Audio-gd Digital Interface
May 4, 2012 at 3:52 AM Post #2,777 of 4,156

fourwed

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So, I got my battery in the mail today and nothing has exploded yet. I'm impatient so I put it on the charger for about 30 minutes to get some testing in before going out.
The battery certainly makes an improvement,although it requires careful listening to notice. In comparing to the DI w/ isolator but no power supply, the Improvements seem to be 'sharper' sounding string instruments, 'blacker' background, and slightly more low level details and ultra low frequency bass (<30hz) likely as a side effect of the 'blacker' background.
In one of my main test songs, "Invisible Man in a Fluorescent Suit" by Shpongle, the opening 60 seconds has significantly more subtle details (especially the 'pat tat tat' sort of sound around 0:50-1:00) and the violin sounds more realistic like there is a quicker transition from one movement of the bow to the next. Around 1:59 there's some details in the background that used to be pushed back and required active listening that are now very clear. The drop at 2:29 and subsequent bass-intensive portions thereafter seem to reach deeper in the 20-30hz range.
Overall, it seems like a great upgrade that's worth getting over the power supply. I still can't really tell much of a difference using the power supply, such that it could just be a placebo. The battery is definitely an upgrade in sound quality, but I would say the USB Isolator and hex inverter swap are higher priority upgrades for the DI-V1. The difference in sq upgrade is somewhere between the isolator/hex inverter upgrades and upgrading the USB cable (I use a Furutech GT2).
By the way, regarding the whole switching between battery and usb thing I found it remarkably easy. Sometimes just flipping the switch works (especially if you're not playing anything), but if it doesn't these seem to have 100% success rate:
Switch from USB to Battery:
-Stop all playback on computer
-Unplug USB from DI
-Switch to battery
-Plug USB back in
Switch from battery to USB:
-Stop playback
-Unplug USB from DI
-Switch to USB
-Plug USB back in
edit:
P.S. No dropouts yet on battery, noticed some when switching to PSU.
edit2: changes seem more immediately noticeable on speakers -- very immersive soundstage and deep bass.

 
Good to know that you notice the improvement as I did. Would you please do a comparison without the USB isolator? I really want someone to cocur with me that there is a big improvement, haha, it seems unfair if there is an isolator in between.
 
Besides, I also want to know which inverter you think is the best.
 
May 4, 2012 at 8:30 PM Post #2,778 of 4,156

somestranger26

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The battery makes a very noticeable improvement without the USB isolator, so perhaps they're at about the same priority level for an upgrade. Adding the isolator just makes it that much better. So, as much as leeperry might complain about the switching regulator on the isolator it still seems to beat whatever is coming straight out of the USB. All my impressions are with battery direct to di, not going through the isolator.
 
May 4, 2012 at 10:04 PM Post #2,779 of 4,156

leeperry

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The battery makes a very noticeable improvement without the USB isolator, so perhaps they're at about the same priority level for an upgrade. Adding the isolator just makes it that much better. So, as much as leeperry might complain about the switching regulator on the isolator it still seems to beat whatever is coming straight out of the USB. All my impressions are with battery direct to di, not going through the isolator.

 
Keep in mind that the DI doesn't have a real pulse transformer on its coax output, but a cheaper ferrite bead that doesn't provide full galvanic isolation IME...more like 60dB'ish FWIR. And the built-in power isolator of the Olimex is prolly in the 150mV region, yay.
 
I'm now using another 4160 dongle that has an unregulated PSU input that feeds both the USB device itself and the device side of 4160. SQ is stunning w/ a 5V/1A linear regulated PSU
normal_smile%20.gif

 
May 4, 2012 at 11:06 PM Post #2,781 of 4,156

somestranger26

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Keep in mind that the DI doesn't have a real pulse transformer on its coax output, but a cheaper ferrite bead that doesn't provide full galvanic isolation IME...more like 60dB'ish FWIR.

Do you know if this is the case for the DI-V2?
I'm now using another 4160 dongle that has an unregulated PSU input that feeds both the USB device itself and the device side of 4160. SQ is stunning w/ a 5V/1A linear regulated PSU
normal_smile%20.gif


Which Adum4160 dongle are you using now with the dual psu inputs? Sounds interesting.

JulienM said:
I've been away from this thread for too long... Could someone please point me to the discussion on replacing the hex inverter?

