RevD stuffed board, plus an idea...

[EWBrown]

I like the use of the plug-in terminal strips, and the addition of the AEON and Russian 0.015 uF caps to bypass the electrolytics. I have been using a similar scheme on my SE amps, I'll have to give this a try on my "in-process" Rev D! I also have some of those green Russian caps, haven't yet tried them out.

/ed B in NH

[Shannon Parks]

Looking good, Arco!

So do you plan to have the fan mounted on the bottom with a hole in the chassis, or tall enough standoffs to clear V1 & V2? Although the thermistor circuit is a very cool idea, I think constant operation would be fine. That's just me taking the easy route, though. :)

For those interested in similar sockets, Thermion has bought some just like them at Handmade(no glaze). They look nice, and might be an improvement over the two-piece design. If anyone know of other resellers of this particular type, please let me know.

One note - what values do you have in there for R36 & R37? They look like 3.3 ohms, which isn't good.

I'll just mail you the Klipsch 'Bullshit' pin sometime. Klipschorn owners gotta have a Klipsch pin. PWK, RIP. :bs:

Shannon

[EWBrown]

Let's see... two 3.3 ohm resistors in parallel is 1.65 ohms, given a 3.6 A
total filament current, that will give a maximum 5.94V, so the tube filaments will remain rather cool, and the resistors will become rather hot!
Given 1.65 ohms on each side, and assumint that the filaments are 3.6A
(1.75 ohms hot, and much lower cold resistance) most of th voltage will be lost in the resistors and little will get to the filaments

I would go with 0.1 to 0.18 ohm for R36 and 37, that would drop the filament voltage between 0.72 and 1.3 volts, (0.36 to 0.65 V each side), which would be closer to the desired 6 to 6.3 VAC.

If you use the CL-90 Inrush Current Limiter, this will drop the 230 VAC primary input voltage by a few volts, during normal operation.

/ed brown in NH

[Shannon Parks]

I would go with 0.1 to 0.18 ohm for R36 and 37, that would drop the filament voltage between 0.72 and 1.3 volts, (0.36 to 0.65 V each side), which would be closer to the desired 6 to 6.3 VAC.

You might even just want to put jumpers in there for now, and then adjust during testing. If your filament voltage ends up being +/- 5%, just leave the jumpers in there. If you did have 6.6VAC and wanted to drop .3, then you could use one .1 ohm resistor (and leave the other side jumpered) or two .05 ohm resistors. This option is primarily for Hammond users in the US who can end up will 6.6VAC to 7.0VAC due to our crazy mains voltages and the 117VAC rating of the Hammond power trannies.

Shannon