Crack;Bottlehead OTL - Page 97

Quote:

Originally Posted by Doc B. 

Yes, that is correct. Just a note - I don't make it over here as often as our own forum, so my response time (or that of the other technical guys) on technical stuff might be shorter on the Bottlehead Forum.

Cool. Im kinda thinking I want to use the PT-7 in my Crack build as I have read around the audio forums that its a better transformer than the PT-3. Im just a little concerned with how much I would have to alter the circuit to accommodate it. However if its as simple as omitting the wiring from terminals 6 and 7 to 9 and 10 on the PT-3 (shown on page 26 of the manual) then I'd be good to go to use the PT-7. Can you confirm thats all it would be, or are we talking more in depth circuit alterations here?

I have the Speedball in my Crack (ermmmm.......somehow that doesn't sound right).

In any case, even the stock Crack sounds wonderful. I'm not just some fanboy, and I'm not talking without having a good basis for comparison. I own, or have owned, the following:

HiFiMAN EF-6

Violectric V181
Woo Audio WA22 w/ Princess Sophia, Sylvania brown base driver tubes and Sylvania power tubes
Woo Audio WA6 w/ Princess Sophia and various driver/power tubes and adapters
Balanced ß22 (Beta 22) with dual Sigma 22 power supplies

Burson HA-160D

SinglePower MPX3 Slam

Audio-Gd NFB-10SE

Trends TA-10.2SE

AMB M³ (a/k/a M^3 or MMM)
HiFiMAN EF-5
Eddie Current Laconic EC-01
K.I.C.A.S. Caliente

Objective O2

Beresford Caiman w/ Gator Board and Burson discrete opamp

Graham Slee Novo
Meier Corda Move
Meier Corda Headamp-1
Neco Soundlab BOSFET v2.1 (PCB v7)
Neco Soundlab v3 Portable (18V w/ battery upgrade)
Neco Soundlab Mosfet

And many more besides (yes, I'm serious). The best amp I have heard for my HD800s / HD600s / DT990s (600 Ohm) is the Bottlehead Crack + Speedball. The EF-6 and Violectric V181 are also very good, but the Crack + Speedball is the best I've heard so far.

I'm expecting to receive a Little Dot Mk VI+ tomorrow, maybe that's better, but it seems unlikely. Maybe an Eddie Current Zana Deux would be better - that seems plausible. I've been trying to convince the Bottlehead team to develop a no-holds-barred OTL headphone amp, and they are considering it, but it's not as though the Crack + Speedball has any glaring flaws as-is. And with the money you save vs. other offerings, you can upgrade the tubes or other compotents (e.g., insert film caps or an upgraded volume pot). I don't have either in my Crack yet (just the Speedball), so it's not as though you need those things for the Crack to sound great. Moreover, note that great tubes for the Crack don't cost a fortune. A Tung-Sol 5998 will cost you $85. And the smaller tube variants are all less than $50, even for the most sought-after versions.

Plus, you can customize the look of your Crack and make it look awesome. The kit is easy to build, even if you've never done this kind of stuff before (a little bit of experience soldering is helpful, but not strictly necessary). I did it in two nights.

Best regards,

Adam

Quote:

Originally Posted by ben_r_ 

 I have read around the audio forums that its a better transformer than the PT-3.

The PT-7 is simply more idiot-proof. PJ was always worried that someone was going to DIY some homebrew circuit with the PT-3 and not have enough knowledge to understand that they couldn't wire the two bifilar high voltage secondaries in series without smoking them. Those separate secondaries were put in the PT-3 for a specific design that was improved recently and in the process a PT-7 was spec'd for the sake of simplicity. But the PT-3 with HV secondaries wired in parallel functions the same as the PT-7 would in the Crack. 

Quote:

Originally Posted by Doc B. 

The PT-7 is simply more idiot-proof. PJ was always worried that someone was going to DIY some homebrew circuit with the PT-3 and not have enough knowledge to understand that they couldn't wire the two bifilar high voltage secondaries in series without smoking them. Those separate secondaries were put in the PT-3 for a specific design that was improved recently and in the process a PT-7 was spec'd for the sake of simplicity. But the PT-3 with HV secondaries wired in parallel functions the same as the PT-7 would in the Crack. 

Gotcha. That makes sense. I thought I had remembered reading somewhere that the PT-7 was actually a quieter transformer as well, but I could have been thinking of something else. I get so overloaded with all the stuff I read that in the end I just end up confusing myself sometimes! lol

New Crack head here.  Just got mine today and I have to admit, it's better than I expected.

I have a number of "decent" amps:  WA2, WA6, Headroom Home and even without much 

time to burn in, the Bottlehead doesn't take a backseat to any of them.  This is flat out, the

best my Senn HD 600's have ever sounded.  Diana Krall is simply intoxicating.

Hibuck....

Quote:

Originally Posted by Hibuckhobby 

New Crack head here.  Just got mine today and I have to admit, it's better than I expected.

I have a number of "decent" amps:  WA2, WA6, Headroom Home and even without much 

time to burn in, the Bottlehead doesn't take a backseat to any of them.  This is flat out, the

best my Senn HD 600's have ever sounded.  Diana Krall is simply intoxicating.

Hibuck....

What DAC are you using the crack with?  I am using mine with the Nuforce HDP and feel that the Crack is ahead of it but only a little and I feel it might be time for a dedicated DAC.

Quote:

Originally Posted by Jmstrmbn 

What DAC are you using the crack with?  I am using mine with the Nuforce HDP and feel that the Crack is ahead of it but only a little and I feel it might be time for a dedicated DAC.

That is what I was planning to use as well. What DAC are you looking at getting that youre expecting to be a better pairing?

I haven't really started looking since I don't have the money right now but have read good things about the Schiit Gungir, it seems reasonable for the price.

Quote:

Originally Posted by Hibuckhobby 

New Crack head here.  Just got mine today and I have to admit, it's better than I expected.

I have a number of "decent" amps:  WA2, WA6, Headroom Home and even without much 

time to burn in, the Bottlehead doesn't take a backseat to any of them.  This is flat out, the

best my Senn HD 600's have ever sounded.  Diana Krall is simply intoxicating.

Hibuck....

Bingo!

I'm going old school with a PSAudio DLIII.  Been very happy with it.

For me, detail is important, but tonality is most important.

Hibuck....

Question for you Crack/Speedball owners - what's your gain like? I purchased a pre-built Crack + Speedball and am still trying to pick my jaw up off the floor after hearing how ungodly good this amp pairs with my HD-650. Damn. BUT, I'm barely getting the volume pot to the 8:00 position before it becomes too loud. This amp was designed for high impedance cans, so that kind of gain just seems off to me for a 300 ohm headphone. Any ideas? Or am I just a dunce?

Thanks Draygonn. I'll look into a pair. Where did you get yours if you don't mind me asking?

I'm sure this has already been discussed to death concerning the Crack, but I find it mystifying that the gain issue hasn't been addressed in the design. This amp is specifically targeted at high impedance headphones. It seems weird that I'd have to add kludgy inline attenuators to get an acceptable gain level with the very type of headphone the amp is engineered to drive.