[PeterAES]

I would say that I2S sounds best but it doesn't mean that non of improvement can be noticed with SPIDIF or AES.

From my experience compering those scenarios:

1. Source > usb > DAC

2. Source > usb > U18> SPIDF Coax > DAC

3. Source > usb > U18> SPIDF Toslink > DAC

4. Source > usb > U18> I2S > DAC

Those are combinations that I've tested. I don't have AES cable to try this solution.

Now, let's say option 1 is 5/10, option 4 10/10, 2 and 3 would be 7/10.

Many say that AES is superior to Coax or Toslink so I my opinion I'll notice major difference using DDC like U18 especially in studio environment where multiple devices are used which may generate a lot of noise. USB isolation is main advantage of those DDCs' .

Thanks for the reply !
I am definitely considering the GD as it is superior in sound to U-18, and a guy that owns it just told me that it sounds equally good via AES

 

[phoneslave86]

I would say that I2S sounds best but it doesn't mean that non of improvement can be noticed with SPIDIF or AES.

From my experience compering those scenarios:

1. Source > usb > DAC

2. Source > usb > U18> SPIDF Coax > DAC

3. Source > usb > U18> SPIDF Toslink > DAC

4. Source > usb > U18> I2S > DAC

Those are combinations that I've tested. I don't have AES cable to try this solution.

Now, let's say option 1 is 5/10, option 4 10/10, 2 and 3 would be 7/10.

Many say that AES is superior to Coax or Toslink so I my opinion I'll notice major difference using DDC like U18 especially in studio environment where multiple devices are used which may generate a lot of noise. USB isolation is main advantage of those DDCs' .

USB>Toslink>AES>I2S. High end I2s is also much better than low end I2s. Tubulus Concentus/Audiolund Truesilver > AVplay300 > Blue Jeans and other HDMI (I've tried about 5 other HDMI cables so far). I'd likely pick my black dragon AES over the regular HDMI. It's pretty dang good but the high end I2s cables are just simply in their own league. They are simply magical. The AVplay300 can be my favorite on certain songs as it can sound just wonderfully silky smooth in certain frequencies but it falls short overall. The Tubulus has amazing control, detail, soundstage and bass. The center is put out farther and is smaller than the Truesilver with a more reference and detailed sense with huge bass. The Truesilver is sweet, warm, smooth and musical plus it comes with a lovely easy to hear midrange that is larger and more in your face and just addictive with plenty of detail. It has plenty of bass but not as much as the Tubulus.

A DDC like the U18 will go as far as you build off of it. I think of the U18 as a platform to expand and upgrade as needed. Masterclocks are amazing with the U18. Masterclocks make less fatiguing more precise realistic sound. This means louder listening level which could mean more immersion. It will remove noise from your system and in turn uncover noise that was hidden before too. Must mention the purple fuse and keep it going about the purple fuse. It's worth the upgrade when wants to go farther. A squarewave masterclock was nice and I got another improvement trading in to a higher end sinewave clock later. Worth the money for sure to me easily. The U18 works with both which is nice.

 

[sbgk]

had posted previously about modifying the U18 - removing IEC socket and fuse, soldering mains cable direct to transformer and output wires to circuit board pins.

That saw some improvement, but the transformer in the case was still next to the circuit board, xmos chip and USB input, so I removed the transformer from the case and the sound has really opened up and detail has improved, would describe the previous sound as compressed. Think having the transformer in the case interferes with it's magnetic fields producing eddy currents and also having it next to the USB input and processing chip is just hobbling it's performance

 

[Jake2]

had posted previously about modifying the U18 - removing IEC socket and fuse, soldering mains cable direct to transformer and output wires to circuit board pins.

That saw some improvement, but the transformer in the case was still next to the circuit board, xmos chip and USB input, so I removed the transformer from the case and the sound has really opened up and detail has improved, would describe the previous sound as compressed. Think having the transformer in the case interferes with it's magnetic fields producing eddy currents and also having it next to the USB input and processing chip is just hobbling it's performance

Interesting. For those of us not as bold or technically capable as you for whom moving the transformer is simply not a realistic option, do you have experience with Mu metal magnetic shielding and/or how would you suggest Mu metal (or other additional shielding) be best used in the U18 to reduce the magnetic and electric fields if not quite to the extent you've managed by moving it external?

 

[sbgk]

Interesting. For those of us not as bold or technically capable as you for whom moving the transformer is simply not a realistic option, do you have experience with Mu metal magnetic shielding and/or how would you suggest Mu metal (or other additional shielding) be best used in the U18 to reduce the magnetic and electric fields if not quite to the extent you've managed by moving it external?

no experience of mumetal, but must be worth a try to separate the transformer/IEC socket from the circuit board/xmos chip/USB socket

 

[Getafix]

I went as far as replacing the transformer with a Hammond 229D16 split bobbin type which I happened to have. It’s 8V 48VA and doesn’t radiate as much as toroids. I still housed it inside the U18 though. Result was positive, blacker black, less noise.

 

[Capri87]

Hi, can anyone confirm whether U18 can be used in tandem with a 50ohm clock?

 

[sbgk]

Hi, can anyone confirm whether U18 can be used in tandem with a 50ohm clock?

I use the Leo Bodnar 10MHz, square wave with 50ohm bnc connection

 

[phoneslave86]

Hi, can anyone confirm whether U18 can be used in tandem with a 50ohm clock?

