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I apologize if this subject has already been addressed (I could not find a thread).
What operating LDMOS transistor temperatures are you seeing under normal operation? MY LA-1K is used at my remote station. It has performed very well. An actual-time camera allows me to watch the amp "work" - normally the amp is displaying +32C, but I do see temps elevate under normal use. I'm curious as to what others are seeing.
Thanks for your input!
73 de W7GBA?
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47 degrees after acting as net control for ?an hour- long SSB Net on 75 meters.
I apologize if this subject has already been addressed (I could not find a thread).
What operating LDMOS transistor temperatures are you seeing under normal operation? MY LA-1K is used at my remote station. It has performed very well. An actual-time camera allows me to watch the amp "work" - normally the amp is displaying +32C, but I do see temps elevate under normal use. I'm curious as to what others are seeing.
Thanks for your input!
73 de W7GBA?
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65 degrees Celsius on FT8 and 300 watts. ? Scott Sherer ?
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From: [email protected] [mailto:[email protected]] On Behalf Of Dave Bates
Sent: Monday, July 11, 2022 11:17 AM
To: [email protected]
Subject: Re: [la1k] Operating temps ? 47 degrees after acting as net control for ?an hour- long SSB Net on 75 meters. ? I apologize if this subject has already been addressed (I could not find a thread).
What operating LDMOS transistor temperatures are you seeing under normal operation? MY LA-1K is used at my remote station. It has performed very well. An actual-time camera allows me to watch the amp "work" - normally the amp is displaying +32C, but I do see temps elevate under normal use. I'm curious as to what others are seeing.
Thanks for your input!
73 de W7GBA?
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I have seen low 60s at the end of a long rag chew or when operating In a CQ Party at ~750 watts SSB. ?I pretty much NEVER push the amp beyond 750 W pep. At about 35 watts from the transceiver in SSB.
I notice that at the upper 50 degree range, the fans really kick in at high speed.
I NEVER turn the amp off when it is hot, just let the fans run until the temp is back down at about 25-26 Celsius which is the temp it usually shows when I turn it on.
I just feel it is not good to turn it off when the internal temps are above normal room temp.
Art Gumbus
"The is always a well-known?solution to every human problem -?neat and/or plausible and/or?wrong." - H. L. Mencken
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On Jul 11, 2022, at 4:59 PM, Scott Sherer < ssherer@...> wrote:
65 degrees Celsius on FT8 and 300 watts. ? Scott Sherer ? ? 47 degrees after acting as net control for ?an hour- long SSB Net on 75 meters. ? I apologize if this subject has already been addressed (I could not find a thread).
What operating LDMOS transistor temperatures are you seeing under normal operation? MY LA-1K is used at my remote station. It has performed very well. An actual-time camera allows me to watch the amp "work" - normally the amp is displaying +32C, but I do see temps elevate under normal use. I'm curious as to what others are seeing.
Thanks for your input!
73 de W7GBA??
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With FT8 normally no amp however a few times drive with 14 watts with about 250W output with 45C. Have seen 50C before.
------- Original Message -------
On Sunday, July 10th, 2022 at 22:45, Deacon Dan James <djames.cathedral@...> wrote:
I apologize if this subject has already been addressed (I could not find a thread).
What operating LDMOS transistor temperatures are you seeing under normal operation? MY LA-1K is used at my remote station. It has performed very well. An actual-time camera allows me to watch the amp "work" - normally the amp is displaying +32C, but I do see temps elevate under normal use. I'm curious as to what others are seeing.
Thanks for your input!
73 de W7GBA?
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I look forward to responses on this thread, as I suspect I have an issue with my LA-1K - which operates on 120 Vac into a Palstar HF-Auto Tuner, with a resonant EFHW wire antenna covering 80 to 10 meters.
My LA-1K reaches elevated temperatures, depending on band & mode.? 10 meters is perhaps the worst.? A 10m SSB rag-chew at about 700 watts with a friend across the country saw my Amp climb into the mid/upper 70 deg C range.? He reported his LA-1K was in the high 30 deg C range.? A big difference!? But on 40 meters I can do 950 watts SSB (limited by 120 Vac operation) for hours with lower and stable temps.? So it's band dependent.
