[R-390] Tube List For R-390 (non A)

Fri, 31 May 2002 15:21:21 -0400

At 04:24 PM 5/30/02 -0700, Spence Barton wrote:
>Can anyone point me to a tube list for the R-390? I found many for the A but
>none yet for the non A.

 From my notes file.
Note: there may be an error in one list or the other:

TUBE LIST:
Date: Tue, 20 Jun 2000 17:30:19 -0400 (EDT)
From: Norman Ryan <[email protected]>
X-Sender: [email protected]
To: "Paul H. Anderson" <[email protected]>
cc: [email protected]
Subject: Re: [R-390] R390/391 tube complement and substitutions
In-Reply-To: <[email protected]>
Message-ID: 
<Pine.SOL.3.91.1000620161753.18564B-100000@godzilla2.acpub.duke.edu>
MIME-Version: 1.0
Sender: [email protected]
Precedence: bulk
Reply-To: Norman Ryan <[email protected]>
Content-Type: TEXT/PLAIN; charset=US-ASCII
Content-Length: 2583
Status:

On Tue, 20 Jun 2000, Paul H. Anderson wrote:
 >
 > The following list is what I added up in my R-391. Does this sound right?
 >
 > Tube QTY
 > 5814 6
 > 6BJ6 6
 > 5749 1
 > 6AK6 3
 > 6C4 3
 > 6AJ5 3
 > 6BJ6 1
 > 12AT7 1
 > 6BH6 1
 > 5651 2
 > 6082 2
 > 26Z5W 2
 > 3TF7 1
 > --
 > 32 tubes
 >
 > What reasonable substitutions might I make for sake of longevity and
 > performance?
 >
 > From looking at the archives, I think I can use a 6100 instead of a 6C4,
 > and maybe a 5749/6BA6W for the 6BJ6. Are these correct, and can I make
 > other reasonable improvements, or is that a waste of time?

Hi Paul,
Dunno if the above list is correct or not. If the R-390 is siliar to the
R-391, tube list should be the same, right?
Here is what I come up with in my R-390. I've read the sockets, not the
tubes! :-)
V201 6AJ5
V202 6BJ6
V203 6C4
V204 6C4
V205 6C4
V401 6AJ5
V402 6AJ5
V501 6BJ6
V502 6BJ6
V503 6BJ6
V504 6BJ6
V505 6BJ6
V506 6AK6
V507 12AU7
V508 5749
V509 6BJ6
V510 12AU7
V511 12AU7
RT512 3TF7
V601 12AU7
V602 12AT7
V603 6AK6
V604 6AK6
V605 6082
V606 6082
V607 6BH6
V608 5651
V609 5651
V701 5749
V801 26Z5W
V802 26Z5W
Personally, I'm inclined to stick with the original types as "gotchas" can
arise. For example, the 5814A normally substitutes for the 12AU7.
However, since the 5814A filament current draw is higher, it doesn't work
in all R-390 circuits since most of their filament circuits are in series.
V601 (12AU7) and V602 (12AT7) are in series. If a 5814A is used in place
of the 12AU7, the 12AT7 filament (wired in series) will receive higher
voltage than that of the the 12AT7. V507 and V510, though wired in
series, each have a 120 Ohm resistor across one half of each filament plus
a 22 Ohm resistor in series. Confusing!
Sometimes tubes are pinned a tad differently. If I'm not mistaken, the
6C4A has that or another problem, but not the 6C4WA. The 6C4WA will work
as a replacement for the 6C4 in the R-390A, but I don't know if the
filament current draw is an issue in the R-390.
Bottom line is to study the tube characteristics carefully. A tube
substitution manual can gloss over potential problems such as filament
current draw and pinout.
More importantly, have the depot manual and its schematics handy.
Hope this helps.
73...
Norman

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Work: Voice: 301-975-3254,  Fax: 301-948-6213
[email protected] --