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Crack;Bottlehead OTL - Page 126

post #1876 of 5981
Quote:
Originally Posted by ffivaz View Post

In my opinion, digitally reducing the volume on a USB dac (like the ODAC) equals introducing jitter in the music. And this is equal or quite equal to lower SQ. Am I wrong ?

 

Audible jitter is a figment of your imagination.

 

Reducing digital volume can reduce sound quality at low bit depths or with crappy software. But for a 24-bit DAC with decent software it will be inaudible.

post #1877 of 5981
Quote:
Originally Posted by JmanOfIsrael View Post

Thanks very much for the responses. I am still in awe of how clear the soundstage is on orchestral recordings. I feel like live music is going to have an entire new feel. As this was my first build, I still can't believe I built this thing in 8 hours and I made no (obvious) technical mistakes. Doc B., your instructions were incredibly clear and easy to read while very informative--I felt like I was getting a valuable lesson in electronics! Thanks again!

 

As I burn the Crack in, do you recommend I play music through it, or is it enough just to leave it on for several hours at a time followed by a lengthy resting period?

Music playing is the best way to break in the amp.

 

 

Quote:
In my opinion, digitally reducing the volume on a USB dac (like the ODAC) equals introducing jitter in the music. And this is equal or quite equal to lower SQ. Am I wrong ?

If you have a recording that is distorting from clipping the DAC output at max volume and you feel the SQ will be worse if you reduce the output level to just below clipping, I'm guessing that we probably have different listening habits.

post #1878 of 5981
Quote:
Originally Posted by Doc B. View Post

If you have a recording that is distorting from clipping the DAC output at max volume and you feel the SQ will be worse if you reduce the output level to just below clipping, I'm guessing that we probably have different listening habits.

 

Oh, SNAP.

post #1879 of 5981
Quote:
Originally Posted by JmanOfIsrael View Post

Man, I wish I could give you a hug! That did the trick exactly! This thing with the HD650s is incredible. I've never had such a quiet background with a full sound. My next question: where should I keep the volume on my computer vs. the volume on the Crack?

I know for iTunes on a Mac you have two volume controls.  One for iTunes which I would put at about three quarters of the way up and you can go all the way to about 1 db or 2 below full on the main system volume, as Doc redommended.  I have always found a lot of distortion on the volume with iTunes up too high.  Experiment with this one and find he happy spot for you.

post #1880 of 5981
Quote:
Originally Posted by ffivaz View Post

In my opinion, digitally reducing the volume on a USB dac (like the ODAC) equals introducing jitter in the music. And this is equal or quite equal to lower SQ. Am I wrong ?

 

There is no indication that this is the case. Certainly not jitter. Possibly removing some digital data (but not as much as clipping would cause), depending on the bit rate and other factors - audibility is another question, and for a couple of DB down, would be very hard to demonstrate reliably in objective testing.

post #1881 of 5981
Looks like I confused jitter and dither, which is bad for me, but not for the music. Thanks guys.
post #1882 of 5981

Another Bendix 6080WB arrived today.. this one has the slotted graphite columns (opposed to the solid graphite columns that the other 6080 I have provided impressions of).  Haven't had a ton of time to listen & compare.. but so far, it seems like a marriage between the best aspects of the 6080/solid graphite & the TungSol 5998.

 

The 6080/slotted graphite tube is less liquid, rich, and warm than the 6080/solid graphite.. but it's more transparent, neutral, and resolving.. perhaps even more than the 5998, in fact.  The 6080/slotted graphite's soundstage and dynamics are eye-popping.  Again, it probably has a leg up on the 6080/solid graphite in this area (which, in turn, I found to be more dynamic than the 5998).  It preserves the terrific bass response of the 6080/solid graphite.. but possesses better extension and clarity (from end to end).  The 6080/solid graphite has a 'fatter' bass response.. the 6080/slotted graphite's bass is just as dynamic and punchy. but it's tighter and cleaner than the solid graphite's bass response.  The 6080/slotted graphite's midrange is neutral, smooth, & incredibly vibrant.  The 5998 sounds thin, in comparison (to me).

 

So far, this seems to be my favorite driver tube for Crack.  I'm going to try and get a Sylvania "Gold Brand" 6080.. just to see if it's immense 'liquidity' is all that it's cracked up to be... and for a different flavor.  I'll have more comparisons between the 6080/slotted graphite & the 5998 later.

post #1883 of 5981

Small technical point - in tube circuits the big tube that runs the speaker or headphone is called the output tube - in this case the 6080. The smaller tube that drives the output tube is called the driver - in this case the 12AU7. 

post #1884 of 5981
Quote:
Originally Posted by FlySweep View Post

Another Bendix 6080WB arrived today.. this one has the slotted graphite columns (opposed to the solid graphite columns that the other 6080 I have provided impressions of).  Haven't had a ton of time to listen & compare.. but so far, it seems like a marriage between the best aspects of the 6080/solid graphite & the TungSol 5998.

