems to be dead, is that schematic posted anywhere else?

https://drive.google.com/folderview?id= ... sp=sharing