Does it make sense to buy a $150 USB cable when your DAC sold for $300 in 2014 - Page 2 - AVS Forum | Home Theater Discussions And Reviews
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post #31 of 77 Old 02-13-2019, 12:34 PM
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Originally Posted by emcdade View Post
It’s not about bandwidth, it’s about timing errors and noise.

A good rule of thumb is the shorter the usb cable the better, regardless of cost.
"Timing errors" are inseparable from bandwidth. The same issues that reduce bandwidth increase timing errors.

Noise is more complex, but if the end bit-error rate is unaffected, noise drops out of the picture. You could have a USB cable with lousy shielding, but it's just fine because there's no external noise source strong enough to affect the data stream. You can also have an inductive noise source that goes right through the shield regardless of how good it is. So I guess I don't like "rules of thumb"!

Shorter cables is often better, but sometimes not. For one thing, that is only true when practical routing isn't compromised. I got some 6" USB3 cables to clean up my external HDD array wiring. Turns out, 8" would have been much better.
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post #32 of 77 Old 02-13-2019, 12:42 PM
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Originally Posted by emcdade View Post
It’s not about bandwidth, it’s about timing errors and noise.

A good rule of thumb is the shorter the usb cable the better, regardless of cost.
As a computer scientist and computer engineer with experience on DSP's and DAC's. I'm just going to put this here: https://imgur.com/gallery/qGhiEIe

USB audio is supposed to go through a buffer. By design of the protocol. If the small jitter of USB is causing issues it's your buffer and clock, not the cable. USB protocols work on burst transfers sending chunks of data on agreed upon timings.

The timing errors and noise will have nothing to do with the cable. If the 0's and 1's get from point A to point B you're good. Where differences may come in is if power has to be transferred as well, even then just switch to a shielded USB and you're fine. Also filter power on the pcb and you're even better. You'll get more variation from you're measurements than you should from a certified USB cable.

The clicks/pops/noise/timing errors all have things built into the USB protocol that handle it. Aka the host and and receiver synchronize their clocks every 1ms. The cable will not change this. It won't introduce random jitter. A magic cable won't make the audio better. If the USB protocol is using asynchronous then it matters even less because they're already running off their own clocks.

Any noise is introduced on the endpoints and how they process. Do they send every 250us? Does the DAC have a good clocking mechanism (say a PLL hitting 17.2032 MHz with low jitter)? Does the DAC use the feedback to adjust data rate (this is for asynchronous, not synchronous)? Did the DAC sync to the USB data frame properly? Is the PC counting a second even remotely close to the same as the DAC clock? Again, all of this has to do with the endpoints, and the cable will not add random jitter that throws it all off. That's what the buffer is there to handle.
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post #33 of 77 Old 02-13-2019, 01:20 PM
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Originally Posted by emcdade View Post
Transferring files over USB does not rely on a continuous stream with precise timing like music does. It's a whole different ball of wax.
Yeah, exactly, it doesn't rely on continuous stream. It sends bursts every few μs which are buffered. It's up to the sender and receiver to buffer things and time it right. The precision timing is on the DAC. Not the cable.
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post #34 of 77 Old 02-13-2019, 01:25 PM
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Originally Posted by emcdade View Post
Have you heard noise and timing errors?
On digital audio it's vastly more likely that any noise is from the playback equipment or maybe poor quality encoding.

As far as timing errors go I'm curious how a cable could either create or prevent those. It's a wire. The signal you put into it is going to come out in the same order. It's possible if you have a powerful source of interference the signal could be corrupted but that won't do anything to the timing. It's not really possible to put signal into a wire and have it come out in the wrong order without some kind of active system modifying it in the middle.
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post #35 of 77 Old 02-13-2019, 01:42 PM
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Originally Posted by mushroommunk View Post
... The precision timing is on the DAC. Not the cable.
I thought better cable perhaps has a better AI timer in there.

Na, just kidding.
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post #36 of 77 Old 02-13-2019, 01:44 PM
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On digital audio it's vastly more likely that any noise is from the playback equipment or maybe poor quality encoding.

