There’s GB number 5 GB going on now. Need 30 commitments. Maybe a month after we settle how many people want them.
Regarding trying to drop the threshold, it's really dictated by the voltage drop across the input diodes of the optoisolator. It won't trip unless the offset exceeds what's across this input. Off the top of my head I don't recall what that minimum is. I do know that it is greater than 1V. Trying to modify this circuit for input offsets less than that just plain doesn't work.I have a SSR headphone protection circuit made just for headphones. It’s pretty easy to assemble if you can do basic SMT parts.
https://www.etsy.com/listing/971912371/ssr-headphone-protection-pcbs?click_key=01201391821312372668eff65fb7242f997d9a97:971912371&click_sum=159bf2c4&ref=shop_home_active_12
For the speaker SSR threshold level to be set to a lower value - will require some calculations. Let me ask Jhofland if he has suggested values. What would you like the threshold to be? 1.5v should not destroy a headphone. You might want to keep it to allow deep transient bass kick drums.
The threshold is controlled by an RC circuit R102 and C102. When DC charges this up there is a time constant and this powers an LED in an optoisolator. The output of the optoisolator feeds a comparator. R104 is a 200k resistor that sets the trip point of the comparator. One could make this value larger to force the reference voltage divider to a lower value. Something like 200k to 300k might make it trip at a lower voltage. Depends on where you want it. Changing R102 to a smaller value will let the RC charge up faster for a quicker response.
View attachment 1092733
Great, where can I sign up? I only found old interest lists.There’s GB number 5 GB going on now. Need 30 commitments. Maybe a month after we settle how many people want them.
Cheers, I added myself to the list!
Doesn’t need to be regulated as the SSR has a regulator. But the voltage needs to be 18v or higher.
What kind of terminals were to be used for X105 and X106 as they are left empty now. Something from Digi-Key maybe 🤔 Thank you kindly.
BTW What's the difference between DC Protection on your picture and the one I purchased from you RTR SSR Speaker Protection.
Picture is Gen 1. Yours is the latest Gen 2.3 which has several improvements.
1. Isolated GND on power supply input so that it can be used on bridged amps with floating outputs.
2. Added external logic control to allow remote mute/graceful startup and shutdown with an open collector logic from an MCU.
3. Higher voltage MOSFETs so can handle amps up to 300w.
4. Comes with bonus blank PSU PCB to allow connection to secondary trafo windings to make a low capacitance PSU to provide instant off when power to trafo is cut. This prevents turn off thump.
But speaker and amp connectors are still the same.
1. Isolated GND on power supply input so that it can be used on bridged amps with floating outputs.
2. Added external logic control to allow remote mute/graceful startup and shutdown with an open collector logic from an MCU.
3. Higher voltage MOSFETs so can handle amps up to 300w.
4. Comes with bonus blank PSU PCB to allow connection to secondary trafo windings to make a low capacitance PSU to provide instant off when power to trafo is cut. This prevents turn off thump.
But speaker and amp connectors are still the same.
Again Thank you kindly. Any simple drawing on how to connect this bonus PSU PCB concretely with transformer and SSR
So sorry for too many questions, 🙂
So sorry for too many questions, 🙂
Kokanee summarizes it here - schematics below. Basically load two of the diodes (D3, D4) of the trafo secondary is the same as your main amp rails. Load 10uF to 22uF cap, optional LED and resistor (size for 2mA using R=V/I).
https://www.diyaudio.com/community/...r-protection-and-delay-gb.340694/post-7030406
Connect one of the outputs to the PSU input pin X103. Taking care to observe correct polarity.
https://www.diyaudio.com/community/...r-protection-and-delay-gb.340694/post-7030406
Connect one of the outputs to the PSU input pin X103. Taking care to observe correct polarity.
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I am trying to use parts I have for the low-capacitance psu.
My transformer secondary is 15 V AC , this gives 21 DC, right?
Caps I have at hand are:
4.7 uF 50 V
10 uF 25 V
47 uF 35 V
Is any of these 3 good?
In case I don't need a led and resistor- just put jumpers instead?
Thanks
My transformer secondary is 15 V AC , this gives 21 DC, right?
Caps I have at hand are:
4.7 uF 50 V
10 uF 25 V
47 uF 35 V
Is any of these 3 good?
In case I don't need a led and resistor- just put jumpers instead?
Thanks
10uF should be fine. If no LED needed do not put a jumper as that will short it. Just don’t populate but wouldn’t hurt to put a resistor only and jumper the LED to help bleed down cap faster. 4k7 or so should be fine. It’s nice to have LED to know when it’s powered up though.
Balanced as well I guess, as those outputs are floating as well?Picture is Gen 1. Yours is the latest Gen 2.3 which has several improvements.
1. Isolated GND on power supply input so that it can be used on bridged amps with floating outputs.
For a balanced mono block, one side only of the circuit can be used?
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