KeithL
Administrator
Posts: 9,902
|
Post by KeithL on Mar 12, 2019 8:54:58 GMT -5
Some Class A/B amplifiers have great big heat sinks - and no fans... And some have little tiny heat sinks - and enormous fans that sound like a jet taking off... Most of our amps have no fans... but a few, including the A-300, have small fans that spin when the amp gets warm.
Likewise... Some cars go "grumble... grumble... grubble..." when they idle... And some go "whirrrr...." Electrics don't make any sound at all when they're sitting still (except for the ones that have fans)... And, with some hybrids, the engine cycles on and off when you sit at a traffic light...
And, yes, most of our bigger and more expensive amps have more heat sinks, and no fans. And, yes, fans are cheaper than huge heat sinks - and also lighter.
Amplifiers with fans are also less particular about having lots of clearance around them (convection cooling is more needful of unobstructed air flow).
It so happens that, because of the way the thermostatic control in the A-300 works, the fans sometimes make a slight noise when they're not spinning. (We didn't really think the noise would be noticeable at all, but, since it does seem to bother a few people, we're looking into ways to minimize or eliminate it.)
In the mean time, if it really bothers you, then a different amp would probably be a better choice for you.
This is very sad. The sound and the price for it are excellent. But something is not properly designed. My amplifier A-300 is now under repair, waiting for an answer. While listening to another system. Going to buy Stealth PA-1.
|
|
|
Post by leonski on Mar 13, 2019 1:07:02 GMT -5
Keith makes a reasonable point but doesn't take it to the limit.
Stereophile tests amps at 1/3 rated power for I think an HOUR prior to power and other bench tests. The claim is that this is 'Worst Case' for an A/B amp. Some amps simply don't make it thru
this part of the tests either getting so hot they might emit a strange odor or simply shut down. A subjective call is made about how hot the amp is and if you can touch it or not...and for how long.
Some temp. measurements are provided, too, but I haven't looked at such reviews lately.
Here is a link to the Pass Labs XA200.8 which at nearly 160lb for a 200 watt rated mono bloc seems quite excessive. Until you realize that under NO circumstances will this nearly all Class 'A' amp
warm to dangerous levels. And at 42,000$ per pair, it darn well better be good stuff. A stereo pair SHIPS at OVER 350lb. OUCH!
But the point is heatsink to power / weight ratio.
And wile the tempreture might never get too high, I suspect the amount of HEAT kicked out would destroy my AirConditioning system in my house. But if you live in a cold climate? Welcome heat output.
My old and long-gone Carver Cube emitted a SLIGHT putt-putt noise from the PS Choke circuit. No problem. But other amps, none of which I've owned occassionally will buzz or hum, usually a transformer issue.
But as a rule? A power amp should be dead silent. My parasounds annoy with relays dropping out after the amp has been powered down for a couple minutes. But NO noise during use.
|
|
|
Post by seasoul on Mar 13, 2019 3:21:17 GMT -5
Some Class A/B amplifiers have great big heat sinks - and no fans... And some have little tiny heat sinks - and enormous fans that sound like a jet taking off... Most of our amps have no fans... but a few, including the A-300, have small fans that spin when the amp gets warm.
Likewise... Some cars go "grumble... grumble... grubble..." when they idle... And some go "whirrrr...." Electrics don't make any sound at all when they're sitting still (except for the ones that have fans)... And, with some hybrids, the engine cycles on and off when you sit at a traffic light...
And, yes, most of our bigger and more expensive amps have more heat sinks, and no fans. And, yes, fans are cheaper than huge heat sinks - and also lighter.
Amplifiers with fans are also less particular about having lots of clearance around them (convection cooling is more needful of unobstructed air flow).
It so happens that, because of the way the thermostatic control in the A-300 works, the fans sometimes make a slight noise when they're not spinning. (We didn't really think the noise would be noticeable at all, but, since it does seem to bother a few people, we're looking into ways to minimize or eliminate it.)
In the mean time, if it really bothers you, then a different amp would probably be a better choice for you.
