I have read much on this forum about the topic of the supply voltage. I really don't know it's full effects on the final audio quality. I am sure so areas have very poor power qualities and this obviously would effect performance. With the prices of UPS units and Inverters going down would the use of equipment such as this at least give a stable source without other appliance and line interference? The interference it would give could be predictable so as could work with. Or is the use of this equipment going to add more unacceptable interference due to it's own operation? Or another way to isolate from the AC line would be to run a motor to spin a Generator with a flywheel. The original source of the electron flow would now be reestablished on location in a controlled isolated environment thus eliminating the power grid interference altogether. I think the most pure source would be a bank of batteries with the final output voltage that that we would run the system. The AC voltage would be ran threw a Transformer to charge the batteries when the system is not being listened to.
This post is just food for thought, I am just fine having my equipment on a dedicated circuit.
This post is just food for thought, I am just fine having my equipment on a dedicated circuit.
I think power purity is an important issue. Not to wade too deeply into the issue, for the moment, my sense is that a clean AC source will probably best a battery supply, which is current limited and generates its own noise problems varying with the type of battery used.
On a related topic, if replacing internal wiring with, say, silver wire improves audio throughput, what of the miles of inferior cable bringing AC to your home?
On a related topic, if replacing internal wiring with, say, silver wire improves audio throughput, what of the miles of inferior cable bringing AC to your home?
Hi,
There are basically two types of UPSs:
An off-line UPS has a 'simple' battery charger, an 'up-converter' and a mains failure detector. The battery is kept charged while your load is constantly connected to the supply line. Once power fails, the UPS switches your load from the line to the battery-supplied converter (very quickly).
Obviously, this wouldn't help your equipment power quality.
An on-line UPS transforms the line level voltage down to battery voltage level (using a switching power supply) and uses this to charge the battery and supply it's up-converter at the same time ('in parrallel'). Thus, during a power failure there's no takeover switching and (ideally) no load supply deviation.
While this type delivers good power failure protection even to devices which are sensitive to mains fluctuations, there are other drawbacks.
Almost everything in today's UPS is done using switching regulator principles. While this is good for your THD 'predictability', it won't give you actually low THD. And switching supplies are among the worst mains line polluters!
Using one of them is good for everything with a switching supply itself, but I consider it bad for audio.
Just a thought, either.
Sebastian.
There are basically two types of UPSs:
An off-line UPS has a 'simple' battery charger, an 'up-converter' and a mains failure detector. The battery is kept charged while your load is constantly connected to the supply line. Once power fails, the UPS switches your load from the line to the battery-supplied converter (very quickly).
Obviously, this wouldn't help your equipment power quality.
An on-line UPS transforms the line level voltage down to battery voltage level (using a switching power supply) and uses this to charge the battery and supply it's up-converter at the same time ('in parrallel'). Thus, during a power failure there's no takeover switching and (ideally) no load supply deviation.
While this type delivers good power failure protection even to devices which are sensitive to mains fluctuations, there are other drawbacks.
Almost everything in today's UPS is done using switching regulator principles. While this is good for your THD 'predictability', it won't give you actually low THD. And switching supplies are among the worst mains line polluters!
Using one of them is good for everything with a switching supply itself, but I consider it bad for audio.
Just a thought, either.
Sebastian.
Yes, batteries are current limited as is the current coming into a residence. I think batteries main draw backs would be the space and possibly need for ventilation during charging. Batteries noisy? They do not have the 50 or 60 Hz that has to be evened out for clean power. I would think if enough batteries are used to achieve the desired voltage so as to eliminate circuitry and power transformers and such the system would have the potential of being cleaner. Batteries might have some noise? but isn't that partly why caps are used in power supplies? I am used to automotive and marine batteries that can put out over 800 amps for a short time and 40 or so for many hours. In series at the amps voltage this would have a long play time. If longer time or more amperage was wanted then they could be banked parrlel/series to double the current ability and time. Note these high current DC lines could be very dangerous on of the aspects of safety when towing and servicing electric and hybrid cars.
Hi mgmopar, I'd be interested hearing the results of your investigations. My intuition tells me if batteries were that much less noisy than AC, they would have made a greater appearance in high end gear, where cost is no object. A few companies, like Edge, have experimented with batteries to good effect, though the jury is out, so far as Edge equipment is concerned, whether the trade-offs involved in using batteries renders an overall audible improvement (comparing audible apples to audible oranges here, I realise).
