[cdma2k]

 

 
2 comments:
1. for ultimate SQ, class A is the only choice, not even dynamic biased
2. in fact, class A is a good complement to k612 for warmer, smoother and more liquid sound signatures.

 
I think class A is maybe slightly overrated, I've owned several fullsized stereo amps utilizing pure class A and I've never been struck by any awesomeness or superiority. Quite simply, either a amp is good(well designed) or not regardless of technology used. Class A is just the simplest way(for the engineer) to remove crossover distorsion, at the cost of heat, electricity and durability, The said crossover distorsion can be reduced enough to not be noticeable using more complicated techniques than just pure class A, but requires slightly more skill by the constructor. And there are many other types of distorsion and colourations that may affect a certain amp more than the amount of constant bias applied. For me class A is mostly a buzzword amongst many.
 
Most high class stereo amps do have some constant bias turned on, to reduce distorsion at low level listening, up to 1-5W or so for full sized systems. I'm not talking about headphone amps here. When playing very loud the amount of competing distorsion types rises quickly, like cone breakup, resonances and acoustic distorsions etc etc etc so that any miniscule amount of crossover dist may be impossible to detect anyway.

I agree with you on "class A is maybe slightly overrated" in the sense that not all class A amps are the same. Put it in another words in short, not all the class A amps make the great sound, but it has to be the class A that makes the ultimate SQ. Speaking of distortion and coloration, the rule of thumb is that the signal path between the source and your ears has to be short and simple.

 

[Koukol]

  If you can pick one up used the Keces HA-171 amp works magic with my K612's. My LDMKIII drives them fine but I prefer the Keces. I tried them with my O2 but don't remember off hand how that went.

I have the Little Dot III
Can you tell me why you prefer the Keces?

 

[CADCAM]

 
I have the Little Dot III
Can you tell me why you prefer the Keces?

There is something about the K612 & Keces amp pairing that just clicks for me (IMHO). I initially was going to sell the K612's because I really didn't enjoy the headphones enough with any of my amps and have several other headphones I really enjoy. I only listen to the LD with my Beyer DT880's (600ohm) but I did give a quick listen with the K612 and I guess it wasn't enough to convince me to keep them. Then I tried them with the Keces amp and there was such a synergy I immediately took them off sale and haven't looked back since.
Truth is I also didn't like the Keces amp when I first got it and was was going to sell it off to.
 
The K612 had a strange issue, almost distortion in the upper mids that would manifest itself on some of the discs I have. I hadn't heard this with my other headphones or amps so I attributed it to something in the characteristic of the K612. I was a little sad when I heard it because it was so comfortable on my large noggin. At any rate with the Keces the distortion\issue\upper mid problem is gone and the headphone is fast, detailed and actually quite delicate and delicious in the mids now! These two have become my go to set-up 80% of the time. The Little Dot is a great amp as you must know and I love the sound now that I have the Novosibirsk power tubes and 6ZH1P-EV VOSKHOD driver tubes. 
 
Does that answer your question?

 

[Koukol]

 

 
I have the Little Dot III
Can you tell me why you prefer the Keces?

There is something about the K612 & Keces amp pairing that just clicks for me (IMHO). I initially was going to sell the K612's because I really didn't enjoy the headphones enough with any of my amps and have several other headphones I really enjoy. I only listen to the LD with my Beyer DT880's (600ohm) but I did give a quick listen with the K612 and I guess it wasn't enough to convince me to keep them. Then I tried them with the Keces amp and there was such a synergy I immediately took them off sale and haven't looked back since.
Truth is I also didn't like the Keces amp when I first got it and was was going to sell it off to.
 
The K612 had a strange issue, almost distortion in the upper mids that would manifest itself on some of the discs I have. I hadn't heard this with my other headphones or amps so I attributed it to something in the characteristic of the K612. I was a little sad when I heard it because it was so comfortable on my large noggin. At any rate with the Keces the distortion\issue\upper mid problem is gone and the headphone is fast, detailed and actually quite delicate and delicious in the mids now! These two have become my go to set-up 80% of the time. The Little Dot is a great amp as you must know and I love the sound now that I have the Novosibirsk power tubes and 6ZH1P-EV VOSKHOD driver tubes. 
 
Does that answer your question?

yes...thanks!
 
I rolled in the warmest tubes I could find for the LD (I can't remember at the moment which ones) which really helped my 601's sightly aggressive upper mids.
However, because of the 601's lack of bass (and aggressive mids on some recordings) I decided to add a professional equalizer from a musicians shop.
Most of the time it's bypassed.

 

[CADCAM]

I hear you, I have an Audio Control EQ that I never really use. I hate having another pair or interconnects in the chain.
I am listening to the K612 right now with the Little Dot. When I originally listened to the LD with the K612 I had the Novosibirsk power tubes but not the VOSKHOD driver tubes and I must say it sounds pretty good right now! The characteristic of this tube setup is certainly not "warm" but works really well and I don't feel the high end is too much. You might want to give it a try as the tubes are really inexpensive. Forgot what I paid for the power tubes but paid like thirteen bucks for a pair of matched gold pin driver tubes on ebay. If you want the seller username let me know I'll look it up.
As I listen to this setup right now it might rival the Keces/K612 combo but I still feel some of that magic is missing but man it sounds good!
The LD has some gonads! I'm at like 9:15 on the volume and it has the AKG's in total control. I just ordered a Beresford Capella! This hobby is awesome just hope my wallet can take it!

 

[Koukol]

"If you want the seller username let me know I'll look it up."
 
