[Amps] 3-500Z convertion

[R L Measures]

On Jul 23, 2006, at 5:14 AM, 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!

You only need one tube because the Mu of an Eimac tube and the Mu of  
a Chinese tube is similar. Also, if the tube manufacturer has tight  
tolerances and good quality control, there is no need to match tubes  
because all of the tubes that get through final test will be  
virtually the same.

> 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 at g3rzp.wanadoo.co.uk>
> To: "Hsu" <Jbenson at sohu.co>; <amps at 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 at 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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R L MEASURES, AG6K. 805-386-3734
r at somis.org