I made a specific check using FT8 on 10 meters, as it allows for precise duty cycle timing.? My LA-1K at 200 watts on FT8 will slowly rise into the upper 70 deg C range, then stabilizes.? But increasing to 225 watts will cause additional temperature rise - certainly reaching 80 C, but I halted operation at that point for cool down.
My amp was back to Palstar for warranty repair of a manufacturing problem in the finals (over a year ago).? It was updated at that time to latest specs, and at my request had new quieter fans installed.? It was mentioned the new fans were not quite as efficient, which might result in slightly higher operating temperatures.? But I still suspect I've got a problem - 75 C seems way too hot, but the manual says shut-down will occur at 100 C - which seems crazy!? Been meaning to phone Palstar tech support to discuss.
My Amp performs fine on the air - it just (in my opinion) gets way too hot.? Looking forward to comments from other users.
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Hi Fred? Had my LA-1K in for service in May and they applied the latest release to it.
I run 850 watts out on 6 meters on FT8 and also on Q65-30A. ? My temps never get above 62C. This seems like an improvement over the previous firmware release.
I assume you blow the dust out of the amp periodically so don’t know why you amp is getting so hot with minimal duty cycles.
I would definitely call Palstar and ask their opinion.
Good luck 73 Paul NO0T
I look forward to responses on this thread, as I suspect I have an issue with my LA-1K - which operates on 120 Vac into a Palstar HF-Auto Tuner, with a resonant EFHW wire antenna covering 80 to 10 meters.
My LA-1K reaches elevated temperatures, depending on band & mode.? 10 meters is perhaps the worst.? A 10m SSB rag-chew at about 700 watts with a friend across the country saw my Amp climb into the mid/upper 70 deg C range.? He reported his LA-1K was in the high 30 deg C range.? A big difference!? But on 40 meters I can do 950 watts SSB (limited by 120 Vac operation) for hours with lower and stable temps.? So it's band dependent.
I made a specific check using FT8 on 10 meters, as it allows for precise duty cycle timing.? My LA-1K at 200 watts on FT8 will slowly rise into the upper 70 deg C range, then stabilizes.? But increasing to 225 watts will cause additional temperature rise - certainly reaching 80 C, but I halted operation at that point for cool down.
My amp was back to Palstar for warranty repair of a manufacturing problem in the finals (over a year ago).? It was updated at that time to latest specs, and at my request had new quieter fans installed.? It was mentioned the new fans were not quite as efficient, which might result in slightly higher operating temperatures.? But I still suspect I've got a problem - 75 C seems way too hot, but the manual says shut-down will occur at 100 C - which seems crazy!? Been meaning to phone Palstar tech support to discuss.
My Amp performs fine on the air - it just (in my opinion) gets way too hot.? Looking forward to comments from other users.
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Regarding temps and bands.... I fully do believe that certain bands my provide stress to amps and their tuners... for certain antennas/components.
In Fact I am aware that Elecraft's 1500 amp has a PC app that informs the user of the max PEP they should achieve given the tuner results with the antenna inline.
That is pretty cool. ?No pun intended.... ;-)
I was watching a video of a guy demonstrating the RF Kits. RF2K-S amp and the outputs on various bands did vary with his tune and antenna(s).
But frankly not by a whole lot of watts PEP.
I wonder if reflected power has something to do with the heat...
I do know that Baluns can get hot and when they do... SWR can and will increase.?
And with the SWR rising, so does reflected power back.
High power does reveal stress in downstream components.
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Fred ...
I do not do lengthy contesting.? But I have done fairly lengthy
special events (Missouri Bicentennial comes to mind) where I
paid little attention to heating and let the (original) fans do
their work.
I run my LA-1K off 240 VAC which may or may not be a factor.
I use it almost nightly at 30 wpm CW (full break-in using a
QSK-2500), mostly on 80 and 40, and occasionally longer if I
check-in to an SSB net.? I do no digital operating at all.?
Again, I don't pay much attention to heating.? I do pay
considerable attention, however, to SWR and input power (33 to
40 watts, depending on band).
