NeilBEN
Well-Known Member
Hi folks, I have had a B&K ST-140 since about 1986, and I love the way it sounds. But it has started showing its age - and I have posted on a thread here, about recapping it. Which I have done, and now it sounds better than ever, with better bass, to go along with its outstanding open and clear midrange and highs.
That being said, I got a Schiit Audio Vidar almost 2 years ago, and it is an excellent amp. Since updating the ST-140, I have been using both amps with an active digital crossover - the Vidar on the woofers, and the ST-140 on the tweeters.
That was a stellar combination. I now have done an analog crossover (with a revision coming), so I have once again been able to use just one amp. And in this setup, the B&K is the better sounding amp. The Vidar is a bit closed in sounding, with less midrange detail and dynamics - it sounds (too?) smooth and often flat & a bit dull and 2D. The highs are certainly still there, but it feels like it is either softer (both tonally and volume?) or there is a midrange "suckout".
To add to the issue, the ST-140 has been having issues with the left channel, which make it not "safe" to leave connected to the speaker. I am going to try and figure that out, and I have posted on that other thread. (https://audiokarma.org/forums/index.php?threads/b-k-st-140-recap-bom.816988/page-19#post-15063574)
MY QUESTION: can the Schiit Vidar have its bias tweaked safely - and would this open up the sound clarity in the upper mids and highs?
In their assembly video for the Vidar (starting at about 26:45), they set the bias between 0.40 and 0.50mV on each channel, so I would assume that setting it at close to 0.50mV on each channel that this would slightly affect the clarity, and still be safe within spec?
Other options of course, are other amps - maybe the Aegir, or an Audio by Van Alstine Vision SET 120 (https://avahifi.com/collections/power-amplifiers/products/vision-set-120-power-amplifier), or a couple of Vista Audio Sparks biamping the speakers?
My preamp is an Audible Illusions Modulus 3A. It is rated at Output impedance: 1.2k ohms (main), 150 ohms (tape). Should I look at the output impedance of this vs the input impedance of the Vidar - which is 22k ohms SE, 44k ohms balanced? The B&K ST-140 input impedance is rated at 24.3k ohms, which seems fairly close to the Vidar?
My speakers are mass loaded transmission line - 4 ohm and quite sensitive - the woofers are 92dB at 2.83V, and the tweeters are Linaeum TLS, which are very even impedance of about 7.3 ohm all the way across their spectrum. (https://audiokarma.org/forums/index.php?threads/mass-loaded-transmission-line-speakers.970929/)
That being said, I got a Schiit Audio Vidar almost 2 years ago, and it is an excellent amp. Since updating the ST-140, I have been using both amps with an active digital crossover - the Vidar on the woofers, and the ST-140 on the tweeters.
That was a stellar combination. I now have done an analog crossover (with a revision coming), so I have once again been able to use just one amp. And in this setup, the B&K is the better sounding amp. The Vidar is a bit closed in sounding, with less midrange detail and dynamics - it sounds (too?) smooth and often flat & a bit dull and 2D. The highs are certainly still there, but it feels like it is either softer (both tonally and volume?) or there is a midrange "suckout".
To add to the issue, the ST-140 has been having issues with the left channel, which make it not "safe" to leave connected to the speaker. I am going to try and figure that out, and I have posted on that other thread. (https://audiokarma.org/forums/index.php?threads/b-k-st-140-recap-bom.816988/page-19#post-15063574)
MY QUESTION: can the Schiit Vidar have its bias tweaked safely - and would this open up the sound clarity in the upper mids and highs?
In their assembly video for the Vidar (starting at about 26:45), they set the bias between 0.40 and 0.50mV on each channel, so I would assume that setting it at close to 0.50mV on each channel that this would slightly affect the clarity, and still be safe within spec?
Other options of course, are other amps - maybe the Aegir, or an Audio by Van Alstine Vision SET 120 (https://avahifi.com/collections/power-amplifiers/products/vision-set-120-power-amplifier), or a couple of Vista Audio Sparks biamping the speakers?
My preamp is an Audible Illusions Modulus 3A. It is rated at Output impedance: 1.2k ohms (main), 150 ohms (tape). Should I look at the output impedance of this vs the input impedance of the Vidar - which is 22k ohms SE, 44k ohms balanced? The B&K ST-140 input impedance is rated at 24.3k ohms, which seems fairly close to the Vidar?
My speakers are mass loaded transmission line - 4 ohm and quite sensitive - the woofers are 92dB at 2.83V, and the tweeters are Linaeum TLS, which are very even impedance of about 7.3 ohm all the way across their spectrum. (https://audiokarma.org/forums/index.php?threads/mass-loaded-transmission-line-speakers.970929/)
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