[ffivaz]

My apologies, ffivaz. I just noticed your Crack is currently w/o Speedball. I'm not trying to make you spend more money, really! :evil:  

Hey, I tried the Crack stock for about 6 months, and ordered the speedball a month ago. Will be shipping soon I hope! I ordered an Integration kit for my Reduction, also. October will be upgrade-month!

 

[Loquah]

Loquah that is a smashing write up. I also have the Beyer T1 and HD650 which I am really enjoying and was very interested to read your comments about the T1 and Crack's synergies in the treble area being highly enjoyable and smooth. That is just what I have been hoping for and one of the main drivers behind my recent crack purchase.

Thanks Jamie! Interestingly, I found the Crack to be great with both cans, but I chose different tubes for each headphone. I didn't have the GEC tube back then though.

The Cleartop plus Mullard 6080 was the choice for the HD650s. I was using a GE 6AS7 with Genalex 12AU7 Gold Lion for the T1s

 

[Loquah]

Hey, I tried the Crack stock for about 6 months, and ordered the speedball a month ago. Will be shipping soon I hope! I ordered an Integration kit for my Reduction, also. October will be upgrade-month!

That'll be an awesome October!

 

[Doc B.]

  Crack Review now complete and posted: http://www.head-fi.org/t/683012/bottlehead-amplifier-discussion-comparison-thread-crack-sex-mainline#post_9831525

 
Holy smokes Lachlan! Thanks so much for your effort! Concise, detailed, and very well laid out. I'd like to throw in one little nugget that might help folks understand OTL a little better. The second stage (which is a cathode follower) that is occupied by the 6080 tube is, in concert with the output capacitor, effectively functioning as the output transformer for this amp. It does the job of creating a lower output impedance with better current drive, much the same as an output transformer does. Each of these methods has its benefits and shortcomings, it's really a matter of choosing your poison. One definite advantage of the tube output in this particular case (vs. output transformers) is a substantial reduction in cost, which we can pass along to our customers.

 

[Loquah]

Holy smokes Lachlan! Thanks so much for your effort! Concise, detailed, and very well laid out. I'd like to throw in one little nugget that might help folks understand OTL a little better. The second stage (which is a cathode follower) that is occupied by the 6080 tube is, in concert with the output capacitor, effectively functioning as the output transformer for this amp. It does the job of creating a lower output impedance with better current drive, much the same as an output transformer does. Each of these methods has its benefits and shortcomings, it's really a matter of choosing your poison. One definite advantage of the tube output in this particular case (vs. output transformers) is a substantial reduction in cost, which we can pass along to our customers.

Thanks Doc. That's kind of what I understood from the great article shared by amcananey over on the Crack thread, but it's nice to hear it so concisely and straight from the source.

 

[Loquah]

S.E.X. review and comparison between S.E.X. and Crack now posted: http://www.head-fi.org/t/683012/bottlehead-amplifier-discussion-comparison-thread-crack-sex-mainline#post_9831527
 
Doc, as per the additional information you posted regarding the Crack as an OTL design, please add any insights you care to about the S.E.X.  I for one find them very helpful as I'm learning more about the designs of your amplifier kits.

 

[W0lfd0g]

CURSE YOU, LOQUAH!  Now I have to save the pennies and buy a Bottlehead SEX!
 
Let me be the first to congratulate you on the review.  It answers all the questions I had and some I didn't have the wits to think of. 

 

[Jmstrmbn]

This could turn out to be an expensive read, I've been considering building a full-range speaker system and the SEX would kill two birds... 

 

[Aeolus Kratos]

  CURSE YOU, LOQUAH!  Now I have to save the pennies and buy a Bottlehead SEX!
 
Let me be the first to congratulate you on the review.  It answers all the questions I had and some I didn't have the wits to think of. 

 
Curse you twice, LOQUAH! Why did not you post the review before I bought a wonderful GEC 6AS7G from W0lfd0g, that would have saved me a bunch dollars for buying a SEX!

 
Haha, I'm just kidding.
 
