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Schiit Mjolnir headphone amplifier - Page 111

post #1651 of 3200

Thank you for posting your findings WilCox along with posting a result for the BHA-1 as well.

 

Quote:
Originally Posted by WilCox View Post

 

Measured both my Mjolnir and Bryston BHA-1 tonight with my trusty P3 Kill A Watt EZ and got the following results:

  

HPA

Active Power

RMS Current

RMS Voltage

Power Factor

Line Frequency

Apparent Power

Mjolnir

26.1 W

0.27 A

122.8 V

0.77

60 Hz

33.8 VA

BHA-1

36.3 W

0.38 A

122.9 V

0.76

60 Hz

47.7 VA

 
No measureable change in power consumption when playing loud music with LCD-2.  Not surprising since both are high bias class A.
post #1652 of 3200

I currently use my Lyr per amp to KRK Rokits. I would like to use the Mjolnir with my KRK's if I decide to get it.

post #1653 of 3200
Quote:
Originally Posted by purrin View Post

Well that certainly puts Nelson Pass to shame. I hope the Sumo Ten didn't start fires in the electrical wiring of older homes.

I kind of doubt it, it's still less than the typical 1500 watt space heater.
post #1654 of 3200
Quote:
Originally Posted by Jason Stoddard View Post

 

Sumo Ten = 1200W. Of course, it's a speaker amp.

 

1200W for a speaker amp? Ouch!  It can either be seen as a absurd waste of electricity at today's prices or efficient combination entertainment/home-comfort-system devices. eek.gif  "Fanless, silent heat for your audiophile listening room."  Still, that's nasty for trying to locate hardware in a rack!  Or near one!

 

I wonder if the Green Police would let you build one of those things today?  very_evil_smiley.gif   That would be a lot of compulsory peach tree plantings....

 

Quote:
Originally Posted by Jason Stoddard View Post

 

Yes and yes. Of course, it also had 25" x 7" x 2.75" of heatsink on each side of the amp with fins every 0.375" (just looked at the old drawings). This is what I reference when people say, "Asgard runs hot." Ahhahahhaahahhahaaahaha! No.

 

Geez, and I thought Onkyos ran hot....

post #1655 of 3200
Quote:
Originally Posted by WilCox View Post

 

Measured both my Mjolnir and Bryston BHA-1 tonight with my trusty P3 Kill A Watt EZ and got the following results:

  

HPA

Active Power

RMS Current

RMS Voltage

Power Factor

Line Frequency

Apparent Power

Mjolnir

26.1 W

0.27 A

122.8 V

0.77

60 Hz

33.8 VA

BHA-1

36.3 W

0.38 A

122.9 V

0.76

60 Hz

47.7 VA

 
No measureable change in power consumption when playing loud music with LCD-2.  Not surprising since both are high bias class A.

 

Forgot to show the calculations......

 

Apparent Power  = Voltage X Current

 

Active Power = Voltage X Current X power factor

 

power factor = Cosine (phase angle)

where the phase angle is the phase displacement between the voltage and the current.

if the load is resistance only, then the voltage and current will be in phase, i.e. phase displacement = zero degrees and therefore power factor = 1.0

 

this really tells us almost nothing about the quality of the amps except with that kind of Active Power draw they must be heavily biased into Class A

post #1656 of 3200
Quote:
Originally Posted by jronan2 View Post

Balanced out would mean its also a pre-amp correct? It didn't mention this on Schiit's website, that's why i'm asking. Has anyone has studio monitors hooked up to their Schiit? How do you like it?

I was using M-Audio CX-8/SBX-10 with the Mjolnir. The subwoofer and the M didn't play nice together. When both were hooked up, there was a nasty ground hum. If I removed either of them from the chain, no hum. It served as a great excuse to upgrade to Goldenear Triton2 towers using an Emotiva XPA-2. It sounds heavenly. Very big stage. Very smooth. None of the dreaded 3 blob stereo.

 

There is still a very slight hum at idle when I shove my ear inside the drivers, but it's inaudible when any signal is going through it. Only problem is the dreaded Gungnir "glitch" (brief, sporadic hi freq. resonance/squeal). I hear Mike's doing more equipment torturing to track down the problem.

post #1657 of 3200

Quote:

Originally Posted by kLevkoff View Post

 

From what Chris J says, the BHA-1 has a real balanced input. The main benefit of a balanced input is that it has common mode rejection. This means that any signal equally present on both input lines is rejected (the music is carried as a *difference* between the two inputs). The main benefit of a balanced input is that any hum picked up by the interconnects (which is picked up equally and in phase by both signal leads) is cancelled and so disappears. This is strictly a matter of the *input circuitry* being balanced.

