Marshall 1959 Double Master Mod Help

[rafalynch]

Hi, I have a 1971 Marshall 1959 with a PPMIV installed. I would like to make a modification to increase the volume on guitar arrangements, a double master switchable by pedal like I have installed on my Jcm800 2203. I consulted my repair technician who did the PPMIV mod and he told me that it could not be done on the 1959/1987 models because they did not have a master volume.

 

[rafalynch]

For the JCM 800 2203 I bought this circuit at Tubetow. Is there any way to do the mod on the Marshall 1959? A friend of mine who is into car electronics tells me that it could be done the same way but with two boards in parallel and another double potentiometer of the ppmiv. Please I would be very grateful for any help. Excuse my English. Thanks

Kit Double Relais Switcher, 6 V

Double Relay Switcher for channel switching and similar applications.

www.tubetown.net

 

[rafalynch]

Some photos of my 1971 JMP.

 

[Purgasound]

It can be done but there will be a lot of irreversible damage done to the amplifier and chassis in the process. It's not worth it.
I would recommend getting a Fryette Power Station and it will perform the task you are looking for.
Also with the Power Station you can get rid of that awful PPIMV.
Cheers

 

[rafalynch]

Thank you. I don't like power stations and I won't use it for recording. I only use the Marshall with a Schaffer Replica pedal and a Gibson. I'm very happy with the sound and I don't want to change anything. I'm sorry to disagree with you but the PPMIV is the best thing that has happened to the amp, it's great. I just need a volume jump with a pedal stroke. Thank you.

 

[jagrenet]

I installed PPIMVs on both of my Plexi amps. The only way to fly !!!! - Love them !!

 

[mAx___]

Thank you. I don't like power stations and I won't use it for recording. I only use the Marshall with a Schaffer Replica pedal and a Gibson. I'm very happy with the sound and I don't want to change anything. I'm sorry to disagree with you but the PPMIV is the best thing that has happened to the amp, it's great. I just need a volume jump with a pedal stroke. Thank you.

No master volume(s) will ever sound better than how the original circuit was supposed to work, there's no way around that. Superleads had no MV. The best solution you should at least try is a good attenuator like the Fryette, Suhr, Rivera, etc.
Your amp will sound much better and you won't have to make any alterations to a vintage circuit. Just buy one from a vendor that allows for returns and if you don't like it, send it back. Just give it a try.
EDIT: The JohnH attenuator was developed by a forum member and everybody loves it, look it up.

 

[rafalynch]

Thank you, I have had several power stations and as I said I don't like them... they modify the sound and weigh a lot... I prefer PPMIV a thousand times. The one I have installed doesn't change the sound of the amplifier. Even so, thank you for your advice. I am thinking of building a machine that mechanically moves the potentiometer of the ppmiv by remote control. I will continue investigating. Thank you.

 

[jagrenet]

Thank you, I have had several power stations and as I said I don't like them... they modify the sound and weigh a lot... I prefer PPMIV a thousand times. The one I have installed doesn't change the sound of the amplifier. Even so, thank you for your advice. I am thinking of building a machine that mechanically moves the potentiometer of the ppmiv by remote control. I will continue investigating. Thank you.

Agreed 100%. My Plexis sound exactly as they were before I put the PPIMV in them. Absolutely no difference in the tonal characteristics whatsoever.

 

[dtier]

It can be done with the same kit as it appears to have two channels. The two channels would have to be paralleled to switch together giving you four form C contacts to switch between the two tandem pots. The safety resistors would have to be configured to be around both pots and all contacts to protect against bias failure at any wiper or contact. They should also protect bias during switching. You just have to find someone competent who is willing to do it. If not done right and it fails it could take out tubes and OT.

By the way your V5 output tube appears to be running hot as evidenced by the browning of the logo.

 

[rafalynch]

Thank you very much dtier. I will follow your advice and explain it to my technician to see if we can do it. I already saw the el34 tube with the logo burned. I have replaced it with new ones and done the bias. Thanks

 

[Pete Farrington]

I have had several power stations and as I said I don't like them... they modify the sound

I suggest to try operating your amp as its designer intended, ie with all valves in place and approximately biased, and re-assess.