I know this probably doesn't help you much.
73,
Kent
K9ZTV
On 7/12/2022 1:25 PM, Fred, W9KEY
wrote:
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I look forward to responses on this thread, as I suspect I have an
issue with my LA-1K - which operates on 120 Vac into a Palstar
HF-Auto Tuner, with a resonant EFHW wire antenna covering 80 to 10
meters.
My LA-1K reaches elevated temperatures, depending on band &
mode.? 10 meters is perhaps the worst.? A 10m SSB rag-chew at
about 700 watts with a friend across the country saw my Amp climb
into the mid/upper 70 deg C range.? He reported his LA-1K was in
the high 30 deg C range.? A big difference!? But on 40 meters I
can do 950 watts SSB (limited by 120 Vac operation) for hours with
lower and stable temps.? So it's band dependent.
I made a specific check using FT8 on 10 meters, as it allows for
precise duty cycle timing.? My LA-1K at 200 watts on FT8 will
slowly rise into the upper 70 deg C range, then stabilizes.? But
increasing to 225 watts will cause additional temperature rise -
certainly reaching 80 C, but I halted operation at that point for
cool down.
My amp was back to Palstar for warranty repair of a manufacturing
problem in the finals (over a year ago).? It was updated at that
time to latest specs, and at my request had new quieter fans
installed.? It was mentioned the new fans were not quite as
efficient, which might result in slightly higher operating
temperatures.? But I still suspect I've got a problem - 75 C seems
way too hot, but the manual says shut-down will occur at 100 C -
which seems crazy!? Been meaning to phone Palstar tech support to
discuss.
My Amp performs fine on the air - it just (in my opinion) gets way
too hot.? Looking forward to comments from other users.
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Paul,
What firmware version did they install?? 1.08S is the latest on the website right now.? I'm curious if you got something newer.
73 Fred K3FRK
Hi Fred? Had my LA-1K in for service in May and they applied the latest release to it.
I run 850 watts out on 6 meters on FT8 and also on Q65-30A. ? My temps never get above 62C. This seems like an improvement over the previous firmware release.
I assume you blow the dust out of the amp periodically so don’t know why you amp is getting so hot with minimal duty cycles.
I would definitely call Palstar and ask their opinion.
Good luck 73 Paul NO0T I look forward to responses on this thread, as I suspect I have an issue with my LA-1K - which operates on 120 Vac into a Palstar HF-Auto Tuner, with a resonant EFHW wire antenna covering 80 to 10 meters.
My LA-1K reaches elevated temperatures, depending on band & mode.? 10 meters is perhaps the worst.? A 10m SSB rag-chew at about 700 watts with a friend across the country saw my Amp climb into the mid/upper 70 deg C range.? He reported his LA-1K was in the high 30 deg C range.? A big difference!? But on 40 meters I can do 950 watts SSB (limited by 120 Vac operation) for hours with lower and stable temps.? So it's band dependent.
I made a specific check using FT8 on 10 meters, as it allows for precise duty cycle timing.? My LA-1K at 200 watts on FT8 will slowly rise into the upper 70 deg C range, then stabilizes.? But increasing to 225 watts will cause additional temperature rise - certainly reaching 80 C, but I halted operation at that point for cool down.
My amp was back to Palstar for warranty repair of a manufacturing problem in the finals (over a year ago).? It was updated at that time to latest specs, and at my request had new quieter fans installed.? It was mentioned the new fans were not quite as efficient, which might result in slightly higher operating temperatures.? But I still suspect I've got a problem - 75 C seems way too hot, but the manual says shut-down will occur at 100 C - which seems crazy!? Been meaning to phone Palstar tech support to discuss.
My Amp performs fine on the air - it just (in my opinion) gets way too hot.? Looking forward to comments from other users.
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Hi. In 40 meters in a regular rag chew with heavy compression at 1KW no more than 45C
73, Philip CE4PS
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Hum - Never considered my temperature issue might have been addressed somewhere along the ling via a firmware change.? Interesting thought .....
My LA-1K is running 1.07K. which probably dates back to my return for warranty repair in September 2020.
