[proton007]

Quote:

Well, I was just guessing that WiR3D was saying the impedance was too low for the amp. What I meant was that I've read of people successfully using the Lyr with the K702 at 62 ohms and the LCD-2 at 50 ohms, so I didn't think that the 55 ohm K240 would be an issue, and that going by impedance alone might not yield the best solutions. I thought that the issue might be with something else like we discussed earlier in the thread, or with the amp, like you said.

Agree.

 

[WiR3D]

Quote:

Well, I was just guessing that WiR3D was saying the impedance was too low for the amp. What I meant was that I've read of people successfully using the Lyr with the K702 at 62 ohms and the LCD-2 at 50 ohms, so I didn't think that the 55 ohm K240 would be an issue, and that going by impedance alone might not yield the best solutions. I thought that the issue might be with something else like we discussed earlier in the thread, or with the amp, like you said.

 
sigh its so complicated because the more factors you bring into the equation the more uncertain things become. 
I guess sensitivity defined as the headphones ability to pick up noise levels is the best way to go about it. But even then I never considered the K242 sensitive, and definitely not in CIEM ranges

 

[Papander]

Pretty sure the amp is at fault here. If you do the calculations with manufacturers sensitivity and impedance numbers, you will notice that K240 is actually harder to drive than the Q701. So they are not "too sensitive".

If you get the Q701 you will also hear the humm noise and probably earlier than with your K240. So I wouldn't suggest on doing that. Return the amp and ask for a new lyr model or change to another brand entirely.

 

[WiR3D]

Quote:

Pretty sure the amp is at fault here. If you do the calculations with manufacturers sensitivity and impedance numbers, you will notice that K240 is actually harder to drive than the Q701. So they are not "too sensitive".
If you get the Q701 you will also hear the humm noise and probably earlier than with your K240. So I wouldn't suggest on doing that. Return the amp and ask for a new lyr model or change to another brand entirely.

I knew I wasn't imagining it! The yare harder to drive, but still not very hard to drive.
 
On a side note the old AKGs are the ones that required a boat load of power correct?

 

[Papander]

Also if you take a look at headphone.com graph for the 240 mkii, you can see a impedance bump in the 100Hz region.

http://graphs.headphone.com/graphCompare.php?graphType=7&graphID[]=2611&graphID[]=2931

@wir3d, well the 240 sextett and monitor were both 600 ohms so they needed lots of voltage.

 

[hikari]

Quote:

Pretty sure the amp is at fault here. If you do the calculations with manufacturers sensitivity and impedance numbers, you will notice that K240 is actually harder to drive than the Q701. So they are not "too sensitive".
If you get the Q701 you will also hear the humm noise and probably earlier than with your K240. So I wouldn't suggest on doing that. Return the amp and ask for a new lyr model or change to another brand entirely.

 
I was told by Jason at Schiit that the 701's and 702's work fine which is why I ordered the Q701's. 
I only have one pair of can's so makes it a bit difficult to test so ordering the 701's will be my final step before returning for something else. 
 
Just trying to understand the audio lingo.

 

[WiR3D]

Quote:

Also if you take a look at headphone.com graph for the 240 mkii, you can see a impedance bump in the 100Hz region.
http://graphs.headphone.com/graphCompare.php?graphType=7&graphID[]=2611&graphID[]=2931
@wir3d, well the 240 sextett and monitor were both 600 ohms so they needed lots of voltage.

DAMN now thats quite a bump, 300%.
 
Hikari what we are trying to say is.... erm, thats actually a good question, but I assume is that it doesnt make sense that the k701 would work and the K240 not. 

 

[hikari]

Yha that was exactly what I think Wired.
But i'm no audio expert and this is what the founder of Schiit is telling me.
 
Thank you at least I am not feeling that off my rocker its not just me. 

 

[hikari]

Wow... 
 
Ok guys the problem was basic. 
I didn't have a 3prong to 2prong AC adapter with me yesterday. 
But I did plug the unit into an APC battery backup figured that would clean any grounding issues. 
Testing in the wall and with the APC and had the hum in both places. 
 
Well today I found a power cord laying around and pulled the ground off of it. 

Low and behold the hum is gone.. 
 
This is weird because it doesn't sound like noise it sound like hum and as I increase the volume so does the hum increase. 
 
really don't understand the ground hum. 
M-audo is USB only use low voltage grounded to computer. 
Computer grounded to APC
Schiit tried ground to wall (even tough this is the same power run the APC is on) also tried in the APC..
 
Thank you all for the educating me I feel more informed now. 
I still have the 701's coming tomorrow will still test them out just because

 

[hikari]

Any how since it's not the unit and works fine with my headphones I published my post at (http://www.lifewithtech.net/reviews/review-schiit-lyr/)
There is video, pics and manuel there as well
 
Here is a copy and past of it
 
 
Company: SCHIIT
Model: LYR
Color: Aluminum
Size: 9 x 6.75 x 3.25"
Weight: 7 lbs
Price: $449
Warranty: 5 Year
Website: www.schitt.com
 
