VOGONS


First post, by BLockOUT

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I have one of these speakers and it came with a massive power brick
when i look at the specs of the brick i find interesting that while it is big bulky and heavy, the voltage and amps are common

I also remember that eveything back then came with a bulky power brick that was heavy and really bulky, for example A sega genesis, an ADSL modem, etc.

while now they sell AC or DC adapters that can provide same voltage and amps that are tiny and weightless.

did this change that much over the years?

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Reply 2 of 14, by XCVG

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Yep. Older ones use a transformer to step down and sometimes a linear regulator to output a steady voltage. These are big and inefficient, especially the regulated ones, and only work with a certain mains voltage. The smaller ones are switching adapters that are considerably more complex electronically, but much more efficient, can deal with a wide range of mains voltages, and (of course) are smaller. At some point electronics got cheaper than transformers and these became the more common type.


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Reply 3 of 14, by Jo22

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True. The transformer-based brick PSUs came in different types, also.
a) AC models (required the device to have a built-in rectifier or voltage regulator. Examples: Euopean NES, SNES)
b) DC models, unregulated (cheap and were common for simple devices. Speakers, toys, etc. Voltage was higher without a proper load)
c) DC models, regulated (best, voltage was constant. But also failed more easily if the device was exceeding the PSUs specs. -> If device was requirng more Ampére than the PSU could supply)

That beeing said, there's something to keep in mind.

While switching PSUs are common now, can deliver more amps and are more efficient, they also provide lower quality power
and produce RF noise by design.
A good, non-broken transformer PSU provides clean DC, just like a battery would do.
That's why lab equipment was transformer-based for a long time.

Of course, time didn't stand still. Not all current switching PSUs are crap (modern switching lab PSUs, as used for ham and CB radio, are fine). 😉
Some have a lot of complicated circiutry built-in to emulate the characteristics of a good transformer PSU.

Edit: Some typos fixed.

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Reply 4 of 14, by .legaCy

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Some vintage equipment may not like switch mode adapters.
There is a nice youtuber called Jan Beta that i follow and recently he bought one drop in replacement for 7805 but it is a switch mode power supply, and it went all nice except when he power off the c64 the sid chip makes a sound that he described as "fart of death", so beware when replacing these power supply.

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Reply 5 of 14, by Zup

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.legaCy wrote:

Some vintage equipment may not like switch mode adapters.
There is a nice youtuber called Jan Beta that i follow and recently he bought one drop in replacement for 7805 but it is a switch mode power supply, and it went all nice except when he power off the c64 the sid chip makes a sound that he described as "fart of death", so beware when replacing these power supply.

I've heard that switch mode adapters produce more ripple than traditional 7805, maybe can be filtered adding more capacitors at the output. Although it can have various effects, it's obvious that audio and video (well, anything analog) circuits will be more affected... or at least you'll notice it faster.

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Reply 6 of 14, by CrossBow777

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Funny you mention Jan Beta and his C64. I've actually done the exact same thing to most of my retro gaming consoles. My SNES jr, Intellivision, Atari 7800, TurboDuo, Atari 5200, and Master System all feature DC-DC converters in them now. I haven't noticed any ill effects in regards to video or audio on any of these systems. But to be fair, I don't use RF from them any longer either and I'm sure that is where I would notice something.

But it does bring up an interesting point. I've noticed over the years that RF seems to get gradually worse in my classic systems over time. I thought at first it might just be the components starting to wear out, or the tuners in modern HDTVs to blame. But now that I think about it, most of the electronics in my home use form or switching power supply in them. That would mean that in these day and times, we have more RF noise floating about than the FCC ever thought they had a fear of back in the 70s- 80s. So maybe the RF on older consoles just looks worse than we remember because of the extra RF noise that is all around us?

In any event, using these DC-DC converters in most classic systems, seem to work just great with the added benefit of better power factor efficiency and little to no heat from the power regulation side of the system.

I do need to mention however, that one classic system did suffer effects from the use of these. That was my Sega Genesis. There was audible electronic noise that was always present, almost like coil whine, but it would change when the system was thinking as it were. I took the DC-DC converters out of the Genesis and put standard linear regulators back into it. But, I do use a switching power adapter for my Genesis system now instead of the original wall wort it came with.

