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| LETTERS 3rd Quarter, 2006 |
All of us at Dagogo would like to thank you, our readers, for taking the time to share your thoughts with us.
We value every opportunity to hear from you, so feel free to type away!
We value every opportunity to hear from you, so feel free to type away!
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Subject = Luminance Audio KST-150 stereo power amplifier
Dear editor,
I read with some fascination Steve Keiser's articles. Based on your review, I purchased a KST-150 from a dealer after
hearing it myself. I must say I thank you for such a lucky find! Incredible sound.
In regards to Steve Keiser's articles, I think it would have served the interests of balanced reporting if you had sought
out the input of John Beyer, the "B" of B&K. Hearing Beyer's account from his perspective as to the nature and reasons
for Keiser's departure from B&K might be a good idea, since I feel in all fairness to Beyer, his story should be told also
in due consideration of fair and accurate reporting which I assume is an approach you endorse.
As things sit now, you have allowed Keiser an unlimited opportunity to promote not only his approach but his company
as well from an editorial perspective. Doesn't this constitute a conflict of interest? From my viewpoint, you must allow all
manufacturers similar opportunity should the request arise. Then again, I see that Luminance is an advertiser in your
publication. Sound familiar. Have been bought?
Andy Bausch
Dear editor,
I read with some fascination Steve Keiser's articles. Based on your review, I purchased a KST-150 from a dealer after
hearing it myself. I must say I thank you for such a lucky find! Incredible sound.
In regards to Steve Keiser's articles, I think it would have served the interests of balanced reporting if you had sought
out the input of John Beyer, the "B" of B&K. Hearing Beyer's account from his perspective as to the nature and reasons
for Keiser's departure from B&K might be a good idea, since I feel in all fairness to Beyer, his story should be told also
in due consideration of fair and accurate reporting which I assume is an approach you endorse.
As things sit now, you have allowed Keiser an unlimited opportunity to promote not only his approach but his company
as well from an editorial perspective. Doesn't this constitute a conflict of interest? From my viewpoint, you must allow all
manufacturers similar opportunity should the request arise. Then again, I see that Luminance is an advertiser in your
publication. Sound familiar. Have been bought?
Andy Bausch
| __________________________________________________________________ |
Subject = Luminance Audio KST-150 stereo power amplifier
Dear editor,
I am writing you to follow up on my previous e-mail concerning the hum problem I was experiencing with my KST-150.
I am reporting to you that my problem has been fully resolved, thanks to the helpful suggestions from Steve Keiser, who
was most generous in the amount of time he invested to fully satisfy my objection. I must say the Luminance company
deserves an A for promptly handling customer complaints. The KST-150 is fantastic. Thanks to your coverage, I figured
I saved thousands. I will continue to read DAGOGO in order to reap similar benefits to the rest of my system.
Donald Pennington
Dear editor,
I am writing you to follow up on my previous e-mail concerning the hum problem I was experiencing with my KST-150.
I am reporting to you that my problem has been fully resolved, thanks to the helpful suggestions from Steve Keiser, who
was most generous in the amount of time he invested to fully satisfy my objection. I must say the Luminance company
deserves an A for promptly handling customer complaints. The KST-150 is fantastic. Thanks to your coverage, I figured
I saved thousands. I will continue to read DAGOGO in order to reap similar benefits to the rest of my system.
Donald Pennington
| __________________________________________________________________ |
Subject = Luminance Audio KST-150 stereo power amplifier
Editor,
I read with great interest your review of Luminance KST-150. I purchased a KST-150 2 months ago, and fully agree as
to the many favorable attributes of this amplifier as outlined in your review. The only problem I experienced is that my
sample is endowed with an unfortunate hum problem that seems to be endemic to the KST-150 itself. None of the
several power amplifiers I have had in the identical system have hummed at all. Did you experience hum in your review
sample?
Donald Pennington
(See Mr. Pennington's next email)
Editor,
I read with great interest your review of Luminance KST-150. I purchased a KST-150 2 months ago, and fully agree as
to the many favorable attributes of this amplifier as outlined in your review. The only problem I experienced is that my
sample is endowed with an unfortunate hum problem that seems to be endemic to the KST-150 itself. None of the
several power amplifiers I have had in the identical system have hummed at all. Did you experience hum in your review
sample?
