JTM 45/100 - Build story

[Xplorer]

another point i'm not sure about : all these wires.
some twist the red and black wires all arround the chassis like on this picture :

[Xplorer]

....... And some others seem to be more authentic, with nice lacing cord, with a shorter lenght of red and black heaters in the end ... but mixed with several other wires ( quite a mess and ... is it bringing noise in these wires ? ) . What is the best ?
these pictures are from the 7206 amp from George.

[AJW]

The two sets of 560v and 490v taps are an either/or option. You choose one set that will go to the power board rectifier. I used the 490v taps which are easier on the modern KT66s I'm using.

C goes to the HT fuse, on it's dedicated board, then to GND.

H goes straight to GND. I think in Larry's ground scheme (which I used) this gets grounded near the inputs.

[Xplorer]

Thanks !
yes, until i'll get some gec tubes, i'll use the 490v tap.

from Brian Wallace as i asked him some help :

"The brown wire is the primary center tap and will be connected to the first four filter caps along with one wire from the choke.

The Orange wire is the common for the OT's secondary and will connect to the ground side of the speaker jacks.

B and D are both the 490V taps, B will go to one side of the three diodes and D goes to the other side. C is the center tap that goes to ground. F is the AC common and ties to the neutral side of the of the wall voltage. H is the center tap for the heaters and will go to ground.

The black wire on the PT is for 100VAC input used in Japan. The 100V tap you are talking about is inside the OT but does not have the wire brought out as it is something that no one uses.

If you are using a voltage selector, just wire the extra wires from the PT's primary to the selector. If you are not using a selector then you can just cut them short and use shrink tubing to insulate the wire from arcing.

Running the heaters under the filter board will not make any more noise than running the AC wires from the PT under the filter board."

so it seems that i have to connect both 490v taps, B and D .. i see now.

[Xplorer]

Here is a quick layout i've made previous to the build and lacing cords ... i'd like to double check the connections. if somebody sees any mistake, please let me know !
there will be a few more connections like where to route each ground points of the amp ( everything goes to a a bunch of screws on the chassis ? ). also the output of the impedance selecor, i have to check where it's supposed to go. And the light indicator.
Anything missing, except for the main board and pots , tube socket connections ?

Thanks !

[AJW]

The power input ground should have it's own dedicated ground point near where it enters the chassis. The light indicator wiring depends on what type of lamp you have. A 120v (or in your case a 220v to 240v) lamp would wire to the main power switch, or 6.3v lamp at the PT heater taps . The output of the impedance selector goes to the output jacks.

[Xplorer]

Thanks ! i appreciate your help.
on George's amp it seems that the bulgin plug is grounded to the chassis by a solder tap screwed on the fuse. would that be just fine ?
So you think it's better to have the heaters CT connected to a separate chassis ground ? V7 solder tap for example ?
i allways have problem with grounding a circuit you know ... there are some sciences to know about that.

strangely, or maybe is it two wires or something i don't understand ... But the Heaters CT ( green wire i guess, from the pictures and the transformer schematic ) on George's amp is going to L of the bulgin plug.

oh yeah, now that you explained it, i see the two purple wires coming from the light indicator, one on the CT, and one on a 3,15v heater tap.
i checked one of my lamps, and one ( looking like the original RS ) seems to handle 240v, from the ebay seller. then i'll just have to connect both sides on the two pins of the AC switch, right ?

[Xplorer]

edit : layout erased for later update.

[BoogieEngineer]

I'd add the purple wire going from the 27K NFB to either speaker jack's ground or 4/8/16 ohm taps. My academic advisor looked at the diagram told me that if you use ground for it you'll have more bass (he explained it but I didn't quite understand ). The higher the tap you use the stiffer and clearer (or less) the bass

[Dom]

generally the CT (brown) of the OT goes to the turret next to the diodes on the main board. Also the choke and the wire from the mains caps.
See:
http://www.amparchives.com/album/Marsha ... 00-17.html" onclick="window.open(this.href);return false;

http://www.amparchives.com/album/Marsha ... _6172.html" onclick="window.open(this.href);return false;

http://www.amparchives.com/album/Marsha ... uit_2.html" onclick="window.open(this.href);return false;

[Homebelly]

generally the CT (brown) of the OT goes to the turret next to the diodes on the main board. Also the choke and the wire from the mains caps.
See:
http://www.amparchives.com/album/Marsha ... 00-17.html" onclick="window.open(this.href);return false;

http://www.amparchives.com/album/Marsha ... _6172.html" onclick="window.open(this.href);return false;

http://www.amparchives.com/album/Marsha ... uit_2.html" onclick="window.open(this.href);return false;

I've been looking at this part of the turret board and wondering if those connections terminate there. Is it a junction to connect those three wires, or is there supposed to be a connection under the turret board to some place else?

[Xplorer]

Oh thanks Dom ! I'll correct this mistake and update the picture.

[Xplorer]

oh, wait ....
in Billy Batz's layout, this is what i see : it goes on the filter board. So how can that be ?

[Xplorer]

On George's amp, it appears that the brown wire from the OT, and the choke wire, are both soldered to a separate turret near the diode, on the filter board, indeed. But they're linked to the power board with a red wire, just where it's shown on Billy's layout. Any thoughts to be sure ?
i'd really have to look at the schematic lol. but schematics won't tell everything about grounding, and places to put this or this wire ... i'm looking at pictures a lot.

[neikeel]

mine is to the extra turret from near the diode

HT feed via red wire from mains caps/rectifier junction underneath into the turret, choke and OT up top, fed through board holes and wrapped around turret.