Right around here: http://www.head-fi.org/t/500369/audio-gd-digital-interface/2625#post_7859266
You need 74VHC04N or 74AHC04N or similar to replace the hex inverter chip in the di. I believe I'm using the 74VHC04N in mine.

Besides, I also want to know which inverter you think is the best.

I forgot to answer you before about this: I have only tried the 74VHC04N and the stock, I didn't get different variations to swap out. The biggest negative of the hex inverter swap is the sound can be a little more 'digital' (slightly harsh highs) but I found it was remedied completely by the isolator and using a good quality USB cable (I love monoprice, but their usb cable didn't seem very good for this purpose). The improvements in detail, soundstage, etc. are totally worth it though in my opinion, and the isolator is pretty much a must if you want the best sound quality.
 
May 5, 2012 at 12:39 AM Post #2,782 of 4,156

JulienM

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Thank you for the link!
 
Not sure if faster hex inverters will be for me. It looks like the sound like fast op-amps: detailed but fatiguing... But I'll give it a try anyway, it's easy enough.
 
What USB cable are you using? I've tried a few "audiophile" USB cables, and kept going back to Monoprice. I feel they are more neutral, less colored. Subtle, but there.
 
May 5, 2012 at 2:39 AM Post #2,783 of 4,156

somestranger26

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Not sure if faster hex inverters will be for me. It looks like the sound like fast op-amps: detailed but fatiguing... But I'll give it a try anyway, it's easy enough.

What USB cable are you using? I've tried a few "audiophile" USB cables, and kept going back to Monoprice. I feel they are more neutral, less colored. Subtle, but there.

Without the usb isolator I found the inverter swap to be a bit fatiguing so I'd agree with that. I'm using a Furutech GT2 that I got for a fairly good price. I had a WW Ultraviolet before that didn't make much of a difference versus the monoprice and another no name usb cable that I compared against. The GT2 actually had a noticeable albeit subtle effect (battery/isolator/inverter are much better $/performance), I found it largely countered the slightly harsh highs caused by the hex inverter swap and some other subtle improvements. Monoprice is definitely good if you're sticking to cheaper cables.
 
May 5, 2012 at 11:49 AM Post #2,784 of 4,156

BoyNamedSue

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Thanks for the links. I think I'll jump on the battery bandwagon. which of the two batteries did you get?

Ok, I have scoured the internet and finally found two batteries with appropriate size barrel connectors.

To answer kr0gg above: as long as you buy batteries that say they have "PCB" or a "protection control module/PCM" or some variant thereof, you should not have to worry about undercharging the batteries. From what I've seen, most of these PCMs trigger a cutoff when voltage reaches 5V, which is still within the DI's input parameters. That is probably why Kingwa insists on 7.4V and not something like 6V. You're not going to find any inexpensive batteries with a charge indicator or anything, so you'll just have to wait til it stops working or periodically recharge (not a problem with Li-Ion since there's no memory effect).
 
May 5, 2012 at 12:22 PM Post #2,785 of 4,156

BoyNamedSue

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Regarding hex inverters, I've noticed that 74AHCU04N provides slightly greater instrument separation and spatiousness in music compared to stock, but the change is more a difference in sound signature than an improvement, with the stock having a slightly warmer and thicker sound. The Olimex Isolator (fed by AG PSU) and upgraded USB cable (ACR silver on audiogon) made slight improvements in that the sound became less muddy and more detailed. The isolater made the most difference in my system, followed by usb cable and hex inverter. 
 
It was a bit tricky finding the hex inverters. I got mine from mouser.com, as suggested by somestranger. They are cheap so I got several of them (e.g., [size=9pt]595-SN74AHC04N, [/size][size=9pt]595-SN74AHCU04N, [/size][size=9pt]512-74VHC04N) [/size]to make the shipment cost worthwhile and do some inverter rolling =). 
 
May 5, 2012 at 1:49 PM Post #2,786 of 4,156

JulienM

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Regarding hex inverters, I've noticed that 74AHCU04N provides slightly greater instrument separation and spatiousness in music compared to stock, but the change is more a difference in sound signature than an improvement, with the stock having a slightly warmer and thicker sound. The Olimex Isolator (fed by AG PSU) and upgraded USB cable (ACR silver on audiogon) made slight improvements in that the sound became less muddy and more detailed. The isolater made the most difference in my system, followed by usb cable and hex inverter. 

