[Amps] amp tubes

[Alek Petkovic]

G'day Carl,

Suspect number 1 is the Autek WM1 meter/s. In my experience with at 
least 6 of those units is that they are very generous with their 
readings. The 2 that I own are now adjusted back to realistic levels.

The Chinese tubes (Shuguang Factory) that I have been buying are a 
direct plug in replacement for the Cetrons. The bias does not need 
adjusting and the gain and power output seem to be in line with 
expectations with perhaps a little more power out than the Cetrons. 
Of course it is hard to say that there is a difference unless you 
make the comparisons with new tubes from both brands.

I have dispersed about 50 of them to various amateurs in VK with 
excellent results. Nobody has reported results like yours so far.

VK hams seem to go through 572B's very quickly because they are 
generally used in amplifiers designed for 230V operation and our 
mains hover around 250V here. Consequently, the filament volts are 
around 7 Volts instead of 6.3V. People do not adjust the filament 
voltage and so they consume tubes very quickly.

73, Alek
VK6APK



At 05:45 AM 9/09/2006, carl s. wrote:
>    I have been working on an amp, fl2100B , and see something I can't
>believe.!!  the amp has 2 ea. New chinese type 572B's.
>    I have two output meters, both WM1 auteks.;  With about 60-80 watts
>input I'm seeing almost 1 kw. *output*. Is this anywhere near logical
>??  The HV is about 2200-2300 under load. !! It just doesn't seem
>possible, and I've never seen anything like this
>  before !!!
>      I've worked on many other amps ( similar ) and have never seen
>anything like that much output.!!
>      BUT, I've never used *chinese* 572'B s either !!
>      Do any of you have any spec's that might differ from the
>    U S. ( IE ) taylor ,l or other mfrs. Specs as to the gain factors
>between the US and chinese specs'?????>
>      I'd appreciate any info anyone might have !!!!!
>      carl / kz5ca
>
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