I've spoken with Serge Schmidlin of Audio Consulting who has experimented rather alot with batteries. He found that battery type noticeably affected resulting sound, and that certain battery types generated too much noise for his liking. I think he prefers the batteries he now uses to AC.
I've spoken with Serge Schmidlin of Audio Consulting who has experimented rather alot with batteries. He found that battery type noticeably affected resulting sound, and that certain battery types generated too much noise for his liking. I think he prefers the batteries he now uses to AC.
I would agree but size and ease of use is needed for consumer acceptance. Most consumers would not want to have a bank of batteries in their basements nor the duct work to vent them outside. I also think high end equipment designers would have trouble getting such equipment UL listed.
Do you recall what type of batteries made the noise?
Sorry for the late answer
This is a good idea in order to keep the influences of surges, voltage fluctuations and occasional dropouts small. I've actually seen UPSs used for this purpose in recording studios. But one shouldn't expect too much improvement from a UPS.
Well designed audio gear doesn't really 'suffer' from power line problems. Today's electronics design possibilities make it rather easy for circuit designers to rule out audible influences from the power supply. As an example, most line level equipment and even many power amplifiers achive a reduction of the influence of power line variations better than 1:1000000; which means that a change of one volt on the power line would be recognized by the audio circuit as a change of 0.000001V - and even then, this change wouldn't neccessarily be recognized by the actual audio signal!
As a conclusion, special care to the power line stability is only required with not-so-well-designed gear. A good internal power supply in a good preamp or cd-player doesn't have to fear power line stability too much. OTOH, a cheapish unit won't sound better with better power line quality, it has to be improved in other regards, first. There are actually very few cases in audio where power line stability is a true problem.
If you're planning to achieve high quality audio in the carribean or suffer from occasional power line problems at home, then UPSs are a must, though...
A completely different story is distortion and noise on the powerline, I'll explain that after your next question
It depends.
In general, inverters - and basically all types of swithing power devices - are considered one of the main polluters of the power lines, with only high-power motors and load-switches nearby being much worse.
But there are quiet inverters (or converters, as I prefer to call them), though. That fact just doesn't help you out in case yours is noisy...
The usual inverters in UPSs come in very different flavours, the most expensive devices usually having the quietest inverters. In cheap gear, the up-converters don't even have a real sine wave generator. They just generate an AC waveform, convert this from battery to power line level and clean it 'a little'.
Widespread are inverters with triangular or trapezoidal output waveform. Imagine a triangular wave at 230Volt, carrying 10A of current. Now that's a lot of distortion and noise! Those bugs not only pollute the connected equipment, but also the power line (if any) and anything that might be sensitive to radio frequency interference in an area around them.
On the other hand, there are inverters with true sine wave generators. Those sine waves are mostly generated by ADCs and have a sinusoidal stair step characteristic, but there are some with very good sine wave reproduction. The keyword here is THD, the harmonic distortion that lets the stair step differ from a true sine.
And while the actual power line can have reasonable THD sometimes (due to switching supplies, motors, hair dryers! and such), the real problem is the variation in these properties. The 'same' powerline never measures the same. There usually is a periodic characteristic, a typical difference between night and day, working days and weekends, neighbours' day rhythms (remember: motors, switches, hair dryers...), nearby industry, train schedules and whatever. You can never rely on the distortion properties of your power line...
That's a true benefit of a UPS or a battery with a good inverter. It gets the THD content of the supply line known and kind of 'ensured'. But that's all, there's nothing more an inverter can do to your power line quality.
The distortion and noise it produces have to be something you can get by (or live with), then it's worth a try.
BTW: A UPS of the kind I described as good (e.g. 'active' or 'on-line' type, sinusoidal output wave form with low THD) doesn't need to be unplugged in order to get good sound out of the connected gear, because it can't get lower than it's minimum THD by just unplugging it. At least not to a significant amount, I guess (because then it wouldn't be a device with low enough THD, wouldn't it?).
Oh, and the sealed 'lead-gel' type of batteries used in UPSs doesn't need air conditioning and works independent of orientation. But they are still large, heavy, expensive, ugly, need quality (!) charging and are not noise free! That's probably why they don't come built in inside every cheap stereo or home cinema set
Ciao,
Sebastian.
