[Collins] 30L-1 811A Tubes, Electrolytics, Diodes, Fan

[Carl]

----- Original Message ----- 
From: <whitebear1122 at comcast.net>
To: "Byron Tatum" <bjtatum1 at att.net>
Cc: <Collins at mailman.qth.net>
Sent: Thursday, January 26, 2012 9:38 AM
Subject: [Collins] 30L-1 811A Tubes, Electrolytics, Diodes, Fan


>
>
> Hey Byron et al, long time no chat. I can share my experience with my 
> 30L-1 tubes. After buying my 30L-1, one 811 shorted out after maybe 6 
> months. I replaced it with some used hamfest purchase . A few months later 
> another original one crapped out. That's enough so I bought two full sets 
> of 811A's from Frank Krize K5SVC I think is his call. I figured I'd put in 
> one set now and have one set for standby for the future. They were NOS 
> Cetron's and the price was good. I put the set in and it's been running 
> just fine for all these years. Gosh those may have been in for 12 years or 
> more. I bought mine from him direct but I don't have his email anymore. I 
> see he does sell 'Bayside'. I don't think it has to be complicated with 
> hunting for particular branded old tubes.
>
>
>
> I am aware of the Chinese 811 discussions where those are not recommended 
> for the 30L-1 because tube element sag from the horizonal positioning. 
> Don't know if my Cetrons are Chinese tubes or not. All I know is that 
> they've been running for 12 years without any problems. So you might check 
> out Frank Krize.
>
>


The filament orientation issue was resolved decades ago but its still a good 
idea to check any purchases.

The big problem these days is Chinese quality that is not up to the voltages 
used. The Ameritron AL-811 amps are blowing tubes left and right and often 
taking out SS transceivers in the process.

For the 30L1 and other 811 amps I recommend 572B's as the Chinese are at 
least fine at those voltages plus can take tuning abuse. Dont try to drive 
them any harder as the power transformer isnt up to it.

I still hear of many using WW2 surplus 811's and wondering why they melt 
down. The amp was designed for the higher dissipation 811A which didnt 
arrive until 1949. Using any old tube is risky as anode outgassing or slight 
seal leaks (gas and air are considered seperate problems here, and to the 
purist I know air is considered a gas) can cause internal arcs unless 
regettered first.

Carl
KM1H