I have a SPA1000 plate amp that my customer didn’t like because it would annoyingly click on and off to classical music. I tried it out and it is super annoying!
Does anyone know how to either bypass the auto on/off or remove it?
Thanks!
Does anyone know how to either bypass the auto on/off or remove it?
Thanks!
Disconnect the input sensing circuit from the audio signal circuit, and feed it with a 60/120Hz power frequency of a suitable level.
Many of the solutions on the internets say to increase the input level but I don’t see how that would help if there isn’t any information below 200hz where the amp works.
I’m thinking there is a ‘timing‘ capacitor somewhere. If I could identify that then I could replace it with a bigger one.
I’m thinking there is a ‘timing‘ capacitor somewhere. If I could identify that then I could replace it with a bigger one.
Without a schematic, and if you don't feel like reverse engineering it, perhaps consider building an ultra-low frequency oscillator, 15Hz for example. Gate it with a timer, and mix in with the audio input signal, for one second every 10 minutes. This will keep the amp awake. adjust the level of the mixing so that it's just enough to keep the amp on.... Of course, this one is easier said than done too...😉
I sure can. My wife has me scheduled for digging up the garden, so maybe later today or tomorrow. Thanks!
OK. Here are some pictures. Let me know if you would like me to disassemble it further. The pre-amp board is pretty clear, the power amp board is covered by the wires and transformer. One tiny board stands out from the power amp board and looks like a thermal shutdown, it’s connected to the heat sink. Thanks again for any help!
Attachments
On the photo #2, check the circuit around Q1, it looks like the auto sensing circuit quite simular to ESP project #38.
Thank you so much! Is IS01 an optocoupler Instead of a relay? Interesting.
J5 connects to the power amp board so this makes a lot of sense.
I’m reading up on Project #38, sounds so scary! 😱 Like in Stranger Things. I’m hoping I can solve my problem simply by increasing a resistor. If not, maybe I can bypass all that mess. I might put the switch on the front of my subwoofer, what a concept!
project #38: https://sound-au.com/project38.htm
J5 connects to the power amp board so this makes a lot of sense.
I’m reading up on Project #38, sounds so scary! 😱 Like in Stranger Things. I’m hoping I can solve my problem simply by increasing a resistor. If not, maybe I can bypass all that mess. I might put the switch on the front of my subwoofer, what a concept!
project #38: https://sound-au.com/project38.htm