Hello all, I am wondering what I can look at in order to trouble shoot this problem.
Currently my right hand Monoblock will often switch off when playing at loud levels, but when I power it back on it seems ok.
However, if playing at loud levels, and we get to a relatively loud and busy passage of music, both mono blocks will switch off.
My setup consists of:
BHK 300’s nearly 2 years old with minimal use until the last 3 months. (Power source is straight from wall)
PrimaLuna - EVO 400Pre amp
Ella Baby power cords (products)
Osbourne EPITOME Tower Speakers (https://www.osbornloudspeakers.com.au/epitome-towers)
Bi Wired Speaker cables Banana Plugs (Cant recall brand, Mogami perhaps)
More information regarding your system would be helpful in providing some advice on the matter. For instance what is the power source for the BHK 300 amplifiers, power cords used, speakers, and speaker cables. When one or both amplifiers shut down are they hot to the touch?
Edit:
Have you confirmed speaker cable terminations are tight, power cords are firmly seated, and interconnects are firmly seated.
apologies weedeewop, I will update my post with more information. Yes they are hot to the touch, but to be honest I thought they did run a little hot any ways.
All terminations are seated correctly and are firmly connected but I will double check again tonight.
Hi Elk, yes I think it does blink, but I will take more notice next time. I cant recall if the blinking was when I re turned it on, or it switched off completely ie no blinking, I think the later.
I guess its hard for me to say how loud, but I have played louder!
An important point are your speakers!!! What speakers do you have? I also have large, low impedance speakers. Minimum about 3 ohms Not every amplifier likes them and the overload protection responds. My solution to this were amplifiers that can deliver the appropriate power and without any problems up to 2 ohms. Otherwise, just listen quietly.
Mark:
While unfamiliar with your speakers looking at the specifications the BHK 300 monoblocks should have no problem driving the speakers to realistic levels. Summarizing the speakers are 91dB efficient and a 4 ohm load with a power rating of 0 WRMS minimum and 200 WRMS Maximum.
It is possible your power source is not up to the task for providing ample current with constant voltage to the BHKs. Many choose to run two dedicated 20 amp circuits directly to their stereo equipment, often upgrading the receptacles. Not owning PS Audio amplifiers, I’m guessing that the blinking PSA logo on the affected amp indicates thermal shutdown. Low input voltage is one possible cause. Otherwise I’d suggest contacting PS Audio technical support. Nice speakers BTW, reminds me of the early, 1990s, KEF Reference series. Osborne Epitome Tower
For technical support I suggest the following, and best to follow-up email communication with a phone call. A response may take several days.
From the BHK 250/300 owners manual:
If the front panel logo light begins blinking and no sound comes from the amplifier it means the BHK has gone into fault mode. This can happen for a number of reasons including: protection from low impedance, short circuit protection on the speaker terminals, exceeding the amplifier’s wattage rating, excessive heat, or DC present on the outputs. Typically you can just press the logo button and the amplifier will return to normal operation. If the amplifier tries to turn on and returns to protection mode, check all of the aforementioned causes and correct the problem before trying again. If nothing seems wrong, remove both inputs and outputs and try again. If that still does not release the unit from protection mode, remove all power from the amplifier and check the fuses. In the unlikely event none of these remedies work, call your dealer, or PS Audio, for help.
If loudspeakers can be specified with a standard impedance of 4 ohms, the actual impedance may deviate from this. Mine are also 4 ohms according to the standard. below 150 Hz they are at 3.1 ohms.
The speakers have quite good drivers from Seas and Scan Speak The basses most probably used have 6.2 ohms. Two connected in parallel 3.1 ohms. Depending on the bass choke and cable used, you have to add some resistance. I guess that the resistance in the bass should be below 3.5 to about 3.2 ohms, depending on the coil used in the crossover.
Here, too, the manufacturer could provide more precise data.
But the BHK 300 amplifiers should be able to handle it.
Phase angle comes into play, and a reactive load will enjoy current, high volumes exacerbating the condition. As you say the BHK 300s should be able to handle it based on the published information from the speaker manufacturer and PS Audio. As I recall the BHK 300 is capable of 300 WRMS @ 8 ohm, 600 WRMS @ 4ohms, and 1,000 WRMS @ 2 ohms, more than capable.
You need two dedicated 20 amp lines. It’s a relatively inexpensive job for a licensed electrician. This assumes you live in a house that you can access the breaker box, not an apartment. Also not sure what power cords you use …
Is this issue new? Have these amps performed properly until now? Has anything in the chain changed?
I can’t imagine an amp, especially one the size of BHK 300s self protecting at any listening level that humans can stand. There must be something wrong somewhere.
I would check off every instance that is suggested in the owners’ manual under “self protection”.