My belated condolences. Your dad was obviously a talented and imaginative craftsman as his legacy clearly demonstrates.
Blame for the thread hijack is mine. Thanks to all for your indulgence and now back to your regularly-scheduled programming.
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Double Bass Acoustic Image Focus heat issues???
- Thread starter james condino
- Start date
Blame for the thread hijack is mine. Thanks to all for your indulgence and now back to your regularly-scheduled programming.
Very cool care derail! I wanna drive that to the next gig!
'Gotta agree with that. There are a HUGE amount of ACME haters around here, many who have never even used them. I went through close to 20 different cabs from all of the contemporary builders and kept going back the the ACME B1s for what I'm looking for soundwise. A single doesn't do much, but a pair is quite a treat. Two small 10" cabinets conservatively rated at 175 watts each are not going to shut down an 800 watt amp because some people percieve them as inefficient. I've used the same amp with a pair of B2s (2x10s each) and with ACME flatwounds, both much more power hungry, and run three of them combined with no issues in the past (the sound was tremendous!). These are new ACMEs that have the internal gadget that is supposed to blow before anything else, not the old motorcycle fuses, and I've never blown a fuse in the amp.
Thanks for all the perspectives. The scenario happened when I started out in the shade and then as the day progressed the sunshine moved over us; hard to fight for space on a small stage. Still- it was barely 70, not a 105+ degree summer day. I talked with the folks at AI today and I'll likely send it back for a checkup sometime soon; great folks and local.
During the event, when it went out, I did what I could and then thought to myself, "What would Ed F do? He would call me a sissy for even bringing an amp and he'd pull so hard on the strings that nobody would even notice...." So that's what I did....thanks Ed!
'Gotta agree with that. There are a HUGE amount of ACME haters around here, many who have never even used them. I went through close to 20 different cabs from all of the contemporary builders and kept going back the the ACME B1s for what I'm looking for soundwise. A single doesn't do much, but a pair is quite a treat. Two small 10" cabinets conservatively rated at 175 watts each are not going to shut down an 800 watt amp because some people percieve them as inefficient. I've used the same amp with a pair of B2s (2x10s each) and with ACME flatwounds, both much more power hungry, and run three of them combined with no issues in the past (the sound was tremendous!). These are new ACMEs that have the internal gadget that is supposed to blow before anything else, not the old motorcycle fuses, and I've never blown a fuse in the amp.
Thanks for all the perspectives. The scenario happened when I started out in the shade and then as the day progressed the sunshine moved over us; hard to fight for space on a small stage. Still- it was barely 70, not a 105+ degree summer day. I talked with the folks at AI today and I'll likely send it back for a checkup sometime soon; great folks and local.
During the event, when it went out, I did what I could and then thought to myself, "What would Ed F do? He would call me a sissy for even bringing an amp and he'd pull so hard on the strings that nobody would even notice...." So that's what I did....thanks Ed!
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another little trick--put the amp on its side. takes up less space that way, and easier to find shade for it too.
Dude, you're WAAAY off: You need at least 10,000 watts for an 8-Ohm Acme. 50,000 for a 4-Ohm. ;-)
It will be good to send the amp back to AI, to make sure that the amp is working nominally. That will take the amp off of the "what if" list. Rick (the owner) absolutely stands by his products.
In regards to the shutdown, +1 for Mark Gollihur's input; the sunlight on the case puts the amplifier in a "non-ambient" environment compared to say a room at an average of 73 degF. Even if the outside temperature is 70 degF, the black metal case will be much warmer than the surrounding air. Think of the temperature of a metal car body in the sun on a moderate day. Heating the case and the surrounding air will slow the convection flow of heat away from the transistors-->case-->air; allowing the thermal sense circuitry to sense an abnormal rise in temp. IF there's a fault in the protection circuitry, it may cause a trip into to protect mode earlier than intended.
Anyway, good luck with your situation.
