1960B Jack Plate replacement query

[Maidenmatt]

Hey guys,

I’m having some issues with my JCM900 1960B Cabinet. It is intermittently cutting out and dropping volume. Upon doing some research, I believe it to be the mono/stereo plate. Upon testing my JVM through my 1936 2x12 using the same speaker cable etc it is rock solid.

Would you guys recommend getting a direct replacement plate or hardwiring to 16ohm mono?

I’ve seen a few diagrams and links to more American websites but no so much UK sites where I can source the bits I would need.

Would love to get the cab up and running considering it cost me a grand total of £75 (Yes, £75!) from one of my best mates!

Cheers in advance for any help offered!
Matt.

 

[fitz]

There is a genuine Marshall replacement.

Jack Plate - Marshall, Switchable Stereo / Mono | Antique Electronic Supply

Switchable stereo/mono jack plate for back of cabinets.

www.tubesandmore.com

Also, an aftermarket that doesn't have a switch to fail.

https://www.tubesandmore.com/products/jack-plate-plug-and-play-mono-stereo

Available from multiple sources, but T&M is my go-to.

 

[BlueX]

Good advice above.

If you're fine with mono I would keep the plate, remove the existing jacks, and put in a new Cliff jack and solder the wires for mono. Plug any remaining holes. Should be the cheapest, easiest, and most reliable way.

 

[Maidenmatt]

Good advice above.

If you're fine with mono I would keep the plate, remove the existing jacks, and put in a new Cliff jack and solder the wires for mono. Plug any remaining holes. Should be the cheapest, easiest, and most reliable way.
View attachment 154208

Thank you for both of your replies!

And BlueX if you’ll please excuse my ignorance, would this Cliff jack be the correct one?

https://modulusamplification.com/cliff-uk-jack-socket---switching-mono---metal-nut-3048-p.asp

And I’m guessing metal vs plastic nut is not going to make any difference?

Cheers!
Matt

 

[BlueX]

Thank you for both of your replies!

And BlueX if you’ll please excuse my ignorance, would this Cliff jack be the correct one?

https://modulusamplification.com/cliff-uk-jack-socket---switching-mono---metal-nut-3048-p.asp

And I’m guessing metal vs plastic nut is not going to make any difference?

Cheers!
Matt

I prefer plastic nuts for speaker connections. There's some effect out from the amp, and non-conductive materials feel better.

Chromed metal nuts are used for input jacks on the front of amps, where you can see them (but the electrical effect is very small).

I would choose this jack

Cliff UK Jack Socket - Switching Mono Plastic Nut

1/4" CLIFF UK JACK SOCKET - SWITCHING MONO Genuine Cliff UK panel mount 1/4" Jack Socket, with switching contacts for muting input when

modulusamplification.com

Note that there are two lugs each for tip and sleeve. One of them is switching (disconnects) so best is to solder the wire to both unless you're sure which is non-switching.

 

[Maidenmatt]

I appreciate your help greatly, thank you very much!

 

[Dogs of Doom]

for Cliff™, I'd get this one: mono non-switchable w/ solder lugs

 

[Kendall124]

Hi guys. I don’t want to hijack this thread, but could you expand on the reason why you prefer a plastic jack socket and nut over a metal one?

 

[Purgasound]

Hi guys. I don’t want to hijack this thread, but could you expand on the reason why you prefer a plastic jack socket and nut over a metal one?

It's insulated from the jack plate itself.

 

[Deftone]

Good advice above.

If you're fine with mono I would keep the plate, remove the existing jacks, and put in a new Cliff jack and solder the wires for mono. Plug any remaining holes. Should be the cheapest, easiest, and most reliable way.
View attachment 154208

Definitely doing this to mine. Heard horror stories about the factory stereo/mono plate failing and causing damage to the amp (IIRC)

FWIW I tried stereo and was not impressed. I like two amps and two cabs for stereo. YMMV

 

[Maidenmatt]

I prefer plastic nuts for speaker connections. There's some effect out from the amp, and non-conductive materials feel better.

Chromed metal nuts are used for input jacks on the front of amps, where you can see them (but the electrical effect is very small).

