1969 JMP 50 watt Lead (#1987) questions

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Hello,

I just acquired a '69 1987 small box, S/N 30XXA. Good condition, sounds glorious (had a recent check-up by reputable amp guy). Still some questions though:

- It has gotten a new OT at some point. It's not a Drake 784 139 like it should be, but it's not clear to me what it is. It's obviously a fine OT, as it sound just right and is installed correctly. Only markings are a handwritten sticker saying 'Marshall Output 50W buis' (means 'tube' in Dutch) and 'T89'. Can anyone shed some light on this, or comment? Also a Line Out has been installed at some point. Will have that removed.
- Should I start looking for a period correct 784 139 OT, or leave it as it is? (it sounds fine).
- IF I want a period correct OT, what would be a reputable and trustworthy place to look? And what other details of the OT would I have to look for to get a correct one for this amp? (I will NOT be installing the OT myself, my tech will).

Other remarks or insights welcome! See pics

Thank you IMG_4560.jpg IMG_4561.jpg IMG_4562.jpg IMG_4563.jpg IMG_4564.jpg IMG_4566.jpg IMG_4569.jpg IMG_4570.jpg IMG_4572.jpg IMG_4573.jpg
 
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neikeel

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Looks very good, an early 69 (before they introduced the longer board for the diode block rectifier and snubbers.
The OT looks like a correct -139 (the codes suggest the replacement was fitted some time after September 1985), similarly the wire codes are correct for an original Drake. The only point I would make is that the secondary wires are far too long and they need routing correctly and shortening (at least for me!) but if you are happy as is.....
I see a replaced/repaired pilot lamp and an added line out (shame about the hole - but I would live with it (maybe using a matching Cliff jack - they do turn up NOS now and again). A couple of solder joints appear to have been touched up but that is all.
Great amp!
 
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Seanxk

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Very nice indeed, I was going to say that the switches may have been changed but it might be a period after the torotors and before the black bats.

This must be one of the very first stand up 50w PT's?
Guessing June 69?
 
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Very nice indeed, I was going to say that the switches may have been changed but it might be a period after the torotors and before the black bats.

This must be one of the very first stand up 50w PT's?
Guessing June 69?
The label on the chassis inside dates October 1969.
 
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Looks very good, an early 69 (before they introduced the longer board for the diode block rectifier and snubbers.
The OT looks like a correct -139 (the codes suggest the replacement was fitted some time after September 1985), similarly the wire codes are correct for an original Drake. The only point I would make is that the secondary wires are far too long and they need routing correctly and shortening (at least for me!) but if you are happy as is.....
I see a replaced/repaired pilot lamp and an added line out (shame about the hole - but I would live with it (maybe using a matching Cliff jack - they do turn up NOS now and again). A couple of solder joints appear to have been touched up but that is all.
Great amp!
Thank for the input! So you are saying that this OT is a genuine replacement Drake 139, post 1985?
 

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