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Reply 7 of 14, by 133MHz

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CrossBow777 wrote:

But it does bring up an interesting point. I've noticed over the years that RF seems to get gradually worse in my classic systems over time. I thought at first it might just be the components starting to wear out, or the tuners in modern HDTVs to blame. But now that I think about it, most of the electronics in my home use form or switching power supply in them. That would mean that in these day and times, we have more RF noise floating about than the FCC ever thought they had a fear of back in the 70s- 80s. So maybe the RF on older consoles just looks worse than we remember because of the extra RF noise that is all around us?

Spot on. Our electromagnetic spectrum is way, way noisier than it was in the 20th century. Not only do we fill up our houses with crap switching PSUs from China, we also replaced our incandescent/halogen/magnetic fluorescent lamps with LED and CFL equivalents sporting (noisy) switching converters, not to mention pretty much anything nowadays seems to include various kinds of radio transmitters all fighting to get themselves heard, along with many more broadcast stations cluttering up the airwaves.

Another cause is that manufacturers seem to have stopped caring about how much noise their devices radiate. I've found out that many cheap modern-ish (post-2000) TV sets actually interfere with themselves on the analog VHF-Low band. If you use a regular twin-lead aerial and put it on top of the TV like usual the reception of channels 2 to 6 is atrocious, but if you use high quality RG-6 coax to connect an antenna far away from the TV itself the noise goes away. No wonder anything analog looks so bad with all that noise pollution floating around.

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Reply 8 of 14, by .legaCy

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133MHz wrote:
CrossBow777 wrote:

But it does bring up an interesting point. I've noticed over the years that RF seems to get gradually worse in my classic systems over time. I thought at first it might just be the components starting to wear out, or the tuners in modern HDTVs to blame. But now that I think about it, most of the electronics in my home use form or switching power supply in them. That would mean that in these day and times, we have more RF noise floating about than the FCC ever thought they had a fear of back in the 70s- 80s. So maybe the RF on older consoles just looks worse than we remember because of the extra RF noise that is all around us?

Spot on. Our electromagnetic spectrum is way, way noisier than it was in the 20th century. Not only do we fill up our houses with crap switching PSUs from China, we also replaced our incandescent/halogen/magnetic fluorescent lamps with LED and CFL equivalents sporting (noisy) switching converters, not to mention pretty much anything nowadays seems to include various kinds of radio transmitters all fighting to get themselves heard, along with many more broadcast stations cluttering up the airwaves.

Another cause is that manufacturers seem to have stopped caring about how much noise their devices radiate. I've found out that many cheap modern-ish (post-2000) TV sets actually interfere with themselves on the analog VHF-Low band. If you use a regular twin-lead aerial and put it on top of the TV like usual the reception of channels 2 to 6 is atrocious, but if you use high quality RG-6 coax to connect an antenna far away from the TV itself the noise goes away. No wonder anything analog looks so bad with all that noise pollution floating around.

Indeed, AM Radio reception inside my house is a nightmare, outside is a little bit better, personally i never experienced 70s and 80's , i'm a 90's kid but my father was into ham radio, and anything radio related, he mentioned the AM reception was WAY better back in the day, not sure if it is the EM spectrum that changed or newer receivers are crappier(just like the lastest batchs of 3.5" floppy disks).

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Reply 9 of 14, by Errius

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Some of these modern energy-efficient light bulbs interfere with radio. When I switch one on while listening to radio an audible 'buzz' can be heard.

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Reply 10 of 14, by Jo22

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Errius wrote:

Some of these modern energy-efficient light bulbs interfere with radio. When I switch one on while listening to radio an audible 'buzz' can be heard.

I second that. The irony is that the modern technology in itself is not the culprit. The situation doesn't have to be like that.
The blue-white LEDs on their own are just fine. It's rather the lamp's cheap power converter that's making the noise, I think.
Makes me wonder as to why FCC and similar organizations do just watch that issue growing these days. Back in time, they were so
agressive that they treated users of imported landline telephones like criminals. Even if these phones complied to all specifications.
And now they are so relaxed that they seemingly allow any violations to the shortwave spectrum (0-30MHz) and beyond.
Except to the cell phone and wi-fi frequencies, maybe, not sure. Anyway, I don't mean to go too much into politics here.
It's just an observation that makes me wonder why it needs two kind of extremes. A good balance between both would be nice.

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Reply 11 of 14, by 133MHz

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Jo22 wrote:

Makes me wonder as to why FCC and similar organizations do just watch that issue growing these days.

Same reason why the post office and customs are overwhelmed pretty much everywhere - they can't deal with the massive influx of cheap stuff from China.

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Reply 14 of 14, by Errius

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I would assume that during the Cold War policing the radio spectrum was important for national security reasons that don't exist anymore.

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