Schiit Magni Headphone Amplifier - Page 68

Ok having some more hum/static/buzzing issues.  Using my magni to connect to my HD cable box to watch ondemand and such via RCA cables.  I am getting a loud buzzing/humming that slowly rises and peaks and then falls again in a cycle.  It does not get louder with the volume pot.  It goes away when the RCA's are not connected and I have tried different wall socket and plugging magni into same surge protector as cable box. Just touching either of the RCA cables to the inputs on the magni generates the buzz.  Is this a function of my cable box not grounded properly or just magni is sensitive enough to pick up on this?  I don't hear it when using my E7.    Any ideas? Do I need a DAC with optical?

 

Hmmm, in that little box? 

 

I would think you would need something like this to regenerate the AC wave form: http://www.psaudio.com/shop/p3-power-plant/

Furman makes professional grade products for the music industry.  33yrs.

Think rock concerts.... Pearl Jam, Jimmy Buffet, Prince.

http://www.furmansound.com/page.php?div=01&id=ARTISTS

 

I am very found of my Furman.

Shoot me the Make and Model of your cable box.

I want to look at the docs.

 

First of all the Magni is an Amp not a DAC.

 

You may be cabling up 2 outputs.

Also.  Never ever cable two devices together with the power turned on.

You must power off the cable box.

Edited by Iamnothim - 1/24/13 at 6:33pm

Motorola DCT 3416.  I know Magni is an amp lol I meant adding in a DAC to run optical out from cable box instead of straight from RCA out's.  Wasn't aware I shouldn't be cabling powered devices.  For what its worth when I initially connected them both were turned off.  I'm running from Red/White RCA out on back of cable box to R/W input on my magni.  I also have HDMI running into my TV and an optical audio running out to my HT Receiver.  I could try removing the optical and see if anything changes.

+1 on Furman. Even their lesser offerings are superb for the coin.

A system usually sounds better after " Furmanizing " !! :)
Unusual that the Magni sounds better in my system straight-into the wall. But then again, I'd never use a power conditioner for amplification unless it was a regenerator.

What i'm trying to figure out is what exactly is causing this degraded sound. At first I thought it was the noise filtering, but I don't think that's it.

I think it's just that MOV based surge protection is the cause and maybe that it limits current. Highly impossible you'd think...

I just know that when using a MOV based surge protector it makes my DJ100 too warm and bloated in the bass. Not too badly. Like the soundstage is badly compressed.

 

I think I need this type of surge protector:

http://en.wikipedia.org/wiki/Surge_protector#Transient_voltage_suppression_.28TVS.29_diode

 

I found one in my house labeled as that, but I think it's not really the type i'm looking for because still degraded the sound slightly.

 

I think this is though:

http://www.amazon.com/Furman-SS-6B-Outlets-Standard-Conditioning/dp/B0002D017M

 

Guitar Center sells them and I might pick it up. I don't think it's MOV based and is the type in the wiki link.

 

I bought a Tripp Lite ISOBAR4, but it didn't help since it's MOV base too.

 

I'm not qualified to talk about surge suppressor design.  At least not yet.

I'm reading a lot about electronics fundamentals and a bought a Fluke MM and an Oscilloscope so I can build some kits.

 

Anyway my belief is that sensitive  audio equipment needs more than a simple surge suppressor.  IMO the device must be able to condition the power too.  I cannot talk about the technology that makes it happen.   I just knew what I wanted in a power accessory and thought the AC-215a was a great value.  So I got bought one.

 

I use garden variety APC and Monster surge strip for my media room equipment.   I did not want to pay for conditioning.  However,  I bought the Furman specifically for the Lyr because tube amps are more sensitive than SS.   I am also buying vintage tubes that tend to have micro phonics issues.

I am going to try one my monster powercenter powerstrips and see if that helps the buzzing i am getting.  Currently cable box etc..plugged into cheapest thing possible.

tdoc,

 

I hang my AC-215a off a port on an APC surge strip.  Since it cleans power, I figured it would condition the power from the APC.  (Anyway everything sounds great)

I dedicate one Furman port for the Bifrost and one for the Lyr.

 

The AC215a is rated for 10A RMS power output combined.

That should be enough power that you could plug a conventional power strip into one outlet and power a couple more devices that require clean power.

Ok just so I had my bearings I looked at the manual and the rear connections.

 

I know you did this right but I'm just checking.  Of the 2 vertical rows of 3 RCA connectors you should be in the left side bottom and middle.

As you said.  Red and White.   The RCS above that is the yellow composite video.The right row of 3 are component video.

 

Looks fine to me.  Outputs on the motorola to the Magni inputs.

I have never used Audio out from a cable box.  I have U-verse and a Motorola VIP 1225.

 

I use HDMI for video and Optical Toslink for audio into an Anthem AVM20.

Wish I had more to offer.

Thanks!

Thanks for the response!

btw:

 

B&H has them for $106

That's a great price.

 

http://www.bhphotovideo.com/bnh/controller/home?is=REG&Q=&A=details&O=productlist&sku=379136

Talking about price - in Australia the retailer here has just listed the magni price... It's the same as the O2 at $189 AUD.

Damn I'd been basing my magni vs O2 comparison assuming the magni would be listed approx 20% less.