Joe,
Yes, I fully understand this. The Ameritron amp is not a class B amp either. I
didn't see a listing included in the PDF for a class AB if I recall. It should
be better operating in class AB. The other curves though are for higher plate
voltage and currents than listed under maximums. These are for pulse rated,
etc. The class B maximums do show though that a drop in plate voltage, and a
small drop in plate current (10 mA) betters the IMD performance by 5 dB. It's
sure to better it in class AB and A too.
Best,
Will
*********** REPLY SEPARATOR ***********
On 6/27/06 at 12:29 PM Joe Subich, W4TV wrote:
>Will,
>
>The numbers you quote are based on Eimac's suggested operating
>conditions for a particular class of operation, input power
>and plate voltage. The do not necessarily represent the best
>IMD performance available from the tube.
>
>The Eimac datasheet is based on the old 1 KW DC input rules. If
>you look, it is for class B at 1000 W PEP input and 2500 V on
>the plate.
>
>The AL-80/SB-1000 is AB2, 2700 - 3000 Volts on the plate and
>about 1500 watts PEP input.
>
>73,
>
> ... Joe, W4TV
>
>
>
>> -----Original Message-----
>> From: amps-bounces@contesting.com
>> [mailto:amps-bounces@contesting.com] On Behalf Of Will Matney
>> Sent: Tuesday, June 27, 2006 9:07 AM
>> To: amps@contesting.com
>> Subject: Re: [Amps] IM distortion and such
>>
>>
>> Tom,
>>
>> It says it on page two of the Eimac 3-500Z spec sheet. See
>> the one the link was provided for earlier.
>>
>> Quote;
>>
>> RF Linear Amplifier
>> Grounded-Grid, Class B
>>
>> Maximum Ratings
>>
>> Typical operation (Minimum distortion products at 1 KW PEP input)**
>> DC Plate Voltage 2500V
>> Zero Signal DC Plate Current* 130 mA
>> Single-Tone DC Plate Current 400 mA
>> Single-Tone DC Grid Current 120 mA
>> Two-Tone DC Plate Current 280 mA
>> Two-Tone DC Grid Current 70 mA
>> Peak Envelope Useful Output Power 600W
>> Resonant Load Impedance 3450 Ohms
>> Intermodulation Distortion Products -33 dB
>>
>> *Approximate Value
>> ** Measured Data From A Single Tube
>>
>> End Quote
>>
>> Better IMD was obtained by lowering the plate voltage under
>> "(Minimum Distortion Products)" at -38 dB, 500W, and at 2000 Vdc.
>>
>> Best,
>>
>> Will
>>
>>
>>
>> *********** REPLY SEPARATOR ***********
>>
>> On 6/27/06 at 5:46 AM Tom W8JI wrote:
>>
>> >> They can be used on up in current, say for pulse circuits
>> >> and RF heating. The 400 mA is the maximum plate current at
>> >> single tone for minimum distortion. That's for 600 watts
>> >> PEP useful power each. That's listed in the tables on page
>> >> 2 or 3 under a class B RF amp.
>> >
>> >Will,
>> >
>> >Where did you get the idea 400mA is a "minimum distortion"
>> >condition?
>> >
>> >73 Tom
>> >
>> >
>> >
>> >
>> >
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>>
>>
>>
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