Crack;Bottlehead OTL
Apr 4, 2014 at 3:36 AM Post #4,517 of 12,335
  Before you put too much time into that verify whether the hum goes up and down as you turn the volume control. If it changes then it is possible that hum is being picked up somewhere ahead of the volume pot like the input wiring, or your interconnects or your source component. If the hum stays the same regardless of the volume setting don't waste too much effort on that part of the amp as that means the hum is coming in after the volume pot, like maybe a tube that has a little heater-cathode leakage or there is some interference in the room like maybe a power transformer on another piece of gear that is close to the amp.

Hi! 
 
I checked the volume nob, the background noise is the same regardless of position. Also tried plugging in the amp to another wall-jack and the noise was still the same. I don't even know what heater-cathode leakage is, and is it possible to check wheter my tubes suffer from that without buying new ones? 
 
edit: Okay tested with two different of the small tube (is this the driver tube or whatever you call it?) and the background noise is slightly higher using one of them compared to the other but still present. Unfortunaly I don't have a spare of the big one to try with.
 
Apr 4, 2014 at 9:45 AM Post #4,519 of 12,335
 it's actually 8 Outlet Surge Protector (don't remember the name) ..I just call it power strip ,sorry 

 
I personally stick with Belkin and APC. They cost between $15-$35 depending on the unit, but to me its worth paying a bit more for a reputable name brand.

That's why i recommend the Furman one which is designed for Audio/Video use
 
Apr 4, 2014 at 11:08 AM Post #4,520 of 12,335
excuse me Doc B., may I ask one thing? about the Crack OTL Headphone Amplifier Kit voltage input. If I order it with 240VAC power transformer, can it still be used in a place with 100sVAC?


As someone else mentioned, you would need to use a 100v to 240v stepup transformer to use a 240v Crack amp in a 100V country. Or should I say the 100v country, is 100v used anywhere besides Japan? We don't provide universal transformers because they require additional primary winding taps and terminals that significantly increase the labor cost of the power transformer. Based upon the very small number of amps that we hear of moving between different AC mains voltages this seems to be the most cost effective approach to offer our customers. Those few users who do move a piece of gear seem happy with fairly inexpensive step up or step down transformers.
 
Apr 4, 2014 at 1:04 PM Post #4,521 of 12,335
Hi! 

I checked the volume nob, the background noise is the same regardless of position. Also tried plugging in the amp to another wall-jack and the noise was still the same. I don't even know what heater-cathode leakage is, and is it possible to check wheter my tubes suffer from that without buying new ones? 

edit: Okay tested with two different of the small tube (is this the driver tube or whatever you call it?) and the background noise is slightly higher using one of them compared to the other but still present. Unfortunaly I don't have a spare of the big one to try with.


I've found noise to be a much more prevalent issue with my various power tubes. Without a doubt, the first thing to try is picking up some cheap mil spec 6080's off ebay. There are almost always some up with buy it now + shipping for less than $10.

I have a fancy power conditioner that I used to use with my crack. When I moved the crack to another room, I found it was still dead quiet with a cheapie surge bar. My guess is that this is only really an issue if you have particularly dirty power.

As a last resort, you could try redoing the input wiring from the rca's to your pot. My braid is really tight, as depicted below. (An older pic, prior to my most recent cap upgrade) My understanding is that this can play a real role in limiting noise. Good luck!


 
Apr 4, 2014 at 5:19 PM Post #4,526 of 12,335
A $100 will get you a surge protector that has some filtering. You'll spend quite a bit more for a "conditioner".
 
Apr 4, 2014 at 5:34 PM Post #4,527 of 12,335
is anyone here using NuForce Icon HDP with Crack ?...I have the upgrade itch and was wondering if this DAC is worth pairing with El Crack ,another one I'm interested in is JDS Labs - Standalone ODAC
 
Apr 4, 2014 at 5:52 PM Post #4,528 of 12,335
I did have that combo once upon a time and thought it was quite good. Looking at your current gear though, I'd say save up for a bigger jump unless the functionality of the HDP appeals to you (like the separate headamp for low impedance headphones, preamp capabilities, digital inputs, etc).
 
Apr 4, 2014 at 6:00 PM Post #4,529 of 12,335
is anyone here using NuForce Icon HDP with Crack ?...I have the upgrade itch and was wondering if this DAC is worth pairing with El Crack ,another one I'm interested in is JDS Labs - Standalone ODAC

Never tried the ones you mentioning but getting higher end Dac does make the difference. Arcam irDac and Matrix X-Sabre are the most noticeable among those i have tried
 
Apr 4, 2014 at 6:02 PM Post #4,530 of 12,335
  is anyone here using NuForce Icon HDP with Crack ?...I have the upgrade itch and was wondering if this DAC is worth pairing with El Crack ,another one I'm interested in is JDS Labs - Standalone ODAC


I used to use the HDP and the HRT Music Streamer II with the Crack. Both were very fine. I couldnt tell a difference.
 

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