 

The 6080/slotted graphite tube is less liquid, rich, and warm than the 6080/solid graphite.. but it's more transparent, neutral, and resolving.. perhaps even more than the 5998, in fact.  The 6080/slotted graphite's soundstage and dynamics are eye-popping.  Again, it probably has a leg up on the 6080/solid graphite in this area (which, in turn, I found to be more dynamic than the 5998).  It preserves the terrific bass response of the 6080/solid graphite.. but possesses better extension and clarity (from end to end).  The 6080/solid graphite has a 'fatter' bass response.. the 6080/slotted graphite's bass is just as dynamic and punchy. but it's tighter and cleaner than the solid graphite's bass response.  The 6080/slotted graphite's midrange is neutral, smooth, & incredibly vibrant.  The 5998 sounds thin, in comparison (to me).

 

So far, this seems to be my favorite driver tube for Crack.  I'm going to try and get a Sylvania "Gold Brand" 6080.. just to see if it's immense 'liquidity' is all that it's cracked up to be... and for a different flavor.  I'll have more comparisons between the 6080/slotted graphite & the 5998 later.

I jsut got one of the Bendix slotted 6080 the other day from a friend who gets NOS tubes for $35.  He's bringing me some clear top RCA's for $5 today.  Once I get some technical issues sorted out with my crack I'll get a chance to run these through their paces.

post #1885 of 5981
Originally Posted by Doc B. View Post

Small technical point - in tube circuits the big tube that runs the speaker or headphone is called the output tube - in this case the 6080. The smaller tube that drives the output tube is called the driver - in this case the 12AU7. 

 

Thanks Doc.. I tend to mix those terms up when I ramble on. 


Originally Posted by Dark Helmet View Post

I jsut got one of the Bendix slotted 6080 the other day from a friend who gets NOS tubes for $35.  He's bringing me some clear top RCA's for $5 today.  Once I get some technical issues sorted out with my crack I'll get a chance to run these through their paces.

 

Looking forward to your thoughts on the Bendix tube.. glad to see someone else getting their hands on one.  Terrific price you got it for, too.

 

I rolled the Tung-Sol "black plate" in with the 6080/slotted graphite tonight.. oh my goodness.  The HD800 sounds unreal.  I could go on and on about all the impressive sonic aspects.. but one particular thing that kept impressing me was the wonderfully natural separation of sounds, voices, and instruments.  Opposed to some tubes that "lift" a particular band (i.e. vocals) above the rest to perpetuate a (false) sense of separation, this combo separates everything with incredibly natural, realistic precision.  For anyone who thinks the HD800 doesn't do metal as well as some other TOTL phones hasn't heard it with the 6080-slotted graphite/TS "black plate" combo.  If you listen to rock music, this may be a 'holy grail' tube.  The crunch of electric guitars is so full bodied, articulate, and.. here's that word again.. realistic.

 

I found the slotted graphite/TS BP combo preferred to be played at slightly higher volumes, too.  Dynamics seem to find their sweet spot with a bit more gain.  I've been listening to a lot of my favorite rock & metal albums and even at high volumes, fatigue never set in thanks to this tube's ability to sound very lively, dynamic with impeccable control.  After listening for the last three or fours hours, I realized why I'm so impressed with the 6080-slotted graphite/Tung-Sol "black plate" tube combo: it harmoniously balances the best aspects of (what I traditionally associate with) solid state & tube sounds.  I'm not sure how the BP sounds in other OTL amps, but it's a "tour de force" in the SB'ed Crack.

post #1886 of 5981

Well, well.. maybe I've been impatient with the 5998 or it's just now opening up.. looks like I might be eating some of my words on it's performance.  It's ok, though.. this is the best tasting crow I've had in awhile.

post #1887 of 5981

No having any luck at the Bottlehead forum so I'll ask here.  I just installed the Goldpoint MiniV stereo Attenuator in My Bottlehead Crack.  In the process of doing so I had to remove some components and when I went to do my voltage check I noticed that at terminal 6 and 10 it measures 40V, when it should measure 0V.

post #1888 of 5981

Well, that kinda tells me that something that should be grounded... isn't. 

post #1889 of 5981
Quote:
Originally Posted by Dark Helmet View Post

No having any luck at the Bottlehead forum so I'll ask here.  I just installed the Goldpoint MiniV stereo Attenuator in My Bottlehead Crack.  In the process of doing so I had to remove some components and when I went to do my voltage check I noticed that at terminal 6 and 10 it measures 40V, when it should measure 0V.

 

I'm not surprised you aren't having luck, because you haven't exactly given us much to go on.

 

What, exactly, did you have to remove? Any photos? What have you actually tried to do to fix it?

 

[EDIT] OK, so I whipped out my schematic, and terminals 6 and 10 are after the output capacitors and are connected directly to the headphone jack. This means that the capacitors are not bleeding down the DC; I hope you didn't plug your headphones in. I suspect that either your grounding at the headphone jack has been disconnected from both the volume pot and terminal 12, or your resistors at the headphone jack are not connected properly.


Edited by Beefy - 6/19/13 at 4:19am
post #1890 of 5981
Quote:
Originally Posted by Dark Helmet View Post

No having any luck at the Bottlehead forum so I'll ask here.  I just installed the Goldpoint MiniV stereo Attenuator in My Bottlehead Crack.  In the process of doing so I had to remove some components and when I went to do my voltage check I noticed that at terminal 6 and 10 it measures 40V, when it should measure 0V.

 

Stupid is as stupid does.  beyersmile.png

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