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Recommendation for input coupling caps

Hey,
I’m building a headphone amp and need a recommendation for a 0.47uF input coupling cap.
It is a discrete circuit and the output is direct coupled.

I have built this amp before and used Mundorf Supreme in this position.
I felt it sounded "compressed" and lacked dynamics (compared to other amps I built, albeit they were different designs).

Also, the headphones I will be using tend to be a bit bassy so would like something that is known for not bloating the bass and may bring the mids forward (if that is even possible to achieve by simply a cap).

Based on size and price, these seem like viable options:
Auricap XO
Mundorf Supreme Silver Oil
Jantzen Superior

I have also read about Jupiter and Sonicap Platinum but honestly can’t justify the price for this build.

I could be over-estimating the impact of this capacitor on the overall sound though, and can just go back to the same Mundorf Supreme.
Your thoughts are greatly appreciated

itsikhefez
loayo
4 posts
 
Hi I am new here and is new to this audio components. I will have my first DIY amp pretty soon. As an analog engineer I am wondering what specifications of the cap that are important to the circuit are these options based on? Do these caps have specs that you can compare with? And do we know what those specs are that matters the most to achieve specific results?
 Again I'm not trying to say anything but just want to get more info before I start playing with the circuit.
Thanks
motokokusanagi
65 posts
 
"Agreed that I don't have good evidence.. none the less am interested to try something else, which I could then compare to my current amp and see the if capacitor has the effect or not" - fair enough!  

Just one last thought, can the input cap not be omitted entirely if your source has no DC offset? 
itsikhefez OP
50 posts
 
@motokokusanagi Yes, I believe it can be omitted...
If I put a dac board in the same chassis and connect directly, probably safe. But since the source is connected externally and can be replaced over time, probably best to say safe
viridian's avatar
viridian
4,184 posts
 
The only way that obviates the need for the input coupling cap is if all the sources used will be cap coupled, or have DC servos. DC in the signal path will surely have catastrophic results if there are no DC blocking caps. Hey lots of folks skip the condom, but once in a while it results in an itch that won’t go away.

Loayo, the primary measurement that quantifies the electrical performance of a cap is ESR, equivalent series resistance, which can be easily measured. Unfortunately, the caps with the lowest ESR are not always those that IMHO sound the best, so there are probably parameters that we have not evolved standardized testing for yet.
terry9
931 posts
 
In my experience, DA (dielectric absorption) is negatively correlated with sonics (higher DA ==> worse sonics). Similarly for dielectric constant.  Think electrolytic caps: high measures and low sonics. Vacuum caps: low measures and high sonics.

Except for teflon. Neither explains why teflon caps tend to be bright.
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