[Amps] my little amp project of many hours..maybe 50% done

[PA3DUV]

Chuck,

The DX2sp from  Emtron uses a GU84B @ 2500 VDC on the plate. That unit puts 
approx. 2000 watt.

My own Emtron DX4 with 2 x GU84B and 3000 VDCD on the plates (under load) 
puts out approx. 6000 watt.
At that Vp the Ip is approx 3.5 A

The GU84B is a low Vp tetrode and has the advantage of a high filament 
voltage.

Typical power gains achieved in my system are between 18-20 dB.

There are a number of  DX2sp owners on the yahoo Emtron forum who might be 
able to give you some more operational and constructional details of that 
single GU84B amplifier. http://groups.yahoo.com/group/emtrondx15/
Also pictures and circuit diagrams of the twin GU84B amp can be found in the 
file and picture archives on that yahoo group.


Cheers, Dick
PA3DUV



----- Original Message ----- 
From: "Partain, Chuck" <Chuck_Partain at maxtor.com>
To: <amps at contesting.com>
Sent: Friday, January 06, 2006 3:20 PM
Subject: Re: [Amps] my little amp project of many hours..maybe 50% done


>
> looking back, I seem to remember 4kv being the good fit on this tube.
> Looking now that folks have more info, perhaps its a bit too high. Looking
> thru sites that list specs on it, I see 2.2-4.25kv listed as a suitable
> plate voltage.
>
> With my PS sitting at 3900v no load(250k bleeder) what can I expect to see
> loaded? i'm sure I'll see drop. also I'm a bit concerned now with some 
> internal arcing
> if it way too high?
> Not as concerned with whats going on inside the case, i'm 
> designing/thinking of
> heavier components on that side(tank/blocking/plate choke) anyway
>
> Any more thoughts?
>
> thanks.
>
>
>
>
>>>Hi Chuck,
>
>>>I think your anode voltage will be a bit high.
>>>The GU84B is a medium voltage, high current tube
>>>and normally sees 2,2KV.
>>>With the high impedance at 4KV you will run into
>>>trouble on 10m as the bandswitch is a bit far away
>>>and the minimum capacity of that tuning capacitor
>>>will be not low enough for reasonable Q on that band.
>>>If the ht-transformer has a center-tap I would go for
>>>half the anode voltage
>
>>>73
>>>Peter
>
>
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