PS: Oh, and exactly those units as required didn't get much cheaper over the last couple of years. It's the low quality type of inverters that got cheaper due to mass production...
This is a good idea in order to keep the influences of surges, voltage fluctuations and occasional dropouts small. I've actually seen UPSs used for this purpose in recording studios. But one shouldn't expect too much improvement from a UPS.
Well designed audio gear doesn't really 'suffer' from power line problems. Today's electronics design possibilities make it rather easy for circuit designers to rule out audible influences from the power supply. As an example, most line level equipment and even many power amplifiers achive a reduction of the influence of power line variations better than 1:1000000; which means that a change of one volt on the power line would be recognized by the audio circuit as a change of 0.000001V - and even then, this change wouldn't neccessarily be recognized by the actual audio signal!
As a conclusion, special care to the power line stability is only required with not-so-well-designed gear. A good internal power supply in a good preamp or cd-player doesn't have to fear power line stability too much.
OTOH, a cheapish unit won't sound better with better power line quality, it has to be improved in other regards, first. There are actually very few cases in audio where power line stability is a true problem.If you're planning to achieve high quality audio in the carribean or suffer from occasional power line problems at home, then UPSs are a must, though...
A completely different story is distortion and noise on the powerline, I'll explain that after your next question
It depends.
In general, inverters - and basically all types of swithing power devices - are considered one of the main polluters of the power lines, with only high-power motors and load-switches nearby being much worse.
But there are quiet inverters (or converters, as I prefer to call them), though. That fact just doesn't help you out in case yours is noisy...
The usual inverters in UPSs come in very different flavours, the most expensive devices usually having the quietest inverters. In cheap gear, the up-converters don't even have a real sine wave generator. They just generate an AC waveform, convert this from battery to power line level and clean it 'a little'.
Widespread are inverters with triangular or trapezoidal output waveform. Imagine a triangular wave at 230Volt, carrying 10A of current. Now that's a lot of distortion and noise! Those bugs not only pollute the connected equipment, but also the power line (if any) and anything that might be sensitive to radio frequency interference in an area around them.
On the other hand, there are inverters with true sine wave generators. Those sine waves are mostly generated by ADCs and have a sinusoidal stair step characteristic, but there are some with very good sine wave reproduction. The keyword here is THD, the harmonic distortion that lets the stair step differ from a true sine.
And while the actual power line can have reasonable THD sometimes (due to switching supplies, motors, hair dryers! and such), the real problem is the variation in these properties. The 'same' powerline never measures the same. There usually is a periodic characteristic, a typical difference between night and day, working days and weekends, neighbours' day rhythms (remember: motors, switches, hair dryers...), nearby industry, train schedules and whatever. You can never rely on the distortion properties of your power line...
That's a true benefit of a UPS or a battery with a good inverter. It gets the THD content of the supply line known and kind of 'ensured'. But that's all, there's nothing more an inverter can do to your power line quality.
The distortion and noise it produces have to be something you can get by (or live with), then it's worth a try.
BTW: A UPS of the kind I described as good (e.g. 'active' or 'on-line' type, sinusoidal output wave form with low THD) doesn't need to be unplugged in order to get good sound out of the connected gear, because it can't get lower than it's minimum THD by just unplugging it. At least not to a significant amount, I guess (because then it wouldn't be a device with low enough THD, wouldn't it?).
Oh, and the sealed 'lead-gel' type of batteries used in UPSs doesn't need air conditioning and works independent of orientation. But they are still large, heavy, expensive, ugly, need quality (!) charging and are not noise free! That's probably why they don't come built in inside every cheap stereo or home cinema set
Ciao,
Sebastian.
PS: Oh, and exactly those units as required didn't get much cheaper over the last couple of years. It's the low quality type of inverters that got cheaper due to mass production...
Thanks for the info. I probably am just going to continue to use my dedicated circuit to power my system. The information you gave helped me come up with an idea to investigate. I have a various switching power supplies running in my home 24/7 file and web servers as well as UPS supply's (most likly noisey ones). I don't recall if I used the same phase (leg) off the breaker panel. I am going to investigate the circuits in the home and try to divide them to keep cleaner loads on the same leg as I have my audio. Put the nosier loads on the other phase (leg).
