Understood now.
One problem that needs to be resolved is the input network. I dont believe
there is sufficient tuning range for the driving impedance of one tube.
Why do you want to run only one tube? If it is for power restrictions why
not just less drive?
Carl
KM1H
----- Original Message -----
From: <on4aef@base.be>
To: "Carl" <km1h@jeremy.mv.com>
Cc: "Colin Lamb" <k7fm@teleport.com>; <amps@contesting.com>
Sent: Tuesday, January 26, 2010 10:12 PM
Subject: Re: [Amps] HELP Modifications for a Kenwood TL922
>
> It is not a question of money or to put some other types of tubes.
> It is a question of using only one 3-500Z in this amplifier and what I
> have to change to realise this not more !
> Of course I have to change the filament transformer into a 5VAC version
> because originally both 3-500Z's are in series on 12VAC !!
>
> Regards Jean ON4AEF.
>
>
>
> On Tue, 26 Jan 2010 15:21:29 -0500, "Carl" <km1h@jeremy.mv.com> wrote:
>> A. A new 3-500Z costs around $150
>>
>> B. The grids are not grounded in a TL-922.
>>
>> C. I dont think there is top clearance for a 4-400
>>
>> Carl
>> KM1H
>>
>>
>> ----- Original Message -----
>> From: "Colin Lamb" <k7fm@teleport.com>
>> To: "BEHIELS JEAN-PIERRE" <ON4AEF@base.be>; <amps@contesting.com>
>> Sent: Tuesday, January 26, 2010 2:50 PM
>> Subject: Re: [Amps] HELP Modifications for a Kenwood TL922
>>
>>
>>> Hello Jean:
>>>
>>> I see the problem as follows:
>>>
>>> You got an amp that uses two 3-500 tubes, but you only got one 3-500
>>> tube.
>>> An additional 3-500 tube would cost more than the amplifier and you
> want
>>> a
>>> cheap solution.
>>>
>>> You can use two 4-400 tubes ore even 4-250 tubes and should be able to
>>> trade one 3-500 for two of those tubes. In Europe, there are QBL
>>> equivalents to the 4-250 and 4-400 tubes. The tubes will fit in the
>>> sockets. These tubes are tetrodes, but the socket will ground both the
>
>>> screen and the control grid. These tubes like higher voltage and will
>>> not
>>> run as much power - but they will work.
>>>
>>> 73, Colin K7FM
>>> _______________________________________________
>>> Amps mailing list
>>> Amps@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
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