Bottlehead Forum

Bottlehead Kits => Crack => Topic started by: lextek on January 17, 2015, 03:26:03 AM

Title: Crack as Preamp?
Post by: lextek on January 17, 2015, 03:26:03 AM

Still loving my Crack.  Was wondering if a Crack could be used as a preamp or be converted to one? 

Title: Re: Crack as Preamp?
Post by: Paul Birkeland on January 17, 2015, 08:44:07 AM

Yes, all you need to do the conversion is a 1/4" TRS to RCA cable, or a similar adapater.

-PB

Title: Re: Crack as Preamp?
Post by: Deluk on April 24, 2015, 01:21:04 PM

Slightly agent provocateur here but used as a preamp would it drive a pair of Quad II's? ;) My Crack is a few weeks away as yet but I do have the Quads.

Title: Re: Crack as Preamp?
Post by: Paul Birkeland on April 24, 2015, 02:07:58 PM

Quote from: Deluk on April 24, 2015, 01:21:04 PM

Slightly agent provocateur here but used as a preamp would it drive a pair of Quad II's? ;) My Crack is a few weeks away as yet but I do have the Quads.

Yeah, sure that would work.  I'd put a pair of Harrison labs -12dB attenuators in front of the Quads.

-PB

Title: Re: Crack as Preamp?
Post by: Deluk on April 25, 2015, 06:51:18 AM

Thanks for that.
Harrison not a name that comes up here in the UK, but I've found these, which are switchable 10/15/20db. Being able to do this could be useful. I have Klipsch Quartets which don't need the volume control up too far!
http://www.amazon.co.uk/Stageline-21-2840-Passive-Level-Attenuator/dp/B0057G44WM/ref=pd_sim_sbs_ce_1?ie=UTF8&refRID=1CK3CPCDNH91KAKFKHAX
The other make is Rothwell which have 10 and 20db versions.
http://www.amazon.co.uk/Rothwell-RCA-In-Line-Attenuators/dp/B00B7383F8/ref=pd_bxgy_MI_text_y
Being nearly twice the price for a fixed attenuation Rothwell, makes the Stageline ones look to be much better value.
Any comments

Title: Re: Crack as Preamp?
Post by: Paul Birkeland on April 25, 2015, 08:03:04 AM

Yeah, your amplifiers are overly powerful/sensitive for such high efficiency speakers, so -20dB of attenuation might be a better idea.

-PB

Title: Re: Crack as Preamp?
Post by: Deluk on April 25, 2015, 09:04:59 AM

Thanks. The Quad II's are only 15 watts each so not overtly beefy but then Valve watts always do seem more powerful. Currently using a Luxman L30 and that's only 2 x 30 watts. Neither the Quads or the Luxman need a delicate touch on the volume control but both can supply the Quartets more than I or my neighbours need......  8)

Title: Re: Crack as Preamp?
Post by: Paul Birkeland on April 26, 2015, 12:18:59 PM

Yeah, you are likely in the 1-2 Watt power level for full listening level.  With a 15+ Watt amp with .7V input sensitivity, you'll need a significant gain reduction from your preamp for a comfortable listening level (or pads at the input of the amps).

-PB