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

Crack;Bottlehead OTL - Page 346

post #5176 of 8084
Quote:
Originally Posted by mordicai View Post
 

Installed the switch mod with 470 resistors on the speedball for the E 80cc tube. Sounds very good but I can only just crack the volume control in term of loudness. Seems that there is way too much gain. I'm not sure the best way to proceed with this. Install a Potentiometer, or use a resistor in the volume pot?  
Any advice would be appreciated. Can't imagine how much better a Mainline would be then this Crack. It may sound different, but would it be better?   Max

 

From the Crack sticky notes (I used this method for a while. After fitting a stepped attenuator I found there to be better range in the volume and removed the resistors soon after). The resistors are a easy and cheap fix if you are unable to alter the your sources gain.

 

http://bottlehead.com/smf/index.php/topic,4295.0.html

 

"3.  I can barely turn my Crack up at all before it's far too loud, what do I do?

Remove the white wire from the left RCA jack at the rear of the chassis.  Solder in a 270K resistor to the solder cup on that jack, solder the white wire to the other end.  Repeat this for the red wire with another 270K resistor.  This will give you about a -10dB pad at the input.  If you still have the issue, try 470K instead.  The wattage of these resistors isn't all that important, anything between 1/16 Watt and 1/2 Watt is reasonable, with metal film and carbon film types being most recommended."


Edited by JamieMcC - 6/1/14 at 2:48pm
post #5177 of 8084

Can someone post a couple of links to recommended resistors? 

 

thanks...

post #5178 of 8084
Quote:
Originally Posted by MattTCG View Post
 

Can someone post a couple of links to recommended resistors? 

 

thanks...

ebay search for  270K resistor and you will be spoilt for choice.

post #5179 of 8084
Quote:
Originally Posted by atsq17 View Post
 

A true audio and visual treat. 

Warning: Spoiler! (Click to show)

 

 

 

Me likes!!! Congrats

post #5180 of 8084
Quote:
Originally Posted by JamieMcC View Post
 

 

From the Crack sticky notes (I used this method for a while. After fitting a stepped attenuator I found there to be better range in the volume and removed the resistors soon after). The resistors are a easy and cheap fix if you are unable to alter the your sources gain.

 

http://bottlehead.com/smf/index.php/topic,4295.0.html

 

"3.  I can barely turn my Crack up at all before it's far too loud, what do I do?

Remove the white wire from the left RCA jack at the rear of the chassis.  Solder in a 270K resistor to the solder cup on that jack, solder the white wire to the other end.  Repeat this for the red wire with another 270K resistor.  This will give you about a -10dB pad at the input.  If you still have the issue, try 470K instead.  The wattage of these resistors isn't all that important, anything between 1/16 Watt and 1/2 Watt is reasonable, with metal film and carbon film types being most recommended."

Thanks Jamie, I'll pick up a couple tomorrow and give it a shot.

post #5181 of 8084

One other question on this volume issue. My RCA's come from a Emotiva Dac1 which has a variable pre amp volume. When I reduce the input gain from the DAC the sound seems muddy.  However I assume this is the same thing as adding resistors to the RCA inputs? What will a Potentiometer do for me?

post #5182 of 8084
Quote:
Originally Posted by mordicai View Post
 

One other question on this volume issue. My RCA's come from a Emotiva Dac1 which has a variable pre amp volume. When I reduce the input gain from the DAC the sound seems muddy.  However I assume this is the same thing as adding resistors to the RCA inputs? What will a Potentiometer do for me?

 

It might be that the Emotiva removes the volume control from the circuit when it's at full volume (depending on the design). If that's the case then what you're hearing is the difference added to the sound by the Emotiva's volume control. There is no reason to expect the resistors to sound the same so it's still worth a try.

 

Alternatively, it's possible that you're actually listening at a lower volume than you think when you drop the Emotiva volume and that will definitely reduce dynamics, etc. Try turning the Crack up a bit more and see if the sound opens up.

 

A potentiometer is exactly what you've already installed in the Crack as the volume control. The only benefit of changing to a different potentiometer would be more transparency. Changing to a stepped attenuator, however, can provide more range of volume based on my experiences with the Dale stepped attenuator I installed in my S.E.X. amp. I assume this has something to do with the exact resistors used for each step.

post #5183 of 8084
Quote:
Originally Posted by Loquah View Post
 

 

It might be that the Emotiva removes the volume control from the circuit when it's at full volume (depending on the design). If that's the case then what you're hearing is the difference added to the sound by the Emotiva's volume control. There is no reason to expect the resistors to sound the same so it's still worth a try.

 

Alternatively, it's possible that you're actually listening at a lower volume than you think when you drop the Emotiva volume and that will definitely reduce dynamics, etc. Try turning the Crack up a bit more and see if the sound opens up.

 

A potentiometer is exactly what you've already installed in the Crack as the volume control. The only benefit of changing to a different potentiometer would be more transparency. Changing to a stepped attenuator, however, can provide more range of volume based on my experiences with the Dale stepped attenuator I installed in my S.E.X. amp. I assume this has something to do with the exact resistors used for each step.

Thanks Loquah, I've been a-b ing using the Emotive volume control and I thinks its really o.k. I'll try some resistors tomorrow just to check

post #5184 of 8084

Loquah,I believe that:

 

Dale 23 Step Ladder-type Potentiometer Volume Control Log 100k Ohm Stereo you used in the sex you also used in the Crack. I that correct? It will fit with modifications in the Crack with Speedball? Thanks, Max

post #5185 of 8084
Quote:
Originally Posted by mordicai View Post
 

Loquah,I believe that:

 

Dale 23 Step Ladder-type Potentiometer Volume Control Log 100k Ohm Stereo you used in the sex you also used in the Crack. I that correct? It will fit with modifications in the Crack with Speedball? Thanks, Max

 

Hi Max. That's correct. The fit in the Crack is a little trickier. You need to enlarge the main hole for the volume spline slightly as well as adjusting the hole for the locking tab. In addition to that, I loosened off the the nearest Speedball board and remounted it on a slight angle to sit in the groove between the 2 rows of resistors on the attenuator with some insulating tape to ensure nothing touched where it shouldn't.

 

There's nothing too complicated or risky - just some minor fiddles.

post #5186 of 8084

Great Ill give a shot thanks

post #5187 of 8084

Sorry for a rookie question, but how do I post images here. When I try to use the image button, it says that my account dont have required permission?

post #5188 of 8084

Just for the heck of it here are the two Cracks I built.

 

First is CrackPipe (source is a Raspberry Pi, get it?) and 2nd is KrispyCrack.  KrispyCrack is in my daughters possession.

 

post #5189 of 8084
Quote:
Originally Posted by Lugnegaard View Post
 

Sorry for a rookie question, but how do I post images here. When I try to use the image button, it says that my account dont have required permission?


If I remember correctly, your account must have >20 posts in order to post images on the forum, but I'm not sure :D

post #5190 of 8084

Looks cool, like some pop-art :) The green chassi turned out nicely :)

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