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[AMPS] Caveat on Dentron Filaments + MLA-2500B Notes

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Subject: [AMPS] Caveat on Dentron Filaments + MLA-2500B Notes
From: (measures)
Date: Mon, 31 Jul 2000 17:55:57 -0700
>> Yes, Dentron used the Dale resistors ... not a good choice.
>Okay...let's replace it.....
>Was 100 ohms a bad choice also for a pair of 8875's?

?  Yes.   Also, the orig. shunt resistor was wire wound.  The cathodes 
themselves are c. 27-ohms avg. so a series cathode-resistor is needed to 
increase the driving Z of the cathodes.  Another circuit improvement is 
to add a ultra fast recovery 1a/400v  diode in series with the shunt R.   
The diode is oriented to prevent current from flowing in the shunt R when 
the tubes are conducting.  This makes for a more balanced load on the 

>I happen to have a carborundum 72 ohm @ 50 would that be?
?  Probably ok provided you pick an appropriate value for the cathode 
feedback resistors.  I would start with about 40-ohms for each cathode.  

later, Phil

-  Rich..., 805.386.3734,  

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