In regards to the shutdown, +1 for Mark Gollihur's input; the sunlight on the case puts the amplifier in a "non-ambient" environment compared to say a room at an average of 73 degF. Even if the outside temperature is 70 degF, the black metal case will be much warmer than the surrounding air. Think of the temperature of a metal car body in the sun on a moderate day. Heating the case and the surrounding air will slow the convection flow of heat away from the transistors-->case-->air; allowing the thermal sense circuitry to sense an abnormal rise in temp. IF there's a fault in the protection circuitry, it may cause a trip into to protect mode earlier than intended.
Anyway, good luck with your situation.
LOL!
The first favorable reviews I read of the Acme B1 were based around using a 1000 watt Walter Woods head with single cabinet. It was Bass Frontiers mag I think. Must of been 15 years ago..it was an exotic concept then, and still is. It would be interesting to know what the guy at AI has to say about using cabinets like the Acme for situations like the one James was in. Outdoor gigs can really be the acid test for the true reliability of a custom rig.Interesting. I wonder how much would eq play into the amp failure. Would pushing the available low and or low mid eq (after any hp filtering) suck more power or cause the load to drift below 2ohms? Playing outdoors can have a whole different set of volume perimeters too..whats shouting loud indoors can be quite tame outdoors, depending. Plus James mentioned there were lots of pretty girls in summer dresses..that might push the volume knob up even another notch, even two
"I wonder how much would eq play into the amp failure. Would pushing the available low and or low mid eq (after any hp filtering) suck more power or cause the load to drift below 2ohms?"
Using a lot of eq will cause the amp to push more power to the frequencies boosted, causing more heat to be generated in the amp and the speaker. In regards more power affecting speaker impedance, more power applied generates more heat in the speaker coil, raising the resistance and with it the impedance.
Using a lot of eq will cause the amp to push more power to the frequencies boosted, causing more heat to be generated in the amp and the speaker. In regards more power affecting speaker impedance, more power applied generates more heat in the speaker coil, raising the resistance and with it the impedance.
One could easily apply more power than is rated from the power amp. Amplifier power is specified at a specific distortion level. The amplifier is capable of delivering more power if a higher distortion level is used as a qualifier. Sometimes it's difficult to tell how much power at what distortion level is being delivered. Outdoors, lots low frequency eq, low efficiency cabinet....etc. Our ears are tolerant to higher levels of distortion than one would think.
Beaucoup power being delivered, plus the sun restricting the cooling could easily push the amp to "I'm turning myself off, now.." mode.
That's why I suggested that the amp be serviced by AI to either eliminate it from being a suspect of the problem, or fix what ails it. The amp is not new, and all things age.
Beaucoup power being delivered, plus the sun restricting the cooling could easily push the amp to "I'm turning myself off, now.." mode.
That's why I suggested that the amp be serviced by AI to either eliminate it from being a suspect of the problem, or fix what ails it. The amp is not new, and all things age.
For reference, I've talked with Andy at ACME, and he uses Acoustic Image heads with his cabs and I've talked with the folks at Acoustic Image and they have a set of B1s; those two know how to play well with each other. I've also used the same cabs with one a Thunderfunk head and it sounded amazing, but it is a lot larger to haul around. I'll be playing the same venue Saturday, so the pretty girls in summer dresses is a whole different conversation....!
LOL!
Interesting. I wonder how much would eq play into the amp failure. Would pushing the available low and or low mid eq (after any hp filtering) suck more power or cause the load to drift below 2ohms? Playing outdoors can have a whole different set of volume perimeters too..whats shouting loud indoors can be quite tame outdoors, depending. Plus James mentioned there were lots of pretty girls in summer dresses..that might push the volume knob up even another notch, even two
Classic example of over-thinking. Except for the girls in summer dresses.
...the way of solving problems is to under think ?
How do you measure that on an emeter? Hope James' amp is fixed soon.Hmmm... good point....the way of solving problems is to under think ?
Just what problem, exactly, are you trying to solve?
I doo not think considering low efficiency loudspeakers, heat and outdoor playing conditions is nescessarily overthinking, just my 2c.
