Thanks for that, @Mooly - I got a bit confused by the BOM, as it says "for 12VAC supply" under notes near the 5V relay option. I did think it was off as it would be well over 10VDC rectified, but assumed there was something at play beyond my understanding. Turns out this is a rare instance of me actually being on the right track. So, thanks again for the clarification.
I don't actually have a transformer as yet (or even the board), as I'm in the preliminary 'can I get the parts and understand this' stage. Ideally I'd like to build a HoneyBadger, but I have a lot of reading and researching yet to get to that point! I'll look for a 9VAC toroid. Did you have a recommendation on VA for the transformer? Looks like almost anything would do?
I don't actually have a transformer as yet (or even the board), as I'm in the preliminary 'can I get the parts and understand this' stage. Ideally I'd like to build a HoneyBadger, but I have a lot of reading and researching yet to get to that point! I'll look for a 9VAC toroid. Did you have a recommendation on VA for the transformer? Looks like almost anything would do?
Thanks again. I'm a dingus - I was thinking about the primaries being in series (for 230VAC mains) and somehow thought that had anything to do with current on the secondaries.
I will take a look at el core and other transformers, too. I know people tend to prefer toroids for big transformers, wasn't sure if the same justifications applied for small ones.
I will take a look at el core and other transformers, too. I know people tend to prefer toroids for big transformers, wasn't sure if the same justifications applied for small ones.
Assuming two 115V AC primaries would be connected in series for 230 volt mains. The secondaries you can do as you wish, in parallel for double current or in series to double the voltage (current stays the same as each single winding). The phasing of the windings has to be correct in all cases.
Noted, thank you. That was makes sense (with my morning coffee).
Seems like most of the transformers I can access in the appropriate voltage and VA are PCB mount.
For example, this would do nicely:
https://www.altronics.com.au/p/m4318-powertran-9-9v-pcb-10va-toroidal-transformer/
I know I can get the little breakout PCBs for these from the usual iffy websites, but if anyone knows where I can get the nicer, fused kind (PCB or Gerber), I'd be most appreciative. Kind of like this kit, but scaled down for the 10VA dimensions:
https://www.jlmaudio.com/shop/world-transformer-kit.html?display_tax_prices=1
Seems like most of the transformers I can access in the appropriate voltage and VA are PCB mount.
For example, this would do nicely:
https://www.altronics.com.au/p/m4318-powertran-9-9v-pcb-10va-toroidal-transformer/
I know I can get the little breakout PCBs for these from the usual iffy websites, but if anyone knows where I can get the nicer, fused kind (PCB or Gerber), I'd be most appreciative. Kind of like this kit, but scaled down for the 10VA dimensions:
https://www.jlmaudio.com/shop/world-transformer-kit.html?display_tax_prices=1
I hear you. Honestly I'd be happy with that solution, too. That would probably rule out the HoneyBadger without a bit of rejigging then, as that seems to want something north of 40V for the supply. The reconfiguration you mention is a bit outside of my skillset right now. Might work with the new F5M with an 18v supply if I find suitable 12V relays.
I was reading up on relay substitution and found this article:
https://techcircuit.org/relay-substitution-and-coil-resistance/
Which has been helpful. Seems like there's a few equivalent options, however all the Omrons are now 360ohm coil resistance. That's just within the 10% the above article quotes, but I dunno whether it's better to go with the more exact (if less well-known brand) relays that are 400ohm.
eg. https://au.mouser.com/ProductDetail/Song-Chuan/833H-1C-S-12VDC?qs=Me3ZrpFQdnzTJnNcagt%2BNw==
I was reading up on relay substitution and found this article:
https://techcircuit.org/relay-substitution-and-coil-resistance/
Which has been helpful. Seems like there's a few equivalent options, however all the Omrons are now 360ohm coil resistance. That's just within the 10% the above article quotes, but I dunno whether it's better to go with the more exact (if less well-known brand) relays that are 400ohm.
eg. https://au.mouser.com/ProductDetail/Song-Chuan/833H-1C-S-12VDC?qs=Me3ZrpFQdnzTJnNcagt%2BNw==
Can someone please explain what power supply I should use for the board. It's frustrating that this basic information isn't provided on the DIY audio shop and there isn't even a basic build guide. Just assembly photos. Some people seem to suggest the board can be powered with AC by a separate power transformer some seem to suggest that it can be powered by the DC supply from the main amp power supply board. It's frustrating that beginners are not catered for in this environment.
Is this what you're looking for?
https://www.diyaudio.com/community/...soft-start-board-v3.247280/page-2#post3832887
https://www.diyaudio.com/community/...soft-start-board-v3.247280/page-2#post3832887
Sorry, see post #39...https://www.diyaudio.com/community/threads/speaker-turn-on-delay-and-dc-protector-board-set-v3.247279/page-2.
Here's a link to an older assembly document...https://www.diyaudio.com/media/build-guides/diyaudio-speakerprotector-build-guide-v1.0.pdf
I have to go find my notes on the project but I'm headed out somewhere right night. Later.
Hope this helps
Here's a link to an older assembly document...https://www.diyaudio.com/media/build-guides/diyaudio-speakerprotector-build-guide-v1.0.pdf
I have to go find my notes on the project but I'm headed out somewhere right night. Later.
Hope this helps
So either. But I'd agree the thread isn't the clearest on the site. It's too much X-Files IMO.
It actually doesn't matter whether you apply a DC voltage or AC to the board provided the voltage is correct. If DC then you apply around 12 volts. If AC you need a 9 volt transformer which after rectification by D6 on the board will give about 12 volts DC.
It doesn't matter where you get those voltages from as long as the supply voltage remains present under all conditions where you would want the speakers to be disconnected (such as a fault).
This has been my experience, too. It's weird so much of the focus is on the soft start, when that seems to be eschewed in favour of thermistors 9 times out of 10.
Even more frustrating, when you ask about how to wire the DC protect into a specific amp in the relevant amp thread, the answers are invariably "I don't use one" or "you shouldn't need that if you build it right", which to me is like asking how to wear a bicycle helmet and having people tell you "just don't fall on your head". It's like the community is almost embarrassed the board exists. Which is just odd. Seems a very sensible thing to me.
I'm hoping to incorporate one of these into a future F5M build, and may just have to document the whole thing to contribute to the knowledge base - providing I can get it to work. It'll be a ways off though - gotta build a whole amp first, and I'm fast discovering that ain't cheap!