Thinking of selling my ol' Marshall JMP 50 1987 head (from 1968) .....

SpankThePlank

Further to my thread about letting things go...

I am considering selling or even trading the above. I have owned it since I was a teen (in the mid-80s) and at that point it had a really tatty homemade head box, which didn't really dawn on me until a bit later. No idea what the story may have been.

FF to now... In 2016 I made a much nicer box for it so to the non-expert it looks mighty attractive.  I realise there are aftermarket repro jobs available from people like @Modulus_Amps but it was for the fun of it as much as anything else, and really I made it for myself so I didn't mind a few shortcomings (ie not correct tolex and used the ply I had - 18mm instead of 15mm.

One thing it had not had for a looong time was a thorough service.  Since I had commissioned an Aviator combo from Gartone, I decided to give the head to Martin.  He did a great job sorting everything out and was typically thorough and sensitive to the period.  I still have the old parts and receipt.  Some things that I found interesting were that there was something unusual about the way the power was organised (I have no idea what he was on about!)and he reckoned it was a transitional design (quite dangerous, iirc) and that he had never seen it before.  Also he had a '65 JTM in at the same time and he said mine blew it away and was probably the best Marshall he had ever heard by the time he was finished.  I was amazed and obviously had never heard it at its best!

Trouble is I never use it these days as I have a Cornell 18/20 combo - much more practical and whilst not the same, close enough sound.

So if I were to sell, should I buy a better box and what about a fair price? Or should I keep it? I have seen these described as Holy Grail and silly prices on Reverb.  Even my wife is unsure about me selling!

I am thinking about building up the funds for an old ES345.

Ossyrocks

Value is hard to determine as you don’t have the original head cab. But it is defo worth quite a bit and they are sought after. Some pics of the chassis would help.

ICBM

Sounds like an early ‘68 transitional JMP with a transformer intended for a valve rectifier, but fitted with a solid-state one - that was done briefly before the transformer spec was changed. This gives a very high HT voltage, just over the original filter cap rating (450V), although modern replacements are available at 500V.

You could increase the value a lot by finding another original head box - from an amp of a similar age that’s been modded heavily or otherwise damaged - but that will still cost a fair amount. Replacing it with any other non-original box probably won’t make much difference.

They do sound great, but whether you have any practical application for it is another question...

brooom

I'm exactly in the same situation as you. I have a 1968 Marshall plexi 50w bass model (1986). Pretty much like the amp used by Duane Allman. It has a replaced OT (a Marstran), although I have the original damaged OT.

I've been playing with the idea of selling it. I once had it for sale on reverb and the guy from musicground bought it for £3000. I refused to sell it to him and refunded his money. I couldn't stand the idea of having my amp butchered for parts.

But I might sell it later this year, as I'm not playing it.

Modulus_Amps

@brooom said:

, although I have the original damaged OT.

Would you sell that, or send it to me for a rewind?

Modulus_Amps

@SpankThePlank ;

Looks is everything, a good repro cab will get you more money that a custom cabinet, If I saw your amp in a non original cab I would be looking for a bargain.

Transformers are key, if they are original then that sticks the price up.

Photo's of the insides, the work Martin did etc would help a lot too.

I have worked on a few amps from that era, usually they are a mess inside from half assed techs not doing a great job on them.

If I had money I would consider buying from you if the photo's were good.

If it sounds so good you could get me or another good amp builder to properly blueprint it to build a clone for your own use and sell that one on.

Good luck whatever you do, I would be interested in seeing some photo's

SpankThePlank

Thanks for the excellent comments and observations etc.

I am going to try and resolve my blockage with posting pics  - separate hard drive and so on.  Will try and work that out now.

If buying a box for, say,  £500 adds £1000 then I might be up for that but if it isn't worth it, I am maybe not bothered.

I am pretty sure the internals have not been messed about much. Only thing I  remember was the presence knob was not original, nor one of the rear selector plugs.The neon was literally broken but Martin replaced it with one that looks the sameThe switches are common to many old amps - one black, one silver.  IIRC the caps and choke were replaced, but there were other things too.  I only play them! :-)

Mr Modulus - very interesting idea to have the amp copied.  But surely that would cost a load?

Anyway - back soon with pics if I can work it out.

Cheers

shaunm

@SpankThePlank this is not the forum for cost effective guitar playing. This is a den of wolves that drag you further down the hole of spending money. 

You’ve come on here for advice on selling an amp. Inadvertently you’ve now thought of buying a new casing and cloning the amp. Ha.

I am jesting not course. I’m always amazed at the knowledge and ideas that comes from this forum. It’s great. 

Anyhow I have very little to add other than I wish I had the money to take that amp off your hands and the occasion in which I could use a monster like that. Just last night I was having a chat with someone about how good these amps are. 

SpankThePlank

@shaunm - thanks.... I think ;-)  Yes, you are absolutely right. I am new here but I am learning!
I have nearly got the pics together...

SpankThePlank

https://imgur.com/Wlyaq0m

SpankThePlank

Balls.

I can't work out how to do more than the above yet. Does it work for you?

All my pics were in the wake of the cab build, which was before Martin serviced it, so guts somewhat different later.

JezWynd

SpankThePlank

A fail

SpankThePlank

Thanks @JezWynd ;;

I can't figure it all out - I give up! Sorry, admin!!

SpankThePlank

Modulus_Amps

You would be getting a lot more than  £1k for a vintage Marshall that age. Have a look at eBay so see what amps gave sold fir in the past. 

brooom

@Modulus_Amps ; - I'll PM you.

SpankThePlank

Modulus_Amps said:

You would be getting a lot more than  £1k for a vintage Marshall that age. Have a look at eBay so see what amps gave sold fir in the past. 

Maybe there has a misunderstanding. I'm considering the merits of buying the old box vs the extra value generated. 
I guess this amp might be worth £3k or so.  

I may try and dismantle again for some fresh guts pics though the more people come on and say how great these are the more it makes me want to hold on to it.

Maybe the Cornell should go instead!

beed84

Dude, listen to your wife. She sounds awesome.

SpankThePlank

Lol! She is, though not usually not when  it comes to gear! 

lukedlb

From my understanding, a black switch indicates a replaced part, common since they were often broken in transport. The presence pot was probably changed unnecessarily: presence is rarely moved and so develops noise. Getting a vintage box will cost a lot and will nevertheless not be original. Buying vintage at excess prices requires all original parts. As this isn’t a FS thread, I would suggest that 3k is too high. It’s a 68, true; still, in a homemade box I’d say 1500, 2k with a new original spec case. Priced to sell that is. If you have the patience to wait out the coronavirus impact over the next year, then you should get more.