They share the same return but I would think this will help isolate the majority of noise created from within my home, from the power line to my audio system.
They share the same return but I would think this will help isolate the majority of noise created from within my home, from the power line to my audio system.
Are you hosting an ISP at home?
Well if you really have serious power line noise problems in your audio equipment, you should probably try to solve them at the source first, that's right.
Why don't you just take a long extension cord or cable drum to a wall outlet somewhere completely different, e.g. where you know your switchers have no influence? This saves you the hassle with shutting down servers!
Do you have the possibility to measure your power line wave form with a scope? That would be helpful. You should compare your actual to your temporary replacement power line for THD+N in conjunction with doing listening tests. Perhaps the power line quality is not an issue as much as you think (e.g. perhaps the noise is coupled in via electric or magnetic fields).
Regards,
Sebastian.
A rather inexpensive and very effective way to clean up a dedicated AC circuit is to use an isolation transformer with dual primaries and dual secondaries and wire it for balanced power. You get +/-60V supply with true groud reference. This lowers the noise floor and makes systems much less prone to ground loops. A used or surplus 2000VA isolation transformer can be bought for $30.00. Look for one with an electrostatic shield. There are a few websites describing the benefits of balanced power, most notably equitech.com. I've seen a nice personal web page with prescription for hooking up the different available transformers to deliver proper balanced AC. I can't find it right now, but a google search comes up with a lot of good links. I have been using balanced power for years both in a recording studio and at home. Especially in the studio situation where there are literally hundreds of audio connections the difference is very obvious. In home audio setup the difference is more subtle, but not hard to hear either.
If you try it, use it in line with a power strip supplying AC to all your audio gear, or mount it permanently after a circuit breaker and clearly mark which outlets get the balanced AC (the orange isolated ground AC outlets are a very good way to go). Then plug all your motorised stuff in the normal AC and your A/V equipment in the balanced power outlets.
If you try it, use it in line with a power strip supplying AC to all your audio gear, or mount it permanently after a circuit breaker and clearly mark which outlets get the balanced AC (the orange isolated ground AC outlets are a very good way to go). Then plug all your motorised stuff in the normal AC and your A/V equipment in the balanced power outlets.
Sebastian
My line noise isn't exactly a serious problem. I would like to clean it up if possible.
My switchers are possibly interfering the line at the panel? I already have a dedicated line for the audio. So I could just move the breaker in the panel, instead of plugging into other outlets I am also unsure of. I don't have to worry about shutting down the servers. I have enough power backup to run them for about 6 hours without interruption.
I should scope the line. But I have looked at my breaker panel and have two breakers in a row running backups and switching power supplies. This means both lines into the house will have some noise. the same line (phase) is on every other breaker in the US (I don't know how anywhere else does it). Anyway I will be moving a couple breakers. I am sure this can't hurt. Maybe sometime when I am done I can scope the two separate lines into my home and see if I can detect a difference. I have misplaced were ever I put the case for my hookup leads for my scope
I haven't needed it all lately so hasn't been a worry.
Great suggestion EMF or magnetic fields. I did have a new DSL router not work at all in a location that had a prevouis router working for 4 years before! I ended up using my EMF detector and found the new router put out more EMF. By itself wouldn't have been a problem but the input line had about 6 loops of wire stuffed into the wall. This was enough with the field to act as a line filter and no dsl signal would make it threw with that router in place. I also at the same time could hear some noise on that phone line. My amps are about 20 feet away so I think EMF influence would be already eliminated.
My line noise isn't exactly a serious problem. I would like to clean it up if possible.
My switchers are possibly interfering the line at the panel? I already have a dedicated line for the audio. So I could just move the breaker in the panel, instead of plugging into other outlets I am also unsure of. I don't have to worry about shutting down the servers. I have enough power backup to run them for about 6 hours without interruption.
