Ready-to-Run (RTR) SSR DC Speaker Protection and Delay GB

[Vunce]

Hi Hugh,
We appreciate you sharing your sweet sounding designs with us and the forum. I’m not so adept at design, but love to build and listen 😀

Cheers,
Vunce

 

[gary s]

Hugh, I am with Vunce - your designs keep coming and seem to improve with age, you might have to slow down though as we can't keep up with your design enthusiasm for new hobbyist products.

Well done I say.

 

[gary s]

Hi X,

Can you confirm that for use of the 4 pole Molex connectors X105 and X115 for In and Out on the SSR pcb it has all 4 pins in use (so one can connect a wire to any of the 4 pins - or 2 off for higher current and more reliability).

 

[xrk971]

No, 2 wires are +ve and 2 are GND. The top 2 are GND and bottom 2 are +ve from amp on left and to the speaker on right side. Just look at the traces. They are paralleled for more current.

 

[gary s]

Thanks X, that answer is very clear as always from you.

 

[tcpip]

Just got mine. They travelled halfway around the world to Bombay.

This is a bundle of six modules. Till you hold it in your hand, you don't realize how small each is, and how much work went into kitting and packing.

Thanks so much, X.

 

[xrk971]

Hi Tcpip,
Thanks for the note to let us know it all got there in good shape. Thanks for your order - 6 is a lot to send to Bombay! I think the packaging worked out well then.
Let us know how they work out!
Cheers,
X

 

[tcpip]

Hi Tcpip,
Thanks for the note to let us know it all got there in good shape. Thanks for your order - 6 is a lot to send to Bombay! I think the packaging worked out well then.
Let us know how they work out!
Cheers,
X

I most certainly will (let you know). I'm currently slightly worried about electrostatic damage to the MOSFETs in storage, since I'll take a few months to put together the amps which will use these modules.

 

[xrk971]

Just put them in some aluminum foil wrap or an anti static bag if you are concerned. I haven’t had any problems with ESD (knock on wood).

 

[tcpip]

Just put them in some aluminum foil wrap or an anti static bag if you are concerned. I haven’t had any problems with ESD (knock on wood).

Aluminium foil seems perfect. Will do right away. [emoji106]

 

[xrk971]

I just finished installing a set of these SSR's on my new Alpha Nirvana amp. Using only a single spade connector for IN and OUT and a Molex KK with amp PSU (provided through matching Molex KK header built into the Anlpha Nirvana PCB for the SSR). Sot it was all very easy and quick work to have SSR speaker protection now in place. No more turn on thump!

See the 2pin Molex KK connector at the bottom right of the PCB?

 

[gwmorgan]

Hi I have some interest in these,I use Valeman boards at the moment which are OK but have relays in the speaker lines.The amps boards I use have separate earths for the front and back ends and join together with the speaker earth at the star point on the power supply.The Valeman is also earthed there can your board be connected in the same way
,also what is the resistance of the 2 FETs in the positive line?

 

[jhofland]

gwmorgan,
The FETs used are Nexperia BUK9Y15. The spec value RDSon is 12.1milliohms typical, 15 milliohms max so the incremental resistance through the FETs is less than 30 milliohms. Sensing for output DC offset is with respect to the amp out low side which would be the same as what you refer to as speaker earth. It should work just fine with your described arrangement.

 

[meanie]

Hi X,

One question, I am about to connect up this SSR board into my amp.
I will connect the supply to the 24V+ and Gnd of the SLB respectively.

Upon switching off, how fast can the SSR disconnect the speakers, when the SLB supply slowly decays away?

Thanks

 

[jhofland]

meanie,
The answer to your question depends on a number of uncontrolled variables. If there is an amplifier offset on power down and there is still power to the SSR circuit tripping will occur in a few milliseconds.There are a number of other scenarios during power down where it is less predictable.

 

[meanie]

Oh SSR so smart!

Thanks, jhofland.

That's more than a good answer than I need, knowing my speakers are well protected.

 

[xrk971]

The smarts in the SSR are all the result of jhofland’s super design. They do work incredibly well in all situations that I have encountered. Very unobtrusive and can be retrofitted to the tightest of spaces.

 

[gwmorgan]

gwmorgan,
The FETs used are Nexperia BUK9Y15. The spec value RDSon is 12.1milliohms typical, 15 milliohms max so the incremental resistance through the FETs is less than 30 milliohms. Sensing for output DC offset is with respect to the amp out low side which would be the same as what you refer to as speaker earth. It should work just fine with your described arrangement.

Ok thanks that's clear.

 

[JOIMONF]

I bought 2 of the last 10 units in the store. I don't wants damage my expensive field coil full range. I ordered years ago. Is hand made craftsman in Germany, I am afraid my chip amp is proud to pass DC, and has already damaged an speaker voice coil.
Also I have a project, a 6w. ACA amp. (Class A solid state), I don' t know If also this will require protection.

 

[xrk971]

Hi Joimonf,
A driver like that looks irreplaceable and SSR is perfect. You don’t need it for ACA as that is capacitor coupled output. Never passes DC unless that main output electrolytic fails.