 
About:
Built here in the USA the Lyr is a extremely high-output headphone amplifier with a new Dynamically Adaptive output stage that provides high voltage output into virtually any headphone—up to 6 watts into 32 ohms—while maintaining excellent overall efficiency. Lyr isn’t just about brute force. Sure, it has dynamics to spare, but it also delivers music with grace and finesse. Its hybrid design uses tubes for the input stage, and the topology is DC coupled at the input and output to ensure the purest, most direct signal path.The new Dynamically Adaptive output stage packs almost 6X the output power of Asgard into an amp that runs slightly cooler. (Now, that doesn’t mean it runs cool. If you want a cold amp, you need to look elsewhere.) It works by sensing the current flowing through the output stage, and dynamically reconfiguring from Class-A single-ended to push-pull Class AB. The result is both pure Class-A sound and the ability to drive virtually any headphone, including low-impedance and low-efficiency models. Lyr ships with either new-production JJ ECC88 tubes or NOS GE 6BZ7 tubes. The ability to use different tubes lets you tune the overall sound signature of Lyr to your specific needs.
Specifications:
Headphone Impedance: 8-600 ohms
Gain: 10 (20 dB)
Frequency Response: 2Hz-200KHz, -3dB
Maximum Output: 40V P-P into 32 ohms typ
THD: Less than 0.1%, 20Hz-20KHz, at 1V
Topology: Dynamically Adaptive Dual-Mode Class A, zero feedback, noninverting, hybrid tube/MOSFET, single voltage gain stage, DC-coupled input and output
Tube Complement: ECC88 or 6BZ7 dual triode, 1 per channel (rollable to all 6922/6DJ8/ECC88/6BZ7 types and similar)
Power Consumption: 30W
Size: 9 x 6.75 x 3.25”
Weight: 7 lbs
First impressions: While unboxing you can feel how solid this amp feels with it's Aluminum case. I do like the design and look very much fits right in with Apple's MacPros.  Top drop tubes were easy to install and remove. Flip power switch on that back it a bit out of the way however you will not hit it by accident. Volume knob very smooth no stutter or cracking going from 0-100. I went with the 6N1P tubes which notes to run a bit warmer(heat) on there site.  Since this is a tube amp it does take a few seconds to turn on and warm up. After 14 Seconds from a cold start you will hear a click followed by your audio. I burned in for one night close to 10hours also wanted to see how hot it would get to my surprise even with the 6N1P tubes this unit did not get hot however warm to the touch. I was able to rest my hand fine on the unit. I'm very impressed with the build quality of this unit and it's a plus that it's built in the USA...
Test Gear Setup:

1. Amp: SCHIIT LYR (unit being tested)
2. Stock Tubes: GE 6BZ7
3. Upgrade Tubes: OTK 6N1P (russian NOS tubes stock in Valhalla)
4. Headphones: AKG K240 MK2 Studio
5. Microphone: Heil P40
6. DAC: M-Audio C400
7. Computer: MacPro dual 2.8 quad core (OSX Lion)
8. Software source 1: Itunes (Bitrate: 320bit)
9. Software source 2: Spotify paid account (Bitrate: 320bit)

Sound Quality: The K240's i'm using are pretty neutral which is why I have them for podcasting. I wasn't expecting much of an improvement, however to my surprise the LYR did improve the midrange quite a bit. The LYR has more then enough room to push the K240's. I tend to listen to music on the louder side with these headphones being semi open I would not go past 60% on the LRY.
Unboxing Video:
 

 

[WiR3D]

Quote:

Wow... 
 
Ok guys the problem was basic. 
I didn't have a 3prong to 2prong AC adapter with me yesterday. 
But I did plug the unit into an APC battery backup figured that would clean any grounding issues. 
Testing in the wall and with the APC and had the hum in both places. 
 
Well today I found a power cord laying around and pulled the ground off of it. 

Low and behold the hum is gone.. 
 
This is weird because it doesn't sound like noise it sound like hum and as I increase the volume so does the hum increase. 
 
really don't understand the ground hum. 
M-audo is USB only use low voltage grounded to computer. 
Computer grounded to APC
Schiit tried ground to wall (even tough this is the same power run the APC is on) also tried in the APC..
 
Thank you all for the educating me I feel more informed now. 
I still have the 701's coming tomorrow will still test them out just because

 
wow interesting, the simple explanation is it could be dirty power, but you would need someone with much better electrical knowledge like stv0124 to explain it

 

[proton007]

@hikari
The hum you heard is being created due to a grounding problem, known as ground loop.
Its a hum because its related to the AC signal frequency.
Maybe its a power supply issue, maybe the amplifier power is not completely isolated from the mains.

 

[hikari]

Thanks.
 
This didn't sound like a typical ground loop hum to me. Maybe being a tube amp(never had one before) offset the tone or something...
 
Also seeing that the amp and computer are plugged into different UPC backup's ( have 2 in my office) I didn't think there would be a ground hum problem.
 
And yes I understand this is a safety issue here. I will not be leaving it this way was just posting the findings of the test. 
 
I'm not really sure how to go about getting rid of the hum with out an isolator. 
 
My whole office outlets are run off the same AC line so can't run an extension or anything along those lines. 
 
 
Any thank you guys for all your help. 
It's really nice to find a forum where people try to help each other. 

 

[proton007]

To expand further, I also feel the amp's signal and power should be isolated. The amp part should use the signal ground as reference, otherwise it will amplify any interference from the power supply, which is happening in your case. So I guess there's poor isolation in the amp as well. I'll suggest to use some other amp than Lyr.