Hi!
I'm a new forum user. I signed up to ask for advice on the construction of my amplifier.
I got a Sure AA-AB31314 amp board and a Mean Well RSP-500-48 PSU.
In order to protect my speakers I want to create a circuit to avoid spikes during turn off/on (I don't want to modify the amp because of warranty).
I found timed relays to decouple the speakers during power up but ... the idea of passing the amplified signal inside a relay does not excite me at all.
So, I thought of an alternative circuit, but since I'm not too expert in electronics, I need a help...
I am thinking of connecting the positive pole that goes to each speaker to ground, through a relay that is closed during the power on and the power off (without music playing) and open with music playing (in this way the power signal does not pass through the relay).
Leaving aside the way in which I control it (which is not a problem with an Arduino type controller) I would like to know if this circuit can actually avoid overvoltage peaks to the speakers, or if it's idiocy ... 😛
I thank in advance anyone who wants to help me.
I'm a new forum user. I signed up to ask for advice on the construction of my amplifier.
I got a Sure AA-AB31314 amp board and a Mean Well RSP-500-48 PSU.
In order to protect my speakers I want to create a circuit to avoid spikes during turn off/on (I don't want to modify the amp because of warranty).
I found timed relays to decouple the speakers during power up but ... the idea of passing the amplified signal inside a relay does not excite me at all.
So, I thought of an alternative circuit, but since I'm not too expert in electronics, I need a help...
I am thinking of connecting the positive pole that goes to each speaker to ground, through a relay that is closed during the power on and the power off (without music playing) and open with music playing (in this way the power signal does not pass through the relay).
Leaving aside the way in which I control it (which is not a problem with an Arduino type controller) I would like to know if this circuit can actually avoid overvoltage peaks to the speakers, or if it's idiocy ... 😛
I thank in advance anyone who wants to help me.
You don't ever want to short your amplifier's output.
This can be done in line level sources (usually through a series resistor),
but few power amplifiers are ok with a direct short on their output.
This can be done in line level sources (usually through a series resistor),
but few power amplifiers are ok with a direct short on their output.
You don't want to connect either pole of either speaker output to ground. Since it's a single-supply system, the two outputs are two bridged pairs of amplifiers, so they idle at half-supply. What you're suggesting is... not recommended, let's just say.
Ok, I understand...
So, is there a way to avoid spikes on speakers with discrete circuit, without to alter the audio signal?
So, is there a way to avoid spikes on speakers with discrete circuit, without to alter the audio signal?
Tom Christiansen has a couple of such devices in his product catalog - check out the Guardian686, if for nothing else but an explanation as to why he does it this particular way.
Guardian-686: High-End Speaker Protection Circuit for DIY Amplifiers – Neurochrome
Guardian-686: High-End Speaker Protection Circuit for DIY Amplifiers – Neurochrome
Thank you for your suggestion.
I have looked at the product, but honestly a mosfet circuit convinces me much less than a relay. My electronics knowledge is limited, however a relay should be a resistive load, therefore it only introduces attenuation and not distortion, unlike an inductive circuit like that of the link. But I could easily be wrong...
In my case, with a BTL configuration in idle (no audio reproduction) the relay positioned on one pole of the two going to the speaker (hot/cold), should not be minimally stressed during switch, because there should be no difference in potential.
With audio being played it may be different. I calculated that the peak current is around 6 amps in my case. An Omron G2R-1 relay withstands up to 10A, so it shouldn't be a problem if it sometimes switch in this condition. Moreover, I would use the version with gold-plated contacts, that has max 100 mOhm of resistance...
I repeat, maybe I'm wrong, but the latter solution seems better to me than the mosfet.
But the idea of inserting a power relay (the signal ones cannot withstand currents over 2A) is still something that disturbs from the audiophile point of view....... 😛
I did a quick search on eBay for "speaker protection BTL" and it gave me more than a two dozen options (about half look like good options). Most are relay based.
I always test eBay purchases before relying on them to protect my speakers, but a fairly simple circuit to implement.
If you are worried about a MOSFET based protection - keep in mind every amplifier is made up of transistors, so they can't be too bad - just need to be implemented correctly with the proper parts. the Neurochrome products are well developed and tested vigorously before distribution. It will suit your purpose for sure.
I always test eBay purchases before relying on them to protect my speakers, but a fairly simple circuit to implement.
If you are worried about a MOSFET based protection - keep in mind every amplifier is made up of transistors, so they can't be too bad - just need to be implemented correctly with the proper parts. the Neurochrome products are well developed and tested vigorously before distribution. It will suit your purpose for sure.