 

The main benefit to differential amplifier sections is that, since you are using two of the same amplifier out of phase, the distortion and nonlinearities of both cancel out, presumably giving you lower overall distortion and possibly lower noise. This is quite separate from the benefits of a balanced connection.

 

Maintaining a fully balanced fully differential signal path all the way through isn't always a plus, however. True, you get a fully symmetrical signal path, which should lead to lower distortion. You may, however, actually end up with more noise. Let's assume you DO have hum on those input lines. If the balanced input is converted to single ended, the hum is cancelled out at that stage. If, instead, the device is "fully differential", then each half of the amplifier will amplify the hum that was present on its half of the input. If everything works perfectly, the hum will indeed be cancelled at the output. But, if there are flaws elsewhere, or you connect the output to a downstream component that doesn't have a real balanced input, then the hum will suddenly reappear at that point (since it never had a chance to really be cancelled). In that case, a device that had a balanced input, but converted the signal to unbalanced at the input, will actually deliver *less* noise.

(You have the hum flowing through both halves of the amplifier, with the assumption that it will be cancelled at the output.... when maybe it would have been better to eliminate it at the input stage.)

 

kLevkoff

 

-------------------------------------------------------------------------------------------------------------------------------------------

 

While I certainly did hope I would have stopped discussing the topology differences between Mjolnir and the Bryston BHA-1, this excellent post from kLevkoff leads me to make one post more. But this may very well be the last one.

 

Why? Because when reading the quoted post, the BHA-1 topology suddenly started making sense to me. Then the differences between the two made sense, and something subtle about why the Mjolnir is built so different finally settled in my mind. This is my interpretation, don't take it as anything else.

 

A key thing to note is that the BHA-1 is aimed to please the professional crowd as well. There's a version that will mount in a standard 19" rack. The topology of the BHA-1 makes sure that the main benefits of balanced connections and balanced amps (as outlined in kLevkoffs post) are made good use of, regardless of the situation.

 

The Mjolnir is not about serious business. The Mjolnir is about fun. The topology of the Mjolnir is about achieving maximum performance for the money, and that is achieved by not caring too much about other things. Like unbalanced headphones, for example. Or the not-very-likely case that kLevkoff explains in the last paragraph. Audiophiles, as opposed to audio professionals, can rather like to have a little challenge in getting the best sound possible out of their rig.

 

Let's wrap this up with a car analogy, just because I like those. If the BHA-1 is a Porsche Cayenne, the Mjolnir is a Lotus Elise. Performance-wise, they're not that far from each other. But if you end up on a bumpy road the small sports car will be uncomfortable (hum or some other interference), if you end up in a forest it gets stuck (that's the unbalanced headphones). The SUV will still be going. On smooth roads (no problems) it's just a matter of taste. On a tight and twisty road, the Elise would be more fun, and it would have the upper hand in performance. On autobahn, the Cayenne would be the more comfortable, and be the performance leader. The Cayenne is clearly the more versatile, but it's also double the cost... this analogy is indeed spot-on.

 

 

Well, I'm going to bed. See you tomorrow, I guess :)

 

EDIT: Tried to find the reason the quote lost it's frame, but I couldn't.


Edited by O8h7w - 10/23/12 at 2:44pm
post #1658 of 3200

Here's another thought.....

 

Modern music tends to be more highly compressed than older recordings.

 

Assuming that the files were properly encoded, the maximum signal level (0 dB) is fixed.

This means that, if the older files are less compressed (=greater dynamic range), then the AVERAGE level on them will be lower.

Since your brain judges "loudness" based mostly on average level, that means that you will have to turn them up higher to get the same average level.

(Since the newer files are more heavily compressed, they actually sound louder at a lower gain setting...)