1.07K doesn't even show up as a valid firmware on Palstar's website, so perhaps never released to the general public??
Unfortunately, reading through the revision history, I don't see anything related to temperature.
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Fred,
If your EFHW antenna is resonant, then why use the tuner??? Could it be that the amp is being more stressed on 10 Meters and it is not matched properly???
Can you try running into a good dummy load and carrying on an extended (talking for a minute or more at a time)? "QSO"? at the same power levels???? Or try? FT8-like transmissions of 15 sec on/off for a couple of minutes to see if the temp still climbs when operating into the dummy load.?? Of course we are assuming that in your 10 meter SSB example both shacks are at a similar ambient temp starting out.
Ron?? WA2EIO
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Ron (WA2EIO) - Thanks for interesting suggestion. While I have a Palstar DL1500, it's duty cycle derating curve is ambiguous, so thought I'd just run the test On-Air.? 10 meters was quiet, but open somewhat this morning.? Made 11 contacts!? Hope the pasted Excel chart properly displays below.? If not, I'll re-post with actual data values.? Suspect there may be something wrong with my Amp - it sure runs hot - but otherwise seems fine and can do 950-1000+ watt peaks on SSB with 45w drive (120 Vac input).? Output power monitored with HF-AUTO Metering (Ppk).? Temperature rise is worse on higher frequency bands. Perhaps others can perform a similar test and report back? 73 ..... Fred,? W9KEY Test Parameters:LA-1K:? Input drive 12 - 13w for ~250 watt Ppk output into EFHW resonant antenna, 120 VAC Mains Antenna:? EFHW resonant wire (80 - 10 Meters); ~135 feet long, 35 feet AGL SWR = 1.6 (per LA-1K metering) at 28.074 MHz Ambient Room Temp = 75 deg F / 24 deg C HF-AUTO Tuner in "Bypass" mode (but useful for monitoring 250w Ppk power) Test Transmissions:? FT-8 mode (15 sec On, 15 sec Off) ; Frequency = 28.074 MHz Test Duration:? 50 minutes ; LA-1K Temperature recorded each minute Test Results: (Operating Time in "Minutes" ; Temperature in deg "C" per LA-1K metering) Note - Missed part of a Tx cycle at the 19 minute mark Amplifier reached 70 deg C (after Tx) at the 10 minute operating point Test Concluded when Amplifier Peak Temp (during Tx) reached 80 deg C at 50 minute mark. 
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Hi Fred: I just wonder what your temps would be if you were inputting AC power at 240V vs 120V? Is the 240V AC more “efficient” from a power and resultant heat perspective? ?
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Ron (WA2EIO) - Thanks for interesting suggestion. While I have a Palstar DL1500, it's duty cycle derating curve is ambiguous, so thought I'd just run the test On-Air.? 10 meters was quiet, but open somewhat this morning.? Made 11 contacts!?
Hope the pasted Excel chart properly displays below.? If not, I'll re-post with actual data values.? Suspect there may be something wrong with my Amp - it sure runs hot - but otherwise seems fine and can do 950-1000+ watt peaks on SSB with 45w drive (120 Vac input).? Output power monitored with HF-AUTO Metering (Ppk).? Temperature rise is worse on higher frequency bands.
Perhaps others can perform a similar test and report back?
73 ..... Fred,? W9KEY
Test Parameters:
LA-1K:? Input drive 12 - 13w for ~250 watt Ppk output into EFHW resonant antenna, 120 VAC Mains
Antenna:? EFHW resonant wire (80 - 10 Meters); ~135 feet long, 35 feet AGL
SWR = 1.6 (per LA-1K metering) at 28.074 MHz
Ambient Room Temp = 75 deg F / 24 deg C
HF-AUTO Tuner in "Bypass" mode (but useful for monitoring 250w Ppk power)
Test Transmissions:? FT-8 mode (15 sec On, 15 sec Off) ; Frequency = 28.074 MHz
Test Duration:? 50 minutes ; LA-1K Temperature recorded each minute
Test Results: (Operating Time in "Minutes" ; Temperature in deg "C" per LA-1K metering)
Note - Missed part of a Tx cycle at the 19 minute mark
Amplifier reached 70 deg C (after Tx) at the 10 minute operating point
Test Concluded when Amplifier Peak Temp (during Tx) reached 80 deg C at 50 minute mark.
