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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
cal3713's avatar
cal3713
1,421 posts
 
@itsikhefez  If they fit, I have some Duelund .47uf tinned copper CAST capacitors I can sell you.  I tried them in my Coincident Frankenstein 300b amplifiers and they sounded great, but reduced the bass from the stock Solens.  Because I'm driving the Coincident PREs, my bass is already a little "shy", so I couldn't use them.  They've got about 200 hours on them, so they're just barely broken in...

https://www.partsconnexion.com/DUELUND-81946.html
terry9
2,342 posts
 
Itsikhefez, I for one applaud you for trying different components. My experience is that MIT RTX styrene caps were most neutral, but that teflon caps imparted some brightness. The two teflons which I found most refined were Solen and RelCap teflon (tested by inserting in the RIAA circuit, different components in each channel).

Good luck!
itsikhefez OP
63 posts
 
Thanks for all the suggestions... hard to make a decision here.

My top budget would be in the price range of ~$40 per cap, which is already really pushing it as the entire build is not that high end.

@cal3713 thanks for the offer but those are way over my price range. (probably even at used price). they are also quite big, not sure if they would fit.

@terry9 the MIT RTX look reasonably priced at around $25 a cap, I'll take a loopk. The RelCap TFT's are too expensive at over $100 per cap.

@erik_squires @hifijunky will take an additional look at those MR/CMR's

@motokokusanagi the design is the RJM Sapphire v4. I participate in the build thread in DIY audio but most members there experimented with limited types of caps. My first choice (the Mundorf) was based on impressions there. 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


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
189 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? 
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