[diablo9]

I am making a pimeta for my friend, just realized a question, do you guys populate C1 in pimeta? I read tangent explanations about input cap back when I was making my first CMOY.
http://tangentsoft.net/audio/input-cap.html
I know C1 is to remove the DC offset from source, I was under the impression that C1 is usually populated since nobody can guarantee a low DC offset source won't be problematic tomorrow and it's always safe to populate a C1 here. but unlike on MINT, tangent leave a trace shorting C1 for a reason, right? So, probably in his mind, C1 is NOT populated by default, right? I know that result in better SQ but what about protecting your cans? What makes PIMETA different from MINT so that the default C1 on MINT is not populated on PIMETA by default?

 

[diablo9]

to thank those coming in to help me, or at least take time to read my questions, your reward is.... a couple of pics of my HD600 recable.

 

[diablo9]

Mogami 2534 quad, NEUTRIK NP3X-B, the pins are bought from another fellow Head-Fier.
about how to position the pins, there is a little trick, too tired today, will release detail tomorrow.

 

[skyskraper]

why don't u post the senn recable info in one of the senn recable threads to make it easier for epople searching?

 

[blip]

I didn't populate the C1 on my PIMETA... But I keep an old meter sitting next to my desk (suprising how often it comes in handy) and I probably check my system offsets once every couple of weeks. (in fact, that reminds me...)

It's still living a bit dangerous, but I honestly don't lose sleep over it. I've never seen an amplified offset in my system (i.e. what the headphones see) over 10 mV.

Anyway its worth it to me just to not have to audition different caps until I find one I like (and can afford!)

Also, nice new cable... Gahh! I really need to redo my HD 580s... I swear I sometimes think I'm the only Senn-File still using stock cables!

 

[Porksoda]

If you're making it for a friend, I would populate it. Use a good quality cap, and save yourself the worrying. I'd feel bad if someone's gear got ruined because I didn't AC couple the amp I made them. For myself, I left it uncoupled.

 

[The Monkey]

Just curious, What do you lose by populating C1?

 

[Teerawit]

Quote:

Originally Posted by The Monkey Just curious, What do you lose by populating C1?

Sound quality, by putting a cap in the signal path..

But you also lose any source offset.

 

[The Monkey]

Quote:

Originally Posted by Teerawit Sound quality, by putting a cap in the signal path.. But you also lose any source offset.

Thanks, is the SQ difference very nocticeable?

 

[diablo9]

most likely yes, that's why they don't populate it.

Quote:

Originally Posted by The Monkey Thanks, is the SQ difference very nocticeable?

 

[Porksoda]

As far as the SQ difference, I used to have C1 populated on my pimeta, and then removed it for the enhanced sound quality, and I don't hear any HUGE differences. Mind you, I have no way to A/B test, and I would never try to claim anything unless I can at least A/B two devices. I brought my pimeta (with C1 populated) to a meet and it was well-reviewed by a number of fairly well-known head-fi'ers. Keep in mind, if C1 was really that detrimental to the sound of the amp, it wouldn't even be an option.

 

[Xakepa]

I had initally 2.2uF polyester caps in my A47, and I wasn't happy - low bass/boxes were definitely smeared; with .22uF polypropylene it was even worse. I ended up shortening the input and the sound improved quite a lot...no need to A/B really.

So IMHO the diffrenece is not huge, but it's definitely percievable. I never tried, but I guess with a better choice of cap(s) that could be minimized.

 

[Porksoda]

what was the impedence of the resistor after the capacitor?

 

[diablo9]

Quote:

Originally Posted by Porksoda what was the impedence of the resistor after the capacitor?

R1. 4.32K
schematic here；
http://tangentsoft.net/audio/pimeta/misc/schematic1.pdf

 

[Porksoda]

Sorry diablo, my post was in response to Xakepa's A47. The resistor I was referring to is the equivalent of R2 on the pimeta. That and the capacitor set the pass frequency of the filter. I was just thinking that Xakepa's experience might been because of a poor choice of that resistor.