This is very sad. The sound and the price for it are excellent. But something is not properly designed. My amplifier A-300 is now under repair, waiting for an answer. While listening to another system. Going to buy Stealth PA-1. 1. The amplifier is not a machine, it is not supposed to make noises. The noise from the A-300 is very noticeable, unfortunately. 2. Many people complain. In the Russian forums this is evident. 3. My amplifier A-300 made a noise after several hours of operation, but the fans never turned on. 4. It is a pity that people after acquaintance with the A-300 malfunction will gain distrust of the company Emotiva. 5. :–)) But everyone likes the sound of the A-300, and me too! Sorry, sorry, sorry.
|
|
KeithL
Administrator
Posts: 9,902
|
Post by KeithL on Mar 13, 2019 11:37:40 GMT -5
First off, I agree that some A-300's seem to make enough noise to annoy some folks, and that is unfortunate.
However, fans are rather common in all sorts of electronic gear; some amplifiers have fans, and some do not; and some fans are quieter than others. My XFinity X1 cable box has a fan, as do many amplifiers and receivers, some Blu-Ray players, most projectors, and most computers.
(And there are both benefits and drawbacks to fans).
The noise sometimes audible in the A-300 may occur while the fans are not spinning. The thermostatic controller applies more power as the temperature increases to make the fans spin faster. However, at low temperatures, even when the controller hasn't decided the fans need to spin, it may send the occasional power pulse to the fans as it "idles"... And, with some fans, these faint electronic pulsations may cause the motor itself to vibrate and make the faint noises you hear. And, yes, we are looking into ways to address this issue.
Some Class A/B amplifiers have great big heat sinks - and no fans... And some have little tiny heat sinks - and enormous fans that sound like a jet taking off... Most of our amps have no fans... but a few, including the A-300, have small fans that spin when the amp gets warm. Likewise... Some cars go "grumble... grumble... grubble..." when they idle... And some go "whirrrr...." Electrics don't make any sound at all when they're sitting still (except for the ones that have fans)... And, with some hybrids, the engine cycles on and off when you sit at a traffic light...
And, yes, most of our bigger and more expensive amps have more heat sinks, and no fans. And, yes, fans are cheaper than huge heat sinks - and also lighter.
Amplifiers with fans are also less particular about having lots of clearance around them (convection cooling is more needful of unobstructed air flow).
It so happens that, because of the way the thermostatic control in the A-300 works, the fans sometimes make a slight noise when they're not spinning. (We didn't really think the noise would be noticeable at all, but, since it does seem to bother a few people, we're looking into ways to minimize or eliminate it.)
In the mean time, if it really bothers you, then a different amp would probably be a better choice for you.
1. The amplifier is not a machine, it is not supposed to make noises. The noise from the A-300 is very noticeable, unfortunately. 2. Many people complain. In the Russian forums this is evident. 3. My amplifier A-300 made a noise after several hours of operation, but the fans never turned on. 4. It is a pity that people after acquaintance with the A-300 malfunction will gain distrust of the company Emotiva. 5. :–)) But everyone likes the sound of the A-300, and me too! Sorry, sorry, sorry.
|
|
|
Post by davidl81 on Mar 13, 2019 12:37:22 GMT -5
First off, I agree that some A-300's seem to make enough noise to annoy some folks, and that is unfortunate.
However, fans are rather common in all sorts of electronic gear; some amplifiers have fans, and some do not; and some fans are quieter than others. My XFinity X1 cable box has a fan, as do many amplifiers and receivers, some Blu-Ray players, most projectors, and most computers.
(And there are both benefits and drawbacks to fans).
The noise sometimes audible in the A-300 may occur while the fans are not spinning. The thermostatic controller applies more power as the temperature increases to make the fans spin faster. However, at low temperatures, even when the controller hasn't decided the fans need to spin, it may send the occasional power pulse to the fans as it "idles"... And, with some fans, these faint electronic pulsations may cause the motor itself to vibrate and make the faint noises you hear. And, yes, we are looking into ways to address this issue.
