[DefQon]

  How much is the Bottlehead Crack? How much of an improvement would the Crack be over the JDS O2/Odac combo?

 
I think this it the proper time to use: a big night and day difference.

 

[LugBug1]

So....

I got to work before 8:30am this morning. It is almost 2am and I'll be here for at least two more hours. I was getting slightly drowsy, so I slipped on my HD600s that I keep at work and fired up Hem's album "Departure and Farewell". Wow...chills down my spine. I'm awake again! I love the HD600s and always will.

Back to work...

You work too much! 

 

[FlySweep]

 

So....

I got to work before 8:30am this morning. It is almost 2am and I'll be here for at least two more hours. I was getting slightly drowsy, so I slipped on my HD600s that I keep at work and fired up Hem's album "Departure and Farewell". Wow...chills down my spine. I'm awake again! I love the HD600s and always will.

Back to work...

 
Right on, Adam.
 
I had a freakin' ball rolling a few 6F8G/6C8Gs into the Crack/HD600 tonight.. namely, the Mullard 6F8G.. this thing seemingly took forever to 'break-in'.. but when it did,.. wow.  I loved the RCA 6F8G, as well.. it carries a superb delicacy.. like the RCA "clear top" 12AU7 on steroids:  bigger staging, better separation, more clarity, etc.
 
I've been rolling in a few 12AU7s I've recently fell in love with again:  the Mazda CIFTE remains one of my favorite tubes ever.. a 50's RCA "long black plate" 12AU7 is very addictive, too.  The Tungsram 12AU7 has always been a favorite for it wonderfully liquid presentation.
 
I can't say it enough.. the Crack+HD600 kicks ass... it's like they were made for each other.

 

[StanD]

To get good damping factor (Electrical) on an HD600, your amp should have an output impedance of less than 37.5 Ohms. Where does your amp stand?
 
There are many silly myths about damping.
 
Tyll at InnerFidelity says, "While there's no hard and fast line in the sand here, it is commonly accepted wisdom that a damping factor greater than 8:1 is desirable for tight control. Bottom line: the 50 Ohm output impedance of the old Explorer is too high even for high impedance cans like the Sennheiser HD 600."

 

[palmfish]

  To get good damping factor (Electrical) on an HD600, your amp should have an output impedance of less than 37.5 Ohms. Where does your amp stand?
 
There are many silly myths about damping.
 
Tyll at InnerFidelity says, "While there's no hard and fast line in the sand here, it is commonly accepted wisdom that a damping factor greater than 8:1 is desirable for tight control. Bottom line: the 50 Ohm output impedance of the old Explorer is too high even for high impedance cans like the Sennheiser HD 600."

Try telling that to Bottlehead Crack owners... lol

 

[kazsud]

A buddy of mine is looking to buy a pair of new HD600s. Where can these be bought for around $300-350 new?

 

[StanD]

 
Try telling that to Bottlehead Crack owners... lol

Yes, Galileo learned about religion the hard way - lol. Heck if they enjoy it as is, who am I to deny anyone their pleasure. I'm only trying to spread around good technical engineering information, the same stuff that is used to design the gear we love to listen to.

 

[StanD]

A buddy of mine is looking to buy a pair of new HD600s. Where can these be bought for around $300-350 new?

Most places that are legit dealers sell them for $399.95 and if you can wait, they occasionally go on sale. Though you can grow old waiting for these babies to go on sale.

 

[Headzone]

   
I think this it the proper time to use: a big night and day difference.

In which areas? I heard someone saying it has too big an output impedance; that would lead to increased bass, and to some people "excitement" but not actual clarity-

 

[StanD]

  In which areas? I heard someone saying it has too big an output impedance; that would lead to increased bass, and to some people "excitement" but not actual clarity-

A low damping factor means that the amp cannot control the excess excursion of the diaphragm which leads to sloppy uncontrolled bass, etc. Not what I'm looking for. 

 

[Keithpgdrb]

so your saying the crack is not a good match for the 600?  I'm confused.  even tyle likes it.

 

[K.T.]

Regarding the Berning Micro ZOTL, I actually never recalled getting my 600's to sound satisfactory with it.
 
I already owned my ZOTL when I purchased my 600's. I recall the sound of the two together to be stiff - music didn't really breathe. It actually sounded clinical compared to the amp with my old 580's.
 
I took it to mean that the 600's were brand new and just didn't have time to burn in yet. I let them play unattended for many hours, and some days and weeks later they did open up a bit. But I never thought the pairing sounded optimal. It still had a stiffness and distant sound to it.
 
Though the ZOTL and the 600's weren't floating my boat, the sound of the amp with Grado phones was great. This amp had a grip and immediacy that was breathtaking. It really shined with the Grados, in my case the SR125's. It was also great with a pair of Lowther loudspeakers I was using at the time. A really clear, punchy, tight sound with great timing and still slightly euphonic.
 
Then I modded my ZOTL. From what I understand, David Berning assembled these amps with a lot of manual hand work. The parts he used were fairly standard, no boutique parts. Just standard resistors, etc, like you would source for a production item. Everything except for decent Panasonic electrolytic caps, which are not boutique parts, but affordable and known to sound good. Those and a Noble potentiometer were the only concession to going upscale in the stock amp.
 
