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THE AM BULLETIN BOARD => Technical Forum => Topic started by: WA2SQQ on February 20, 2018, 05:52:17 PM



Title: 6CW4 vs 6DS4
Post by: WA2SQQ on February 20, 2018, 05:52:17 PM
Doing a small restoration project on a receiver that uses 2 6CW4s. One tests marginal. I have a new 6DS4 which Iím told is interchangeable. Anyone know the difference?


Title: Re: 6CW4 vs 6DS4
Post by: WD4DMZ on February 20, 2018, 06:12:25 PM
According to this list the answer is yes:

http://www.nostalgickitscentral.com/info/tubexref6.html

Scroll down to the 6CW4.

Rich


Title: Re: 6CW4 vs 6DS4
Post by: w8khk on February 20, 2018, 06:34:17 PM
According to the RCA receiving tube manual RC-24, the 6CW4 has slightly larger transconductance 9800 umhos compared to the 6DS4 with 9000 umhos.  The plate resistance of the former is slightly smaller, 6600 ohms, compared to the latter 7000 ohms.  Thus the characteristic curves are slightly dis-similar.   

The manual also states that the 6DS4 is used in circuits to reduce cross-modulation because of its cutoff characteristics.  All other ratings are identical, so it should work fine as a direct replacement for the 6CW4.
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