JTM45 with the twist...

[mcinku]

Just finished this amp and I thought it would be worth sharing...
[img:777:580]http://shrani.si/f/32/eL/4MQbXBFy/jtm452.jpg[/img]
[img:777:580]http://shrani.si/f/2U/RZ/EoardwN/jtm451.jpg[/img]

This JTM45 has split chathode network on V1, 500k bass pot, push/pull pot on normal channel (bright cap), 0.068uF instead of 0.1uF on PI and HUGE custom built toroidal transformers.
OT has 7k5 primary impedance... and what is interesting when I measured DC resistance across primary taps it was 94ohms on both sides.... I mean within 1ohm difference. Usually you don't see this on the OTs.

[Stevem]

Nice nice job !!
One thing to make note of if I might with the Torroidal transformers is how they are clamped down.
From what I have seen they need a double thick rubber pad on each side and the hold down ring needs to have very rounded over edges !
As of late I have seen 4 expensive items. Of audio gear with toroidal power have shorts I n the windings that where directly related to mounting short falls!

[mcinku]

I used 4mm thick rubber pads on both sides.... it should be OK but I guess time will tell.

[Structo]

Nice!

Have you used the toroids before?

[mcinku]

No this is my first amp... but I've heard some others and even a D style amp as well.
Nothing wrong with it.... it takes a bit more room, but it's lighter and it sounds great.



Here's the final picture of the amp...
[img:669:474]http://shrani.si/f/3L/UI/5pG1gFm/jtm45.jpg[/img]