Donald Pennington
(See Mr. Pennington's next email)
| __________________________________________________________________ |
Subject = Designing the Luminance Audio Preamplifier, Part 1
You call your power amp the "fastest amp in the word". Would you still maintain that claim after reviewing product specs
at www.spectralaudio.com ?
Maybe I confuse speed quantifiers ( micro, pico or whatever seconds..) but it seemed to me that the Spectral amps
feature significantly faster rise times than your designs.
People looking for high speed in amplifiers as a quality designator will doubtlessly be aware of Spectral's position in this
field and so it may not serve your purpose to claim fastest amplifiers, if in fact they maybe not.
Alternatives to the Spectral designs (and price stickers) would be very welcome though.
Regards
Jeremy Whitewell
(Response from Steve Keiser of Luminance Audio)
At first, I had to confirm that such a statement exists somewhere in the Luminance literature or website. The statement
does in fact exist. I suppose one could apply a specific set of parameters on who would qualify as to define an
amplifier’s speed and then to adjust the amplifier's circuit performance, or just make "adjustments" in the specific
qualities set out in the specification, in which a given amplifier would handily meet.
In other words, the statement as alluded in the literature is highly subjective, meaning I would personally define an
amplifier’s speed as to describe the frequency response of its open-loop gain and closed-loop gain characteristics. If an
amplifier uses no overall feedback, then the slew rate and frequency response would, by themselves, define a measure
of an amplifiers speed. When closed-loop and open-loop time constants pertaining to frequency response match
precisely (as they do in KST-150), according to analog computer solutions of feedback systems, any further extension
of frequency response as measured from an external source forcing the signal applied to the input will not change the
time domain characteristics of the circuit.
Thus, if we compare the “on paper” specification of slew rate and frequency response bandwidth, the Spectral is faster.
The unknown consideration here is whether or not the Spectral uses negative feedback, and to what relationship does
that feedback have as a function of frequency. Since I haven't studied the circuit schematic of the Spectral, I cannot
definitely say which amplifier under dynamic real world conditions would be faster. As to the statement "the fastest
amplifier in the world", it is a far sweeping self-promotional, eye-catching exaggeration which, in my opinion detracts
more than adds, because it conjures up inquiry of the nature being addressed here. I will discuss and advocate the
statement's removal from the website, since it’s a claim I would never endeavor to defend. When I alluded to my
partners the KST-150 possessed the highest slew rate of any amplifier I have ever measured, I did not mean to imply I
have measured every amplifier ever manufactured. The "in the world" part of the statement has to be deleted and
replaced with the conventional method of defining speed, that is slew rate.
Thank you for pointing out this surface grammatical ineptitude.
Steve Keiser
You call your power amp the "fastest amp in the word". Would you still maintain that claim after reviewing product specs
at www.spectralaudio.com ?
Maybe I confuse speed quantifiers ( micro, pico or whatever seconds..) but it seemed to me that the Spectral amps
feature significantly faster rise times than your designs.
People looking for high speed in amplifiers as a quality designator will doubtlessly be aware of Spectral's position in this
field and so it may not serve your purpose to claim fastest amplifiers, if in fact they maybe not.
Alternatives to the Spectral designs (and price stickers) would be very welcome though.
Regards
Jeremy Whitewell
(Response from Steve Keiser of Luminance Audio)
At first, I had to confirm that such a statement exists somewhere in the Luminance literature or website. The statement
does in fact exist. I suppose one could apply a specific set of parameters on who would qualify as to define an
amplifier’s speed and then to adjust the amplifier's circuit performance, or just make "adjustments" in the specific
qualities set out in the specification, in which a given amplifier would handily meet.
In other words, the statement as alluded in the literature is highly subjective, meaning I would personally define an
amplifier’s speed as to describe the frequency response of its open-loop gain and closed-loop gain characteristics. If an
amplifier uses no overall feedback, then the slew rate and frequency response would, by themselves, define a measure
of an amplifiers speed. When closed-loop and open-loop time constants pertaining to frequency response match
precisely (as they do in KST-150), according to analog computer solutions of feedback systems, any further extension
of frequency response as measured from an external source forcing the signal applied to the input will not change the
time domain characteristics of the circuit.
