Query failed: connection to localhost:9312 failed (errno=111, msg=Connection refused).
It looks like you're new here. If you want to get involved, click one of these buttons!
Subscribe to our Patreon, and get image uploads with no ads on the site!
Base theme by DesignModo & ported to Powered by Vanilla by Chris Ireland, modified by the "theFB" team.
Comments
When we touch, when we kiss.
My trading feedback: https://www.thefretboard.co.uk/discussion/210335/yorkie
Bandcamp
Spotify, Apple et al
Because the power supplies already exist so it's convenient. It's also simple to regulate 9V down to the 5V most digital chips use while leaving enough headroom for the analogue input and output stages.
More complexity and potential unreliability than the job needs. The great beauty of a 9V battery is that you can change it in seconds if you need to. You can even nip out of the venue to a handy all-night shop if you've forgotten to bring a spare one!
It might be a worthwhile idea, but the historical incompatibility of pedals built before it was introduced would hinder uptake, I think. It wouldn't be particularly attractive to small builders either, the extra circuitry to sense and control the voltage is not something most would probably want to try implementing... since I suspect it's one of the main reasons even something as relatively simple as buffered bypass switching is rarely used.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Just because I don't care, doesn't mean I don't understand." - Homer Simpson
In most drive, compressor pedals etc the circuit required to handshake with the PSU would be more complex than the actual pedal circuit. And make the pedal much more unreliable, plus add a load of noise.
I write off a lot of laptops boards because this handshake portion of the circuit is quite easily damaged, leaving a laptop stuck at 5V rather than 20V it needs.
If you consider something like a Tubescreamer, it's not really a 9V circuit. You can run it form 3V or 20V as long as the caps are within their max voltage. The actual circuit operates at half the supply, it's biased in the middle so it can swing positive and negative directions in order to follow the positive and negative waveform from the guitar. So 4.5V is a kind of fake 0V that can be swung below or above by roughly 4V either way. If you connect a 5V battery then the bias network would set it at 2.5V as the actual bias is normally achieved with a simple resistor voltage divider. If 2 identical value resistors are put in series across a voltage difference then their junction will be half that voltage difference. If you use a lower voltage you won't notice until your signal is larger than the circuit can amplify without hitting the voltage limit of it's rails. Then it will run out of headroom and distort. That's what headroom is .... how much voltage swing between barely registering and clipping the rail. The higher the voltage rail the more headroom .... but big headroom in a pedal is pointless as the input of the amp will clip before the pedal a lot of cases.
For my own designs I tend to use 12V AC because it's relatively easy to get a dual supply from a single ended AC meaning I can run the internal circuit at +12 - 0 - 12V which simplifies coupling opamps and allows a larger swing for line level circuits.
My trading feedback: https://www.thefretboard.co.uk/discussion/210335/yorkie
Fascinating. Where can I read about the relationship between voltage and headroom? I don't immediately understand what headroom means.
My trading feedback: https://www.thefretboard.co.uk/discussion/210335/yorkie
Any makers reading this: please forget I've said it, it's a really, really bad idea.
Jon
My trading feedback: https://www.thefretboard.co.uk/discussion/210335/yorkie
There are USB rechargeable power supplies now available, but no idea if they’re any good.
Not just the expertise, but the patience most folks here show with newbies like me. I would never have posted these questions on a different forum. This is a truly special place.
Jon
My trading feedback: https://www.thefretboard.co.uk/discussion/210335/yorkie
Take the mains rings in a house. It was good idea after the war as it saves on copper and back then everything ran on 240 but it's not the best or safest way to run a house now. Only around 10% of the stuff in a house actually runs from a native 240V, the other 90 % has to rectify this voltage to 320V DC and then switch it down to something that is usable for modern electronics.
The American system has a lot of flaws (lack of fuses in plugs etc) but the way they implement their 240V is a lot better with a centre tap. So most things run from a safer 120V around the house with the full 240V generally going to big things like aircon units and washing machines.
Take lighting in a modern house. We can easily generate a perfectly good low voltage from solar panels / storage batteries more or less perfect for modern LED bulbs but in out current setups this low voltage is stepped up to 240V with an inverter only to be sent to the bulb and electronically switched back to 5V or so within the bulb. That's around 15 to 20% power lost to heat in pointless conversion.
At some point hopefully there will be a rethink as the complexity and cost of our common electronics could be reduced and safety improved if we redesigned our mains system to suit the way we live now.
Anything that needs 240V in a north American house is either wired directly into the wall or uses one of 3 special high voltage plugs.
They also don't tend to use mains rings on circuits so don't suffer the fault where someone can breach on end of the ring leaving the rest of it only capable of carrying half the current without anyone being any the wiser in older installations.
As for one end of a ring consider a typical mains ring and then disconnect one end to simulate someone cutting through it with a plasterboard saw.
Your mains ring will still work, all sockets will still work, you will be none the wiser but it will now only be capable of half the current it was before.
I also wouldn’t totally discount cable losses even over distances in a house, at the sort of currents a house full of 24V devices will draw in total.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Just because I don't care, doesn't mean I don't understand." - Homer Simpson
So lights, laptop, printer, beer fridge, router are basically what's needed. I thought maybe I could build a large battery pack from 18650 cells, put some solar panels on the roof to charge it with the option of also charging from a mains cable if necessary Then put a 20V and a 5V rail around the place to power the various bits and pieces.
Heating would be an issue but my house is more than big enough so wouldn't bother using it in the winter.
There are even some old guitar amps that do - I’ve worked on a couple of very early late-40s/early-50s Selmers like that - as you can probably imagine, they’re very difficult to make safe for modern use.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Just because I don't care, doesn't mean I don't understand." - Homer Simpson
110V is safer (not safe) than 240V for obvious reasons relating to Ohms law
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Just because I don't care, doesn't mean I don't understand." - Homer Simpson