<dummyfile.0.part>
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On 220 I have no temperature problems whatsoever at max power no matter how long I talk FT eight different story
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On Jul 19, 2022, at 3:46 PM, W1SWL <artgumbus@...> wrote:
? Hi Fred: I just wonder what your temps would be if you were inputting AC power at 240V vs 120V? Is the 240V AC more “efficient” from a power and resultant heat perspective? ? Art W1SWL
Ron (WA2EIO) - Thanks for interesting suggestion. While I have a Palstar DL1500, it's duty cycle derating curve is ambiguous, so thought I'd just run the test On-Air.? 10 meters was quiet, but open somewhat this morning.? Made 11 contacts!?
Hope the pasted Excel chart properly displays below.? If not, I'll re-post with actual data values.? Suspect there may be something wrong with my Amp - it sure runs hot - but otherwise seems fine and can do 950-1000+ watt peaks on SSB with 45w drive (120 Vac input).? Output power monitored with HF-AUTO Metering (Ppk).? Temperature rise is worse on higher frequency bands.
Perhaps others can perform a similar test and report back?
73 ..... Fred,? W9KEY
Test Parameters:
LA-1K:? Input drive 12 - 13w for ~250 watt Ppk output into EFHW resonant antenna, 120 VAC Mains
Antenna:? EFHW resonant wire (80 - 10 Meters); ~135 feet long, 35 feet AGL
SWR = 1.6 (per LA-1K metering) at 28.074 MHz
Ambient Room Temp = 75 deg F / 24 deg C
HF-AUTO Tuner in "Bypass" mode (but useful for monitoring 250w Ppk power)
Test Transmissions:? FT-8 mode (15 sec On, 15 sec Off) ; Frequency = 28.074 MHz
Test Duration:? 50 minutes ; LA-1K Temperature recorded each minute
Test Results: (Operating Time in "Minutes" ; Temperature in deg "C" per LA-1K metering)
Note - Missed part of a Tx cycle at the 19 minute mark
Amplifier reached 70 deg C (after Tx) at the 10 minute operating point
Test Concluded when Amplifier Peak Temp (during Tx) reached 80 deg C at 50 minute mark.
<dummyfile.0.part>
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Good afternoon... ??? The temperature accumulation will not vary by whether or not the amplifier is running on 120 or 240.? Any slight difference caused by the power supply would be un-detectable in the thermal readout since that is sensing heat-sink temperature very close to the LDMOS devices.? I run two amps in parallel through a combiner simultaneously each putting out the same power, one amp runs on 120, the other on 240.? The case temperature readouts on both amps are within one or two degrees of each other.? In general, the amp temperature is going to vary by your duty cycle (of course) but also by your altitude and ambient temperature.? Also, anything higher than a 1:1 SWR will generate additional heat.? There are differences in the efficiency of the amp on various bands.? The same input power will generate different output power (and resultant different temperature readings) depending on the band you're on, generally getting more efficient on the higher bands.? Six meters will produce less heat than 160 for a given power input.? Six meters is upwards of 70% efficient vs. 50% on 160.? These differences are due to the nature of the LDMOS technology, which generally perform better at the higher frequencies.? There will be minor variations in the efficiency numbers going up through the bands due to minor differences in the low-pass filters.? It's not a straight-line increase from 160 to 6. Best, Dennis N0SP
On 7/19/2022 at 1:46 PM, "W1SWL" <artgumbus@...> wrote: Hi Fred: I just wonder what your temps would be if you were inputting AC power at 240V vs 120V? Is the 240V AC more “efficient” from a power and resultant heat perspective? ? Art W1SWL
On Jul 19, 2022, at 3:05 PM, Fred, W9KEY <fred.schwierske@...> wrote:
Ron (WA2EIO) - Thanks for interesting suggestion. While I have a Palstar DL1500, it's duty cycle derating curve is ambiguous, so thought I'd just run the test On-Air.? 10 meters was quiet, but open somewhat this morning.? Made 11 contacts!?
