Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: Rublyow on October 30, 2014, 09:21:39 AM

Title: Best way to attenuate volume?
Post by: Rublyow on October 30, 2014, 09:21:39 AM

I've seen this problem come up elsewhere, and I was wondering the best way to deal with it. Basically the volume using Crack is so loud that I only have to nudge the volume pot a tiny bit to have it at a comfortable level. But, I also don't have any fine-scale control over the volume. I've seen other people use in-line attenuators, and I was wondering what the best solution is.  Right now the problem is most pronounced when listening to vinyl records, where I'm running a Clearaudio Maestro wood cartridge (output 3.6 mV) though the Eros Phono and Crack w/ speeball.

Any thoughts or suggestions about what works best, hopefully with minimal coloration to the overall sound?

Thanks!

Title: Re: Best way to attenuate volume?
Post by: Paul Birkeland on October 30, 2014, 03:53:25 PM

You can solder a 33K resistor across each pair of outside lugs on each level of the volume pot, then solder a 75K resistor between the red wire coming from the RCA jacks and where it attaches to the volume pot, as well as another 75K resistor between the white wire coming from the RCA jacks and where it attaches on the volume pot.

This isn't all that different than an inline attenuator, but it will maintain high input impedance in the amplifier.

-PB

Title: Re: Best way to attenuate volume?
Post by: Nathan on October 31, 2014, 12:49:50 AM

That's what I did with excellent results

Title: Re: Best way to attenuate volume?
Post by: Rublyow on October 31, 2014, 04:13:03 AM

Great, I'll give that a go. Just to double check, if the lugs were labeled U1, U2, and U3, for the upper level and L1, L2, L3 for the lower level, then you are saying to solder a 33k resistor from U1 to U3 and another resistor from L1 to L3, right?

Also, does it matter what type? Just like a little 1/4 or 1/2 W film resistor?

Title: Re: Best way to attenuate volume?
Post by: Paul Birkeland on October 31, 2014, 07:31:34 AM

Yes, you need a pair of resistors there, and a pair of resistors between each hot signal wire feeding into the amp.

I would recommend 1/4 watt metal film, simply due to ease of use.

-PB

Title: Re: Best way to attenuate volume?
Post by: Nathan on October 31, 2014, 11:22:45 AM

I used 1/4 watt metal films to great effect. Best way to go.