My view is that pulling a pair of EL34 is a bad idea, as the amp's power supply then becomes super stiff.
Hence the absence of sag makes the operating point much harsher, which perhaps may be the cause of the overheating valve in the V5 socket.

Operate the amp properly, let it breathe, and attenuate the power output as required.

 

[rafalynch]

I have more Marshall JMP heads, some with all 4 tubes and others with power stations. I recommend you try using your 1959 with just two tubes and the ppmiv, you will see how you can get that sound that only a 1959 gives but at useful volumes live in small venues and pubs. Of course when I play on big stages I carry two half stacks switched with an ABY pedal to turn up the volume on guitar arrangements. I understand that you like power stations, but I don't. Thanks for your advice.

 

[rafalynch]

Hello again. I'm a very stubborn guy with my equipment and I like to try everything, I would almost say it's sick, but it's my hobby and there are few things I like more than spending an afternoon at my place with friends trying out equipment with other points of view and ways of playing from other colleagues. Here there were many who recommended the Fryette to me and there was even someone who criticized the PPmiv that I use in my Marshalls. little more than calling it "Horrible". Well, I had to buy it and also the most expensive model to be able to have "My" opinion. Tomorrow I'm putting it up for sale, it sucks up the TONE of the Marshall... the sound is muffled without that Marshall crackling that makes the difference with other amplifiers. THERE IS NOTHING to lower the volume on a Beast like my 1959 Superlead from 71' like a well-installed PPmiv. I recommend it here and I insist on the huge waste of money that this type of attenuator is. save that money and invest in a better Marshall.

 

[rafalynch]

 

[jagrenet]

Hello again. I'm a very stubborn guy with my equipment and I like to try everything, I would almost say it's sick, but it's my hobby and there are few things I like more than spending an afternoon at my place with friends trying out equipment with other points of view and ways of playing from other colleagues. Here there were many who recommended the Fryette to me and there was even someone who criticized the PPmiv that I use in my Marshalls. little more than calling it "Horrible". Well, I had to buy it and also the most expensive model to be able to have "My" opinion. Tomorrow I'm putting it up for sale, it sucks up the TONE of the Marshall... the sound is muffled without that Marshall crackling that makes the difference with other amplifiers. THERE IS NOTHING to lower the volume on a Beast like my 1959 Superlead from 71' like a well-installed PPmiv. I recommend it here and I insist on the huge waste of money that this type of attenuator is. save that money and invest in a better Marshall.

I agree 1000%. I have installed the Lar-Mar style PPIMV on ALL of my1959 Plexi's. I believe it to be "standard" equipment now and somewhat of a "pre-requisite" before even thinking about bringing them into a gigging scenario. For me it's PPIMV or nothing at all. By the way .... all of my Plexi's are absolutely vicious - tone quality, gain for days ... and no degradation of the original sound whatsoever.

 

[Creach]

Hello rafalynch,
There is different way to have a volume boost without even mod the ppimv : switchable cathode bypass capacitor, tone stack lift, switchable nfb...

The simplest is a variable tone stack lift, you don't even need a relay, and the potentiometer can be installed in the footswitch. (but this will produce a more lead sound).

Are you looking something like a boost or just volume difference?

 

[rafalynch]

Thank you very much Creach. I am looking for a volume increase to stand out in guitar arrangements. What you are saying seems very interesting. Do you have a wiring diagram so I can take it to my technician to see if he can make the mod? Thanks again.

 

[EndGame00]

Instead of having 2 MV's, What about a clean boost pedal for solos?

 

[Creach]

Thank you very much Creach. I am looking for a volume increase to stand out in guitar arrangements. What you are saying seems very interesting. Do you have a wiring diagram so I can take it to my technician to see if he can make the mod? Thanks again.

You could try first the variable tone stack lift and see if you like it.
This mod is easy and you can use the hole of the second speaker jack (actually you can use the jack itself if it's a switched one), so no drills in the chassis and easy to go back to stock if you want.

Here is a layout, your tech just have to disconnect the ground of the mid pot and follow the layout, left side is what to do in the amp, right side is how to build the footswitch.
For the footswitch you could also have a female jack and use a cable that you already have. And the led is not mandatory.

I'm hoping that my layout is good enough to be understood, feel free to ask if you need more infos.