I should scope the line. But I have looked at my breaker panel and have two breakers in a row running backups and switching power supplies. This means both lines into the house will have some noise. the same line (phase) is on every other breaker in the US (I don't know how anywhere else does it). Anyway I will be moving a couple breakers. I am sure this can't hurt. Maybe sometime when I am done I can scope the two separate lines into my home and see if I can detect a difference. I have misplaced were ever I put the case for my hookup leads for my scope
I haven't needed it all lately so hasn't been a worry. Great suggestion EMF or magnetic fields. I did have a new DSL router not work at all in a location that had a prevouis router working for 4 years before! I ended up using my EMF detector and found the new router put out more EMF. By itself wouldn't have been a problem but the input line had about 6 loops of wire stuffed into the wall. This was enough with the field to act as a line filter and no dsl signal would make it threw with that router in place. I also at the same time could hear some noise on that phone line. My amps are about 20 feet away so I think EMF influence would be already eliminated.
jan
Thanks for the suggestion, I will consider installing an Isolation transformer/tranformers on that line also. I am pretty sure just keeping my phase clean in the house will help noise (for free!). But I would think using an isolation transformer would help with ground loops and such and eliminate noises that are caused by other influences as well.
Thanks for the suggestion, I will consider installing an Isolation transformer/tranformers on that line also. I am pretty sure just keeping my phase clean in the house will help noise (for free!). But I would think using an isolation transformer would help with ground loops and such and eliminate noises that are caused by other influences as well.
Hmmm, I guess the cheapest and easiest cure could be to 'test' the UPSs every time you listen to music, then
Just make shure everything is supplied uninterruptible, even a lamp (light source, not linux apache server
) that you need nearby the computers. You could then just switch off the line breaker in the panel and have a listen. But not until the batteries are drained, that's too long to still enjoy it, right? Well, an isolation transformer just isolates, it doesn't neccessarily filter! A line filter does that (sometimes in conjunction with an isolation transformer), but you wouldn't need an isolation transformer just to do line filtering.
What Thunau suggested is not just isolating the line, but changing the way the existing line between breaker panel and audio equipment 'carries the power'.
Using a symmetric power line makes it almost immune against EMI into it, but only over the symmetric distance between symmetry-transformer and audio gear. Regarding your idea of preventing ground loops by leaving the isolated line unprotected ('ungrounded'): you shall not disconnect the line after an isolation transformer from your protecting earth! While you might know what you do, you could also risk the health of anyone who enters the room...
You seem to have some options at hand now.
Does it already make a sonic difference whether the line arm with the UPSs and Computers is temporarily disconnected (breaker open)? If not, there probably just is no problem with your power line? Now that would be a cheap and easy solution, wouldn't it?
Ciao,
Sebastian.
PS: There's still a question unanswered.
Sebastian
I understand for safe operation eliminating the ground on a unit could lead to a dangerous situation. But the "return" in the USA is practically the same as the ground. This basically creates two paths to the amp one to the transformer and one to the chassis. I would think an isolation transformer possibly would benefit by the isolation of the return. The chassis could still be wired to earth ground for saftey
PS: Yes, their is a sonic diffence with the breaker off, It seemed to sound diffent also when I moved the postion to the other leg in the panal. Between the two, I am not yet sure.
I understand for safe operation eliminating the ground on a unit could lead to a dangerous situation. But the "return" in the USA is practically the same as the ground. This basically creates two paths to the amp one to the transformer and one to the chassis. I would think an isolation transformer possibly would benefit by the isolation of the return. The chassis could still be wired to earth ground for saftey
Yea, now all I need is the time. Thanks for the information now my mind can ponder.
I have a WebServer that I host about a dozen local businesses on. Enough to pay for the line and power for the equipment. I guess that is sorta a ISP?
PS: Yes, their is a sonic diffence with the breaker off, It seemed to sound diffent also when I moved the postion to the other leg in the panal. Between the two, I am not yet sure.
Nope. The ground wire is a replacement return path parallel to the neutral wire. It's there in case the neutral wire breaks or gets disconnected! Imagine some circuitry inside your metal case fails to keep it's isolation between phase and metal enclosure. Who would conduct the current (mains potential at the case) back to ground? You, trying to find out what's wrong!
It's the same in germany, BTW. Breakers with current detectors in the 'protecting earth' line are only required in bathrooms and for outside installations, although it's wise to use it anytime and everywhere!
Sebastian.
Sebastian
I understand the ground runs parallel and thus acting as a safety path. That is why I wrote "practically the same" I was NOT trying to say they were interchangeable or anything. I guess I was just thinking this dual path forms a large loop and might allow for added interference.
