Getting started on SE build

[smbrown]

I built a SE board about 2yrs ago, but moved about a year ago and gave it away without really giving it much opportunity to be heard. So I've decided to build another and ordered a board yesterday. A couple questions: I am not finding the dual To220 heatsinks listed in DigiKey. Does anyone have an alternative part number or vendor? Also, given my desire to mount the tubes closer to the surface and the board under the surface of a chassis (as many of you do), has anyone tried a hard-wired version of this? I'm actually thinking of separating the PS part of the board and using it, but using point-to-point on the amp section. Not sure if that can be done, we'll see when the board arrives.

[boywonder]

..You can populate the PCB on the underside, and only have the tube sockets on the top, then "hang" the board from the top deck with standoffs. Depending on what sockets you have, you'll probably have to tweak the length of the standoffs. Mine were around 7/16" or so on my first build (300B). I'm building a 45 version now using the same technique.

Besides getting the holes aligned in the top deck, the only tricky parts are the filament regulator and the three legged critter next to it........You've got to bend/reverse the leads.

Here's a related thread:

Underside Pics Of TSE
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As for the dual T0-220 heatsink from Digikey, try HS369-ND.....

[smbrown]

Thanks Boywonder! Since the regulator would be most difficult to mount "upside down" and apparently requires the most substancial heat sink, I'm thinking maybe that should be mounted just off board and short leads run back to its location. I've read about potential issues with oscilation if the MOSFETs are mounted off board, but I don't think the regulator would offer any such challenges. By the way, I'm planning on using 300Bs and James OPTs. Not exactly sure on PT yet. I have a couple candidates, but they may come in a bit hot. One is the replacement transformer sold of Dynaco ST35's - 660vct with two heater windings (6.3v). Potentially use damper diodes and put in a second heater tfr for the rest of the board.

[boywonder]

Originally Posted by smbrown

By the way, I'm planning on using 300Bs and James OPTs. Not exactly sure on PT yet. I have a couple candidates, but they may come in a bit hot. One is the replacement transformer sold of Dynaco ST35's - 660vct with two heater windings (6.3v). Potentially use damper diodes and put in a second heater tfr for the rest of the board.

You may already be aware of this, but Rknize here had a custom Edcor made that is now P/N XPWR-131-120 it has two HV windings, one appropriate for 300b's and the other for 45's, etc.

If you already have the ST-35 transformer and are worried it will be a little hot, you can add an extra RC (or LC) stage off of the board in the power supply to drop some volts and do more smoothing.

Are you planning on the James 6123HS? They have 2.5K, 3.5K, and 5K primaries and 4/8/16 ohm secondaries so they are pretty versatile.

[rknize]

Edcor Universal Power Transformer for Tubelab SE