Spectacular job, Loquah, your presentation is just outstanding

 

[Zashoomin]

  This could turn out to be an expensive read, I've been considering building a full-range speaker system and the SEX would kill two birds... 

If you want to power both speakers and headphone I highly suggest you get the impedence switch upgrade as you will probably want to have different impedences depending on the what you are going to be using. 
 

  S.E.X. review and comparison between S.E.X. and Crack now posted: http://www.head-fi.org/t/683012/bottlehead-amplifier-discussion-comparison-thread-crack-sex-mainline#post_9831527
 
Doc, as per the additional information you posted regarding the Crack as an OTL design, please add any insights you care to about the S.E.X.  I for one find them very helpful as I'm learning more about the designs of your amplifier kits.

 
Very well done review I had fun reading it 

.  Wait til the C4S upgrades comes...it will sound even better. Can't wait to read your next findings.  
 
   

 

[Loquah]

  CURSE YOU, LOQUAH!  Now I have to save the pennies and buy a Bottlehead SEX!
 
Let me be the first to congratulate you on the review.  It answers all the questions I had and some I didn't have the wits to think of. 

 
Haha - thanks Nathan! I think you'll love the S.E.X. and it is a great complement for the Crack rather than a direct replacement as such.
 

  This could turn out to be an expensive read, I've been considering building a full-range speaker system and the SEX would kill two birds... 

 
Yes, I should have apologised to everyone's wallets up front, shouldn't I? As for the full-range speaker system, just make sure you build something that's nice an sensitive for it to pair well with the S.E.X.
 

   
Curse you twice, LOQUAH! Why did not you post the review before I bought a wonderful GEC 6AS7G from W0lfd0g, that would have saved me a bunch dollars for buying a SEX!

 
Haha, I'm just kidding.
 
Spectacular job, Loquah, your presentation is just outstanding

 
Wow, I'm getting cursed a lot today! 

 
There is no doubt that the 6AS7G absolutely maximises the Crack's potential and the mid-range it produces is clearly superior to the S.E.X. so don't sweat it - now you can just add the S.E.X. so that you have creamy, lush midrange from the Crack and for high impedance cans, and clarity, imaging and detail from the S.E.X. and for all range of cans.
 
Also, @Zashoomin, I'm definitely looking forward to the C4S kit and also getting a response about the differences made by the wiring of the output transformers. I maybe should ask that on the Bottlehead forum so it's not all on Doc to answer. I'll see what I can find out...

 

[Doc B.]

I am up to my armpits servicing our ancient oil furnace today, but I just wanted to clarify that the noise floor of the S.E.X. amp goes down as the output tap gets lower, i.e., 4 ohms will have the lowest noise. The 32 ohm tap is going to be useful when you have relatively insensitive, power hungry cans, but you may hear the noise floor with sensitive cans on that tap. So use the lowest tap that still gives you enough volume for the cans you are using.

 

[Loquah]

I am up to my armpits servicing our ancient oil furnace today, but I just wanted to clarify that the noise floor of the S.E.X. amp goes down as the output tap gets lower, i.e., 4 ohms will have the lowest noise. The 32 ohm tap is going to be useful when you have relatively insensitive, power hungry cans, but you may hear the noise floor with sensitive cans on that tap. So use the lowest tap that still gives you enough volume for the cans you are using.

Thanks Doc. I'll edit the review to clarify.

 

[Aeolus Kratos]

Wow, I'm getting cursed a lot today! 

 
There is no doubt that the 6AS7G absolutely maximises the Crack's potential and the mid-range it produces is clearly superior to the S.E.X. so don't sweat it - now you can just add the S.E.X. so that you have creamy, lush midrange from the Crack and for high impedance cans, and clarity, imaging and detail from the S.E.X. and for all range of cans.
 
 

Hi Loquah,
 
There's one interesting thing I've just recently noticed. Your SEX wood base's color is nearly the same as my Crack's one

 

 
 

 

 
Sexy brown

 

[BIG POPPA]

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