Lightspeed Attenuator - Best Preamp Ever?

I don't know of one resistor based passive that doesn't vary the output impedance based on the attenuation level. I think it is just the nature of the beast and as Andrew mentioned the LDR design is not immune to this (Side Note: The Truth Preamp does not vary the output impedance but that is because it uses active buffers on the outputs). It is one of the reasons why it is important to get the right impedance matching and in some cases to pay attention to cabling to attain the best sound from such a design. TVC passives have the same issue (see here, scroll down the page http://www.stevens-billington.co.uk/page102.htm) but are more forgiving. It was one reason I preferred TVCs earlier on before encountering the LSA.

Also, Ralph Karsten mentioned a number of times that the best sound from a passive will occur closest to the maximum point on the volume control (least attenuation). That is because the further around the dial you go the lower the output impedance. I'm never at much lower than 12 o'clock on my LSA and with my Atma-Sphere S-30 amps where I can vary the input sensitivity and gain, I'm never at less than 3 o'clock. So it's safe to say I'm operating at lower output impedance running into high input impedance amps (minimum 100k ohm, maximum 250k ohm).

Tvad, you understand me correctly. Sorry I should have been more clear perhaps. Further, so we can get on more common ground around this topic, I feel the software/recording used to judge accuracy should be one that is very close to live sound - a great recording. This gives a good base in which to judge the system. If I have heard a given brand/type piano in an intimate setting on many occasions I have a good sense of how its sound. When I listen to good recording of said piano on a system, I am in a good position to judge that system's accuracy.

If it sounds thin or lacks body, then I know that system is not getting it quite right in that particular area. I now understand this system will behave the same way on any recording regardless of the recording's quality.

A recording may be heavy laden with warmth and body, but this system will play it with less of those attributes and therefore not be true to the recording.

I have good recordings of piano and Van the Man and have seen both live on many occasions. Based on this I prefer one system over another.

George, it does not make sense to state that system synergy manifests as 2D or 3D. Please explain.

"What you should do Grannyring to see if the Dude is artificially giving depth, is what I preach all along, put your CDP straight into your poweramp (Bolero Test) no preamp. Put on a quite cd so you can then ascertain a good level of cd to play, then swap in the Lightspeed then your Dude and see which is closer to no preamp. The one that is, is the one that is truer to the source."

I have done that test repeatedly. Digital done direct (Bolero Test) always sounds flat, hard, and 2D. Not like real life at all. Not sure what that specific test adds.

Ah! A good music recommendation, I will get that.

I never compared the Atma-sphere preamp with the LSA as I use it with the Atma amps in all balanced connection, so I jave not been able to compare them with the same amp.

I use the LSA with the Music Reference RM10 (summer) and RM 9 Special Edition (Fall), both amps single-ended. I went through a series of preamps, most recently the CAT SL1 Ultimate, Lamm LL2, and Joule LA150 Signature Edition. Of these, the Joule was the one I liked most and could live with it forever, but I decided to try the LSA just to see what it might do versus one of the best sounding active tube linestages I have owned. I kep going back and forth for a few months, and without too much analysis, I simply felt I liked the LSA better, certainly as much as the $7,000 Joule - seemed silly to keep both with that kind of price differential and since I only have one source, low capacitance cable (Cardas GR), and both MR amps were designed by Roger Modjeski speciofcally to be passive friendly (High input impedance, high sensitvity <1v) I figured that while an active will sound better with a wide range of sources, amps, and speakers, my particular system is really passive optimized and that under those circumstances a passive should be better at passing the signal undamged from source to amp.

The LSA is very, very quiet, seems to be very well balanced from lows to highs, has a very wide and deep sounstage with recordings that have wide and deep sounstages - soundstaging with this preamp really is a reflection of the recording and not a constant attribute, and imgaging and localization is very precise and unwavering, and instruments seem to have their naturural size and instrumental bloom. I also notice that music can be played louder without unpleasant shout that can occur with some systems.

Within my system, there is really a hairsplitting comparison with the CAT, Lamm, and Joule - they are all exceptional pieces of equipment and enjoyed all of them. There is not however a hairsplitting difference in price - which is why I love the LSA, it can give audiophiles without deep pockets SOTA sound if they pick their sources, cables, and amps carefully/properly. Or, if you have the money, you can buy one of these great linestages and have a great system too, without worrying much about system matching.

Arthur Salvatore says that if your system sounds better with an active linestage, your system needs an active linestage - but if you don't need one, a passive is the way to go. I think this in part explains why some folks swear by passives, and others say they much prefer actives; I suspect where you fall depends on your system as a whole, and not necessarily a reflection the inherent qualities of either approach - why as they say wisely, your milage may vary.