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The New iRiver AK100: A High-End DAP - Page 213

post #3181 of 8981
Quote:
Originally Posted by goodvibes View Post

Coax done right is always better IMO. Less jitter, more bandwidth etc. Isolation is easy to sort if there's space for a small xformer. In this case, with battery power and no risk of a ground loop, the need may be marginal.

I think it depends upon the coax and the optical being used. I use a 1300 individual fiber optical with the AK and have converted a H140 to coax while retaining the optical. With 1300 fiber optical you get rid of almost all the reflections and end up with a very good signal. With coax, you are often better off with a coax of around 3 feet due to reflections. They are both good when done right and since many dacs have coax, it is excellent to have both and it would be nice if the AK would come this way but nice that someone can modify it if needed.


Edited by jamato8 - 3/12/13 at 4:18pm
post #3182 of 8981

I agree with jamato8, and will add that with coax, impedance matching is very important.  Using 3.5mm jack is not going to be true 75-ohm, nor will the plug for the 75-ohm coax cable.  Impedance mismatches = reflections = jitter = distortion.

 

This is why I don't understand while very good dacs still use RCA jacks for their coax inputs instead of a 75-ohm BNC jack.  The same for the source end of a transport.  Because when you use 75-ohm BNC jacks/plugs with a 75-ohm coax cable, the improvement is very noticeable compared to using RCA jacks/plugs which vary in impedance from 75-ohm, and you can see the reflections on the line with a scope.

 

Re: optical - stay away from the cheap plastic ones and go with glass.  You'll be glad you did, make sure the plugs are clean.

 

Vinnie

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post #3183 of 8981

Quote:
Originally Posted by jamato8 View Post

I think it depends upon the coax and the optical being used. I use a 1300 individual fiber optical with the AK and have converted a H140 to coax while retaining the optical. With 1300 fiber optical you get rid of almost all the reflections and end up with a very good signal. With coax, you are often better off with a coax of around 3 feet due to reflections. They are both good when done right and since many dacs have coax, it is excellent to have both and it would be nice if the AK would come this way but nice that someone can modify it if needed.

 

Reflection and diffraction is also inevitable in the optics.

In very short distance btwn DAP and DAC, they will more effect (as with small R or reflected from section).

And also physical toughness is required in portable application especially.

The more light conduction gets, the more easier to be cracked and reflecting, and this is what he (takoyaki) concerned about.

Additionally images of coax out mod what I've seen (as like in iHP) often omit 75 ohms in series and might bring about huge reflection to.

Of course I added into his, but not only it.

 

He is using FTVS305 from Oyaide and mono-plug, so Cstray is very low and won't become a matter.

Furthermore I felt 50 ohms cable made better in some situations.

 

And just what I said to you in email, the capacitors will solve it.


Edited by ryuzoh - 3/13/13 at 12:16am
post #3184 of 8981
Quote:
Originally Posted by ryuzoh View Post

 

Reflection and diffraction is also inevitable in the optics.

In very short distance btwn DAP and DAC, they will more effect (as with small R or reflected from section).

And also physical toughness is required in portable application especially.

The more light conduction gets, the more easier to be cracked and reflecting, and this is what he (takoyaki) concerned about.

Additionally images of coax out mod what I've seen (as like in iHP) often omit 75 ohms in series and might bring about huge reflection to.

Of course I added into his, but not only it.

 

He is using FTVS305 from Oyaide and mono-plug, so Cstray is so low and won't become a matter.

Furthermore I felt 50 ohms cable made better in some situations.

 

And just what I said to you in email, the capacitors will solve it.


I understand. On the optical I use an optical that is 1300 individual fibers. The reflections are almost nill. There is an audible difference. I have also tried a 13,000 fiber but didn't notice any improvement and the 13,000 is delicate and not good for portable but the 1300 does work and hold up well. On my home unit, (dac) which I built, I used coax and a Audio Note silver transformer for the input from the transport. So yes, I do like well done coax as my transport was optical and I converted it to coax. Audio Note is another world of quality though. :^)

post #3185 of 8981
Quote:
Originally Posted by jamato8 View Post


I understand. On the optical I use an optical that is 1300 individual fibers. The reflections are almost nill. There is an audible difference. I have also tried a 13,000 fiber but didn't notice any improvement and the 13,000 is delicate and not good for portable but the 1300 does work and hold up well. On my home unit, (dac) which I built, I used coax and a Audio Note silver transformer for the input from the transport. So yes, I do like well done coax as my transport was optical and I converted it to coax. Audio Note is another world of quality though. :^)

I also have Joseph's 1300 with 1 feet length, and tried comparison with other formed 1300 which is dedicated for iHP120 and D12.

Honestly difference is very small, but expression in treble gets slightly peaky, so assumed it's jitter.

The 1300 is so excellent at all, but too short connection and hard bending is always spoil signals.

