JTM 45 Gathering

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niilopi
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JTM 45 Gathering

Post by niilopi » Tue Sep 05, 2017 2:34 pm

Hellö,

I sold my vintage -76 JMP 100W 2203 cause it was modded and kind of raped in a way that it wouldnt have any value left. Ive been looking at JTM´s anyway for some time because JMP was always too rocknroll for me as im more of a bluesy player.

I started lookin around and doing research. JTM reissue was about the only option for me for 1300-1500euro pricerange and any good boutiques werent available anywhere used atm. So i found this cool handbuilt chassis on ebay. This seller has more stuff for sale so check out : http://www.ebay.co.uk/usr/retrotronicst

Its made with NOS components as close as possible to the original JTM:

2mm aluminium chassis
3mm paxoline board with NOS vintage split top turrets
NOS original Phillips Mullard Mustard capacitors
NOS Morganite/Piher/Beyschlag resistors
F & T filter capacitors
Cliff jacks vintage style
British made Castelco power and stby switches
Magnetics components choke
Belton Micalex tube
Littelfuse US fuse holders
Alpha pots, set-screw knobs

Its missing the OT, PT, Tubes and a box.

Transformers:

So i did my research and ended up looking at Metro/Marstan/******/Classic Tone for the right transformers to make this baby sing. At the end it really came down to the price and tone. Ive heard a lot of good from all of these manufacturers and the prices vary very much from 140dollars to 365dollars for OT+PT. The cheapest one Classic Tone and most expensive ******. I tried contacting Marstan for an order but they didnt answer me so i turned to Classic Tones which is a bargain of a price also! I got Classic Tones shipped to europe for 230 dollars/ 200euro. One huge aspect on choosing classic tones was availability! They were ready to ship once the other ones would take 2-3weeks to manufacture.

Box:

For boxes in europe i found two pretty cheap solutions. Mostly they will cost you around 350euro + shipping for a good box. However i found a few pretty good choises:

-Modulus Amplifications in UK makes JTM boxes for 165pounds + shipping, +20bucks for custom colour tolex
-Tube-town.net sells a JTM box for 230euro + shipping

Tubes:

Im still looking for the right tubes to get the sounds to the top. KT66 will be my valve choise.

Price:

The prices for re-issues used are around 1000euro. The new one from thomann costs 1400-1500euro. Good boutiques can be found for 1500euro used but are not often available as in my case.

My project costs: includes shipping:
By far:
730e The chassis with all components except OT, PT and tubes.
200e Classic Tone OT and PT
Expecting:
210e Box
150e Tubes

So im looking at ~300euro for a full spec JTM 45 with close as possible original spec components! I think thats a good choise for a re-issue even if it doesnt carry the real Marshall name and resale value. Im looking for a players amp.

Getting an idea about the tubes trying to use my local tube shop:

Kt66
TAD premium matched

Gz34
TAD 5AR4 premium selected (mullard replica)

Ecc83
V1 & v2
7025 S TAD premium selected Mullard style. For v1 5751 or 12ax7.
V3 ?? 12ax7 vs 12at7


The next thing to worry about is getting the transformer wirings right when they arrive from the US.

niilopi
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Re: JTM 45 Gathering

Post by niilopi » Tue Sep 05, 2017 2:42 pm

Heres some pics of the chassis

https://m.imgur.com/a/WFzNQ

danman
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Re: JTM 45 Gathering

Post by danman » Tue Sep 05, 2017 9:00 pm

Looks like it's gonna be a great project! Classictone makes excellent iron and you can't beat the price. Be sure to post lots of pics when your finished. :rock:

niilopi
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Re: JTM 45 Gathering

Post by niilopi » Wed Sep 06, 2017 8:12 am

Could someone check these pictures i made just to make sure i understood the ceriatone transformer schematics right.

https://imgur.com/a/OJzSs

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neikeel
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Re: JTM 45 Gathering

Post by neikeel » Wed Sep 06, 2017 5:51 pm

You linked to Classic tone PT which looks spot on for a Marshall 50w or JTM45 PT.
Neil

niilopi
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Re: JTM 45 Gathering

Post by niilopi » Thu Sep 07, 2017 3:52 am

Hey, there should be 4 pictures in the link. 2 of the schematics for classic tone PT and OT. And two that i made where the colours are written to the amp schematic.
neikeel wrote:
Wed Sep 06, 2017 5:51 pm
You linked to Classic tone PT which looks spot on for a Marshall 50w or JTM45 PT.

rootsikal
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Re: JTM 45 Gathering

Post by rootsikal » Mon Oct 23, 2017 7:21 am

Hello niilopi, just wondering if you were able to easily complete your JTM45 build ? How does it sound ? Would it be possible to get some sound samples ? I contacted the seller retrotronicst too some time ago, and for people who might be interested by lower power amps they also make custom 2 channels 18TMB type amps too with presence/master/treble/middle/bass/2 volumes :
channel 1 : added stage gain and 2 volumes (gives AC/DC to Van Halen sound)
channel 2 : normal plexi channel with master).
Variable Voltage Regulator or PPIMV options are also available for no extra cost.
They even sent me a picture of a nice custom 3 channels foot switchable Vox/Marshall voiced amp they realized for a client,
it's a pity that they don't have a website and no sound clips can be found yet. Hope you enjoy it!

niilopi
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Re: JTM 45 Gathering

Post by niilopi » Sun Apr 15, 2018 8:59 am

Hey man.. sorry for the late reply. Yeah i finished the build and it sounds just like a jtm45 should. Still tweaking the bass side a bit as the normal channel is pretty bassy for some pickups on les paul. But overall im happy with the amplifier.

There are some videos on my youtube channel with the JTM45
https://www.youtube.com/channel/UC8zB08 ... subscriber

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