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description: Audio advice and discussions with audiophiles and professionals. Free discussion forums, open to all and frequented by industry experts. Ask questions and get advice on stereos, speakers, hi-end amplifiers, pre-amps, home theater, tube hi-fi, turntables, vinyl, tweaks, music, films, video, DVDs and more.
items: Soundlab A3 6db crossover out Acoustat 121 set up in!!!!
items: Re: Soundlab A3 6db crossover out Acoustat 121 set up in!!!!

Soundlab A3 6db crossover out Acoustat 121 set up in!!!!
type: item
description: Look at what is in my SL A3s The bass control chooses which of three primary windings in the bass/midrange audio transformer are engaged. This seems to affect efficiency and probably affects the impedance in the extreme low frequency range. The mid-range control chooses one of 3 possible inductances vs no inductor (4 positions, I think) that will be seen by the driving amplifier in series with the bass/midrange transformer. Any of the inductors effect a 6db per octave low pass filter with a -3db point dependent upon the choice of the inductance. The frequency of the cross-over to the treble transformer is fixed with respect to that tranformer by an RC network (hi-pass filter), typically at about 550 Hz. The Brilliance control is not a "brilliant" idea, but it places a resistance in series with the treble transformer and thereby cuts gain to the treble. Unfortunately, the Brilliance control is an L-pad type of potentiometer and cannot sound good. I and others have long advocated bypassing it OR choosing a setting which pleases you, measuring R across the control at that setting, and then replacing the control with a single high-quality resistor of like value. Even if you open up the Brilliance control all the way, so that there is effectively zero resistance across it, there is still an audible benefit to bypassing it or removing it, because otherwise the audio signal has to pass across it. An how about the Ratshck.parts in the Soundlabs thanks
creator: tubevibb
date: 2007-11-07T15:07:06-00:00

Re: Soundlab A3 6db crossover out Acoustat 121 set up in!!!!
type: item
description: ever checked the sound with an rta? interesting to know before and after snapshots of the response curves.
creator: valveman
date: 2007-11-07T18:46:09-00:00