I get a pretty noticeable click from the speaker relays engaging on my speakers. When I initially tested these amp modules they were long settled to a couple millivolt DC offset before the relay engaged. Solid state relays are likely the only cure for this. That's probably the next evolution I'm going to look into for the board.
Jeff, do you mean mechanical click from the relays? Or "electric" one from the speakers? My build of CFA-CFPx2 settles to couple of millivolts DC in about a second.
I mean a click through the speakers. On the bench I measured a couple millivolts long before the relays cut in. These speakers are very sensitive.
A very good question, Rens
(although you're not the first asking it )...A couple of big enough gold-plated contacts don't add any noticeable distortion - I tested it, I measured it - I know it.
But, somehow - I'm an ancient dinosaur
- I never tried the MOSFET relays. However, I'd like to. So, this is the next thing to try and measure
I agree - fan control is a cool idea, but in this case it's better to have analog reading from the sensors. At the currrent board design it's possible to use an unused channel to switch the fan on and off according to certain conditions, otherwise it requires pretty much of a redesign...
A very good question, Rens
A couple of big enough gold-plated contacts don't add any noticeable distortion - I tested it, I measured it - I know it.
But, somehow - I'm an ancient dinosaur
I've been looking at some of Elliot's designs for Mosfet relays. They don't look too terrible to work with. I've never even considered SS relays in the past because of resistance when closed and off state never really being off but these issues seem to have resolved long ago.
