The zener in the SB-220 is a 5.1V 10W !!
/ SM2EKM
-----------------
Carl wrote:
> Last time I looked it was a 9.1V zener and providing a positive voltage bias
> which is different than most tubes.
>
> If you read my post the -80V is for the TB3/750 REPLACEMENT in a SB-220.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Jim W7RY" <w7ry@arrl.net>
> To: <amps@contesting.com>
> Sent: Sunday, November 01, 2009 10:11 AM
> Subject: Re: [Amps] SRS 360?
>
>
> - 80 volts bias on a SB-220? Last time I looked at a SB220 the bias was
> provided by a 5 volt zener diode.
>
>
> How about -80 volts is what the SB-220 uses to cut off the tube during
> standby?
>
>
> 73
> Jim W7RY
>
> ----- Original Message -----
> From: "Carl" <km1h@jeremy.mv.com>
> To: "Karl-Arne Markström" <sm0aom@telia.com>; "Paul Gerhardt"
> <phgerhardt@gmail.com>; <amps@contesting.com>
> Sent: Sunday, November 01, 2009 6:17 AM
> Subject: Re: [Amps] SRS 360?
>
>
>> Interesting site, however no mention is made of IMD performance with the
>> TB3/750 which is NOT a zero bias tube as claimed.
>>
>> As a Class B GG 3-500Z replacement in say a SB-220 a bias of
>> approximately -80V is required with a resultant 180-200 ma idle current.
>> For a much cleaner signal AB2 a ~ -50V bias is required with a resultant
>> Ip
>> of over 500 ma for the pair! At 2500V this is approaching the Pd of the
>> tubes resulting in excessive transformer and tube heating for the cooling
>> fan under even moderate SSB use. An electronic bias circuit would just
>> about
>> be mandatory.
>>
>> In addition a completely redesigned input circuit is needed along with
>> sufficient drive to overcome the bias.
>>
>> If a clean signal is of importance then the TB3/750 or 5867 is not an
>> acceptable tube for SSB at typical 3-500Z plate voltages.
>>
>> Carl
>> KM1H
>>
>>
>>
>> ----- Original Message -----
>> From: "Karl-Arne Markström" <sm0aom@telia.com>
>> To: "Carl" <km1h@jeremy.mv.com>; "Paul Gerhardt" <phgerhardt@gmail.com>;
>> <amps@contesting.com>
>> Sent: Sunday, November 01, 2009 3:47 AM
>> Subject: Re: [Amps] SRS 360?
>>
>>
>>> The SRS360 was the DDR manufactured equivalent of
>>> the TB3/750 or 5867A.
>>>
>>> It is a 350 W dissipation medium-mu triode which needs a bias circuit to
>>> work properly.
>>>
>>> An RF amplifier circuit using the TB3/750 can be found at
>>>
>>> http://www.xs4all.nl/~pa0fri/Lineairs/Frinear750/FRI750uk.htm
>>>
>>> 73/
>>>
>>> Karl-Arne
>>> SM0AOM
>>>
>>>
>>> ----- Original Message -----
>>> From: "Carl" <km1h@jeremy.mv.com>
>>> To: "Paul Gerhardt" <phgerhardt@gmail.com>; <amps@contesting.com>
>>> Sent: Saturday, October 31, 2009 10:21 PM
>>> Subject: Re: [Amps] SRS 360?
>>>
>>>
>>>> Ich bien be usen en infernalmachen.
>>>>
>>>> Looks like an Amperex 5868 clone or similar. Industrial class C tube;
>>>> good
>>>> for Class B audio also.
>>>>
>>>> Carl
>>>> KM1H
>>>>
>>>>
>>>>
>>>>
>>>> ----- Original Message -----
>>>> From: "Paul Gerhardt" <phgerhardt@gmail.com>
>>>> To: <amps@contesting.com>
>>>> Sent: Saturday, October 31, 2009 5:10 PM
>>>> Subject: [Amps] SRS 360?
>>>>
>>>>
>>>>> Do these ever get used in Amateur service?
>>>>>
>>>>> Looks like a 3-500z
>>>>>
>>>>> http://www.radiomuseum.org/tubes/tube_srs360.html
>>>>>
>>>>> ?
>>>>>
>>>>> Paul K3PG
>>>>>
>>>>>
_______________________________________________
Amps mailing list
Amps@contesting.com
http://lists.contesting.com/mailman/listinfo/amps
|