> -----Original Message-----
> From: amps-admin@contesting.com [mailto:amps-admin@contesting.com]On
> Behalf Of Ku4uk@aol.com
> Sent: 12 April 2002 21:21
> To: amps@contesting.com
> Subject: [Amps] GS35B
>
>
> I have heard that a GS35B is a good sub for a 8877? I know that a
> 8877 is 5v
> fil. Where the GS35B is 12.6 V Can I change the volts and use
> this tube in
> an amp that use a 8877?
If the upper frequency limit is 10m then most probably yes, there is some
8-10pf more stray capacitance with a GS35B than with a 8877. Also the GS35B
has 3-4dB less gain but you can drive it harder. If the amp with the 8877
produces 1.5kW output with 50 watts of drive then you will need 100watts for
the same output with a GS35B. The input impedance on the GS35B is around 80
ohm with 21pf between cathode and grid so if you have a tunable input you
should be ok, it will be in the matching range of most 8877 input circuits.
Will the same socket work? ku4uk@aol.com
The GS35B is essentially a bolt down to the chassis device but you must
allow some airflow back to the cathode, you would need to make a grid block
which sits below the chassis. Look at
http://www.qsl.net/g0ruz/6m_gs35_cathode_compartment_close_up.htm to see a
photograph of the grid block, these are made by OZ1GOK
http://home19.inet.tele.dk/oz1gok/idex.html .
So you would have to do some fairly extensive mods. The GS35B is a good
rugged tube but the 8877 is much better in my opinion. Stick with the 8877
if you can afford to.
73
Conrad G0RUZ
>
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