JTM 45/100 - Build story

[Xplorer]

Some more parts, nos RS turrets

[VintageCharlie]

cool
I'm looking myself for some of these and another original RS hole board - they're the toughest to find bits.

[Xplorer]

Sure ! i wish i had more of these !
more parts for a second jtm45/100,and one or two superleads.

[Xplorer]

Alright ! the build !!!!

starting with the blank rear chassis, digging holes for the nos selectors , plug , jacks and fuse.
Sanding it, with wate in the end. And some "mirror".shiny

[Xplorer]

and ....

[Xplorer]

it suddenly looks like an amp , from the outside.

[Xplorer]

Now the inside. Putting the puts ( i guess it will be ok with some alphas, linear instead of audio for some, as i think the audio curve wouldn't be precise enough with these, if i wanted to clone the lin/log of the originals, from what greg germino and george say. so typicaly like in billy batzs layout ) . some jacks, transformers, heater wires, 1 ohm 2w resistors. drilling mounting holes for the internal fuse holder.
That's where i am at the moment.
i'll have to figure how to connect correctly the heaters, power transformer and output transformer.

[VintageCharlie]

Now it's getting interesting, huh?
I was wondering what pots are you using for the build - brand/resistances/tapers?

[Xplorer]

hi ! well, simply some alpha pots, the values of billy batz"s layout ^^ what did you use ?

[VintageCharlie]

i used alpha too. It's just that pots are extremely important to get the tones right - the correct tapers, as well as within the same type of taper there are big differences - from what i've read none of the modern log pots really have the same tapers as the old RS ones and that changes quite a bit of the tone. As well as tolerances on these, which used to be wild back then, from what i've read. I never got confident about the correct taper types to use for a proper clone. TO best of my knowledge the most accurate specs would be all log pots, except the 5k presence. I went with that, but i do have a 25k lin instead of the log, because there are simply no Alpha pots with metric bushing in this taper, so i plan to switch it out for a proper 25k log at some point. Btw. there are some threads here and on vintageamps forum about soldering some resistors of a specific values (don't recall the exact instructions, but it's probably easy to find) in order to approximate the vintage tapers. I think parkhead had a good post on this. Just another thing to worry about

[Xplorer]

I've found the correct alpha 25klog. They're rare but they exist.
Interesting stuff about the resistors. I'd love to see more about that.

[Roe]

looks nice - where did you get the backpanel? (I need a super 100 one as well as a superlead one)

[Xplorer]

Dom, a member here that you certainly know, sold me these back pannels, they're great.
i got some decals from steve marshall, for the "100"

[BoogieEngineer]

Congrats dude, looks great so far. I dig the sanding you did to the chassis' surface, not too shiny but still classy

[Xplorer]

Thanks man, yes i thought it was enough sanded. i wish i could continue the build right now but ... work ... holidays to come ... so it won't be finished soon enough. But anyway, this project learned me patience lol, 20 months looking for parts and i don't even realise yet that it's getting built, still have in my mind the need to find the parts