If I must use electrolytic coupling caps...

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Chuck Fry
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Joined: Sat Oct 13, 2007 8:54 am
Location: Silicon Valley, CA, USA
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If I must use electrolytic coupling caps...

Post by Chuck Fry »

... at the input of a mic pre, then what are some of the better caps for the job? The audiophools are drooling over the Black Gate N series, but I've also seen references to Nichicon Muse ES and Elna Silmic and Cerafine.

The reason I ask is I'm POOGEing a MOTU 896 A/D-D/A interface. The OEM caps are 47 uF 50V. Since there are 8 channels of mic pres and 2 caps per channel, cost is an issue. The Black Gates are $10 each!

Also, is there any audible advantage to bypassing the electrolytics with film caps?
producer4000
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Joined: Tue Aug 14, 2007 2:49 am
Location: Memphis, TN USA

Re: If I must use electrolytic coupling caps...

Post by producer4000 »

Chuck Fry wrote:The OEM caps are 47 uF 50V.
For starters, I assume (not looking at schematic) phantom could be present. I would replace with nothing less than a 63v rating.
As for the other, you just have to try a bunch of different ones and see what suits you. Try the cheap ones like Nichicon PW or HE series. You'll find something you like if you look a bit and experiment.
"Come smell my fringy shirt." Lonesome Cowboy Burt
Chuck Fry
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Joined: Sat Oct 13, 2007 8:54 am
Location: Silicon Valley, CA, USA
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Re: If I must use electrolytic coupling caps...

Post by Chuck Fry »

Good suggestion about the 63V rating on the DC blocking caps. Yes, the 896 has per-channel-switched 48V phantom power.

Do any of you folks use film caps to bypass 'lytics in this application? What's a good starting point for a value, .47 uF or so?

I'm tempted to disconnect the phantom power on a couple of channels and DC couple them for use with dynamic mics, just for grins. Might be a real ear opener!

I'd love to show a schematic, but MOTU doesn't make them available. I asked. Anyone from S&S Research on this board? My eyes aren't good enough any more to trace a surface mount board. :roll:

The components used in this box are decent - INA163s for the mic pres, DRV134s for the balanced outs, AK5383 A/Ds, AK4382 D/As, NJM4580 op amps everywhere. The 4580s aren't great, but at least they're not 4558s. I'm planning to swap out a few of these.
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