Of course the Citation tube amps were pretty good. And when halfway-decent PNP power silicon was available, Bart Locanthi conjured one of the first fully-complementary-output power amps, the JBL-branded SA 600. He was disappointed that a patent couldn't secured for his "T Circuit". That must have been when the USPTO was a bit more diligent, as it really was a pretty obvious design, one that a clever diagram didn't make a whole lot more innovative-looking.
Back on power. Attached is a first step of a sketch showing an average hifi setup with an average UK ring main. Note walls etc not shown. For this case low power stuff on a rack in a corner, monoblocks driving 2 speakers.
For an average UK living room the ring main makes a loop antena centred around 22MHz, which is in the area where power line networking can be very active and a single ferrite certainly won't kill any of the radiation. So IMO and for a UK style wiring setup I agree with Bonsai that power line networking looks a bad thing.
Moving on, I have marked location of some sockets in the room. It might seem to make sense to plug the equipment rack into the nearest socket to them and the monoblocks into the other one. But as has been noted before that gives you a considerable increase in loop area and everything should be run off one double socket. It's a 32A ring after all, plenty of power there!
What this does of course lend itself to is equipotential bonding, as everything is close enough to be fairly easy to bond without your listening space taking on the look of a data centre or mad science lab. Yet few talk about this, which seems odd.
Of course all of this is only if you think you have a problem. I remain openminded, but unconvinced (other than of the evils of PLC. Adding wideband noise to the mains feed on purpose just doesn't seem sensible).
For an average UK living room the ring main makes a loop antena centred around 22MHz, which is in the area where power line networking can be very active and a single ferrite certainly won't kill any of the radiation. So IMO and for a UK style wiring setup I agree with Bonsai that power line networking looks a bad thing.
Moving on, I have marked location of some sockets in the room. It might seem to make sense to plug the equipment rack into the nearest socket to them and the monoblocks into the other one. But as has been noted before that gives you a considerable increase in loop area and everything should be run off one double socket. It's a 32A ring after all, plenty of power there!
What this does of course lend itself to is equipotential bonding, as everything is close enough to be fairly easy to bond without your listening space taking on the look of a data centre or mad science lab. Yet few talk about this, which seems odd.
Of course all of this is only if you think you have a problem. I remain openminded, but unconvinced (other than of the evils of PLC. Adding wideband noise to the mains feed on purpose just doesn't seem sensible).
Attachments
Hey I'm willing to say those three words "I don't know". Never realized that SiC etc has made inverters operating at 1800V DC now practical so I was wrong and put both feet in mouth.
That's why I asked.
Adds argument for an inductance in series with the equipment PEs.
Dan.
I did work for JBL as an outside vendor and that was one disorganized group. Their wood shop couldn't seem to get things the same twice and that was rather a pain in the rear. Always wanted perfection but surely didn't want to pay for it. That was the JBL XPL series of speakers. At least I made some money.
That is one h*** of a speaker. The ONLY real shining star of the last few years. It images like a mf'er.
Pardon my french!
Correct, you can filter without using Y cap to hot. And this is a discussion about audio, so the culprit is anything in a home; I think it's reasonable to add studio as well.
One must design for unknowns, as per se, which makes your other questions odd since there's no requirement for them given a non-hypothetical discussion about Y caps to hot.
The only thing you told me is you have non-audio related experience, for a facility that's proprietary. BTW I've one across other EE's that hate Y to hot as well.
Your best bud on here loves Bybees, do you really mean to tell me something no where nearly as controversial by large assortments of EE's that work with audio is worth picky a fight with?
Correctly used yes, forms of inductors work flawlessly. Sadly many use them a bit Willy-nilly so they have a bad reputation.
SurgeX and Audience Adept use them, no complaints. Other companies brag about not having them because places like Monster or whatever gave them a bad name.
I have a power amp prototype that's supposed to have about 2uV/rtHz output noise. I see about 50mVpp noise on the oscilloscope. Am I right that this is too much noise? 2uV/rtHz*(1MHz*1.57)^0.5=2.5mV.