As far as timing errors go I'm curious how a cable could either create or prevent those. It's a wire. The signal you put into it is going to come out in the same order. It's possible if you have a powerful source of interference the signal could be corrupted but that won't do anything to the timing. It's not really possible to put signal into a wire and have it come out in the wrong order without some kind of active system modifying it in the middle.
If gravitation field can bend light, why not screw up that digital stream.
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post #37 of 77 Old 02-13-2019, 02:00 PM
 
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Originally Posted by qirex View Post
On digital audio it's vastly more likely that any noise is from the playback equipment or maybe poor quality encoding.

As far as timing errors go I'm curious how a cable could either create or prevent those. It's a wire. The signal you put into it is going to come out in the same order. It's possible if you have a powerful source of interference the signal could be corrupted but that won't do anything to the timing. It's not really possible to put signal into a wire and have it come out in the wrong order without some kind of active system modifying it in the middle.
I have a premium Monoprice digital coax cable that I found to intermittently drop or cause playback errors. Not often, about once a week. I initially thought is was my network, as the streamer is built into the CD player, but also found the CD (I seldom play CDs) will also have the same problem.

I ended up tightening the locking RCA connector which helped quite bit, but I plan to change it down the road. My theory is that the connector doesnt get tight enough, and the heavy cable and poorly designed unit cause the weight to cause the errors.
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post #38 of 77 Old 02-13-2019, 02:14 PM
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I've never liked Monoprice's digital coax cables. The ones I've used also had connectors that were too loose, sometimes to the point of being disconnected just from falling off.
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post #39 of 77 Old 02-13-2019, 02:17 PM
 
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Originally Posted by mushroommunk View Post
Yeah, exactly, it doesn't rely on continuous stream. It sends bursts every few μs which are buffered. It's up to the sender and receiver to buffer things and time it right. The precision timing is on the DAC. Not the cable.
Yes, the sender sends a squarewave electrical signal through the cable the the receiver. The squarewave is susceptible to noise and interference the same as any other electrical signal. Any cable that preserves the correct squarewave is ideal, and any poor quality cable that allows degradation to the squarewave is bad.

Whoever wants to hook up their DAC with the cheapest printer cable you can find, be my guest. I'll pay a little more for my cable and the world will keep on turning.

I use a PCI-E USB ouput card powered by a linear power supply and a $50 USB cable that's well built. Certainly nothing crazy, and no magical thinking involved.

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post #40 of 77 Old 02-13-2019, 02:39 PM
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Originally Posted by emcdade View Post
Yes, the sender sends a squarewave electrical signal through the cable the the receiver. The squarewave is susceptible to noise and interference the same as any other electrical signal. Any cable that preserves the correct squarewave is ideal, and any poor quality cable that allows degradation to the squarewave is bad.

Whoever wants to hook up their DAC with the cheapest printer cable you can find, be my guest. I'll pay a little more for my cable and the world will keep on turning.
You're confusing digital and analogue. As long as the voltage of the top of the squarewave is above a certain threshold then it is registered as a 1. Below a certain threshold and its a 0.

It then stores that 1 (or 0) in the buffer. It loses all sense of the noise. It doesn't store a sort of 1. It doesn't store .995 or .005. It's a 1 or 0.

A little bit later, the DAC, at the timing of it's choosing, looks at the buffer and decides what to do with that 1 or 0.

The entire point of the USB specification is to certify that any CERTIFIED usb cable and CERTIFIED usb connectors will work. I don't know about you but the printer cable I just looked at is certified, so I'd 100% trust it.

The funny thing is there is a very valid possibility where USB audio could have major noise and drop outs. You haven't mentioned anything about the fact that usb audio uses the isochronous functionality of USB transfer, meaning if there is a checksum (crc) error then the data isn't resent. Again though, either the cable works or doesn't. It isn't going to magically make voltage disappear one second and re-appear the next. This may be the "noise" you refer to on some systems But then I challenge you to prove that both the sender and receiver were in compliance and using a certified USB cable. But changing for a different certified cable reduced the number of checksum errors.

