Leigh,
Not to drive everyone up a tree with this topic, but do you know of any
non-proprietary designs that might serve at least as a basis for a
properly-done EBS implementation?
I'm not thinking so much of modifying my (newest) commercial amp, but I
do have a YC156 project that seems to be in eternal overhaul, as well as
a Henry 3KA that could benefit from such a beast.
Along that line I also (still) have one Alpha 77 left with their EBS,
but I'm not sure I'd qualify that one as more than a good start at
"properly done", at least by today's standards. (It's from before they
added the control pot, early design)
Thanks,
Jim N7CXI
On 4/1/2012 7:18 PM, Leigh Turner wrote:
>
> That's right Peter; horses for courses / no free lunches concisely sums up
> the tube comparison quite well. The choice is largely a personal preference
> one with diehard aficionados in both camps.
>
> If high ZSAC is a concern then a competently executed progressive tri-state
> EBS scheme will mitigate that concern. Whereas a poorly applied EBS is a
> horrid abomination, a properly done EBS implementation will work a treat for
> reducing heat dissipation with no detrimental impact on the amplifier's
> signal spectral quality.
>
> 73
> Leigh, VK5KLT
>
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Peter Voelpel
> Sent: Monday, 2 April 2012 8:13 AM
> To: amps@contesting.com
> Subject: Re: [Amps] Cheap auxiliary amp cooling
>
> There is no free lunch, either use triodes with low ZSAC and small gain or
> tetrodes with 20db+ gain and high demand of ZSAC.
>
> I have no problem to let my YL1056 idle with 1100W ZSAC and use the same
> tube since 1978. I remember my 30S1 did not consume much less while idling.
>
> 73
> Peter, DJ7WW
>
> -----Original Message-----
> From: amps-bounces@contesting.com [mailto:amps-bounces@contesting.com] On
> Behalf Of Carl
> Sent: Freitag, 30. März 2012 17:41
> To: audioguy@q.com; Amps@contesting.com
> Subject: Re: [Amps] Cheap auxiliary amp cooling
>
> Isnt that exciting having to run almost 1100W idle with 2 tubes only rated
> at 1200W dissipation total? No wonder they dont last long and availability
> is drying up.
>
> Carl
> KM1H
>
>
> ----- Original Message -----
> From: "Jim Barber"<audioguy@q.com>
> To:<Amps@contesting.com>
> Sent: Friday, March 30, 2012 3:29 AM
> Subject: [Amps] Cheap auxiliary amp cooling
>
>
>> While playing with my new toy, (QRO HF2500DX) I found that I was able to
>> confirm that it does indeed need auxiliary cooling for high duty cycle
>> modes. Even at relatively low or no power output - just the ZSAC is
>> 450ma @ 2400V, or over 1000 watts of just plain old heat.
>>
>> I decided to check my computer parts supplier to see if there was
>> anything that looked like it might work for a "booster" exhaust fan, and
>> it turned out that a 250mm (10"!) 12V PC case fan has a brushless (no RF
>> noise) DC motor, turns slow and makes little audible noise, but manages
>> to move 105 CFM of air. (at zero back pressure, of course) They cost
>> $26.99 USD in single units.
>>
>> I haven't built a sealed mount yet, but just sitting the fan on top of
>> the case above the tubes dropped the exhaust temp 40-50F during
>> 375/1500-watt AM transmissions. The noise of the "booster" fan is so low
>> compared to the internal 50CFM blower that I can't really hear it.
>> Legal-limit SSB conversations (with modest compression) get the
>> airstream only lukewarm now, instead of 130F+ .
>>
>> I also bought a 243 CFM 8" 12VDC Conair-Rotron hurricane generator that
>> I want to build a temperature-ramped PWM controller for when I get A
>> Round Tuit. (probably 25khz, 30-100% duty cycle to copy the newer PC
>> controllers, which work well) In the meantime, the cheap PC case fan
>> seems to be getting the job done.
>>
>> 73,
>> Jim N7CXI
>> _______________________________________________
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>> Amps@contesting.com
>> http://lists.contesting.com/mailman/listinfo/amps
>
>
>
>
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