Here is a link to a restoration of a R1155 where the previous owner had replaced the VR99 tube with a 6K8G. Per the article, this is described as a "Sensible" replacement for the VR99: http://www.chavfreezone.me.uk/t1154r1155/2012/r1155a.html
Just relaying what was said, YMMV. 73, Gordon KJ6IKT
On December 20, 2022 at 11:45 PM Al Klase <[email protected]> wrote:
Hello Jacques,
I believe that the 6K8 and CV1099 are interchangeable. But, can't swear to it. However, here are the drawings I just dug up:
Pin-outs look the same to me.
Al
On 12/20/2022 9:31 PM, Jacques_VE2JFE wrote:
ARK Sig BlockHi Al,
In the R1155, V4 is not a 6K8, it is a Osram X66 (CV1099 / VR99) and this tube cannot behave as a 6K8 because the grid 1 and 3 are interchanged between the two types.
73, Jacques, VE2JFE in Montreal
De : [email protected] <[email protected]> De la part de Al Klase
Envoyé : 18 décembre 2022 16:28
À : [email protected]; ARC-5 <[email protected]>; milsurplus@mailman <[email protected]>
Objet : Re: [MMRCG] Hello R1155 Fans
Hi Dave,
Thanks for the video. I don't know much about the LO pulling except from, just now, looking at the schematic. The cathode and grid-return of the triode section of V4 go directly to ground. So it's hard to see when the interaction comes in.
The first thing I'd do is swap out V4, a 6K8, in case there is some internal leakage from the AVC'ed signal grid..
A stitched together copy of the N-schematic is attached.
This was another case of the original .pdf's I was working with being locked up so I couldn't extract the images. However, today there is an easy fix for that: Printing the file using Microsoft "Print to PDF" gets you an unlocked copy. Extract the schematic images a .png's and stitch them together using "Image Composite Editor" another free marvel from Microsoft .
Merry Christmas,
AlAl Klase - N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/_._,_._,_
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