Edit: I see you added the cost of your cable after I posted so I'll say this. $50 is crazy. Absolutely. Go spend $11 on a regular certified cable and send the remaining $39 on charity. Multiply that by the number of crazies buying crap like overpriced usb cables and it's downright depressing.
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post #41 of 77 Old 02-13-2019, 02:56 PM
 
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I've never liked Monoprice's digital coax cables. The ones I've used also had connectors that were too loose, sometimes to the point of being disconnected just from falling off.
Good to know its not just me and my imagination.
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post #42 of 77 Old 02-13-2019, 05:12 PM
 
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You're confusing digital and analogue. As long as the voltage of the top of the squarewave is above a certain threshold then it is registered as a 1. Below a certain threshold and its a 0.

It then stores that 1 (or 0) in the buffer. It loses all sense of the noise. It doesn't store a sort of 1. It doesn't store .995 or .005. It's a 1 or 0.

A little bit later, the DAC, at the timing of it's choosing, looks at the buffer and decides what to do with that 1 or 0.

The entire point of the USB specification is to certify that any CERTIFIED usb cable and CERTIFIED usb connectors will work. I don't know about you but the printer cable I just looked at is certified, so I'd 100% trust it.

The funny thing is there is a very valid possibility where USB audio could have major noise and drop outs. You haven't mentioned anything about the fact that usb audio uses the isochronous functionality of USB transfer, meaning if there is a checksum (crc) error then the data isn't resent. Again though, either the cable works or doesn't. It isn't going to magically make voltage disappear one second and re-appear the next. This may be the "noise" you refer to on some systems But then I challenge you to prove that both the sender and receiver were in compliance and using a certified USB cable. But changing for a different certified cable reduced the number of checksum errors.

Edit: I see you added the cost of your cable after I posted so I'll say this. $50 is crazy. Absolutely. Go spend $11 on a regular certified cable and send the remaining $39 on charity. Multiply that by the number of crazies buying crap like overpriced usb cables and it's downright depressing.
I don't think i'm confused or mis-stating anything. Since I have neither the time nor inclination to write a dissertation for you on digital audio, I'll simply link this video for those in the crowd who care to learn more.

I also think you're crazy for hooking up your DAC with an $11 printer cable if you want the best quality, but I don't presume to tell you how to spend your money.

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Originally Posted by emcdade View Post
I don't think i'm confused or mis-stating anything. Since I have neither the time nor inclination to write a dissertation for you on digital audio, I'll simply link this video for those in the crowd who care to learn more.

I also think you're crazy for hooking up your DAC with an $11 printer cable if you want the best quality, but I don't presume to tell you how to spend your money.

https://www.youtube.com/watch?v=grzoqEb2KMk
Yes, it can have errors but the nature of digital errors is that they have an obvious audible signature as mentioned a couple posts up by someone who experienced a failing digital cable. If you are getting drop-outs you should absolutely invest in a more robust cable, but that likely means the $10 cable instead of the $5 one. Or maybe just a different $5 one. Digital signal transmission over a few feet at the rates demanded by USB audio is not a demanding task and does not require esoteric engineering.

Quote:
A CRC error would produce a sudden drop out or “snat” not a color or timbre change. I’ve heard plenty of drop outs in my 20 years of engineering using digital equipment. Gordon’s right when he says that USB can have “quality” issues. What is not made clear in the piece is that the quality is an all or nothing affair when the analog playback is experienced. You either hear the music or you don’t. How many times have you experienced a drop out when using your external DAC? I would guess not very often.
http://www.realhd-audio.com/?p=5971
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post #44 of 77 Old 02-13-2019, 07:36 PM
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Originally Posted by emcdade View Post
I don't think i'm confused or mis-stating anything. Since I have neither the time nor inclination to write a dissertation for you on digital audio, I'll simply link this video for those in the crowd who care to learn more.

I also think you're crazy for hooking up your DAC with an $11 printer cable if you want the best quality, but I don't presume to tell you how to spend your money.

https://www.youtube.com/watch?v=grzoqEb2KMk
I apologize for the more personal attack. Uncalled for on my part.

