Sennheiser HD650 & Massdrop HD6XX Impressions Thread
Sep 1, 2015 at 12:05 PM Post #28,456 of 46,534
Thanks to all of the replies here, lots of good information.  I went ahead and ordered the JDS Labs O2 Amp+ODAC Custom with the 6.3mm jack instead of the standard 3.5mm.  At ~$300 I felt like it was a good starting point that I wouldn't want to upgrade immediately but also wouldn't need to take out a second mortgage for.  I'll report back later this week after I receive it!
 
Sep 1, 2015 at 4:35 PM Post #28,457 of 46,534
  Thanks to all of the replies here, lots of good information.  I went ahead and ordered the JDS Labs O2 Amp+ODAC Custom with the 6.3mm jack instead of the standard 3.5mm.  At ~$300 I felt like it was a good starting point that I wouldn't want to upgrade immediately but also wouldn't need to take out a second mortgage for.  I'll report back later this week after I receive it!

Congrats and enjoy your new sound.
 
Sep 1, 2015 at 8:54 PM Post #28,458 of 46,534
Changing gears...are there any larger ear cushions available out there?  The default cushions are big enough to fit around my ears but they aren't deep enough which causes my ears to push against the foam discs on the inside.  I feel like an extra 1/2 inch of depth would give me the room I want, but I'm not really looking to get into arts and crafts to adjust them.
 
Sep 1, 2015 at 9:15 PM Post #28,459 of 46,534
Are these new or used headphones?
 
Sep 1, 2015 at 9:27 PM Post #28,460 of 46,534
Brand new.  Maybe they're supposed to fit like this, but they aren't as comfortable as the PC 363D that I just switched from.  Looking at the PC 363D's the difference seems to be that the cushions on those sit on top of the housing while the HD 650 cushions are recessed into the housing.
 
Sep 1, 2015 at 9:35 PM Post #28,461 of 46,534
I would give them time, you may adjust to the feeling and you won't notice it.  Mine just touch my ears, and at first it was something I noticed but it does not bother me now at all.  Changing the ear pads will change the sound of the headphones. This is from an article from the designer of the Ember amp.......
HD650 pads
The measurements of the headphone above are made with a black driver + old type pads.
Most likely the old pads once were a bit stiffer and the foam inside will be somewhat decayed/softened over time.
The newer pads indeed sound ‘brighter‘ and ‘clearer‘ and relatively the old pads sound ‘darker’ or ‘warmer’ with less clarity/treble presence.
I was curious what caused the differences as side by side they looked very similar in height.
The old pad = 30mm high, the new pad 32mm, the colour of the new pad is darker and the velours of the newer pads feel less ‘soft’ to the skin.
The new pads also come with new foam inlays.
The new pads have the product code: 050635. They are suited for HD545 / HD565 / HD580 / HD600 / HD650 / HDI850.

Time for some measurements to show the differences between the 2 pads (right channel only).
The measurements are done with the same test-voltages from a low output R amplifier and the same driver/channel.
The old pad has a good 2dB more presence below 1000Hz and is also a bit louder in SPL. The amount of treble (> 4kHz) is about the same level.
The new pad is more balanced and the ‘warmer’ signature is gone. More towards the HD580 / HD600 signature.

What isn’t very obvious when wearing these is the fact that the old pads compress a lot more than the newer (less compliant) ones.
When placed on the test rig this became quite evident though.
Quite possible the older pads may create a slightly better seal on some heads (depending on bone structure) as well.
Using the older pads the drivers are thus much closer to the ears which results in a slightly higher SPL below 1kHz.
To check if the pad thickness is indeed the only parameter that changed I pressed the new pads against the rig to the same driver-rig distance as the old pads did by themselves. Below the result of this small test.

This test shows that the newer pads do not have any different absorbtion or other acoustical effects and the differences in sound signature and SPL between the two pads is now the same. They sound equally ‘warm’ under these conditions.
What became quite obvious is that while the old and new pads differ only slightly in height when laying flat on the table (30mm vs 32mm) as shown in the picture above, but the pads compress in a substantially different way when being pressed against the skull with the same clamping force.
Below 2 pictures of both pads with 1kg weight on top of them. Roughly equating to about 10 Newton force which is a bit north of firm pressure but it shows the differences better.
With 10N on the entire surface of the pads the total height of the pads was reduced from 30mm to 20mm. Considering the mounting plate was also included (which is 5mm) the actual pad thickness reduced from 25mm to 15mm a 40% reduction.

