background clipping-static with amp is it the amp, or double amping that's causing it?
Jul 22, 2015 at 4:00 PM Thread Starter Post #1 of 16

mrconfuse

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AK100 to FIIO E7 to SE425, volume set at max on AK100. Anything I play I hear some static noise/clipping in background which I know isn't there when I listen to the AK100 straight. If i turn the volume done to like 50 on the AK100 it's fine the clipping/static noise  is gone. I'm hesitant to go down to 50 on the AK100 for volume because I've read (in the AK100 thread) that it should be set to MAX and let the amp handle the volume. If this is an amp issue, because the amp is to old or just not good enough to handle max volume from the AK100 I can look for a new amp. I just don't want to buy another amp and then find out that it's an issue with double amping
 
Jul 22, 2015 at 5:56 PM Post #2 of 16

NA Blur

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If you are double amping you need to lower the volume of the first amp because it will clip the input on the 2nd amp.  Keep the volume on the player at 100%.
 
Does the 2nd amp give you the volume you need?  It may be best not to utilize the 2nd amp in this situation.
 
Jul 23, 2015 at 12:47 AM Post #3 of 16

PurpleAngel

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  AK100 to FIIO E7 to SE425, volume set at max on AK100. Anything I play I hear some static noise/clipping in background which I know isn't there when I listen to the AK100 straight. If i turn the volume done to like 50 on the AK100 it's fine the clipping/static noise  is gone. I'm hesitant to go down to 50 on the AK100 for volume because I've read (in the AK100 thread) that it should be set to MAX and let the amp handle the volume. If this is an amp issue, because the amp is to old or just not good enough to handle max volume from the AK100 I can look for a new amp. I just don't want to buy another amp and then find out that it's an issue with double amping

 
Any chance the AK100 has a setting for the output, chances the headphone output to a line-output?
In the manual for the AK100 II, on page 16, it talks about line-output settings.
 
Jul 23, 2015 at 8:35 AM Post #4 of 16

mrconfuse

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According to some people in the ak100 thread, the headphoNE out acts a line out only when at max volume . Anything less than that and it won't act as a line out. Some say that there isn't really an amp on the ak100, that it's a variable buffer (something to that extent) with impedence on the head phone out.
 
Jul 23, 2015 at 12:14 PM Post #6 of 16

mrconfuse

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With an optical cable in the headphone on the ak100 you would get true line out. It would bypass the internal dac and amp. However I'm not using an optical cable on the go and the E7 doesn't tape optical cable. I'm using a 3.5 mm to 3.5mm cable. AK100 don't really say much about having a line out without an optical cable.
 
Jul 23, 2015 at 12:44 PM Post #8 of 16

ClieOS

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  With an optical cable in the headphone on the ak100 you would get true line out. It would bypass the internal dac and amp. However I'm not using an optical cable on the go and the E7 doesn't tape optical cable. I'm using a 3.5 mm to 3.5mm cable. AK100 don't really say much about having a line out without an optical cable.

 
If it is optical-out (TOSLink), then it is a digital-out. Line-out refers only to analog-out at line level.
 
AK100's headphone-out is actually pretty much a line-out when you maxed out the digital volume control, as iriver didn't really implement a 'typical' amp section in it (which IMO, it can't even be referred as amp section at all)., just some transistors to boost current and resistors to shield the DAC output from a direct load.
 
Jul 23, 2015 at 12:57 PM Post #9 of 16

PurpleAngel

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According to some people in the ak100 thread, the headphone out acts a line out only when at max volume . Anything less than that and it won't act as a line out. Some say that there isn't really an amp on the ak100, that it's a variable buffer (something to that extent) with impedance on the head phone out.

 
True, a dedicated headphone jack can also somewhat function as a line-output, but a true line-output sends a better signal to an external amplifier.
 
Jul 23, 2015 at 3:39 PM Post #10 of 16

mrconfuse

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If it is optical-out (TOSLink), then it is a digital-out. Line-out refers only to analog-out at line level.
 
AK100's headphone-out is actually pretty much a line-out when you maxed out the digital volume control, as iriver didn't really implement a 'typical' amp section in it (which IMO, it can't even be referred as amp section at all)., just some transistors to boost current and resistors to shield the DAC output from a direct load.

 
That's the problem, I have to max the line to get line out. However when I max the volume with the FIIO E7 connected I get this noise in the background (like static/clipping). I'm wondering if the AMP just can't handle the output from the AK100 at max out put and i need a better amp.
 
Jul 23, 2015 at 10:14 PM Post #11 of 16

ClieOS

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That's the problem, I have to max the line to get line out. However when I max the volume with the FIIO E7 connected I get this noise in the background (like static/clipping). I'm wondering if the AMP just can't handle the output from the AK100 at max out put and i need a better amp.

 
IIRC E7's analog input clips at around 1.25Vrms. I don't know the line-out on AK100, but given it is WM8740, I'll assume it is probably around 2Vrms - that means yes, AK100's line-out is probably clipping E7's amp section.
 
Jul 24, 2015 at 1:03 AM Post #13 of 16

mrconfuse

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IIRC E7's analog input clips at around 1.25Vrms. I don't know the line-out on AK100, but given it is WM8740, I'll assume it is probably around 2Vrms - that means yes, AK100's line-out is probably clipping E7's amp section.


you're right, when at max volume the AK100 volume is at 2 VRMS. Thanks, you just confirmed that I need a new AMP. Where did you get the 1.25 VRMS from? 
 
Jul 24, 2015 at 1:04 AM Post #14 of 16

mrconfuse

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  yup. If the input impedance of the A7 is over 500 ohms or so (over 1k is preferred) you could put a 22 ohm resistor across the output of the AK120 and reduce the voltage by 1/2. 1/4 watt should be acceptable in this config. and could be put in the cable pretty easily. 

 
Well I have the AK100 not AK120 and the Ak100 already has a HO impedance of 20/22
 
Jul 24, 2015 at 8:19 AM Post #15 of 16

ClieOS

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you're right, when at max volume the AK100 volume is at 2 VRMS. Thanks, you just confirmed that I need a new AMP. Where did you get the 1.25 VRMS from?

 
An ex-forumer called NwAvGuy did some measurement on it.
 

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