[ThurstonX]

The other factor people need to remember about USB Audio Player (and Recorder) PRO vs. other Android audio players is that the former use a custom USB audio driver that bypasses the native audio chain in the device and shunts the digital signal directly to the attached (external) USB audio device.  That's why it's possible to play hi-res (24/96, or whatever your USB audio device is capable of decoding) files with USB Audio Player/Recorder PRO.  Unless you've got a seriously fancy Android device that has a built-in DAC with those capabilities (I've never read about one), you're limited by the built-in DAC and audio chain.

 

[imackler]

Quick question about how bass boost works. Here's the background: the ER4PT is the ER4S minus 75ohms of resistance. The ER4PT has increased db in both bass and treble. Now here's the question: If decreasing resistance adds bass to the ER4PT, does the bass boost on the C5 increase bass on the ER4S by similarly decreasing resistance? Is that how bass boost works, by decreasing resistance? Not sure if I'm completely insane or even sound sane. 

 

[ClieOS]

  Quick question about how bass boost works. Here's the background: the ER4PT is the ER4S minus 75ohms of resistance. The ER4PT has increased db in both bass and treble. Now here's the question: If decreasing resistance adds bass to the ER4PT, does the bass boost on the C5 increase bass on the ER4S by similarly decreasing resistance? Is that how bass boost works, by decreasing resistance? Not sure if I'm completely insane or even sound sane. 

 
Definitely no.
 
There are a few ways to do bass boost, but the most common bass boost circuit is usually done by creating a high pass filter inside the feedback loop of the opamp. Opamp is designed to balanced between positive and negative input (where you feed back the output to), and when you offset the negative input, you 'trick' the opamp to believe it need to increase the output, and that's how you set the gain of circuit. By creating a high pass filter in the feedback loop, the opamp will try to increase the output on the lower frequency (which is blocked by the high pass filter) but not on the higher frequency, therefore increasing the bass output. The deeper the corner frequency of the high pass filter, the more bass boost it will be. Also, as high pass filter is made out of RC (resistor-caps) circuit, you can also design where the corner frequency will be and therefore control how wide the bass boost will affect. This is kind of complicated and not easy to explain just by words.

 

[miceblue]

Yay RC circuits.

 

[imackler]

   
Definitely no.
 
There are a few ways to do bass boost, but the most common bass boost circuit is usually done by creating a high pass filter inside the feedback loop of the opamp. Opamp is designed to balanced between positive and negative input (where you feed back the output to), and when you offset the negative input, you 'trick' the opamp to believe it need to increase the output, and that's how you set the gain of circuit. By creating a high pass filter in the feedback loop, the opamp will try to increase the output on the lower frequency (which is blocked by the high pass filter) but not on the higher frequency, therefore increasing the bass output. The deeper the corner frequency of the high pass filter, the more bass boost it will be. Also, as high pass filter is made out of RC (resistor-caps) circuit, you can also design where the corner frequency will be and therefore control how wide the bass boost will affect. This is kind of complicated and not easy to explain just by words.

 
Thanks a ton for the help, ClieOS. Boy was I barking up the wrong tree. 

 

[miceblue]

I think I had too much fun with the C5D's Arduino firmware code in the past week. XD

I changed the C5D's code to have 5 modes of operation:

• DAC circuit off, amp circuit on (low gain), volume change via potentiometer, solid LED, press gain to switch to next mode
• DAC circuit off, amp circuit on (high gain), volume change via potentiometer, blinking LED, press gain to switch to next mode
• DAC circuit on, amp circuit on (low gain), volume change via potentiometer, faster blinking LED, press gain to switch to next mode
• DAC circuit on, amp circuit on (high gain), volume change via potentiometer, even faster blinking LED, press gain to switch to next mode
• DAC circuit on, amp circuit on (high gain), DAC filter change via potentiometer, fastest-blinking LED, press gain to switch back to mode 3

I plan to do a battery test with the amp section only enabled (modes 1 or 2) since the stock C5D code has the DAC portion always enabled (thus sucking up some battery life I think).

 

[imackler]

Does anyone have any experience comparing the Magni to the C5? I know its apples to oranges, but I mainly use my ER4S at work where I listen to lots of classical and I'm wondering if its worth dropping $200 on the C5 over the cost of the Magni, if I don't really need a portable amp. The ER4S is interesting because it is 100 ohm impedance, which means I don't really need the sensitivity of the C5. Of course, if I got the C5, I'd be able to use it with my SE535, too, but I don't feel they benefit a ton from amping. 