I modded the amp in the usual audio tweaker way:
 
I replaced as many of the stock resistors as I could with some boutique choices. In this case, with Riken and Kiwame carbon films. I couldn't get these in every value used in the amp, so I tried to get as many in the signal path and audio circuit as possible. Maybe half of the resistors in these circuits, as well as a few in the power section were changed out.
 
I also peeled the skins off of the electrolytic caps. There's some debate about if this does anything to the sound or not, but I noticed it did open up the sound in some other amps I've done this to.
 
Then I changed out the critical signal capacitors. The stock signal caps were those poly caps, the ones that look like little orangeish-brown square or rectangular pieces of Chicklet gum. I swapped out the first stage caps with TRT Dynamicaps, which I had good results with before. The caps in the second stage were changed to Auricaps. I went with these because they were the best reasonably-priced good-sounding caps I could fit onto the circuit board. Even then, I had to do some creative lead bending. My first choice would have been some oil caps, but no way was there enough room to even consider them.
 
I also changed out some of the stock TO-220 diodes (I think that's the package designation) to fast switching, soft-recovery models.
 
Well, you would think the SQ would have improved by leaps and bounds. It did in some ways, but what I realized is that Mr. Berning did a great job in balancing the sound of his amp. While the new configuration was more refined, it introduced or uncovered a brightness and hardness that wasn't there before. The sound was cleaner and more resolved, but it seemed more tilted to the treble and not as bouncy and fun. Of course, this was worse than the original configuration when used with 600's, which sounded stiff and distant in the first place.
 
As a final tweak, I changed out the potentiometer to one of the deluxe TDK soundboard units, where each detented position puts a single surface mount resistor in the signal path. The sound cleaned up even more. Really neutral, but it didn't do anything for the already too clean sound of the tweaked amp.
 
So my experience with the ZOTL and the 600's hasn't been great. It may be that other have gotten good results with it, but it didn't pan out for me.
 
My next and final tweak (it's actually been many years since I've had time to work on audio projects) will be to replace the TDK pot with a warmer sounding PEC carbon pot (which sounds great in my tubed Cary preamp). I actually tried it once in ZOTL, but thought it sounded too rich and slow. But that was with the already warm 580's. Now that I re-listened to the 600's with the ZOTL and was reminded of how bright it sounds, I think I have to put the PEC back in and see.
 
BTW, the FiiO E09k, while much less expensive than the ZOTL, is much more balanced sounding and, I think perhaps, a much better match for the 600's than the Micro ZOTL. I'm very satisfied with it!
 
K.T.

 

[amcananey]

Look, I'm not saying that damping is BS. I'm not saying that good engineering practices are BS. I'm not saying that scientific measurements are BS. Nor am I saying that I have golden ears or that I would generally survive a double-blind test of much of my gear. But if there is anything in this hobby that I am confident in, after trying dozens and dozens of amps and headphones, it is that the HD600 and Crack are an outstanding combination, fully the equal (in terms of delivering pure pleasure) to many, many combinations costing thousands more. I'm not claiming that it will yield the best test results in the lab, but in terms of musicality AND detail AND bass AND sparkle AND mids AND PRAT AND speed, the only thing better that I've experienced is the HD800s + Crack, or the HE-6 + certain select amps.

 

[StanD]

Peeling the skins off of the electrolytic caps, does nothing. Changing the resistors will do nothing at audio frequencies or at the gain levels used for audio, although tightening the tolerances between the same resistors in the right places in opposing (left/right) circuits can improve the balance. Changing to a wirewound resistor may cause trouble if there any inductive properties that might factor into the circuit. Changing capacitors to better types can yield some improvements in certain circuits, but not all.
When we work hard to get an improvement many times it will affect our subjective judgement. If that works for someone, let it be. Electrical Engineering is applied physics. A better apple will not fall from the tree any faster, it will accelerate the same as per the laws of gravity. It may taste better, but that's chemistry not physics.

 

[StanD]

Look, I'm not saying that damping is BS. I'm not saying that good engineering practices are BS. I'm not saying that scientific measurements are BS. Nor am I saying that I have golden ears or that I would generally survive a double-blind test of much of my gear. But if there is anything in this hobby that I am confident in, after trying dozens and dozens of amps and headphones, it is that the HD600 and Crack are an outstanding combination, fully the equal (in terms of delivering pure pleasure) to many, many combinations costing thousands more. I'm not claiming that it will yield the best test results in the lab, but in terms of musicality AND detail AND bass AND sparkle AND mids AND PRAT AND speed, the only thing better that I've experienced is the HD800s + Crack, or the HE-6 + certain select amps.

An amp is a total package. One can have excellent damping but fall flat elsewhere. The HE-6 is tough to drive because it has an efficiency of only 83.5 dB.
All of this engineering can be tough to swallow for the lay person. Audiophiles are passionate about their gear and the pursuit of best sound and are susceptible to subjective perception and the stories that circulate. Companies like Monster love to take advantage of this.