diytube ST35 docs & mods for Rev C & D

for the DIY ST35, the Dynakit and every other PP EL84

diytube ST35 docs & mods for Rev C & D

Postby Shannon Parks » Wed Dec 28, 2005 8:33 pm

Manual:
diytube ST35 Rev C manual (with schematics and parts list) (Rev C boards are available from Triode Electronics)
diytube ST35 Rev D manual (with schematics and parts list) (Rev D boards are no longer available)
Ned Carlson's tubezone ST35 manual

Cut-N-Paste Mouser Bill of Materials (BOM) (Compatible with Rev C & Rev D):
diytube st35 BOM
or
diytube st35 BOM Mouser Direct Link

Tube Rectifier Mod:
5AR4 and Hammond 372HX Connections (with schematics and parts list)
Changes to Power Supply
Text Detailing Changes

Rev History:
3/22/11 - Added Rev C manual.
9/3/10 - Updated Mouser BOM & Direct Link. Compatible with reversion to Rev C as well as Rev D.
4/6/09 - Added Mouser Direct Link.
11/30/08 - Cleaned up manual, parts list and BOM. There's a couple temp subs in the BOM header, but I think the backordered parts will arrive sooner than later.
Last edited by Shannon Parks on Tue Mar 22, 2011 7:04 am, edited 14 times in total.
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ST35 Data

Postby Shannon Parks » Thu Mar 09, 2006 7:32 am

I'm testing out my new audio analysis software and here's some first fruits:
ST35 Rev D Excel Files

I've got Excel files with log charts of distortion and gain for open loop, 1W, 10W and 14.8W outputs. Neat stuff!

Shannon
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Postby Shannon Parks » Mon Dec 01, 2008 6:50 am

Updated the ST35 Rev D parts list, BOM and manual (mostly the annoying font). I have finally omitted the filament dropping resistors. They seemed important at one time, but not as much now. Plus we want those electrons percolating as much as possible.
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Reversion to Rev C

Postby Shannon Parks » Sun Sep 12, 2010 6:48 am

9/3/10 - Updated Mouser BOM & Direct Link. Compatible with reversion to Rev C as well as Rev D.

*****************************************

Howdy Gents,

The Rev D boards have sold out and I don’t plan on ordering any more of these. Since the company I had them fabricated at went under in 2008, I would have to redo the tooling at another company and the specs of this particular PCB make it an expensive board to manufacture. Indeed, the cost would almost double at the new PCB fabricator.

Instead, I will backtrack to my old supply of ST35 Rev C boards. These boards are functionally equivalent but needed few slight changes to the BOM and manual. They look almost identical and have the same dims and will fit the same chassis.

Warm Regards,
Shannon
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Postby EWBrown » Sun Sep 12, 2010 2:05 pm

But then they don't take the LM317 "undocumented feature" ;)

Has anyone else other than I, tried using LM317 CCS on the EL84 cathodes? Actually, that is kinda misleading, I tried it on a 6S4-modified Rev D. (25 mA @ 325VDC B+) Still have to work out a couple resistor valuechanges in the VA/PI section to make it 100% right...

More mod-madness, for those who dare....

Got lots of 6GK6s, (or 10/16GK6s) ?

Another mod I haven't yet tried, but it should work for 6GK6s. This method requires a bit of etch surgery around each EL84:

Cut the etch between each EL84's pin 9 and the UL tap on the terminal board.

Connect/jumper pin 8 to the UL tap.

Connect pins 1, 3, and 9 together (this connects the cathode to G3).

Don't like butchering the board ? =:o

Alternate, no-etch-cutting procedure, for a new build: O:)

Cut or bend pin 9 on each of the EL84 PC board tube sockets, so that it doesn't make contact with the pin 9 pad on the board.
Jumper pins 8 and 9 on the board, then install the socket(s).

Jumper pins 1 and 3 on the bottom side of the board - pin 9 isn't really necessary, as it is a duplicate connection, or if you bent the pin, then it could be connected to pins 1&3.. This connectrs the 6GK6's G2 to pin 9, so the PC board doesn't require any surgery, and additionally connects G3 and Cathode.

All I need is to get ahold of a virgin rev C or D board and give it a whirl...

/ed B
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