 

 

 

Quote:
Originally Posted by mikek200 View Post

Not sure,I am posting this in the right thread,or.??..anyway,here goes:

 

A few days ago,I got delivery of the mjolnir & He-6's

After many,many hours of testing,with certain typed of music,mostly classical,& some vocals...I'm finding that I have to crank up my volume levels to about 3 o'clock..these are older cd's that I downloaded as apple lossles files

On newer rock,jazz,blues cd's..that have been recently purchased ...the volume levels are around 11-12-1 o'clock.

 

Is it safe to assume,that the higher volume levels needed on the older cd's are  a result in poor recording qualities?

OR ,should I assume the Mjolnir,cannot properly drive the He-6.? ..and... a speaker amp ,might be needed??

Has any other head-fier experienced this ,with this particular  setup?

 

I should add,that I also have the Lcd-2's,and my usual volume level is around  ..9-11 o'clock

I know the lcd's are much easier to drive..

 

Any advise will be greatly appreciated.

Thanks,

Mike

post #1659 of 3200

Suggestion about USB noise.....

 

I haven't had this sort of trouble with my Bifrost, but I have had other DACs occasionally pick up assorted chortling noises and such (you usually get little whining, chortling, and zizzing noises rather than hum) when connected via USB. It is common with USB -powered mini-DACs, but can happen with others. Since it's really a matter of the computer's dirty ground disagreeing with the audio system ground, it can also pop up later when you connect something else that's fussy about ground to the DAC. If this is what's happening, there is a very simple solution....a "USB galvanic isolator".

 

Note that this is NOT an expensive USB/SPDIF interface (like the HiFace or the AudioPhilleo); it's just a little gadget that goes between your computer's output and the USB cable you connect to the DAC - it isolates the signal and USB power from the computer's ground (basically, it's a ground loop isolator for USB). (Some DACs already do this internally, but most do not.) It's really worth trying if you have this sort of problem and use USB - and it's worth having one in your toolbox. You can get expensive ones, but the $30 - $40 ones work just fine. Olimex makes a cheap one that people seem to like; I've got one I ordered from these guys (in a nicer box than the Olimex) for about $50 that seems to work fine. There are plenty of others. (You want one based on the Analog Devices ADUM series isolator - which most of the cheap ones are).

 

 

 

Quote:
Originally Posted by tokendog View Post

 

I haven't experienced any of those issues with my Schiit gear, but it's something to watch for.  I have a Mjolnir coming this Tuesday and I'll see if it has any of the issues you mentioned.  The Lyr is somewhat known for the noise, but I haven't read much about the Mjolnir having those issues.

post #1660 of 3200
I thought Schiit dacs already had galvanic isolation. I seem to recall it being in the group of techobabble Jason mockingly listed when the Bifrost came out.
post #1661 of 3200

Hi Jason,

 

I saw Schiit's importer's web in Taiwan.

 

They said they'll provide XLR to 1/4 plug adapters for customers who don't has balanced mod. with headphone cable.

 

So, it's that safe to use adapters?
 

Thanks!

 

Pal

post #1662 of 3200
Quote:
Originally Posted by palchiu View Post

Hi Jason,

I saw Schiit's importer's web in Taiwan.

They said they'll provide XLR to 1/4 plug adapters for customers who don't has balanced mod. with headphone cable.

So, it's that safe to use adapters?

 
Thanks!

Pal

No, it's been said multiple times that shorting the negative outputs together like that will trip the mjolnir's protection circuitry. You won't get sound
post #1663 of 3200
Quote:
Originally Posted by SoupRKnowva View Post


No, it's been said multiple times that shorting the negative outputs together like that will trip the mjolnir's protection circuitry. You won't get sound

But obviously the Taiwan importer has tested this out and it's fine. Thus, why they're selling adapters, right...

post #1664 of 3200
Quote:
Originally Posted by SoupRKnowva View Post


No, it's been said multiple times that shorting the negative outputs together like that will trip the mjolnir's protection circuitry. You won't get sound

 

Yeah, but will it at least work as a small space heater?

post #1665 of 3200

I have an adapter that was made by Zu Audio a while ago when I purchased my Mobious cable from them, it go in the 4pin xlr to a female 1/4".  It works on my LD MK6 and it works with my Mjolnir.  But since most of my cans are now recable to 4pins I dont use the adapter anymore.  I was able to test the D7000 which I never modded it.  What is cool is I got a dual 3pin xlr adapter to 4pin, now that way I can listen to two cans in the same time with the Mjolnir.  Very good when comparing cans. 

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