1. The amplifier is not a machine, it is not supposed to make noises. The noise from the A-300 is very noticeable, unfortunately. 2. Many people complain. In the Russian forums this is evident. 3. My amplifier A-300 made a noise after several hours of operation, but the fans never turned on. 4. It is a pity that people after acquaintance with the A-300 malfunction will gain distrust of the company Emotiva. 5. :–)) But everyone likes the sound of the A-300, and me too! Sorry, sorry, sorry. Keith, On the A-300 when it makes that noise it is not anywhere near a "faint" noise. It really does sound like the fans are just jammed and it is a fairly lound, high pitch sound. Much louder than even say a big fan for a tower computer that is trying to cool an overclocked processor. It really does sound like something broken inside when it happens. It has only happened once to me (amps turned on by cleaning lady when I was out of town for a few days), but if the problem occurred to me more often I would 100% send the unit in for repair.
|
|
KeithL
Administrator
Posts: 9,902
|
Post by KeithL on Mar 13, 2019 13:42:07 GMT -5
It is certainly possible that yo have a plain old defective fan... and, if so, then you should have it fixed. (Which is what the warranty is for.)
It should be easy enough to tell if one or both fans is actually jammed. If the fans spin when the amp gets really warm - then they aren't jammed. Specifically, both fans should spin at the same time..... so, if one spins, and the other one does not, then you probably have a jammed fan.
First off, I agree that some A-300's seem to make enough noise to annoy some folks, and that is unfortunate. However, fans are rather common in all sorts of electronic gear; some amplifiers have fans, and some do not; and some fans are quieter than others. My XFinity X1 cable box has a fan, as do many amplifiers and receivers, some Blu-Ray players, most projectors, and most computers.
(And there are both benefits and drawbacks to fans).
The noise sometimes audible in the A-300 may occur while the fans are not spinning. The thermostatic controller applies more power as the temperature increases to make the fans spin faster. However, at low temperatures, even when the controller hasn't decided the fans need to spin, it may send the occasional power pulse to the fans as it "idles"... And, with some fans, these faint electronic pulsations may cause the motor itself to vibrate and make the faint noises you hear. And, yes, we are looking into ways to address this issue.
Keith, On the A-300 when it makes that noise it is not anywhere near a "faint" noise. It really does sound like the fans are just jammed and it is a fairly lound, high pitch sound. Much louder than even say a big fan for a tower computer that is trying to cool an overclocked processor. It really does sound like something broken inside when it happens. It has only happened once to me (amps turned on by cleaning lady when I was out of town for a few days), but if the problem occurred to me more often I would 100% send the unit in for repair.
|
|
|
Post by leonski on Mar 13, 2019 15:03:50 GMT -5
Kieth, Funny you should mention your X-Finity cable box having a fan.....
My DirectTV box ALSO has a fan. I only note this since I heard it last nite for the first time when listening for it.
A very faint fan noise, and nearly impossible to find objectionable, but audible nonetheless. I dont' know that I'd have noted it
UNLESS looking (listening?) for it.
One minor 'heat note' is that in the case of Pass Labs amps? Reviewers have noted the amp doesn't sound 'right' until it reaches full operating temp.
This takes a half hour, sometimes longer and results in a noticeable quality improvement.
|
|
|
Post by Ex_Vintage on Mar 13, 2019 19:21:03 GMT -5
The noise you're hearing is not a problem... and the fans are not stuck.
The fans in the A-300 are thermostatically controlled.... so they start running slowly, when the amp reaches a certain temperature, and then go faster if it continues to get warmer. However, because of how the temperature control works, over a certain narrow temperature range, the fans may "start to think about spinning" before actually turning on. And sometimes, when they do, you may notice a very faint noise, or even an occasional twitch of the fan blades.
This doesn't happen very often, but when it does it is perfectly normal, and nothing to worry about.
