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Crack;Bottlehead OTL - Page 322

post #4816 of 5981
Quote:
Originally Posted by Keithpgdrb View Post

Check the bottlehead forums crack page for a list of possi le tubes

Thank You!

post #4817 of 5981
Thanks for the tips, gents. Always appreciated. I'm going to install it tomorrow and pop the caps out on fly leads. I'll have a proper read of that thread too, Jamie.
post #4818 of 5981

Very informative things here.  i likely won't do all the mods.  I'd like to only really do the ones that will make the biggest impact on the sound.  It seems that changing the caps and adding the choke would be the easiest and most straight ahead.  the volume pot seems intimidating.

 

Side note.  I use my crack with the hd600 and dt880.  does anyone else need to add the resistors to give more play in the volume control?  I can hardly move my volume with the 600's before its too loud.  But I'm not really hip with putting resistors in the signal path.  

 

I'd like to be able to use the pot up to about 12:00, but there is no way in hell that is possible at this point.  can't really even get it to 9:00.

post #4819 of 5981

The other problem is the Crack's channel imbalance is more obvious at low volume positions. Since my DAC has a pre-out volume control, I leave my Crack volume to about 50% and use the volume control on my DAC to adjust the volume. This makes the channel imbalance hardly noticeable.

post #4820 of 5981
Quote:
Originally Posted by palmfish View Post
 

The other problem is the Crack's channel imbalance is more obvious at low volume positions. Since my DAC has a pre-out volume control, I leave my Crack volume to about 50% and use the volume control on my DAC to adjust the volume. This makes the channel imbalance hardly noticeable.

 

Hi!

 

I do the same, it helps when your DAC take 24 bit signal as then volume control in your Mac/PC then still works. May I ask what causes the imbalance, since I experienced that as well and lowering the source volume helps but I like to tackle the cause, rather than the symptom (when I hopefully buy @punit Crack in a few days....). So is there any fix that a beginner can implement? A new poti/volume control maybe?

 

Cheers,

K

post #4821 of 5981
Quote:
Originally Posted by palmfish View Post
 

The other problem is the Crack's channel imbalance is more obvious at low volume positions. Since my DAC has a pre-out volume control, I leave my Crack volume to about 50% and use the volume control on my DAC to adjust the volume. This makes the channel imbalance hardly noticeable.


That is cool if you can do that. I use an UberFrost though, so it is what it is.

post #4822 of 5981
Quote:
Originally Posted by palmfish View Post
 

The other problem is the Crack's channel imbalance is more obvious at low volume positions. Since my DAC has a pre-out volume control, I leave my Crack volume to about 50% and use the volume control on my DAC to adjust the volume. This makes the channel imbalance hardly noticeable.

I have done that to a point, but my dac/pre sounds best between 12 and 3.  so I don't want to move it much lower then that.

post #4823 of 5981

Finally managed to finish my Speed Ball Upgrade today. After some delay because I lost some of the resistors (twice!) I finally got to continue building it yesterday and finished it today.

Disregarding the interruptions, because of the lost parts, everything went quite smooth.

I only had some incidents which were not as planned.

 

As I resoldered some of the my former work I thought I might as well clip some of the wires which I had forgotten the last time. I was wondering why i had that much wire at one point of the transformer and proceeded to cut it through. Well, turned out it was not my wiring at all but part of the transformer. Fortunately it was fastened on both ends and I just cut it through. I "fixed" it by soldering it back together again.

Second one was caused by brain lag on my side. If Doc writes in the manual "DO NOT remove the nuts before you do this" in the step of screwing the standoffs on the board e actually means that you should not remove the nuts. I somehow interpreted this as "do not remove up until this step". If you like dexterity based games, you can do it the same way as I did and remove the nuts and then try to screw them back on, as you already installed the smaller boards.

Which leads to my last error, which I only found out about after I powered the Crack on after finishing everything and wondered, why the LEDs on the right smaller board did not light up. Turned out that I soldered the wire meant for point I to a point with a dash which from the side looked like an I.

 

So all in all only minor problems and the Crack sound even better now.

 

Let's see if my other project for a pupDAC goes as smooth as the Crack build. I somehow doubt it. ;)

post #4824 of 5981
Quote:
Originally Posted by Koolpep View Post

Hi!

I do the same, it helps when your DAC take 24 bit signal as then volume control in your Mac/PC then still works. May I ask what causes the imbalance, since I experienced that as well and lowering the source volume helps but I like to tackle the cause, rather than the symptom (when I hopefully buy @punit Crack in a few days....). So is there any fix that a beginner can implement? A new poti/volume control maybe?

