[Amps] How do you - powering a SS amp with a capacitor?

[Joe Subich, W4TV]

 > Just watch the plate voltage drop in a typical amp as you add
 > compression. Unprocessed SSB in a typical amp may show 100 volt drop
 > while heavily processed with compression and clipping might show a 300
 > volt drop.

A 300 V drop in a 2500V supply is less than 1.5% ... that's not even
in the same league as a 2V drop (11.5V under load) for a 13.8V power
supply. The IMD in a 100W transceiver on a Gamma supply makes the
Italian CB amplifiers look good.

73,

    ... Joe, W4TV


On 8/9/2010 3:09 PM, Roger wrote:
>
>
> On 8/9/2010 11:49 AM, Joe Subich, W4TV wrote:
>>    >   However, by putting a very large capacitor AT THE AMPLIFIER, you can
>>    >   use smaller wires and a smaller power supply. The capacitor charges
>>    >   during periods of low current draw and then supplies power when
>>    >   needed.
>>
>> This only works with CW and unprocessed SSB.  Heavily processed SSB
>> and digital modes have a sufficiently high duty cycle (low peak to
>> average ratio) that the capacitor is not able to completely charge.
>>
>>
> Just watch the plate voltage drop in a typical amp as you add
> compression. Unprocessed SSB in a typical amp may show 100 volt drop
> while heavily processed with compression and clipping might show a 300
> volt drop.  Coming from a different direction, look at the PEP output.
> An amp may be capable of 1100 watts continuous carrier, key down, but it
> might actually make the 1500 PEP legal limit with unprocessed SSB.  NOTE
> both examples are highly dependent on the individual amp so YMMV doing
> your own experiments.<:-))
>
> 73
>
> Roger (K8RI)
>
>
>> This effect is seen with transceivers using the Gamma Research HPS-1A:
>> http://www.gammaresearch.net/hps-1a.html.  Better a properly sized
>> switching supply ... for example, the MFJ-4125 is about $80 on-line
>> for a 22A continuous/25A peak rating vs. $170 for the HPS-1A with its
>> 5A continuous/22A peak rating.
>>
>> 73,
>>
>>       ... Joe, W4TV
>>
>>
>> On 8/9/2010 11:11 AM, Vic K2VCO wrote:
>>
>>> The capacitors don't replace batteries, but they can save a lot in
>>> power supply and cable size. I used to have a ss amp which required
>>> around 90A at 12v, and I used a pair of 75 amp Astrons and some huge
>>> 00 gauge welding cables to keep the drop down (connecting them to the
>>> amp was interesting).
>>>
>>> However, by putting a very large capacitor AT THE AMPLIFIER, you can
>>> use smaller wires and a smaller power supply. The capacitor charges
>>> during periods of low current draw and then supplies power when
>>> needed. These are popular here with the morons that have insanely
>>> powerful audio amplifiers in their trucks.
>>>
>>> On 8/9/2010 2:59 AM, Mike Tubby wrote:
>>>
>>>
>>>> I agree.  With decent AGM batteries I can't really see the need
>>>> for capacitors.
>>>>
>>>> I have worked with AGM SLA betteries for many years in Ambulance
>>>> electrical systems. I also use them to power various repeaters and
>>>> have a split charge system in my SUV for powering ham radio
>>>> equipment.
>>>>
>>>> The trick to getting good performance and good outcomes is all to
>>>> do with how you treat your batteries (charge/discharge).
>>>>
>>>> Most SLA AGM batteries can be used with stepped charging with the
>>>> harder charging at 14.4V and float/maintained charging at 13.8V.
>>>> Most SLA batteries shouldn't be discharged below 10.8V as this may
>>>> permanently damage the chemistry - consider a low voltage
>>>> disconnector.
>>>>
>>>> There's some good information over at Battery university:
>>>>
>>>> http://www.batteryuniversity.com/>
>>>>
>>>> Regards
>>>>
>>>> Mike G8TIC
>>>>
>>>>
>>>>>> Has anyone ever built a power supply system with a capacitor??
>>>>>> what suggestions for doing it right? any url for a source on
>>>>>> such an installation? Anything else need to be added like a low
>>>>>> voltage cutoff, isolator, etc?
>>>>>>
>>>>>> thanks in advance
>>>>>>
>>>>>> chas  k5dam
>>>>>>
>>>
>> _______________________________________________
>> Amps mailing list
>> Amps at contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>>
>>
> _______________________________________________
> Amps mailing list
> Amps at contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
>