'New' Rev a Build Questions & Stability Update Questions

[Kojak]

Greetings from Nashville, TN-

As an intro, I would consider myself an audio enthusiast but not quite an 'audiophile'. I have rebuilt a couple basket case tube radios thanks to Sam's photo facts, I occasionally work with controllers and high power industrial motors for my job, and I have two older Land Rovers (therefore I can troubleshoot and solder circuits Yellow_Light_Colorz_PDT_12 ). That's about the limit of my skills, which are going to be very basic compared to the folks on the forum. I have just enough know-how to make my dumb questions uber-dumb!

I recently picked up a box full of two Eiclone Rev a 12AX7-only boards and what so far appears to be the full complement of parts including chassis w/ tube holes already cut, 1650's, 274BX's, etc. Before this popped up, I had just decided to tone down my DIY tube visions and build a simple SE like a Darling and go with a used or vintage SS amp to keep a tight budget yet cover diverse listening material. Thankfully, I was able to pick up this unfinished project from the original purchaser for even less than I had originally budgeted- and assuming I don't muck it up I think it will work great for my all my speakers- A/D/S monitors, Maggies, and some Klipsch KLF monsters.

I received a full set of invoices, a manual hard copy, and some Feb 2004 emails from Shannon regarding a stability update. Parts for the update were also included. Within the info I have, there seems to be a conflict for C7. Besides that issue, I would most appreciate someone taking a look at those revisions I have attempted to summarize below- maybe this will also help someone else with older boards they have yet to build.

Action------Reference----New Part---------------Old Part
Replace----C7-------------100pF or 560pF?------68pF
New Add---C8-------------820pF, 1kV------------none
Replace----R3-------------1K----------------------jumper
Replace----R4-------------100---------------------1.27K, 1/2W
Replace----R8-------------4.3K--------------------33K, 1/2W

Add------------------------Cx20 and Rx47---------none
Add 120pF then 3.3K in series from V2-4 to ground side of R7

Add-------------------------Rx48 and Cx21--------none
Add 10ohm then .1uF in series from 8ohm pos terminal to ground terminal.

Which C7 (the 560pF was in the parts Shannon sent to the original owner), and is everything else correct and up to date? Am I missing any other revisions for these boards?

Thanks in advance for your help,

Kojak.

[Shannon Parks]

Hi Kojak,

Go here and download the Rev B manual:
http://diytube.com/phpBB2/viewtopic.php?t=836

The schematic and parts on it are the latest and greatest. Even though you have a Rev A it will be the best road map for you. Looks like:
- C7 is 220pF and R8 is 2k
- Cx20 (C8) is 470pF and Rx47 (R49) is 3.3k

[Kojak]

Thanks-

This will keep me busy for a while. I'll try to follow the Rev b schematic to stay on track.

Any other major differences between the Rev a and Rev b boards to keep in mind, besides the 12ax7 / 6sl7 jumpers on a Rev b board?

Thanks!

[Shannon Parks]

Thanks-

This will keep me busy for a while. I'll try to follow the Rev b schematic to stay on track.

Any other major differences between the Rev a and Rev b boards to keep in mind, besides the 12ax7 / 6sl7 jumpers on a Rev b board?

Thanks!

You might leave a .150" gap between the can caps and the board, just to be within spec on the high voltages.