As for the video. I think we're missing the middle here. He says at 8:30 exactly what I was saying. Jitter is caused by the source or receiver. I'm not hearing anything about cable. "It might be caused by bad shielding". Yes, a cable out of specification. Then he gives an analogy about our brains deceiving ourselves. He uses it to dislike something, but it goes both ways, perceive better sound because our brain tricks us. Looking through the comments I see him talking about a 3s buffer not accounting for jitter from the source. I'd say that's a poorly designed buffer but that aside it doesn't say anything about cabling.
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post #45 of 77 Old 02-13-2019, 08:27 PM
 
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I apologize for the more personal attack. Uncalled for on my part.

As for the video. I think we're missing the middle here. He says at 8:30 exactly what I was saying. Jitter is caused by the source or receiver. I'm not hearing anything about cable. "It might be caused by bad shielding". Yes, a cable out of specification. Then he gives an analogy about our brains deceiving ourselves. He uses it to dislike something, but it goes both ways, perceive better sound because our brain tricks us. Looking through the comments I see him talking about a 3s buffer not accounting for jitter from the source. I'd say that's a poorly designed buffer but that aside it doesn't say anything about cabling.
No worries man, I don't get my feelings hurt on internet forums

I also don't find cables very interesting to think about to be quite honest. I have heard differences and heard compelling arguments for why that may be. I have also heard my PC sound awful out of its motherboard USB output into my old DAC. With my new DAC it was noticeably better, perhaps due to its galvanic isolation from the analog output.

The approach I've taken is to try to present the cleanest waveform to the DAC, preserved by a quality cable 1m long, with the least amount of noise on the line as possible (linear PSU on the USB card), and galvanic isolation to prevent any noise from getting to the analog output. A DAC working hard to analyze a poor waveform only increases its own electrical noise.

EDIT: And for the record, nowhere do I state that a cable magically makes jitter and noise appear. That's a classic AVSforum strawman argument on your part.

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post #46 of 77 Old 02-14-2019, 07:46 AM
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All this desperate whataboutism now regarding non-issues like "jitter" and "timing errors". Gee, what happened to all the poetry about wider bass, increased soundstage, higher detail, blah blah blah?
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All this desperate whataboutism now regarding non-issues like "jitter" and "timing errors". Gee, what happened to all the poetry about wider bass, increased soundstage, higher detail, blah blah blah?
Sounds like you don’t have any curiosity about the actual science and would rather just show up and troll.

Your mind is already made up judging by your “non-issue” comment. Non-issue for you maybe, but not to the actual designers of these products I can assure you.
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"Sounds like you don’t have any curiosity about the actual science and would rather just show up and troll."

I think you are confusing science with marketing.
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Save your money.
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post #49 of 77 Old 02-14-2019, 08:31 AM
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Originally Posted by emcdade View Post
EDIT: And for the record, nowhere do I state that a cable magically makes jitter and noise appear. That's a classic AVSforum strawman argument on your part.
Nor can it remove or prevent signal contamination introduced when sent and/or received.



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post #50 of 77 Old 02-14-2019, 01:11 PM
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Sounds like you don’t have any curiosity about the actual science and would rather just show up and troll.

Your mind is already made up judging by your “non-issue” comment. Non-issue for you maybe, but not to the actual designers of these products I can assure you.
I'm not sure we're the designers of these products. Here are some measurements that compare a couple of different cables. It's a non-issue. The software he uses to take those measurements is free, though, so feel free to compare your cables and post your results.
https://archimago.blogspot.com/2013/...-for-dacs.html

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I think you are confusing science with marketing.
In what way?