And I'm now having experiments to install transformer but very hard....(assigning L-R in stereo plug)


Edited by ryuzoh - 3/13/13 at 1:11am
post #3186 of 8981
Quote:
Originally Posted by ryuzoh View Post

I also have Joseph's 1300 with 1 feet length, and tried comparison with other formed 1300 which is dedicated for iHP120 and D12.

Honestly difference is very small, but expression in treble gets slightly peaky, so assumed it's jitter.

The 1300 is so excellent at all, but too short connection and hard bending is always spoil signals.

And I'm now having experiments to install transformer but very hard....


That is why I had Joseph always make up the cable that is bent. He tests it after made to assure that it transmits correctly. I noticed an audible improvement in all areas with the 1300 over the solid core.

post #3187 of 8981

Quote:
Originally Posted by jamato8 View Post


That is why I had Joseph always make up the cable that is bent. He tests it after made to assure that it transmits correctly. I noticed an audible improvement in all areas with the 1300 over the solid core.

Yes, in optical solution, Joseph's is the best in fiber.

But if there would have coaxial option, no reasons to abstain...especially in portable, so I'm very very regretting to omit it onto MB, hahabiggrin.gif

post #3188 of 8981

Got a newb questions. Apologies in advance. I did read through the manual and searched this thread.

 

Can the AK100 be used with the Woo Audio WA7? If yes, how? Optical out? RCA ?? If they can be used together, this setup would also use the amp of the WA7 and not the DAC correct?

 

I'm interested in getting a WA7 for my desktop setup, but wouldn't mind using the AK100 with the WA7 sometimes as a bed-side setup.

 

Thanks!

post #3189 of 8981
Quote:
Originally Posted by Vinnie R. View Post

I agree with jamato8, and will add that with coax, impedance matching is very important.  Using 3.5mm jack is not going to be true 75-ohm, nor will the plug for the 75-ohm coax cable.  Impedance mismatches = reflections = jitter = distortion.

 

This is why I don't understand while very good dacs still use RCA jacks for their coax inputs instead of a 75-ohm BNC jack.  The same for the source end of a transport.  Because when you use 75-ohm BNC jacks/plugs with a 75-ohm coax cable, the improvement is very noticeable compared to using RCA jacks/plugs which vary in impedance from 75-ohm, and you can see the reflections on the line with a scope.

 

Re: optical - stay away from the cheap plastic ones and go with glass.  You'll be glad you did, make sure the plugs are clean.

 

Vinnie

 

sorry asking but i am not sure if understood it. you say ''RCA jacks for their coax inputs instead of a 75-ohm BNC jack.''

does it mean RWAK does not have proper SPDIF out? :-(

post #3190 of 8981

AK100 / RWAK100 have an optical (mini-TOSLINK) optical digital output - not coax.

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post #3191 of 8981

Vinnie, thanks.

post #3192 of 8981
Quote:
Originally Posted by Vinnie R. View Post

I agree with jamato8, and will add that with coax, impedance matching is very important.  Using 3.5mm jack is not going to be true 75-ohm, nor will the plug for the 75-ohm coax cable.  Impedance mismatches = reflections = jitter = distortion.

 

This is why I don't understand while very good dacs still use RCA jacks for their coax inputs instead of a 75-ohm BNC jack.  The same for the source end of a transport.  Because when you use 75-ohm BNC jacks/plugs with a 75-ohm coax cable, the improvement is very noticeable compared to using RCA jacks/plugs which vary in impedance from 75-ohm, and you can see the reflections on the line with a scope.

 

Re: optical - stay away from the cheap plastic ones and go with glass.  You'll be glad you did, make sure the plugs are clean.

 

Vinnie

Oh, I agree with that entirely but even RCA will beat any tos if done right. It's the done right part that comes into play here. TOS trancievers are just rather poor. It's not just the cable. If reflections/jitter/distortion are your questions, TOS is likely not the answer either. Banwidth counts as well. There's a reason tos is more limited to format and distance run.

 

 I only use BNC at home.bigsmile_face.gif If I had to use tos, I'd find an all in one solution instead.


Edited by goodvibes - 3/13/13 at 8:21am
post #3193 of 8981
Quote:
Originally Posted by takoyaki View Post

I received different type of ak100 mod recently.
-Addition of the coaxial output

The following photograph is AK100 mod and xDuoo XD-01.

 

I guess we should defer. Do you prefer the tos or coax?

post #3194 of 8981

For portable device, stick with toslink. There's good reason why coax isn't available for most portable devices but toslink. Given some people favoring by-passed out resistor for beyond the optimum performance, I think using forced coax is OK for people who love to get the most.

post #3195 of 8981
Quote:
Originally Posted by WindowsX View Post

There's good reason why coax isn't available for most portable devices...

 

...and that reason is ????

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