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

[andyr]

Hi X
Some say patience is a virtue.
My two boards arrived safely in Spain after being on the road since 17th March.
Maybe the world is opening up a bit again.
They look good. Thank you.
rebone

Wow - that's a loooong wait!

As X said - they certainly do mean the amp doesn't have a thump on turn on or off.

Andy

 

[xrk971]

There is a 2-3 second turn on delay that should help to avoid turn on thump. If you need a longer delay, one of the RC time constant components (R108 or C108) can be made larger. Generally, the resistor is the easier one to change. Presently, R108 is at 100k.

 

[Vunce]

I successfully received another pair of SSR DC protection boards, thanks X! Their small form factor and simple install makes them a must for all my amp projects. They actually help me get more progress done on the “big stuff” because they are already built

 

[Bones13]

I bought 2 boards, one for each mono block. I finished offset correction, and finally put the SSR DC boards into the circuit, putting both the hot and ground through the circuit. This has introduced a soft thump at power off. (M2x + 97db speakers). My offset was 0-0.5mv last check.

If I isolate the ground directly to the PSU board ground terminal, will the thump go away? I don’t have hum, so I had not moved the output ground yet.

 

[xrk971]

I don’t think changing the ground will make turn off thump go away. What is your PSU? I don’t recall others using the SSR with M2X having turn off thump - it may be your 97dB speakers. Only way is to have a PSU Or soft start board that sends out a logic signal shut down the SSR upon power off.

This will be in gen 2 of SSR combined with gen 2 of SFP board.

 

[Bones13]

Current bog standard DIYStore board with default values. One consideration for later upgrade will be your PSU boards. I think I have some 22v power transformers. But that will be another day.

I did not have the turn off thump without the SSR. I don’t have a turn on thump(now or then), but I don’t think that’s a problem with the big cap on the M2x board.

 

[xrk971]

Now that is strange because the SSR only acts as a wire when it is on, it doesn’t generate any voltage or current. So any thump you get is from the M2X. It might be that it cuts off the normally slow decay of the M2X output abruptly when it switches off and that is the mild thump you hear (sound of higher DC to zero).

 

[stretchneck]

Great job xrk - many thanks. Finally my amplifier is complete! Safe to say this was the easiest part of the project. Bit of a learning curve for me as I’ve never built an amplifier before.

 

[xrk971]

Nice work Stretch! What amp is that? Looks very compact and very high power. Make sure you put some insulator tape on back wide of the RTR SSR board if not mounted on standoffs.

 

[pinnocchio]

Looks like the FirstOne Large

 

[xrk971]

What are the rail voltages on that amp? That SMPS looks massive.

 

[pinnocchio]

Voltage rails should be around +/-65Vdc. Many have assembled this amplifier with dual Hypex SMPS1200A400 but I believe he's using a single Hypex SMPS3KA400.

Do

 

[stretchneck]

Nice work Stretch! What amp is that? Looks very compact and very high power. Make sure you put some insulator tape on back wide of the RTR SSR board if not mounted on standoffs.

Yep FirstOne Large amplifier with additional cap banks and 3KA400 power supply. The speaker wire is solid OCC copper, so the xrk SSR speaker protection modules are held very tightly floating in free air.

 

[J.M.K]

Hi!

I just ordered a couple of boards this morning on your website, and I have a
question, sorry if it's already been answered in this thread.
What is the power consumption of the protection board when it's ON - whilst listening to music ?
Does it create some kind of unbalance between V+ and V- on the amplifier/psu rail?
My amplifiers are FirstOne 1.4M and V4H boards, and Cresnet smps....
Thanks à lot

JM

 

[xrk971]

It uses about 20mA while on. You won’t know it is using any power.

 

[J.M.K]

Great, but I think I also have 24V unregulated DC free connectors that could be used.
JM

 

[xrk971]

Anthing above 18v should work.

 

[J.M.K]

I already have protection boards with mechanical Omron relays, drawing 10 time more power from their dedicated transformers.
I'm going to save some power from my nuclear plant ..... lighten my amplifier case, and maybe have my room a bit cooler next summer ....
JM

 

[pinnocchio]

Hi X,

I have two of these boards and I would like them to cut off when the amp power rails drops below 30Vdc. Is that possible? If I wait for the rails of the PSU to drain, the speaker protection cuts off with a thump noise but I'm thinking I could have it cut close to 30-35Vdc?

Thanks
Do

 

[xrk971]

This is being worked for gen 2 and needs to be used in conjunction with a soft start SSR that sends a shutdown signal to the speaker protect SSR. I have asked Jhofland if there is a way to retrofit this feature but not simple. One possibility is a separate circuit controlled by an MCU that detects a drop in the rail and then a relay to pull down the opto gate.