I accidentally soldered the VAS backwards, resulting in 4 transistors (BC5x0C/KSC1845F) getting hot from Vbe reverse breakdown. I'm thinking they could be noisemakers now.
I accidentally soldered the VAS backwards, resulting in 4 transistors (BC5x0C/KSC1845F) getting hot from Vbe reverse breakdown. I'm thinking they could be noisemakers now.
I am not sure what on earth you are trying to tell me/us. I am just saying you ought to find out what type of noise you have before designing a filter for it. That would take some measuring on your part in the home, studio or where-ever you plan to make things better.
As I said before, most all the noise is generated by the connected equipment within the home.... it is not coming from outside the home into it. So, the typical filter only on the incoming ac line isnt very effective for audio or video.
To save you a lot of test time, it predominately takes the form of DM. Now there can be exceptions and unusual conditions.... if you think that is your situation, then all the more reason you have to measure what you have.
Meld that info into the individual grounding and isolation of connected equipment and you are done. Or, you can just buy off eBay an HTPS-7000. Good for just about anything, anywhere. All the work has been done for you. And it is UL, CSA, VDE et al approved. Designed specially for audio-video home systems. Surge and lightning protection thrown in as well.
THx-RNMarsh
Last edited:
Based on my experience with the low end JBL LSR305 which I got for $99 each on sale, I would buy them in a heartbeat. I think the waveguide "trickled down" or so the story goes.
They are ridiculously good for being so cheap. I use them as PC speakers.
I wonder about a noise fig of 2uV/rt(Hz) being 1000x bigger than expected with standard bjt differential inputs.
Furthermore it might be helpful to monitor the output voltage using a spectrum analyzer.
I agree - as a user of low signal level RF spectrum, can't think of any situation where wideband power line networking is the right solution! It's fizzling out though I think, now BT have stopped pushing it, in the UK.
Unfortunately , IOT is pushing things into the direction of unified wi-fi/bluetooth/
powerline IP combo boxes.
When every toaster , fridge ,shaver , and light in your house spies and serves
up advertisements on a regular basis .... you will end up sitting in "RF soup".
What I mean , is a localized powerline carrier approach.
http://www.ledsmagazine.com/article...-powerline-and-wireless-lighting-network.html
LED lighting = IOT PL RF !
OS
powerline IP combo boxes.
When every toaster , fridge ,shaver , and light in your house spies and serves
up advertisements on a regular basis .... you will end up sitting in "RF soup".
What I mean , is a localized powerline carrier approach.
http://www.ledsmagazine.com/article...-powerline-and-wireless-lighting-network.html
LED lighting = IOT PL RF !
OS
Last edited:
We are already in an RF soup. At least with Wifi and BT you know the frequencies and they are high enough to be easier to kill. ISM bands around 433 and 868(912 IIRC in USA)MHz are low power but some people break the regs by a factor of 1000 of more 'longest range, buy now'. But again, you know the band to filter in. With LTE everything from about 700MHz to 2.6GHz is now fair game, and in europe potentially 350MHz as well. Luckily cognisant radio doesn't work (as we all knew) so whitespace is currently fallow in most areas.
5GHz wifi is nice in that something simple like a wall will stop it dead.
5GHz wifi is nice in that something simple like a wall will stop it dead.
IOT, such as it is, which is nearly all hype currently here! -- is wifi in UK, not PLT. There's some zigbee too but that's either 868MHz or 2.4GHz and lower power than Wifi. Wifi is so cheap now, PLT is costlier even with people like Greenvity doing their thing. We evaluated some of their stuff -- didn't work at all well.
I have high powered 433, 868, 915, 2.4 & 5GHz stuff for work (all licensed...) and high power 144, 432, 1296 amateur radio stuff here - none creates any audio issues.
Even the HF stuff is ok, though it's not aimed at the house and I only run 100W PEP. The touch sensitive lamp the XYL has turns on when I power up on 40 metres though....
Last edited:
- Status
- Not open for further replies.