Cheers,
K

I suspect its the potentiometer but it could also be the tubes. I just think point to point is more prone to imbalance than SS (opamps) because there is simply more margin for error. It's very subtle and I usually dont notice it with the Crack Pot (pun intended) turned up a ways.
Quote:
Originally Posted by ben_r_ View Post


That is cool if you can do that. I use an UberFrost though, so it is what it is.

The pre-out is one of several reasons why I am so fond of the Essence One Muses. It just does so many things so well. Ive heard good things about the UberFrost too and there are other ways to increase the play in the volume control (as discussed here and in the Bottlehead Forums). You have a nice setup and I wouldnt change a thing if I were in your shoes.

Quote:
Originally Posted by Keithpgdrb View Post

I have done that to a point, but my dac/pre sounds best between 12 and 3.  so I don't want to move it much lower then that.

The position of the volume control shouldnt change the sound, it should simply change the volume. I think maybe something else is going on in your chain.
post #4825 of 5981
Quote:
Originally Posted by Keithpgdrb View Post
 

Very informative things here.  i likely won't do all the mods.  I'd like to only really do the ones that will make the biggest impact on the sound.  It seems that changing the caps and adding the choke would be the easiest and most straight ahead.  the volume pot seems intimidating.

 

Side note.  I use my crack with the hd600 and dt880.  does anyone else need to add the resistors to give more play in the volume control?  I can hardly move my volume with the 600's before its too loud.  But I'm not really hip with putting resistors in the signal path.  

 

I'd like to be able to use the pot up to about 12:00, but there is no way in hell that is possible at this point.  can't really even get it to 9:00.

 

So long as you buy a preassembled attenuator (search eBay for Dale attenuator 100K), the swap is pretty easy. You just need to swap the wires from the existing pot to the new attenuator and you might have to enlarge the locking hole in the chassis plate, but you can't see it once assembled so the job doesn't have to look perfect. Other than adding the Speedball (and possibly choke), the attenuator is the next most significant upgrade - more so than caps because the existing pot will actually mask some of the improvements brought by caps.

post #4826 of 5981
Ah. So the choke and the pot should be the next step, as I already have the speedball in.
post #4827 of 5981

I would say so based on my experiences. Caps are a nice upgrade, but they are subtle like tubes versus the volume pot which is a clear and significant upgrade and makes all other upgrades more impactful because you're removing a potential bottle-neck from your Bottlehead. (See what I did there? :tongue_smile:)

post #4828 of 5981
Got my speedball installed today. It would have been pretty quick but I put the heatsink and transistors on the wrong side of the big board and then played merry hell getting them unsolder end and removed to out them on the right side of the board. After that the only issue was space.. My bent metal copper crack has a small interference issue with the volume pot and the right ride small speedball board. I rotated the board about 5 degrees and bent one of the vol pot leads out of the way. The correct solution will have to be a much longer standoff. Thankfully the copper crack design is taller and has lots of space.

I'm also getting a spike over 20v on startup at the headphone jack, the final test. At least I think I am, the auto ranging multimeter changes scale up and down so quickly I'm not sure. I'm going to have to video the multimeter and play it back slow to be sure. All the other tests are inspec.

Sounds great though.
post #4829 of 5981
Quote:
Originally Posted by Serenitty View Post

Got my speedball installed today. It would have been pretty quick but I put the heatsink and transistors on the wrong side of the big board and then played merry hell getting them unsolder end and removed to out them on the right side of the board. After that the only issue was space.. My bent metal copper crack has a small interference issue with the volume pot and the right ride small speedball board. I rotated the board about 5 degrees and bent one of the vol pot leads out of the way. The correct solution will have to be a much longer standoff. Thankfully the copper crack design is taller and has lots of space.

I'm also getting a spike over 20v on startup at the headphone jack, the final test. At least I think I am, the auto ranging multimeter changes scale up and down so quickly I'm not sure. I'm going to have to video the multimeter and play it back slow to be sure. All the other tests are inspec.

Sounds great though.

 

From memory there's a mod posted as a sticky at the top of the Crack threads on the Bottlehead forum to help deal with the voltage spike on the HP jack.

post #4830 of 5981
Quote:
Originally Posted by Loquah View Post

From memory there's a mod posted as a sticky at the top of the Crack threads on the Bottlehead forum to help deal with the voltage spike on the HP jack.

Yes, I just read about that on the bottlehead forum. I may try that tomorrow. For now I just wait 15-20 seconds before plugging my headphones in.

Thanks
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