[Solrighal]

I have both the Q701 & the HD 650. I previously owned the O2 and while it could drive both headphones it wasn't until I heard them powered by a Project Ember that it all started to make sense. Both headphones like power but the HD 650 sounds decent with almost anything but that's not the case with the Q's. They really benefit from masses of current, almost transforming them. I say almost because for me they're still too uneven in their frequency response. There's a spike at 2k that's just painful to me. EQ can help with this but that has knock-on effects elsewhere in the FR. They are also the most uncomfortable headphones I own, due to a combination of bumps on the inside of the headband and very firm earpads. Not for me & now up for sale.
 
The Hd 650's sound pleasant amped with the O2 and if that's all you ever heard I think most would be happy. But driven by a good valve amp they come alive. Some say the treble is recessed but I prefer to think most other headphones have emphasized highs. The bass is real & present, but not too bloated. You buy the HD 650 for the mids though. Totally lush! Vocals are sublime. If they have a weakness it would be - as others have said - the soundstage. It's not huge, particularly if compared back-to-back with the AKG's. So classical is not their forte. Having said that the soundstage does increase to a level I'm comfortable with when driven by the Project Ember. From what I've read the 650 may be even better with the BH Crack. The HD 650 is also the most comfortable headphone I've ever used.

 

[Krutsch]

   
The only genre that I personally do not feel that the 650 excels with is classical. Still it's pretty darn good. It's just that once you've heard classical on the hd800 everything else will be a let down. The 650 will sounds pretty good from any modest source but it's ability to scale with good amps like the Crack will make the goosebumps stand at attention. 
 

 
+1 ... completely agree.

 

[kman1211]

I have both the Q701 & the HD 650. I previously owned the O2 and while it could drive both headphones it wasn't until I heard them powered by a Project Ember that it all started to make sense. Both headphones like power but the HD 650 sounds decent with almost anything but that's not the case with the Q's. They really benefit from masses of current, almost transforming them. I say almost because for me they're still too uneven in their frequency response. There's a spike at 2k that's just painful to me. EQ can help with this but that has knock-on effects elsewhere in the FR. They are also the most uncomfortable headphones I own, due to a combination of bumps on the inside of the headband and very firm earpads. Not for me & now up for sale.

The Hd 650's sound pleasant amped with the O2 and if that's all you ever heard I think most would be happy. But driven by a good valve amp they come alive. Some say the treble is recessed but I prefer to think most other headphones have emphasized highs. The bass is real & present, but not too bloated. You buy the HD 650 for the mids though. Totally lush! Vocals are sublime. If they have a weakness it would be - as others have said - the soundstage. It's not huge, particularly if compared back-to-back with the AKG's. So classical is not their forte. Having said that the soundstage does increase to a level I'm comfortable with when driven by the Project Ember. From what I've read the 650 may be even better with the BH Crack. The HD 650 is also the most comfortable headphone I've ever used.

Comfort, the strange soundstage/imaging, and that annoying rough patch in the 2khz is why I didn't like the Q701 much when I borrowed it. Those bumps are torture devices. The K712 I found fixes all these issues for me, it's so comfy and it actually sounds lush with HD 600/650 like vocals. The HD 650 does love extra power and just sounds very sublime, especially with better gear. AKGs can sound quite bad when underpowered, though it's nothing like my experience with the T50RP, now that thing sounds horrid underpowered. I really want to hear the HD 650 on the Crack, I hear so many good things about that pairing. My Lyr 2 is a good combo for the HD 650 but honestly the K712 sounds better on the Lyr 2.

 

[ZachPtheDude]

The bottlehead crack is entirely worth it. The stock kit punches far above it's weight class (specifically for driving high impedence headphones), and if you add the speedball kit at checkout, coupled with some patience on ebay you can spend less than $200 replacing both coupling caps with film caps, installing a c7x triad choke and replacing the final psu cap with a 100uf film cap, and bypass caps for the other two psu capacitors if you really feel the need. If you know the HD650s are your headphone then you'll have a hard time finding any amp $500 or under that competes. Plus you've built it, you've modified it down to your own personal tastes. That is the real fun.

Edit: I didn't go for the speedball myself, maybe in the future but the fact that it changes the sound character of the crack I'd prefer a proper comparison between the two before I make the purchase. Tuning it for my own personal tastes is one of the selling points after all .

 

[kman1211]

The bottlehead crack is entirely worth it. The stock kit punches far above it's weight class (specifically for driving high impedence headphones), and if you add the speedball kit at checkout, coupled with some patience on ebay you can spend less than $200 replacing both coupling caps with film caps, installing a c7x triad choke and replacing the final psu cap with a 100uf film cap, and bypass caps for the other two psu capacitors if you really feel the need. If you know the HD650s are your headphone then you'll have a hard time finding any amp $500 or under that competes. Plus you've built it, you've modified it down to your own personal tastes. That is the real fun.

Edit: I didn't go for the speedball myself, maybe in the future but the fact that it changes the sound character of the crack I'd prefer a proper comparison between the two before I make the purchase. Tuning it for my own personal tastes is one of the selling points after all .