Thanks for the offer but right now I'm not happy with AKG so I might move on after being dedicated for over 30 years.

 

[shineonyou]

I am just listening to john butler - ocean. Samsung galaxy tab 4 plus akg k 612. Just lovely natural sound on this quite night. It is 10 pm. Love this listening in the night in candle light. aptx

Ps:great soundstage and clarity, even without an afitional amp.

10:30 pm a little change: i am connecting samsung tab 4 to amp pioneer a-30 through philips bluetooth aea2500/12 and a new sound comes To life. Just perfect!

 

[benjitb]

Hi all, i just remembered I said i'd post impressions on the 612's. My AVR didn't seem to do them justice and the cost/array of an amp that would, combined with other headphones rearing their head led to their return. I'll be interested in trying them with a good amp though.
Thanks to everyone for the help, enjoy your 612's!

 

[CADCAM]

  Hi all, i just remembered I said i'd post impressions on the 612's. My AVR didn't seem to do them justice and the cost/array of an amp that would, combined with other headphones rearing their head led to their return. I'll be interested in trying them with a good amp though.
Thanks to everyone for the help, enjoy your 612's!

I think you did the right thing. When you get to certain level\price point with a headphone an amp is almost a prerequisite. I do not and probably could not listen to my headphones without amps.
The amp brings out the potential in the headphone and can add its own personality to the pairing.

 

[Koukol]

My 601's sound horrible without an Amp and a little EQing  (I need to boost the bass and tame the upper mids a little)
Last night I tried them with my Pono DAP and while they weren't as bad as the HD650's they did not shine.
 
The Sennies & AKGs NEED proper amplification.

 

[xeizo]

  My 601's sound horrible without an Amp and a little EQing  (boost the bass and tame the upper mids a little)
Last night I tried them with my Pono DAP and while they weren't as bad as the HD650's they did not shine.
 
The Sennies & AKGs NEED proper amplification.

 
Yes, the K612 Pro needs proper amping for sure, but not only that, it is VERY revealing for everything source(remember it's primarily a studio can).
 
For example great for OP-amp(or Tube) rolling. If there's anything wrong with the matching of the OP:s, it will be very obvious using K612 Pro. The flip side is that when everything matches it sounds beautiful, and any hint of grainy sound was in fact from the electronics and not the can. Grain which HD600 couldn't reveal.
 
With proper source/amp and some eq(lower mid bass up 2dB, 2-4k down 1-2dB) K612 Pro sounds rather close to the HD600 as both basically are neutral cans Still with a larger soundstage, and a more clean deep bass. The flop of the K612 Pro is that when anything doesn't match it goes downhill fast, HD600 is much more forgiving in any respect and stays more close to it's optimal sound signature even using suboptimal equipment. HD600 benifits from upscaling equipment too, but not nearly as much.

 

[cdma2k]

   
Yes, the K612 Pro needs proper amping for sure, but not only that, it is VERY revealing for everything source(remember it's primarily a studio can).
 
For example great for OP-amp(or Tube) rolling. If there's anything wrong with the matching of the OP:s, it will be very obvious using K612 Pro. The flip side is that when everything matches it sounds beautiful, and any hint of grainy sound was in fact from the electronics and not the can. Grain which HD600 couldn't reveal.
 
With proper source/amp and some eq(lower mid bass up 2dB, 2-4k down 1-2dB) K612 Pro sounds rather close to the HD600 as both basically are neutral cans Still with a larger soundstage, and a more clean deep bass. The flop of the K612 Pro is that when anything doesn't match it goes downhill fast, HD600 is much more forgiving in any respect and stays more close to it's optimal sound signature even using suboptimal equipment. HD600 benifits from upscaling equipment too, but not nearly as much.

well said, can not agree more.
I use OPA627AP biased in class A to drive it without EQ at all, tight bass, seducing mid and less grainy but detailed high.

 

[shineonyou]

Yes, the K612 Pro needs proper amping for sure, but not only that, it is VERY revealing for everything source(remember it's primarily a studio can).

For example great for OP-amp(or Tube) rolling. If there's anything wrong with the matching of the OP:s, it will be very obvious using K612 Pro. The flip side is that when everything matches it sounds beautiful, and any hint of grainy sound was in fact from the electronics and not the can. Grain which HD600 couldn't reveal.

With proper source/amp and some eq(lower mid bass up 2dB, 2-4k down 1-2dB) K612 Pro sounds rather close to the HD600 as both basically are neutral cans Still with a larger soundstage, and a more clean deep bass. The flop of the K612 Pro is that when anything doesn't match it goes downhill fast, HD600 is much more forgiving in any respect and stays more close to it's optimal sound signature even using suboptimal equipment. HD600 benifits from upscaling equipment too, but not nearly as much.

I do agree, no amp, not so much fun. I am driving them with fiio x5 right now and they sound a little flat. Only one song sounds better without a serious amp with k612 pro "spy boy/flag boy". When I used thinksound ts02 there was just totally disturbing bass, while using k612, the bass is very good, but that is only by this one song.But one can get used you it.
normally I drive them with pionner amp a 30.the soun is great.
but I am waiting for the geek wave flex And hope that it will be even better then fiio x5.

 

[shineonyou]

HTC one max without external amp and k612pro. There is something disturbing in the bass. it is like a "blob" noise. Like if someone was beating with fingers outside on the headphoneS.

 

[xeizo]

HTC one max without external amp and k612pro. There is something disturbing in the bass. it is like a "blob" noise. Like if someone was beating with fingers outside on the headphoneS.

Sounds like the HTC doesn't have enough juice to drive the bass ...