Thus, if we compare the “on paper” specification of slew rate and frequency response bandwidth, the Spectral is faster.
The unknown consideration here is whether or not the Spectral uses negative feedback, and to what relationship does
that feedback have as a function of frequency. Since I haven't studied the circuit schematic of the Spectral, I cannot
definitely say which amplifier under dynamic real world conditions would be faster. As to the statement "the fastest
amplifier in the world", it is a far sweeping self-promotional, eye-catching exaggeration which, in my opinion detracts
more than adds, because it conjures up inquiry of the nature being addressed here. I will discuss and advocate the
statement's removal from the website, since it’s a claim I would never endeavor to defend. When I alluded to my
partners the KST-150 possessed the highest slew rate of any amplifier I have ever measured, I did not mean to imply I
have measured every amplifier ever manufactured. The "in the world" part of the statement has to be deleted and
replaced with the conventional method of defining speed, that is slew rate.
Thank you for pointing out this surface grammatical ineptitude.
Steve Keiser
| __________________________________________________________________ |
Subject = From B&K ST-140 to Luminance Audio KST-150
Greetings. I just wanted to say hello. I am one of the very few U.S. Luminance dealers and currently have one on
display in my showroom. This article was very interesting as it provided a bit of background that I was not aware of. I
truly feel that with a few more "tweaks", the KST-150 could be a world class performer. I'm impressed.
Sincerely,
Bill Baker
Response Audio
Greetings. I just wanted to say hello. I am one of the very few U.S. Luminance dealers and currently have one on
display in my showroom. This article was very interesting as it provided a bit of background that I was not aware of. I
truly feel that with a few more "tweaks", the KST-150 could be a world class performer. I'm impressed.
Sincerely,
Bill Baker
Response Audio
| __________________________________________________________________ |
Subject = FIM Vivaldi Four Seasons CD
Our compliments for the care in the review.
Best regards from Switzerland!
Burgert Wolfram M.
Producer
Divox
P.S. Our newest (exclusive) Ensemble are the Virtuosi delle muse
(www.ivirtuosidellemuse.com)
Our compliments for the care in the review.
Best regards from Switzerland!
Burgert Wolfram M.
Producer
Divox
P.S. Our newest (exclusive) Ensemble are the Virtuosi delle muse
(www.ivirtuosidellemuse.com)
| __________________________________________________________________ |
Subject = Luminance Audio KST-150 stereo power amplifier
Great review, sir! The technical data was displayed in a way that even I enjoyed reading.
Jeff Sutherland,
Virtual Dynamics (partner company to Luminance Audio)
Great review, sir! The technical data was displayed in a way that even I enjoyed reading.
Jeff Sutherland,
Virtual Dynamics (partner company to Luminance Audio)
| __________________________________________________________________ |
Subject = Harmonix Reimyo DAP-777 (2005)
Hi Laurence,
Would you recommend this unit with the CDP-777 or would it just be overkill?
Thanks & regards,
Richard S.P. Guerreiro
(Response from Laurence A. Borden)
Mr. Guerreiro:
I have had the opportunity to compare the CDP-777 used as a CD player, with the CDP-777 (used as a digital
transport)/DAP-777 combination. As good as the DAP 777 is, the CDP-777 was far better. Whether this is due to the
DACs in the CDP-777 being inherently better, or to the lack of a digital interconnect - or both - I cannot say. What I can
say is that the CDP- 777 is, in my opinion one of the finest CD players ever made. If you own one, color me envious.
Sincerely,
Larry Borden
Hi Laurence,
Would you recommend this unit with the CDP-777 or would it just be overkill?
Thanks & regards,
Richard S.P. Guerreiro
(Response from Laurence A. Borden)
Mr. Guerreiro:
I have had the opportunity to compare the CDP-777 used as a CD player, with the CDP-777 (used as a digital
transport)/DAP-777 combination. As good as the DAP 777 is, the CDP-777 was far better. Whether this is due to the
DACs in the CDP-777 being inherently better, or to the lack of a digital interconnect - or both - I cannot say. What I can
say is that the CDP- 777 is, in my opinion one of the finest CD players ever made. If you own one, color me envious.
Sincerely,
Larry Borden