Like most class D heads (I say "most" but I could say "virtually any"), the AI heads are not designed to run hot, and on normal operation will only ever get slightly warm. Since they, unlike other class D heads (tone hammer, tc heads, markbass), don't have any active cooling (like, a fan), they have to shut off as soon as a certain threshold temperature is reached. If you reach that temperature because of a fault in the unit, or because of sunlight exposure, or because you prefer to warm up your sound by putting the amp in an oven before playing, does not matter to the protection circuit . My 2 cents: Be happy the amp shut off and assume this is a sign of perfect health and, unless this happens again with normal ambient temperature, there is no need to get the amp serviced or checked.
best
sidecar
best
sidecar
So, why shouldn't he have it checked to make sure it isn't the first thing you mentioned? By his post and comments, I don't think he has the equipment or knowledge to discern the differences to that and the other scenarios you mentioned. That's not a problem, but he can choose to eliminate the amp as the cause of failure vs. it just acting normally.
Rich,
these quotes, together with a reasonable amount of positive thinking and a fair amount of experience with and knowledge about class D amplifiers, lead me to the conclusion that there in fact is nothing wrong with the amplifier, until a failure under normal conditions proves the opposite.
I don't remember the AI manual, but I could imagine that operation under direct sunlight in fact is mentioned as "to be avoided".
Of course, the OP can send the amp in, but I say it's likely to be just fine.
best
sidecar
You're right in regards to your circumstances of knowledge and experience; and with my own, I would come to a similar conclusion to yours and not worry about it. However, the OP apparently doesn't have the same perspective, hence the recommendation.
btw, AI doesn't mention the thermal protection cutoff feature in the manuals that I looked at, or warnings about not operating it out in the sun.
Note: I have worked as a service technician on musical instrument amplifiers, pro audio, recording studio equipment...
I would also add, that other people's failure mode experience with a particular amplifier doesn't mean that it'll be the same for everyone. I'll be the first to admit that I would have to see and check out the amplifier under load to come to a definite conclusion about a specific amplifier's behavior.
I own a Focus 1. Great amp.
btw, AI doesn't mention the thermal protection cutoff feature in the manuals that I looked at, or warnings about not operating it out in the sun.
Note: I have worked as a service technician on musical instrument amplifiers, pro audio, recording studio equipment...
I would also add, that other people's failure mode experience with a particular amplifier doesn't mean that it'll be the same for everyone. I'll be the first to admit that I would have to see and check out the amplifier under load to come to a definite conclusion about a specific amplifier's behavior.
I own a Focus 1. Great amp.
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FYI.
I remembered asking Rick in 2010 about driving a 2 ohm load with the Focus, as it was first rated at 4 ohms, while the Clarus models were rated at 2 ohms.
from the manual:
Power Amp (all models)
Topology Class D (PWM)
Switching Frequency 280 kHz, 200 kHz for Focus models
Output Power >200 W @ 4Ω, >300 W @ 2Ω (Clarus)
>250 W @ 4Ω, >350 W @ 2Ω (Clarus SL)
>350 W @ 8Ω, >600 W @ 4Ω (Focus)
Minimum Load 2Ω(Clarus and SL), 4Ω(Focus)
Output Connectors Neutrik Speakon type (pole 1)
This is what he said in our email exchange:
"After the manual was printed, we found that the amp could drive a 2
ohm load. The best thing to do is to try it before the gig. If there
is a problem (ie, the load is too low), the amp will shut off to
protect itself. If you can drive the 2 ohm system hard without any
problems, then you are ok."
I remembered asking Rick in 2010 about driving a 2 ohm load with the Focus, as it was first rated at 4 ohms, while the Clarus models were rated at 2 ohms.
from the manual:
Power Amp (all models)
Topology Class D (PWM)
Switching Frequency 280 kHz, 200 kHz for Focus models
Output Power >200 W @ 4Ω, >300 W @ 2Ω (Clarus)
>250 W @ 4Ω, >350 W @ 2Ω (Clarus SL)
>350 W @ 8Ω, >600 W @ 4Ω (Focus)
Minimum Load 2Ω(Clarus and SL), 4Ω(Focus)
Output Connectors Neutrik Speakon type (pole 1)
This is what he said in our email exchange:
"After the manual was printed, we found that the amp could drive a 2
ohm load. The best thing to do is to try it before the gig. If there
is a problem (ie, the load is too low), the amp will shut off to
protect itself. If you can drive the 2 ohm system hard without any
problems, then you are ok."
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