I should learn how to put together something like the crack sometime. It's a project I'll consider down the road. I do want to get an OTL amp eventually, most of my headphones are high impedance and as good as the Lyr 2 is with a large variety of headphones both low and high ohm, it's not the ideal match for higher ohm headphones. It's best for AKGs and Planars. I'm still trying to figure out if the HD 650 is it for me, it's definitely one of my all time favorite headphones I've owned and the comfort is superb. The HD 650 is one fantastic headphone, but I get the feeling it's held back a bit. I bought the Lyr 2 mainly for the K712 before I had either the HD 600 or HD 650.

 

[ZachPtheDude]

If you feel it's held back and you haven't at least sampled the 650s with an OTL tube amp then I believe that is your missing key

 

[Krutsch]

If you feel it's held back and you haven't at least sampled the 650s with an OTL tube amp then I believe that is your missing key

^^ this ^^ ... and, FWIW, I will also put in a shameless plug for my fav OTL - the Woo WA3.
 
The Crack gets lots of love on this forum, with the DIY 'cred and great sound. I've listen to BH Cracks (both with and without the Speedball upgrade) and it's nice, but like the Woo WA3, tube choice matters - a lot.

 

[kman1211]

^^ this ^^ ... and, FWIW, I will also put in a shameless plug for my fav OTL - the Woo WA3.

The Crack gets lots of love on this forum, with the DIY 'cred and great sound. I've listen to BH Cracks (both with and without the Speedball upgrade) and it's nice, but like the Woo WA3, tube choice matters - a lot.

The WA3 is an OTL amp I've been eyeing. I have heard the HD 650 on an OTL, the WA2, it's why I know it's held back.

 

[DavidA]

 
^^ this ^^ ... and, FWIW, I will also put in a shameless plug for my fav OTL - the Woo WA3.
 
The Crack gets lots of love on this forum, with the DIY 'cred and great sound. I've listen to BH Cracks (both with and without the Speedball upgrade) and it's nice, but like the Woo WA3, tube choice matters - a lot.

Hi Krutsch,
Have you heard the WA7 paired with the HD-650?  I was looking for a DAC/AMP combo, less clutter on my table.  I'll probably look in the WA7 thread but it seems like you have some experience with Woo Audio products.

 

[MattTCG]

I found that the wa3 was a good amp for the 650. But when compared head to head the Crack with speedball is clearly better IMO. The Crack ,in simple terms, resolved the music better, offered a appreciably larger sound stage and better dynamics. 
 
Of course the wa3 comes pre-built which is a nice bonus for many. The chasis is chiseled from heavy aluminum and it's build like a tank. The Crack has that old school retro vibe with the wood base and steel top plate. 
 
The Crack is upgrade friendly whereas the wa3 is upgrade challenging. The Crack also hold the bang for the buck crown when it comes to pricing. 
 
Honestly, when I think about this comparison, the wa2 makes  better head to head competition for the Crack IMO. 

 

[mikoss]

  Hi Krutsch,
Have you heard the WA7 paired with the HD-650?  I was looking for a DAC/AMP combo, less clutter on my table.  I'll probably look in the WA7 thread but it seems like you have some experience with Woo Audio products.

FWIW, I think the WA7+HD-650's sounds "good" but not "great"... The WA2 sounds much better (to me). 
 
The WA7 tube power supply with NOS Mullard 12au7 tubes helps to make it sound "better" with HD-650's, but it still just doesn't shine as much as the WA2.
 
(I own both amps and find the WA7 sounds best with low-impedance phones... Haven't heard the WA3 myself, and all of my subjective findings are based on the fact that I enjoy the romantic HD-650 sound.)

 

[DavidA]

  FWIW, I think the WA7+HD-650's sounds "good" but not "great"... The WA2 sounds much better (to me). 
 
The WA7 tube power supply with NOS Mullard 12au7 tubes helps to make it sound "better" with HD-650's, but it still just doesn't shine as much as the WA2.
 
(I own both amps and find the WA7 sounds best with low-impedance phones... Haven't heard the WA3 myself, and all of my subjective findings are based on the fact that I enjoy the romantic HD-650 sound.)

Thanks for the info.  What DAC do you use with the WA2 if you don't mind me asking?
 
I currently have mostly low-impedance phones: LCD-2f, HE-400/400i/560, SRH-1840, HD-700, RS2e, the HD-650 is currently the only high-impedance phone so the WA2 might not be the best way to go ATM, maybe somewhere down the line if I get more high-impedance phones I'll look at a OTL design like the WA2.

 

[mikoss]

Just using an upgraded Aune T1 which is a tube buffered 24/92 usb DAC for now with the WA2. I also heard good reviews with the Bifrost.

Judging from your headphone inventory, I think the WA7 would be a good choice. Go for the tube ps if you are able, it certainly improves over the stock power supply.

 

[DavidA]

Mikoss, thanks for helping me along.  I was taking to a friend and he as a WA7d that he will let me try.  He also said that he has a Project Ember that I might try so looks like my wallet will be very thin for a few months.
I really like the Bifrost, mostly because its the same size as the Lyr2/Asgard2, but these amps get hot, they say they will get hot but coming from a computer background you try to keep things a cool as possible so I have 140mm fan run off my main rig cooling the Lyr2/Asgard2.

 

[brewmansam]

I just received my Teac HA-501 a few days ago.  I wholeheartedly agree that it is a magical combination with HD 650's.  I never want to come out from under the cans.