Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Crack;Bottlehead OTL
New Posts  All Forums:Forum Nav:

Crack;Bottlehead OTL - Page 113

post #1681 of 5522

guys I tried 2 different 6sn7 (a black glass ken rad and a sylvania ) and the sound is absolutely fantastic, however its very microphonic, you have to shift around till reduce the noise/hum..

and if you adjust to reduce the noise by ear you will hear alot of crackles/pops..I can never get the black background I get with the 12au7..Im not sure if its just my adapter, are you guys getting noise?

is there something you can do to eliminate the noise like a tube shield cover? 

post #1682 of 5522

I also found 6SN7s to be loud. I don't see any reason to use them. I've tried 12AU7s, 12BH7s and E80CCs and they all seem superior/quieter to me.

post #1683 of 5522

Anybody has the mW rating @ 300 and 600 ohms ?
 

post #1684 of 5522

We spec the max voltage output before clipping into 300 ohms as 10Vrms. That would be a power output of about 100V^2rms/300ohms = 333mW rms. Sorry to say I don't have a measurement for 600 ohms handy, but it will probably be pretty close. I can say that the 300 and 600 ohms headphones I have tried have had plenty of output with a reasonable source level.

post #1685 of 5522
Quote:
Originally Posted by Doc B. View Post

That big ol' 6080 heater sucks up a lot of current and the power trans is running pretty much at the design limit current-wise with the addition of the 300mA heater draw of the 12AU7. We felt that the additional 300mA current draw of the most likely octal candidate, 6SN7, would tax it.

 

I just put in an order from Hong Kong for an adapter to try 6SN7 tubes on my amp.  Do 6AS7G power tubes use less heater current?   I notice my aluminum top plate stays much cooler with the 6AS7G tubes than with the two 6080 tubes I have. 

 

Thanks!

post #1686 of 5522

6080 and 6AS7 are essentially identical. But don't worry about using a 6SN7, since I posted that we have determined that the power transformer can handle the extra current draw.

post #1687 of 5522

For whatever it's worth, my transformer doesn't really get that warm.

post #1688 of 5522

I was auditioning the built-in amp on my D100 for a while as I was surprisingly impressed by it. Once or twice I almost caught myself questioning if it was worth keeping the Crack around. However, after switching back to the Crack with a newly arrived 5998 it was as a "veil" was lifted (I hate to use that word but it really is the best word to describe it). A whole new layer of clarity and detail while still being silky smooth. Sound was more natural and airy, imaging and soundstage much better. Sounded as if I was in the the same room as the singer and they were personally serenading me. The lush, sweet mids were the highlight for me.

 

Before, I was using an RCA 6AS7G and the difference between the built-in amp on the D100 and the Crack was much less pronounced (the Crack still being better, but not as obvious).

post #1689 of 5522

Hello guys, anyone among you know the weight in lbs or kg of the headphone amplifier kit because I will use it to compute for its shipping fee. Thank you!biggrin.gif

post #1690 of 5522

7lbs.

post #1691 of 5522
Quote:
Originally Posted by Doc B. View Post

7lbs.

Thanks Sir. Can I know the dimensions of its box, length, width and height please? And also about the 240V AC transformer, can it be placed inside the amplifier kit box, or it comes on another box? And if yes, what its weight and dimensions? Thank you.biggrin.gif

post #1692 of 5522
One box, 10"x12"x6". It's probably easiest to simply contact Eileen at queen at bottlehead dot com and ask her what the shipping would cost.
post #1693 of 5522

For anyone that's put in some big/upgraded caps, how did you mount them?  I'm thinking of using a metal punch to punch holes in the alloy top plate and then using some screw-in zip tie mounts, but would like to hear what anyone else has done.  The caps will be Mundorf M-Cap 100uf/250v, so they're just under silly-huge size for the chassis :).

post #1694 of 5522

I used peel and stick zip tie anchors, 2 per cap.  But, I also routed the fly wires so they helped hold the large caps to the bottom of the plate.

post #1695 of 5522
Quote:
Originally Posted by rs01 View Post

For anyone that's put in some big/upgraded caps, how did you mount them?  I'm thinking of using a metal punch to punch holes in the alloy top plate and then using some screw-in zip tie mounts, but would like to hear what anyone else has done.  The caps will be Mundorf M-Cap 100uf/250v, so they're just under silly-huge size for the chassis :).


Right here man: LINK

 

 

 

 


Edited by ben_r_ - 4/1/13 at 9:13am
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: Headphone Amps (full-size)
Head-Fi.org › Forums › Equipment Forums › Headphone Amps (full-size) › Crack;Bottlehead OTL