Update, my A-300 did end up making this same noise. I was gone for a few days and I think my cleaning lady turned on the unit and I'm sure it stayed on for about three days. When I got home it was making that same sound. The unit was warm, but not hot. After it was off for a few hours I sound went away. I have not heard it since., The fan control without an appropriate level of hysteresis in the control circuit is a design deficiency. The quasi-state operation is obviously annoying to a large segment of customers.
|
|
|
Post by leonski on Mar 15, 2019 20:28:27 GMT -5
I understand Hystersiss, having worked with Hi Precision Temp Control for years, but 'Quasi-state' operation? Can you help me here? I THINK I understand but might actually not......
|
|
|
Post by Ex_Vintage on Mar 17, 2019 21:27:53 GMT -5
I understand Hystersiss, having worked with Hi Precision Temp Control for years, but 'Quasi-state' operation? Can you help me here? I THINK I understand but might actually not...... Lets say the fans are supposed to turn on at 40 degrees C., and they should turn off at say 35 deg. C. If the thermocouple is placed in a good spot (where the temperature does not change rapidly). Then the fans would turn on and stay on until the temp dropped 5 deg. C. IF the thermocouple is placed in an area where the temperature can change rapidly, then the on/off cycle would be relatively fast. The closer the turn on / turn off temperatures, the faster the fans would cycle on and off. If the on/off temperatures were at or near the same temperatures the fans would be in a quasi state where they didn't know if they should be on or off. Also if the power supply to the fans are the same as the power supply to the temperature sensing circuit, the turn on current draw of the fans could effect the voltage to the temperature sensor circuit. This would also cause this undecided or quasi state on/off operation.
|
|
|
Post by leonski on Mar 18, 2019 1:05:57 GMT -5
The way our stuff worked was somewhat different. And since it was for PRECISION temp control, it is probably overkill and not fully applicible for fans / heatsink duties where the requirement is not nearly as rigorous.
First? You have a plus and minus 'band'. Below band the power to the heater element was 100%. Above the band, maybe +8 degrees, is where it goes back to ZERO power.
The faster it approaches setpoint from the below temp, the faster power decreases. This minimizes OVERSHOOT of temp. When over the setpoint, the faster it drops TO the setupoint the more quickly it ramps up power....this prevents UNDERSHOOT.
When I setup a furnace, I tried to minimize the OVER the temp band to maybe 3 or 4 degrees......This ramped the power very quickly back down to zero as it exceeded setpoint.
Somewhere buried in all this math / control algorithms and PID stuff was some kind of 'learning' function. Furnaces would be 'PROFILED' after maintenance or replacement of the NIST traceable Thermocoouple. Each such thermocouple (all 3 zone)
came with a certificate of Calibration in which the output of the TC was related to the standard in Millivolts. So, you'd go to the computer and enter values at I think 5 temperatures so the TC would be 'on' standard over a wide range of temps, in whatever
range the machine was used in. Sometimes for the highest temps? It'd go to 1150C. That's OVER 2100F. A pizza would take 30 seconds and a Rare Steak about 5 seconds.
The Profile function filled in power tables which the program used in some fashion to help stability and control.
You simply do NOT need that complexity for a heatsink fan. I'd be VERY happy with a setup that raised fan speed as it approached than exceeded some setpoint. Maybe even add a way for it to read ROOM TEMP. Fan would ramp up more rapidly in a hot room.....80f or higher, maybe.
Fan should go to ZERO power at maybe 5F below setpoint.....give or take.
I don't like the idea of rapid on/off cycling. Fan should run slowly, perhaps, and slower as it exceeds setupoint.
|
|
|
Post by martindktm on Apr 6, 2019 15:55:56 GMT -5
Getting interested in the a-300... What I think is happening it's that it's not an on/off temp sensor but a variable voltage one. At lower heat temperature it does get some voltage thru to the fan but not enough for the fan to start turning. And the noise would come from there... Just my guess...
|
|
|
Post by leonski on Apr 6, 2019 23:22:29 GMT -5
A device called a thermister....might fill the requirements. A resistor which has resistance vary with tempreture.
|
|
KeithL
Administrator
Posts: 9,902
|
Post by KeithL on Apr 8, 2019 12:00:52 GMT -5
You've basically got the right idea.
Actually, the controller is digital, and sends out pulses at varying rates to control the speed of the fan. And, when the pulses go slowly enough, down almost to zero, the fan doesn't actually spin, but you can still hear the pulses because they make the motor twitch a tiny bit. (Some fans make an audible noise - while others may not - and different controllers start ramping up at slightly different temperatures.)
We are looking into a solution for future production models...
