[Amps] Glitch resistor

[Carl]

The inductance is of no concern as it is after the plate choke and is in 
nichrome wire. L2 in the SB-220 can cause a problem since it is self 
resonant right around the 3-500 parasitic frequency. With just the 
control right settings the strays and the RF cage become a nice cavity 
oscillator.

Every amp should have a glitch resistor, 15-20 Ohms and a 20-25W 
vitreous enamel type only. Mouser carries Ohmite and Vishay/Dale.

Carl
KM1H


----- Original Message ----- 
From: "Bill English" <bill at k4fx.net>
To: "Amps" <amps at contesting.com>
Sent: Monday, December 01, 2008 7:36 AM
Subject: [Amps] Glitch resistor


> Hi all,
>
> I have a question, I was reading on a web site about TL-922 amps that 
> said
> that adding a glitch resistor between the HV sup. and the tubes would 
> add a
> slight amount of inductance, in fact enough to remove L2, the smaller 
> choke
> inside the tube compartment. I have an old SB-220 with an added glitch
> resistor and in looking at the 922 and 220 schematics they are almost
> identical in that respect, only the SB220's L2 is an 8.5 uH and the 
> TL-922's
> L2 is a 12 uH.
>
> I would like to know if you guys agree and think I should remove L2 in 
> this
> SB220? Also what would the added inductance do to the circuit?
>
> Thanks
>
> K4FX
>
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