 

[slackerpo]

Does anyone have any experience comparing the Magni to the C5? I know its apples to oranges, but I mainly use my ER4S at work where I listen to lots of classical and I'm wondering if its worth dropping $200 on the C5 over the cost of the Magni, if I don't really need a portable amp. The ER4S is interesting because it is 100 ohm impedance, which means I don't really need the sensitivity of the C5. Of course, if I got the C5, I'd be able to use it with my SE535, too, but I don't feel they benefit a ton from amping. 

Having tested my se535 with the c5d, i can say theres lots of goods to come about with the couple. I havent tested the modi, but the c5d seems a like a safer catch fosho.

 

[MarkF786]

Would the C5D be a good fit for use with Sennheiser HD580 phones?  I'd be using a MacBook Pro, iPad, and iPhone as sources.
 
I'm currently using an Apogee One, so I'm curious if the C5D would truly be a step-up in sound quality.
 
Are there any other good options to consider?  The FiiO E17 seems like it's not very powerful, so I've ruled that out as an option.
 
Thanks,
 
Mark

 

[ostewart]

It would work fine with the HD580.
 
Step up, the C5D is basically very flat and neutral, you have the bass boost if you want a little extra ooomph down low for movies and gaming, other than that it does what it says very well and is a great piece of kit.

 

[bartus]

I don't have the Apogee One or the HD580 but based on my experiences I would make this a reasonably definite NO. I have the Apogee Mini DAC in my home/speaker setup for the last 7 or 8 years now and if Apogee kept up their game just slightly it will outclass the c5d and Fiio e17. Furthermore your kind of comparing apples and oranges. The Apogee is first of all a portable DAC+ADC where E17 and C5D are more marketed as a headphone amp plus DAC option, the former being a bit more expensive than the latter but also packs more functionality (whether you need it or not).
 
Like I said I can't compare to the Apogee One but my 8 year old Mini DAC outclasses the C5D on every single level sound wise.

 

[MarkF786]

 
I don't have the Apogee One or the HD580 but based on my experiences I would make this a reasonably definite NO. I have the Apogee Mini DAC in my home/speaker setup for the last 7 or 8 years now and if Apogee kept up their game just slightly it will outclass the c5d and Fiio e17. Furthermore your kind of comparing apples and oranges. The Apogee is first of all a portable DAC+ADC where E17 and C5D are more marketed as a headphone amp plus DAC option, the former being a bit more expensive than the latter but also packs more functionality (whether you need it or not).
 
Like I said I can't compare to the Apogee One but my 8 year old Mini DAC outclasses the C5D on every single level sound wise.

 
I agree with you, but the Apogee One might not have enough power to optimally drive 300+ Ohm headphones, like the Sennheiser HD 580s?  The Apogee One does fine with other low impedance headphones I have (Sennheiser HD 558, Sennheiser PX-100, and Shure E4c), but I wonder if the HD 580 phones (and my older 600 Ohm AKG 240 Monitors) would benefit from having an amp.
 
With my higher impedance headphones, I have to turn the volume to 75% or more for them to be at my normal listening volume.  With my other phones, I tend to keep the volume around 50%, maybe a little higher or lower depending on which set.
 
I found some specs on the Apogee One.  It seems to have an output impedance of 30 Ohms and a max output level of +14 dBu (3.9V RMS).  How does that compare to the C5D?

 

[canikickit1]

So the sound quality difference between the C5D and the C5 is more due to the lower output impedance of the C5D vs the C5?
 
Is the bass boost still about the same between the two?

 

[Mmet]

  So the sound quality difference between the C5D and the C5 is more due to the lower output impedance of the C5D vs the C5?
 
Is the bass boost still about the same between the two?

there is no differences of the output impedance between the C5 & C5D any more ..... and they share now the same 3 position bass boost 

 

[canikickit1]

there is no differences of the output impedance between the C5 & C5D any more ..... and they share now the same 3 position bass boost 

Nice- so ultimately both c5d and the (new) c5 would sound similar?

I say (new) C5 as I had the first generation 2.2 output impedance one with only one bass switch. I sent my C5 to JDS labs for them to add the stepped bass to it. I'm very curious on what the new C5 would sound with my dunu dn-2000s. I'd assume the extra output impedance of the first generation c5 would contribute a bit to its brightness (despite the 16ohm impedance rating it had.) would the lower output impedance of the new C5 remove this brightness (which I do like to an extent)?