Total Bithead volume control...microphonics?
Mar 16, 2006 at 10:17 PM Thread Starter Post #1 of 12

The Monkey

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Hi all,

Purchased a Total Bithead used. Looks to be in great shape, but I've noticed a couple of things and would like your feedback:

1) When the volume is low or off, and I turn the volume dial, I can hear it rather clearly in my phones. The sound is like that of the microphonics one would get with an IEM, but this was also happening with my HD 595. Any thoughts?

2) There's a noticeable hiss when I use it with my E4's and my ipod. I'm assuming this is due to the source and low-impedance iems. Can someone confirm?

I just want to make sure this amp is working properly.
 
Mar 16, 2006 at 10:24 PM Post #2 of 12

apostate

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I also get hiss with very low impedance headphones with my Total Airhead (particularly my IEMs but also with my AKGs and Grados if the volume is high and the 595s if it is near max).

As to the volume control I believe that's normal. From the Airhead/Bithead FAQ on Headroom's site:

4. Q. When I adjust the volume control, why does it sound slightly ‘scratchy’?

A. We had a choice when designing the BitHead’s sound control. We could have added DC blocking caps in the potentiometer circuit, thereby making the volume control ‘quiet’ when adjusting it. But by doing so, the caps degrade the overall sound quality of the volume control so much that we decided to go with our second option instead. Our second option was to remove all resistors, resulting with the highest audio quality volume control. The only catch is that you hear a slight scratching when adjusting the volume. We decided that a little noise only 1%-2% of the time was preferable over having noise 100% of the time.


Ant
 
Mar 16, 2006 at 11:10 PM Post #3 of 12

The Monkey

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lol, I suppose I should have found that on my own.
biggrin.gif


Thanks very much for answering my questions, ant. Looks like the amp works just fine.
 
Mar 16, 2006 at 11:11 PM Post #4 of 12

Tyll Hertsens

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Yup, the pot is scratchy due to DC offsets. Noise on IEMs is because they are so efficient, and the gain is rather high on the AirHead. It would be nice if those idiots over at HeadRoom would put a gain switch on the AirHead and havee a low gain setting for IEMs.
very_evil_smiley.gif
 
Mar 16, 2006 at 11:46 PM Post #5 of 12

apostate

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Quote:

Originally Posted by Tyll Hertsens
Yup, the pot is scratchy due to DC offsets. Noise on IEMs is because they are so efficient, and the gain is rather high on the AirHead. It would be nice if those idiots over at HeadRoom would put a gain switch on the AirHead and havee a low gain setting for IEMs.
very_evil_smiley.gif



Aw, give em a break they're pretty good aside from that
biggrin.gif


Though since I seem to be collecting primarily efficient headphones a low gain version would be great (or even a mod to lower the gain for a small fee *hint*). I really like it with my UM1s aside from the hiss, sadly the hiss outweighs the bonuses for me. I really miss the crossfeed though.

Ant
 
Mar 17, 2006 at 12:56 AM Post #6 of 12

TheSloth

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Quote:

Originally Posted by Tyll Hertsens
It would be nice if those idiots over at HeadRoom would put a gain switch on the AirHead and havee a low gain setting for IEMs.
very_evil_smiley.gif



TheSloth looks at the current 'sale' status on the Mobile line and starts to formulate conspiracy theories...
 
Mar 17, 2006 at 3:11 AM Post #7 of 12

Jamey Warren

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Quote:

Originally Posted by TheSloth
TheSloth looks at the current 'sale' status on the Mobile line and starts to formulate conspiracy theories...


No longer a need to conspire.
evil_smiley.gif
 
Mar 17, 2006 at 5:34 AM Post #9 of 12

RnB180

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Quote:

Originally Posted by jamey
No longer a need to conspire.
evil_smiley.gif




Ive been looking for a small all in one amp for my laptop. Id like something smaller and slimmer than the micro stack to use with my super fi pro 5's.

Does this mean a IEM friendly new mobile line will be released?
 
Mar 17, 2006 at 2:08 PM Post #10 of 12

Jamey Warren

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Quote:

Originally Posted by RnB180
Ive been looking for a small all in one amp for my laptop. Id like something smaller and slimmer than the micro stack to use with my super fi pro 5's.

Does this mean a IEM friendly new mobile line will be released?



It just happened.
 

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