I understand the need for a chassis ground to maintain safety. This should be able to be achieved with a ground rod. I have ran a load from power to a ground rod (not to the panel, just a 8 foot pipe hammered into the ground) )in the past as an experiment. I understand that the voltage would not be using the same return path but it should direct the danger of a charged chassis to ground, We can be shocked without touching ground. It sure gets worse when we do!_ I would assume most shocks with appliances are obtained even without the person touching ground to complete the circuit (this has in the past happened to me, I have a bad habbit I don't always kill the power first). I guess the same way a neon test light can light up with only one lead to power. If their still is any worry with the isolation transformer set up. The chassis outer shell could be made up or insulated from the inner with wood or plastic. This also would effectively isolate the possible danger to the operator._ I don't normally worry too much about someone touching my equipment. Safety is still of concern with me. I have read other posts about users bypassing or not using any fuses or breakers for better sound. This is just asking for a fire or something. Even if the sound could be improved by doing this, It is just NOTworth it.
Don't worry I don't yet plan on isolating my line to the equipment. I am satisfied with the results so far just by moving my breakers. I still might consider in the future if I see a large enough isolation or transformer at an auction or something. (I would keep the metal chassis grounded to earth!)_ I still haven't found the scope leads so no tests, other the ear. I might end up ordering a set or making a temporary set. I am now curious just how noisy the other line has gotten compared to the quieter one. __
Does Germany run two hot lines in the home as well. Here they run two 120 volt legs and a return (also connected to ground normaly the water supply pipe in urban areas). So the home has 120 or 240 vac. 60 hz. I know some (or all?) of Europe has higher voltages at 50hz (they sell the adapters here). Do the panels still have even higher voltage available for things like Central A/C and heat?
I understand the ground runs parallel and thus acting as a safety path. That is why I wrote "practically the same" I was NOT trying to say they were interchangeable or anything.
I guess I was just thinking this dual path forms a large loop and might allow for added interference. I understand the need for a chassis ground to maintain safety. This should be able to be achieved with a ground rod. I have ran a load from power to a ground rod (not to the panel, just a 8 foot pipe hammered into the ground) )in the past as an experiment. I understand that the voltage would not be using the same return path but it should direct the danger of a charged chassis to ground, We can be shocked without touching ground. It sure gets worse when we do!_ I would assume most shocks with appliances are obtained even without the person touching ground to complete the circuit (this has in the past happened to me, I have a bad habbit I don't always kill the power first). I guess the same way a neon test light can light up with only one lead to power. If their still is any worry with the isolation transformer set up. The chassis outer shell could be made up or insulated from the inner with wood or plastic. This also would effectively isolate the possible danger to the operator._ I don't normally worry too much about someone touching my equipment. Safety is still of concern with me. I have read other posts about users bypassing or not using any fuses or breakers for better sound. This is just asking for a fire or something. Even if the sound could be improved by doing this, It is just NOTworth it.
Don't worry I don't yet plan on isolating my line to the equipment. I am satisfied with the results so far just by moving my breakers. I still might consider in the future if I see a large enough isolation or transformer at an auction or something. (I would keep the metal chassis grounded to earth!)_ I still haven't found the scope leads so no tests, other the ear. I might end up ordering a set or making a temporary set. I am now curious just how noisy the other line has gotten compared to the quieter one.
__ Does Germany run two hot lines in the home as well. Here they run two 120 volt legs and a return (also connected to ground normaly the water supply pipe in urban areas). So the home has 120 or 240 vac. 60 hz. I know some (or all?) of Europe has higher voltages at 50hz (they sell the adapters here). Do the panels still have even higher voltage available for things like Central A/C and heat?
UPS and Adcom 555
I tried a UPS on my Adcom 555. It ran fine for a few minutes, but when I ham fisted the Volume knob the battery drained and the whole unit shut down. That could be peculiar to the model I was using (Belkin) , but it sent me searching for answers in another direction regardless. And now i just use the UPS for my PC- which is what it is intended for- so much for saving money the "cross-use" way
I tried a UPS on my Adcom 555. It ran fine for a few minutes, but when I ham fisted the Volume knob the battery drained and the whole unit shut down. That could be peculiar to the model I was using (Belkin) , but it sent me searching for answers in another direction regardless. And now i just use the UPS for my PC- which is what it is intended for- so much for saving money the "cross-use" way
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