EDIT: Ah forget it, DEFINITELY not worth my time.
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post #52 of 77 Old 02-15-2019, 01:18 PM
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better USB cables?
i aksded one o me girlfriends if she could provide a better USB cable
so i could hear what i\d been missing on the HiFi
so she shows up buck nekkid with the USB cable wrapped around her breastesus
so yea,
that cable was definately
better
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post #53 of 77 Old 02-15-2019, 01:57 PM
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better USB cables?
i aksded one o me girlfriends if she could provide a better USB cable
so i could hear what i\d been missing on the HiFi
so she shows up buck nekkid with the USB cable wrapped around her breastesus
so yea,
that cable was definately
better
Definitely the best reply in this thread.
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post #54 of 77 Old 02-15-2019, 05:22 PM
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better USB cables?
i aksded one o me girlfriends if she could provide a better USB cable
so i could hear what i\d been missing on the HiFi
so she shows up buck nekkid with the USB cable wrapped around her breastesus
so yea,
that cable was definately
better
What a girlfriend. I need one like that.
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post #55 of 77 Old 02-16-2019, 04:48 PM
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In what way?

EDIT: Ah forget it, DEFINITELY not worth my time.
How much are those speakers in your avatar?

Save your money.
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How much are those speakers in your avatar?
Not cheap at all. Perhaps 5 figures?
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post #57 of 77 Old 02-17-2019, 05:15 AM
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Quote:
Originally Posted by mushroommunk View Post
You're confusing digital and analogue. As long as the voltage of the top of the squarewave is above a certain threshold then it is registered as a 1. Below a certain threshold and its a 0.

It then stores that 1 (or 0) in the buffer. It loses all sense of the noise. It doesn't store a sort of 1. It doesn't store .995 or .005. It's a 1 or 0.

A little bit later, the DAC, at the timing of it's choosing, looks at the buffer and decides what to do with that 1 or 0.

The entire point of the USB specification is to certify that any CERTIFIED usb cable and CERTIFIED usb connectors will work. I don't know about you but the printer cable I just looked at is certified, so I'd 100% trust it.

The funny thing is there is a very valid possibility where USB audio could have major noise and drop outs. You haven't mentioned anything about the fact that usb audio uses the isochronous functionality of USB transfer, meaning if there is a checksum (crc) error then the data isn't resent. Again though, either the cable works or doesn't. It isn't going to magically make voltage disappear one second and re-appear the next. This may be the "noise" you refer to on some systems But then I challenge you to prove that both the sender and receiver were in compliance and using a certified USB cable. But changing for a different certified cable reduced the number of checksum errors.

Edit: I see you added the cost of your cable after I posted so I'll say this. $50 is crazy. Absolutely. Go spend $11 on a regular certified cable and send the remaining $39 on charity. Multiply that by the number of crazies buying crap like overpriced usb cables and it's downright depressing.
Can you please stop debunking erroneous opinions with your facts please?
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post #58 of 77 Old 02-17-2019, 06:23 AM
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Quote:
Originally Posted by mushroommunk View Post
As for the video. I think we're missing the middle here. He says at 8:30 exactly what I was saying. Jitter is caused by the source or receiver. I'm not hearing anything about cable. "It might be caused by bad shielding". Yes, a cable out of specification. Then he gives an analogy about our brains deceiving ourselves. He uses it to dislike something, but it goes both ways, perceive better sound because our brain tricks us. Looking through the comments I see him talking about a 3s buffer not accounting for jitter from the source. I'd say that's a poorly designed buffer but that aside it doesn't say anything about cabling.
What the video also doesn't mention is that there are 1,411,200 bits per second of sampling. If a few actually did get reversed we'd never hear it. But like you said. Nothing to do with the cable as long as interference wasn't present, which the video did address.

Regarding jitter, when I was researching DACs before buying one I ran into this post from Arny Krueger with downloadable jitter-ed FLAC files. Be careful with the volume as there is a tone that starts each one. He has several more samples on that thread.

BTW, after doing research, and also reading a book (Schiit Happened) containing a manufacturer's claim that DACs make a difference because of jitter and whatnot, I wound up buying an inexpensive DAC ... and inexpensive cable.
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post #59 of 77 Old 02-17-2019, 06:28 AM
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Does it make sense to buy a $150 USB cable ...
No.
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post #60 of 77 Old 02-17-2019, 04:12 PM
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Not cheap at all. Perhaps 5 figures?
oh they be 5 figures all right....

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