The U18 has to use a 50 Ohm cable/signal. The clock is just a clock. You just need a clock that convert's it to a 50 Ohm signal. The Afterdark clock can be made to send either 50 or 75 Ohm signal but it's still the same clock. The U18 can use a squarewave or sinewave 50 Ohm signal. Squarewave clock is different than sinewave clock.

*Edited* Don't want to make confusing information.

 

[Capri87]

The U18 has to use a 50 Ohm cable/signal. The clock is just a clock. You do need a clock that convert's it to a 50 Ohm signal. My Afterdark clock can be made to send either signal but it's still the same clock. Highly recommend Afterdark clocks. The U18 with fuse and Afterdark clock sounds like $3000+ of equipment it's every cent that good. That said the U18 is fairly noisy, along with my DAC and tube amp I do have transformer noises far up in the inaudible range which isn't ideal. One might want to just invest in a much lower noise DDC and avoid the cost of the U18 + clock + fuse + power cable + power conditioner that it takes to get the max out of the U18. I can tell you if you go all out the U18 will deliver though! The Holo Red is an incredibly low noise unit, probably more cost effective if you aren't going to go rout. That said I can't say a Holo Red sounds better than a fully supported U18. The lower end squarewave clock from Afterdark did not reveal the transformer hum but the higher level sinewave clock did. I don't know that a Holo Red has the potential of the U18 here at this level as it relies on it's own clock which is part of why I have no regret with my U18. But it took so much money, if you are at a budget were you are going to go for a lower end clock (and avoid the cost of the fuse which is pretty necessary with the U18) I would just go for a Holo Red probably more cost effective.

Thanks for the detailed reply! Just to give a little background, i currently already have U18, afterdark clock and R26 under my stable. Clock is intended for R26 at the moment but I'm contemplating to sell my R26. Thus im thinking if i can use the same clock for my U18 if R26 is sold

 

[phoneslave86]

Thanks for the detailed reply! Just to give a little background, i currently already have U18, afterdark clock and R26 under my stable. Clock is intended for R26 at the moment but I'm contemplating to sell my R26. Thus im thinking if i can use the same clock for my U18 if R26 is sold

Oh nice. If your clock is already putting out 50 Ohm and you have a 50 Ohm cable your good to go as that's what the U18 uses. If I was using a U18 and a R26 in the same chain I would already be using the clock on the U18. I'm guessing you don't have it in the same chain. When you use the clock on your DAC you get one device clocked. When you clock your DDC that runs I2s to your DAC they will be locked together and both will be benefitting from the clock. 2 devices benefitting is better than 1.

 

[Capri87]

Oh nice. If your clock is already putting out 50 Ohm and you have a 50 Ohm cable your good to go as that's what the U18 uses. If I was using a U18 and a R26 in the same chain I would already be using the clock on the U18. I'm guessing you don't have it in the same chain. When you use the clock on your DAC you get one device clocked. When you clock your DDC that runs I2s to your DAC they will be locked together and both will be benefitting from the clock. 2 devices benefitting is better than 1.

interesting, something new to me and thanks for the tip. Shall try to clock my U18 and have a listen!

 

[Jake2]

interesting, something new to me and thanks for the tip. Shall try to clock my U18 and have a listen!

I found dual clocking the U18 and R26 was superior to either alone.

The clock cable is critical... clocked components are highly sensitive to this, similar to what @phoneslave86 described for I2S. Maybe because both were originally designed as very short distance internal connections so they have a need for high precision, low noise/reflections & minimised jitter, in common.

Tubulus Concentus (TC) also rules the roost there:

TC > Harmonic Technology Digital Copper III > Gustard C2/LMR400 > others...

I have the HT DC III, but a number of folk have upgraded to the TC from it. A bit pricey for me for now.

A cheap/almost free tweak, which for me is like upgrading the clock cable, is to wrap the BNC plug/socket junction in copper foil tape with conductive adhesive. Improves all the cables I've tried I list above.

 

[phoneslave86]

I found dual clocking the U18 and R26 was superior to either alone.

The clock cable is critical... clocked components are highly sensitive to this, similar to what @phoneslave86 described for I2S. Maybe because both were originally designed as very short distance internal connections so they have a need for high precision, low noise/reflections & minimised jitter, in common.

Tubulus Concentus (TC) also rules the roost there:

TC > Harmonic Technology Digital Copper III > Gustard C2/LMR400 > others...

I have the HT DC III, but a number of folk have upgraded to the TC from it. A bit pricey for me for now.

A cheap/almost free tweak, which for me is like upgrading the clock cable, is to wrap the BNC plug/socket junction in copper foil tape with conductive adhesive. Improves all the cables I've tried I list above.

Afterdarks 50 Ohm red BNC cable is the best 50 Ohm cable Afterdark has when I got mine. It claims to make a reference sound. It's fairly affordable starting around $200. There are many expensive 75 Ohm cables but not so many decent 50 Ohm cables.

I bought my Tubulus Concentus used for less than 50 percent of it's original cost or I wouldn't have one. Seems like nice cables can be had for a great deal. Most of my stuff is used and I've never had an issue with a single thing yet.

What do you mean by dual clocking? Do you mean a different clock for each?

 

[milkdudd]

On a somewhat related note, everybody will tell you to use the sine wave connection...... Everybody except me that is. I find the square wave sounds noticeably better at least for my C18/U18/A22 combination