It was a bit tricky finding the hex inverters. I got mine from mouser.com, as suggested by somestranger. They are cheap so I got several of them (e.g., [SIZE=9pt]595-SN74AHC04N, [/SIZE][SIZE=9pt]595-SN74AHCU04N, [/SIZE][SIZE=9pt]512-74VHC04N) [/SIZE]to make the shipment cost worthwhile and do some inverter rolling =). 



I also have the the ACR cable... I went back to monoprice after a few months though. I felt the ACR sounded soft. But I think it's time to revisit... Maybe I should build my own USB...

Were you able to compare different hex inverters?

I have the new DI-DSP on order, so all that might be irrelevant if the new DI sounds better than he original. But I'm still keeping my old one for a less critical system...
 
May 5, 2012 at 9:27 PM Post #2,787 of 4,156

somestranger26

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Thanks for the links. I think I'll jump on the battery bandwagon. which of the two batteries did you get?


I bought a 5200 which should last over 10 hours regardless of which DI you use it with. Yes, one could say the hex inverter is more of a flavor swap. For me, the more neutral, detailed presentation is a definite improvement. Kingwa chose the stock chip for a 'warmer/smoother' sound.

edit: battery won't fix dropouts for the original DI.
 
May 6, 2012 at 5:35 PM Post #2,788 of 4,156

leeperry

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Quote:
Do you know if this is the case for the DI-V2?

 
I don't see any change in that section of the PCB.
 
Quote:
Which Adum4160 dongle are you using now with the dual psu inputs? Sounds interesting.

 
http://www.poscope.com/pousbiso
 
It's a dead simple PCB with the 4160 chip, a 150mV ripple 400mA(including the device side of 4160, so more like 300mA for the device itself) power isolator and some diodes to force the use of the unregulated external input.
 
I've tried it w/ three types of PSU's:
-the built-in 150mV power isolator, that sounds nasty and colored to death.
-a 5.25V idle/500mA SONY cellphone wallwart, better SQ than either the computer 5V or the built-in power isolator
-a 5V/1A linear regulated PSU: 
 
stunning SQ!
 
IME and IMHO, all those 4160 isolators that either use a very high ripple power isolator or a SMPS regulated input only give you a glimpse of what 4160 can offer. My next challenge is to use another of those linear PSU's in order to feed the HOST side of 4160, but that's a lot more complicated..
 
jkeny has been recommending this cable on many audiophile forums: http://shop.meconet.de/product_info.php?language=en&products_id=115485
 
but he has never tried it himself, huh...I'm not looking for thrills as a friend of mine tried a few tricks himself w/ USB power and all he managed to do is frying his USB controller 
evil_smiley.gif

 
The problem w/ this kind of trick is that you need to share grounds but you still want to block the nasty computer +5V and replace it seamlessly.
 
May 6, 2012 at 6:04 PM Post #2,789 of 4,156

BoyNamedSue

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I also have the the ACR cable... I went back to monoprice after a few months though. I felt the ACR sounded soft. But I think it's time to revisit... Maybe I should build my own USB...
Were you able to compare different hex inverters?
I have the new DI-DSP on order, so all that might be irrelevant if the new DI sounds better than he original. But I'm still keeping my old one for a less critical system...

 
Yeah, I got the ACR based on recommendations on audiogon. I have the version 2 which isolates the data and power within the same cable, but the haven't tried the version 3 which splits the power and data across separate cables. Compared to some generic USB, the sound was a bit more clear and the bass seemed to extended deeper with the ACR. However, there are so many variables just on the USB section of my system, its hard tell what is improving what anymore.
 
 
I've only been able to compare the 74AHC04N and 74AHCU04N so far, and they sounded the same to me. I believe the latter is just the unbuffered version of the same chip. Both inverters added more instrument separation and spatiousness compared to stock, making the music a bit less congested. The stock sounded a bit more warm and smooth to me. I haven't been able to compare to the 74VHC04N yet.
 
I also have the DI-DSP on the way, and agree that all these little tweaks to the old DI may be irrelevant if the new DSP is better sounding in its stock form. Can't wait for the comparisons!
 
May 6, 2012 at 11:24 PM Post #2,790 of 4,156

kr0gg

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Dear Igor,
The new DI have better detail and neutral sound than the old DI,
But if for the warmer side sounding, the old DI is better.
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Kingwa

 

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