Oh it was a TL922, my misstake.
In any case it should be very similar with a TL922.
Just check so you get correct operating point (ZSAC) for
zero bias, however I more or less "know" that the 4X500
doesn´t work in GG.
73 Jim SM2EKM
--------------
Hsu wrote:
> Jim,
> My TL922 was still on its way.if I get it I'll test the 4X500.
> The FU-500F (4X150) was very easy to get and very very cheap.
> 73! Hsu
>
>
> As far as I remember you can not run 4X500´s in zero bias GG,
> you will not be able to get correct ZSAC for linera operation.
> 4X500´s need screen and grid voltages to get correct operating
> point.
>
> 4-250A or 4-400A or C is OK in SB-220. Just tie all grid pins together
> and ground them directly, also you must short out the "bias"
> zener diode to get correct ZSAC, maybe adjust with a string of
> diodes to get correct ZSAC.
>
> 73 Jim SM2EKM
>
> PS: Think I remember that some 4-400´s was a bit too tall for
> the PA compartment lid to fit, 4-250A is never a problem.
> ---------------
>
> Hsu wrote:
>
>
>>Thanks Peter!
>> I have got a a died TL922 as a junk,I only pay $100 for it.so I don't
>> want pay for it too much.Althought the 3-500Z are made in China, but I call
>> the factory, They ask me pay $500 for a matched pair!Mr.Richard L. Measures
>> have mentioned in the list that 3-500Z can replace by 4-400(need some
>> work),I have a pair 4-400C, but I just test them, they all died!in this
>> weekend, I check my junk box, and find out some NOS Chinese FU-500Fs(same as
>> 4X500A) and its socket, I just read its datasheets , I found the screen and
>> grid dissipation power not too small, so,I think maybe it can work in GG
>> and cathode drive.It have same volt and cureent of filament as 3-500Z.
>> 73! Hsu
>>
>>
>>----- Original Message -----
>>From: "Peter Chadwick" <g3rzp@g3rzp.wanadoo.co.uk>
>>To: "Hsu" <Jbenson@sohu.co>; <amps@contesting.com>
>>Sent: Sunday, July 23, 2006 7:14 PM
>>Subject: Re: [Amps] 3-500Z convertion
>>
>>
>>
>>
>>>Hsu said:
>>>
>>>
>>>>My TL922's 3-500Zs died,I have some 4X500As,it seems the 3-500Z can
>>>>convertion by 4X500A, <
>>>
>>>The 4X500A is an external anode tube, so the cooling won't be right, it
>>>needs a different socket, and it's a tetrode. You'd need to do soem careful
>>>calculation to determine if the grid and screen dissipations would be
>>>exceeded. All in all, i'd say buyin a pair of new 3-500Z is a better way to
>>>o.
>>>73
>>>Peter G3RZP
>>>
>>>
>>>
>>>
>>>
>>>========================================
>>>Message Received: Jul 23 2006, 11:54 AM
>>>From: "Hsu"
>>>To: amps@contesting.com
>>>Cc:
>>>Subject: [Amps] 3-500Z convertion
>>>
>>>Hi, I'm a new member.My TL922's 3-500Zs died,I have some 4X500As,it seems
>>>the 3-500Z can convertion by 4X500A, Does anyone have this experience?Thanks
>>>in advance!
>>>73! Hsu
>>>_______________________________________________
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>>>http://lists.contesting.com/mailman/listinfo/amps
>>>
>>
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>>
>
>
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