Below a picture of the new pads with the exact same weight pressing on it. With 10N on the entire surface of the pads the total height of the pads was only reduced from 32mm to 27mm. Considering the mounting plate was also included (which is 5mm) the actual pad thickness reduced from 27mm to 22mm a 20% reduction.

The question of course is whether or not the old pads had been (much) stiffer when new which is quite likely as the foam inside the pads deteriorates over the years.
If that’s indeed the case then the sonic signature must have become ‘warmer’ over the years without me really noticing it….
 
Sep 1, 2015 at 9:59 PM Post #28,463 of 46,534
Once you get a decent amp you won't notice much other than the music! 
 
Sep 1, 2015 at 10:39 PM Post #28,464 of 46,534
^^^^
Agreed.  
smily_headphones1.gif

 
Mike
 
Sep 2, 2015 at 11:36 AM Post #28,465 of 46,534
I'd been holding off a bit on really commenting on the HD-650 with the Bryston BHA-1 amp. I purchased the BHA-1 from a fellow Head-Fi'er via CAM because I'd heard good things about it, and wanted to try another SS amp (the Gustard H-10 was too warm with the 650's for my taste), and wanted to try going fully balanced from the Teac-UD-501 DAC to an amp and to the headphones.
 
I few cables later I was able to try this out, so here's some (scattered) thoughts:
 
- the BHA-1 is a brighter amp than the H-10 with great detail and quite neutral signature
- the SE output on it uses 1/2 of the amp circuitry, not unusual
- when I tried the SE output with the HD-800 it just didn't have the ooomph to drive 300ohm cans to their full potential, as others have noted in it's thread
- I recently received some custom balanced cables for both the 800 and 650, and the 650 was first up for a listening test, so here's the thoughts
 
- right away the soundstage opened up, very surprising since both IME and as read here the 650 is naturally on the intimate side of the soundstage spectrum
- the tonal signature of the 650 (mid-bass hump and slightly rolled-off highs) paired very well with the neutral-to-brighter BHA-1
- the resulting combo was a real pleasure. The stage was wider and less three-blobbish, the mid-bass bloom disappeared and the highs were more detailed and lively, leading to, I suspect, the increased perception of a wider stage and more air
- there is plenty of power on-tap in balanced mode to drive 300ohm cans to full potential
- detail was very good as expected with a SS amp, without being overly harsh or digital-sounding
- deeper bass was still missing as I expected as neither the 650 or the BHA-1 have much emphasis here
 
Overall it's a great pairing. I think it lacks a little of the musicality I get from my tube amps and is perhaps a bit more digital and grainy than the Crack or S.E.X. With the 650 it has a much more well-rounded or neutral sound than with the H-10, with less mid-bass but more FR balance and a wider field. I fear it may be a bit bright with the HD-800 which I'm only just warming to (pun intended) but I'll find out today.
 
I think I prefer the tube amps with the 650 over the BHA-1 for their musicality as they're more involving and a touch less analytical, but for those who prefer SS (20 year warranty!) or need a wider stage for classical or large-venue performances it's a very worth amp. Factor in the cost of the balanced cables though or you will be disappointed.
 
In it's price-range it matches head-to-head with a Bottlehead Mainline which is supposed to be a very good tube amp and also capable of more than just high-impedance drive. I'm hoping to put that to the test sometime early in the new year.
 
Hope anyone considering this well-regarded and well-built amp finds the above useful, although it's just my opinion after perhaps 10hrs of listening time in balanced. Look forward to any thoughts from others who have tried the pairing!
 
Sep 2, 2015 at 11:53 PM Post #28,469 of 46,534
  @DDDamian, great info on the H-10 and BHA-1, glad I listened to you and others on not getting the H-10 a few months ago.

 
Glad it was useful. The H-10 is a great deal but IMO just not the best with the 650. Perfect for the HE-400. Plenty of power at a great price. The op-amp rollers on its thread have found some other, maybe less-coloured op-amps but with the upgraded combo I have in there it is tilted a bit much to the warm side. I'm pretty sure it's the amps flavour (caps, filters, etc) that make the biggest difference over the specific op-amp model. The BHA-1 is much more transparent and neutral.
 
  Hi im new to Head-Fi, can anyone tell me if the HD650 since it's an open headphone leaks the same volume that the user is listening too?

 
Welcome to Head-Fi :) It leaks a lot (as all open-style cans do). Maybe not equal amounts inside/outside but near enough.
 

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