Hope the pasted Excel chart properly displays below.? If not, I'll re-post with actual data values.? Suspect there may be something wrong with my Amp - it sure runs hot - but otherwise seems fine and can do 950-1000+ watt peaks on SSB with 45w drive (120 Vac input).? Output power monitored with HF-AUTO Metering (Ppk).? Temperature rise is worse on higher frequency bands.
Perhaps others can perform a similar test and report back?
73 ..... Fred,? W9KEY
Test Parameters:
LA-1K:? Input drive 12 - 13w for ~250 watt Ppk output into EFHW resonant antenna, 120 VAC Mains
Antenna:? EFHW resonant wire (80 - 10 Meters); ~135 feet long, 35 feet AGL
SWR = 1.6 (per LA-1K metering) at 28.074 MHz
Ambient Room Temp = 75 deg F / 24 deg C
HF-AUTO Tuner in "Bypass" mode (but useful for monitoring 250w Ppk power)
Test Transmissions:? FT-8 mode (15 sec On, 15 sec Off) ; Frequency = 28.074 MHz
Test Duration:? 50 minutes ; LA-1K Temperature recorded each minute
Test Results: (Operating Time in "Minutes" ; Temperature in deg "C" per LA-1K metering)
Note - Missed part of a Tx cycle at the 19 minute mark
Amplifier reached 70 deg C (after Tx) at the 10 minute operating point
Test Concluded when Amplifier Peak Temp (during Tx) reached 80 deg C at 50 minute mark.
<dummyfile.0.part>
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Fred,
I am on the wait list, still waiting for my amp to be built, but have been reading all I can here and on other forums about its operation, so I can't offer any firsthand information. (yet!)?
Some thoughts:
Were you able to hear if the fan speeds changed as the temp increased?? Can anyone report if theirs do, and at what temps it happens.
According to the Palstar "Troublshooting" section on the website, at 71C the display will be shown in red, and at 100C it the amp will go into bypass until it gets back down to 70C.? .?? Apparently 70C seems to be the hottest temp the amp will be 'happy' with.
Ron?? WA2EIO
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My la seems to have 3 fan speeds as i recall but i do wear headphones so i am not overly aware of the fan speed change.
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On Jul 19, 2022, at 7:43 PM, Ron - WA2EIO <wa2eio@...> wrote:
?Fred,
I am on the wait list, still waiting for my amp to be built, but have been reading all I can here and on other forums about its operation, so I can't offer any firsthand information. (yet!)?
Some thoughts:
Were you able to hear if the fan speeds changed as the temp increased?? Can anyone report if theirs do, and at what temps it happens.
According to the Palstar "Troublshooting" section on the website, at 71C the display will be shown in red, and at 100C it the amp will go into bypass until it gets back down to 70C.? .?? Apparently 70C seems to be the hottest temp the amp will be 'happy' with.
Ron?? WA2EIO
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The fan speed changes at 44C and 63C, and you can clearly hear it. When mine hits 63C I stop operating, because the fan is just too loud. I have to say even at 21C the fan noise is so high that I usually have to operate with headphones. ? 73, Bernd – KB7AK ?
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From: [email protected] < [email protected]> On Behalf Of Ron - WA2EIO Sent: Tuesday, July 19, 2022 4:44 PM To: [email protected]Subject: Re: [la1k] Operating temps ? Fred,
I am on the wait list, still waiting for my amp to be built, but have been reading all I can here and on other forums about its operation, so I can't offer any firsthand information. (yet!)?
Some thoughts:
Were you able to hear if the fan speeds changed as the temp increased?? Can anyone report if theirs do, and at what temps it happens.
According to the Palstar "Troublshooting" section on the website, at 71C the display will be shown in red, and at 100C it the amp will go into bypass until it gets back down to 70C.? .?? Apparently 70C seems to be the hottest temp the amp will be 'happy' with.
Ron?? WA2EIO
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Deacon Dan James
Jerry Repine
Fred, W9KEY
Paul
Philip Smith