[Milsurplus] CV-157

[John Vendely]

The 5751 is a reduced mu 12AX7 with tight specs for precise matching of 
its two triode sections.  I think they were selected from 12AX7 
production lots.  Pairs of well-matched 5814s should work fine as 5751 
subs in the CV-157 AFC drive.  I once tested a bunch of 5751s on a curve 
tracer, and they were remarkably well-matched, even the old ones were 
pretty close...

73,

John K9WT

On 12/23/2015 4:08 PM, WA5CAB--- via Milsurplus wrote:
> One comment - the 5814 and 5814A is medium mu and equivalent to 12AU7 
> and 12AU7A, not high mu like the 12AX7.  Although I once babysat two 
> heavy shipboard transmitters (AN/WRT-2) which used (and regularly ate) 
> several 5751;s in a divider circuit, I don't recall whether 5751 is 
> medium or high.  I just always made sure that Supply kept plenty on hand.
>
> Robert Downs - Houston
> wa5cab dot com (Web Store)
> MVPA 9480
>
> In a message dated 12/23/2015 08:19:53 AM Central Standard Time, 
> jvendely at cfl.rr.com writes:
> ********************************
>> The only "problem" tube may be the 5751 dual triodes in the AFC motor 
>> drive system.  The 5751 has become all the rage amongst guitarists 
>> who believe it will give them a "gutsy" tone their original 12AX7s 
>> cannot.  The formerly cheep 5751 is therefore now priced at a 
>> premium.  The primary reason for using the 5751 in the AFC was that 
>> its two triodes were very closely matched, permitting very good motor 
>> drive amp balance. You could probably substitute well-matched 5814s 
>> or 12AX7s with no problem.
>> *************************
>>
>> 73,
>>
>> John K9WT
>
>
>
>
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