Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: manther on January 26, 2019, 07:29:18 AM

Title: Bypass volume pot for dac stepped attenuator
Post by: manther on January 26, 2019, 07:29:18 AM

Considering a volume pot upgrade then realized my dac already has a good stepped attenuator.

Would like to bypass my crack volume knob for a while.

The two are always used together. (My Dac/crack)

Can anyone advise on bypassing?

Title: Re: Bypass volume pot for dac stepped attenuator
Post by: Tom-s on January 26, 2019, 07:31:33 AM

Just leave it in. Turn it up all the way and you've essentially bypassed it.

Title: Re: Bypass volume pot for dac stepped attenuator
Post by: manther on January 26, 2019, 08:07:35 AM

Ok in searching for the answer I saw Paul b mention this, but wasn't sure if it applied to my situation.

So the brush (excuse my lack of terminology) inside the pot has made direct contact with the internal lead at this point?

And running the amp this way all the time causes no issues?

Thanks!

Title: Re: Bypass volume pot for dac stepped attenuator
Post by: Tom-s on January 26, 2019, 08:41:18 AM

The internal resistance of the pot will be close to 0, yes.

Might get some noise with this situation (see FAQ), this normal, no issues.

Title: Re: Bypass volume pot for dac stepped attenuator
Post by: Crackawaka on March 04, 2019, 10:11:23 AM

What is the point of wanting to bypass the Crack’s attenuator? Is it because the circuit would then be cleaner?

Title: Re: Bypass volume pot for dac stepped attenuator
Post by: rbond on March 13, 2019, 06:23:35 AM

I have a related question: Is there a preferred "balance" to be achieved between the DAC's volume and the Crack's attenuator?  I'm using a Dragonfly USB DAC and currently have it's volume set at about 25%, which gives the Crack's attenuator a fairly broad range.  However, I'm curious whether it would be considered preferable to set the DAC's volume at 100%.  Having tried various settings I really cannot tell much difference, but was wondering if there is a technically correct answer.  Thanks.

Title: Re: Bypass volume pot for dac stepped attenuator
Post by: Paul Birkeland on March 13, 2019, 06:29:19 AM

It kind of depends on how the attenuation is performed in the Dragonfly.  Usually it is preferable to have the DAC all the way up.  You may find that adding the padding resistors described in the Crack FAQ to be helpful under these conditions.

Title: Re: Bypass volume pot for dac stepped attenuator
Post by: rbond on March 13, 2019, 08:47:15 AM

Thanks, I may give the padding resistors a try.  Regarding the volume control on the Dragonfly DAC, it has no physical control.  It is described as having a 64 position analog control that is manipulated by the computer (speaker icon).

Title: Re: Bypass volume pot for dac stepped attenuator
Post by: Paul Birkeland on March 13, 2019, 10:07:38 AM

If it's an analog control, then I wouldn't worry about it.