Sennheiser HD 800 Redux

[spritzer]

It is quite good isn't it... 

[Tyll Hertsens]

Yes....yes it is.

 

[Dusty Chalk]

:kyle:

[spritzer]

Do you have a GS-X or something similar there Tyll?  It's an interesting comparison with the L-2 once you match up the output impedance. 

[complin]

Birgir as the GS-X is aiming to be a zero ohms output impeadance (as other headamp dynamic designs) are you suggesting the 800's need an amp with higher output impedance than this?

Your 48 ohm adapter?

 

I have tried the 800's with various amps claiming output inpeadances varying from 600 ohms down to 100 ohms and personally only found the 800's listenable with the very low impeadance amps (i.e > 1 ohms)

 

Tyll's comments regarding impeadance matching seems to concur with my own listening experience but as he says it is still rather hit and miss!

"Electrical impedance and phase curves show a nominally 300 Ohm headphone, but with a fairly large and wide primary driver resonance impedance change that peaks out at around 100Hz at 600 Ohms. Though headphone amp matching with these headphones seems a hit and miss affair, an impedance swing that large to me would indicate the need for a headphone amp with a lower than 30 Ohm output impedance--but I know it doesn't quite work that way with these headphones."

 

 

 

Do you have a GS-X or something similar there Tyll?  It's an interesting comparison with the L-2 once you match up the output impedance. 

 

Edited July 13, 2013 by complin

[Tyll Hertsens]

"Low output impedance is better" is a good bet usually, but there's something else going on here I don't quite understand.

 

I'd love to hear folks who have a theory expound.

[nikongod]

"Low output impedance is better" is a good bet usually, but there's something else going on here I don't quite understand.

 

I'd love to hear folks who have a theory expound.

I've been saying it for years.

[dsavitsk]

[n_maher]

Is that what shaved high-quality transformers look like?

[spritzer]

Pixie dust is as good an explanation as anything else but I think there are two reasons for this, how the ring radiator behaves and that this is Sennheiser.  The ring radiator has some pretty interesting properties and is clearly undamped in the HD800 so it must need some electrical damping to make it behave and become more linear.  I haven't looked into speaker designs using these but they might be doing something similar there.  They are certainly known for their high HF response so some compensation might be needed to keep them inline. 

 

As for the latter lets bring up the HE60 and HE90.  The drivers in both are kissing cousins aside from the materials used.  Same basic principles, conductive paint on non conductive stators and the same diaphragm material.  Assembly is also very similar though the poly-whatever Senn used on the HE60 meant it could all be integrated into 4 pieces.  Anybody who has listened to these cousins knows how vastly different they sound and more importantly, just how different their amp requirements are.  The HE60 needs power and low output impedance but the HE90 doesn't.  In fact if sounds more placed with higher output impedance.  Transducer size is a factor here as electrostatics are more efficient the larger they are but Sennheiser clearly tampered with the way the drivers behave.  The HD600/650 is a similar case but here the drivers are the same, the baffle is different. 

 

While low output impedance is a good thing there are exceptions that prove the rule.  What I need is a two to 4 gang linear 100R pot to test on the fly but these are not easy to find. 

[jpelg]

Anyone heard the Sennheiser HDVD 800?

 

Headroom specs show it having a 16-ohm output impedance. Not sure if that's for the balanced output, or single-ended, or both.

[spritzer]

I was supposed to get one in February but last I heard nothing had arrived.  It's been confirmed by Sennheiser that the output impedance is 43ohm but they are very tight lipped on the circuit inside.  One of the R&D guys was here in the spring as said the window on top was for people like me, to save me the trouble of opening it up. 

[complin]

Interesting... So could it be a combination of the amps output impeadance and its damping factor?  I know there has been a lot of debate about this with conventional speakers, some say it matters others its irrelevant.  For example many claim that bass from 70's/80's vintage amps is much less controlled due to their damping factor. Amplifiers like the Accuphase E-202 had a control which ebaled you to change the damping factor, I think it had 3 setings. However; it could equally be due to the much better beefed up power supplies we tend to have today.

 

As we all know headphones often magnify these anomolies and seem to be much more sensitive to both the electronics and source than conventional speaker set-ups

 

Unfortunately i'm fresh out of pixie dust   

[spritzer]

Output impedance=damping factor so yeah, it is a huge factor.  With speakers and their often highly complicated crossovers it can be less of an issue but it indeed often overlooked. 