I would choose this jack

Cliff UK Jack Socket - Switching Mono Plastic Nut

1/4" CLIFF UK JACK SOCKET - SWITCHING MONO Genuine Cliff UK panel mount 1/4" Jack Socket, with switching contacts for muting input when

modulusamplification.com

Note that there are two lugs each for tip and sleeve. One of them is switching (disconnects) so best is to solder the wire to both unless you're sure which is non-switching.

An update… thanks to @BlueX (and everyone else’s) help, my Dad helped me solder the Cliff Jack in (I don’t have my own iron) so the cab is now hardwired 16ohm mono!

My £75 bargain cab is now my £76.38 bargain cab!

It's insulated from the jack plate itself.

@Purgasound I coincidentally watched one of your videos on wiring the cab and I’ve only just put two and two together and realised it was your YT channel upon re-reading this thread, so thanks to you too!

And just as a side note, I’ve been trying to date the cab and if I’ve worked it out correctly, I believe the speakers are from the 25th February 1991? If I have it correct than I am just shy of 2 months younger than my cab!

The stamp on the speaker reads
- BZ25/20T7360.

Cheers again guys,
Matthew.

 

[Matthews Guitars]

I consider standard metal Switchcraft jacks to be superior to Cliff jacks, from a durabilty standpoint. I firmly believe that there's no possible way that a Switchcraft jack or a Cliff jack could SOUND any different if both are not broken. However, there's a matter of things being correct and traditional for the type. Marshall has always used Cliff jacks, and they work fine, and they're appropriate. For anything Marshall or Marshall style, Cliff jacks are what I'll use. For anything in the rest of the world like Fender or Mesa, it's Switchcraft jacks all the way.

No way a Cliff jack would survive long if you used one as your guitar's output jack.

 

[guitarbilly74]

I think the switching option on the 1960 is a great feature. You never know what amps you may get in the future, so it's good to have these options.

I, for one, need all the switching options on the cab. I have a Marshall Mosfet that needs the 4ohms output to get full power, I run my tube heads at 16ohms and I have a rack that takes 8/8ohms stereo.

Mojotone has a drop-in replacement for the Marshall 1960 jackplate that is better quality than the original with a thicker PCB. I've been using them for years on my 1960s without issues and I gig them a lot.

Mojotone Stereo/Mono Cabinet 4x12 Wired Jack Plate (Double 1/4")

SpecsDimensions: Outer - 3 1/2" (H) x 4 3/4" (W)Inner - 2 5/16" (H)x 3 9/16" (W)Replacement for the Marshall® stereo/mono 4x12 jack plate (9131200) but withno Marshall® logo. Comes with complete wiring harness for all 4speakers.

www.mojotone.com

 

[BlueX]

An update… thanks to @BlueX (and everyone else’s) help, my Dad helped me solder the Cliff Jack in (I don’t have my own iron) so the cab is now hardwired 16ohm mono!

My £75 bargain cab is now my £76.38 bargain cab!


@Purgasound I coincidentally watched one of your videos on wiring the cab and I’ve only just put two and two together and realised it was your YT channel upon re-reading this thread, so thanks to you too!

And just as a side note, I’ve been trying to date the cab and if I’ve worked it out correctly, I believe the speakers are from the 25th February 1991? If I have it correct than I am just shy of 2 months younger than my cab!

The stamp on the speaker reads
- BZ25/20T7360.

Cheers again guys,
Matthew.

Appreciate the feedback! Hope this cab will serve you well. Did you measure the resistance of the cab, to make sure you've got the correct impedance?

If you need stereo, or different impedance options, in the future there's good advice in this thread.

 

[Maidenmatt]

Appreciate the feedback! Hope this cab will serve you well. Did you measure the resistance of the cab, to make sure you've got the correct impedance?

If you need stereo, or different impedance options, in the future there's good advice in this thread.

Yes, I kept checking impedance at every step and was getting a steady reading of 13.2 ohms from the multimeter. I believe it jumped up to about 14 ohms once the jack was soldered in and the back of the cab was put back on.