Getting interested in the a-300... What I think is happening it's that it's not an on/off temp sensor but a variable voltage one. At lower heat temperature it does get some voltage thru to the fan but not enough for the fan to start turning. And the noise would come from there... Just my guess...
|
|
|
Post by Ex_Vintage on Apr 9, 2019 20:35:00 GMT -5
So for a digital control you need a minimum pulse rate to "start" the fan. Hold off the digital output until the temperature is adequately above the "start" setpoint and then the fans will actually operate at a useful minimum speed.
|
|
KeithL
Administrator
Posts: 9,902
|
Post by KeithL on Apr 10, 2019 9:19:03 GMT -5
Yup.... and, if we'd noticed any noise on the prototypes, we'd have made sure to do it exactly that way. (And, in the future, we probably will.... )
So for a digital control you need a minimum pulse rate to "start" the fan. Hold off the digital output until the temperature is adequately above the "start" setpoint and then the fans will actually operate at a useful minimum speed.
|
|
|
Post by seasoul on Apr 16, 2019 10:33:46 GMT -5
Hooray! 1. I received my A-300 from repair. Changed the entire gain board. Now there is no noise. 2. I received my new Stealth PA-1. Compared the sound of the A-300 and PA-1. Amazing little ones! The sound is similar, but the PA-1 has a better, controlled bass, higher detail. Stealth PA-1 won. (Connection via XLR). A-300 now sell :–))
|
|
|
Post by gzubeck on Dec 2, 2019 13:21:33 GMT -5
I haven't had a problem since the beginning on my a300. Maybe I got a good one (fingers crossed). I wonder if something happened to the russian a300s in transit. Too much salt air etc. ;>)
|
|
|
Post by gus4emo on Dec 2, 2019 18:24:31 GMT -5
I also had the wonderful sounding A 300 in my house, but i gave them back to my german dealer because the fans were constantly working though the unit was only getting as warm as my hands. Even if i switched the unit on, the fans did work. It was so loud that i heared it at my listening place 3,5 meters away. The other thing was that the power supply of the amp was making a loud mechanical noise. My last point of critic was that the A 300 was stinking very much like a new car. However, the sound was from heaven. My Review is here about the A 300: www.boards-4you.de/wbb10/1426/thread.php?threadid=1370&sid=a3567245870d3a3473eff546611a717aAfter that i bought the A-150 - this amp has no fan and creates a warmer sound in comparison to the A 300. I personally prefer the A 150 for my kind of Music (in first line Heavy Metal, Prog Metal, Power Metal). my review and longtime experiences with pictures are here: www.boards-4you.de/wbb10/1426/thread.php?threadid=1456&sid=a3567245870d3a3473eff546611a717aMy question would be, why do new amps of Emotiva smell so bad for some days? It smells like lacque. However, i am full of enthusiasm about Emotiva products and do love them! I also bought the Airmotiv T 2 Speakers and the TA-100 Receiver. My review of T 2 is beginning here: www.boards-4you.de/wbb10/1426/thread.php?postid=37167#post37167And my longtime experience with TA 100 is beginning here: www.boards-4you.de/wbb10/1426/thread.php?threadid=1371&sid=a3567245870d3a3473eff546611a717aAwesome products - amazing! Next month - if my dealer here in Germany and longyeared friend Martin Dittmeier gets the DR product-line i surely will write a test in my Forum and perhaps buy them of course, too. Cheers from Werner The review of the A150, is there an English version?
|
|
|
Post by gus4emo on Dec 2, 2019 18:33:36 GMT -5
Yup.... and, if we'd noticed any noise on the prototypes, we'd have made sure to do it exactly that way. (And, in the future, we probably will.... )
So for a digital control you need a minimum pulse rate to "start" the fan. Hold off the digital output until the temperature is adequately above the "start" setpoint and then the fans will actually operate at a useful minimum speed. Hi Keith, sorry to take you away from this thread, I created one, called Amplifiers Just On, subject is about the XPA7 and the XPA200 being on for hours after being triggered on when zone 2 or 3 are turned on by the receiver, are they safe....I tried to get your attention, but I guess you missed it, I love the amps, just curious if they are not little by little being toasted...
|
|