[n_maher]

If nothing else it's evidence that there really isn't an amp that's perfect for everything.

Tyll, any chance that you'll get to measure the L2?

[Tyll Hertsens]

Balanced ins means I'd have to do some re-writing of the test sequence I have now. And since that isn't really finished...

 

...no. Damit.

 

Though I'm tempted to remeasure the HD 800 using that amp and compare it to measurements using the Balanced Desktop I use for headphone measurements.  I'm really curious if something low level might show up. Maybe slightly smoother impulse response or something. 

[crappyjones123]

L2 or dsha for hd650/hd800? No interest in ever getting grados. Would like to know before Doug is sent a pm. You lot are freaking enablers.

Please don't say both.

Edited July 14, 2013 by crappyjones123

[n_maher]

I like glowing glass thingies so my $ is on the L2 but there's no bad choice there CJ.

Tyll, you might ask Doug if there's a way to feed it from a single ended source. I'm almost positive that there is it'd just mean custom cables. Actually I'm sure you can since that's what I did for part of the review until my dac pooped out.

[spritzer]

It's a transformer based input so the amp doesn't care if it is XLR or RCA input.  Just use a normal XLR-RCA adapter and it will work just fine. 

[guzziguy]

I believe that the L-2 and DSHA-1 ship with such adapters.

[Tyll Hertsens]

I'll look around to see if I have some adapters. None in the box I got, but it wasn't really a "production" shipment.

 

Still loving the shit out of it, BTW. I can't wait for the SR-009 to come in because the HD 800 slays the Abyss and LCD-3 in the current set ups.

 

MacBook>Ayre QB9 USB DAC>

 

L-2>HD 800

 

HiFiMAN EF-6>LCD-3

 

Burson Conductor>Abyss

 

Blue Hawaii>SR-009 coming soon!

[dsavitsk]

Output impedance=damping factor so yeah, it is a huge factor.  With speakers and their often highly complicated crossovers it can be less of an issue but it indeed often overlooked. 

 

I tend to think it is the opposite. With complicated crossovers, a non-zero Zout will lead to the crossovers operating at a different point than they are designed for. It is likely part of the reason that high Z out is not that detrimental to headphones -- they are more like single driver speakers in this regard.

 

 The ring radiator has some pretty interesting properties and is clearly undamped in the HD800 so it must need some electrical damping to make it behave and become more linear.

 

Again, I'd think the opposite: if the drivers are not damped, then you would want a lot of electrical damping. As it is, since high damping factor seems to over damp things, that suggests that the drivers themselves are reasonably well damped.

 

On the other hand, output impedance may well be a red herring here. If the drivers are not damped, then they would kick back lots of back emf, and it could be that they don't play well with amps with lots of feedback due to this. So perhaps they need some electrical damping (and 300/50 = 6 is actually a reasonably high damping factor) and that you want enough, but want to avoid doing it via feedback to keep from generating high order harmonics.

 

Here's the L-2's THD which, if nothing else, is free from high order distortion.

 

 

L2 or dsha for hd650/hd800?

 

DSHA-1 is sold out, if that makes things easier

 

I'll look around to see if I have some adapters. None in the box I got, but it wasn't really a "production" shipment.

 

Adapters are not included, but I end up supplying a lot of them. Part is Neutrik NA2MPMF.

[spritzer]

Could very well be that I've got it backwards as dynamics really aren't "my thing".  The opposite is certainly true for electrostatics but then again we are worlds apart there in almost every aspect of transducer behavior. 

 

The damping factor would actually be higher since the impedance is often quite a bit higher than 300R according to the Headroom graph. 

 

Edit: Won't allow me to attach pnp's so here is the link:

 

http://graphs.headphone.com/graphCompare.php?graphType=7&graphID[]=2321&scale=5

 

Very odd curve to say the least...

Edited July 14, 2013 by spritzer

[K3cT]

I'll look around to see if I have some adapters. None in the box I got, but it wasn't really a "production" shipment.

 

Still loving the shit out of it, BTW. I can't wait for the SR-009 to come in because the HD 800 slays the Abyss and LCD-3 in the current set ups.

 

MacBook>Ayre QB9 USB DAC>

 

L-2>HD 800

 

HiFiMAN EF-6>LCD-3

 

Burson Conductor>Abyss

 

Blue Hawaii>SR-009 coming soon!

 

Are you still running your HD800 modded, Tyll? 

[Tyll Hertsens]

Yupper.