Why I enjoy my Luminous Audio passive unit, vs an additional gain stage ( preamp )


This topic of preamp / passive, has been discussed, ad nauseum. So why am I posting this ?, you ask. Why not, as it is still be discussed heavily here, and elsewhere. This is a short story ( lol ), but a quick read, so be patient, and thank you, in advance, for reading. In the early eighties ( I am thinking ’84 ), PS Audio introduced the model IV preamp, which had a button on the left side of the faceplate, that showed...Gain...active / passive. Interestingly, a year or 2 prior, the CD was introduced. Prior to the cd, we audiophiles and music listeners, listened to vinyl, open reel tape, radio ( tuner ) cassette tape, and in my case, worked a bit with microphones, patch bays, mixing consoles, and dabbled in live recording ( early on ). As most of you know about me from my posts here, I own Klipsch Lascalas ( tweaked and modified ). I met Paul Klipsch, and was, from my very early beginnings, a Klipschaholic. My dad had AR3a’s, driven by a Fisher 500C. My music teacher / singing coach, had Klipsch Cornwalls ( the mid and hf horns were vertically mounted, mirror imaged, and were the only pair I had ever seen with this vertical arrangement ), which soon became mine, as he upgraded to the Khorns. My dad no longer wanted tubes, so he purchased a Sansui 8 Deluxe, and I, the 500 C. Wow !. We were both happy. The Sansui was so much a better match for driving his power hungry ARs, and I was happy with my combo ( this was the late 60s already ). Moving along to the CD era, the typical cd player, produced 2 volts output, which was enough to drive most power amplifiers directly ( just needed a way to control volume ). The early cd players, were large and heavy, and they had, as part of their designs, massive transformers and huge, hefty power supplies. Sony, if I remember (and I could be wrong ),was the 1st company, who offered a variable audio output on their players, and we, the equipment consumers, bypassed our preamps, and were running these cd players, even through receivers and integrated amps, that allowed the disconnect between the pre and power sections, going direct into the power amp sections. Getting back to the introduction of the PS Audio model IV preamp, and its gain switch. This began an onslaught of passive devices ( volume controls / switching units ), without a gain stage, to hit the market. Moving along to modern day, there are hundreds of passives available. Some dac manufacturers claim, they can drive amplifiers directly. As it turns out, within the last several years, manufacturers are now producing integrated amplifiers, sans a preamp gain stage, taking the signal of the source ( not just cd players and dacs ), but tuners, tape machines, computers, phones, outboard phono stages, cable and satellite boxes, etc., and driving the power amp directly, without the need for the extra gain stage. What I want to tell you, is this. With the right system ( and I will use my system as an example ), an extra gain stage ( preamp ), does more harm, than good. A longer signal path ( more parts, more wires, more circuits ), can only destroy finite details, can only add colorations, can only add distortions, if GAIN IS NOT NEEDED. I used to feel this is in part, to the very high sensitivity of my loudspeakers, as any of my ( what remains of my collection ) 20 or so power amps, runs them so very easily. However, I have introduced many folks to the passive band wagon, taught them what to listen for, helped them with their systems, and now, enjoy passive listening. With all types of systems. Jumping back to my Luminous Audio unit ( I am using their top single ended model, but they all share similar topology ). This is a fixed series / variable shunt device. What this means is, the signal never passes through the volume control. The signal travels through 1 high quality resistor, and the amplifier’s inputs are shunted to ground, via the potentiometer, itself. The resistors can be selected, as well as the potentiometers, depending on the model, and Luminous will impedance match your particular unit, to match your system. For a nominal fee, it can be sent back to Luminous, and be designed to match with other / different gear. The beauty of my passive unit, is, that I do not " hear it ", in my system. It is NEUTRAL. Another term popularly used, is COLORLESS. How I know this. Using a self modified Yamaha pro amp from my collection, which has input attenuators ( as all pro amps do ), I hear no difference between my dac feeding the amp directly, vs the Luminous in the system ( although, I do hear the additional 1/2 meter Audio Research Litz interconnect, needed, with the passive ). Yes, this cable has a sound ( all cables, ime, do ). I am not getting paid by Luminous, by Klipsch, by anyone, posting this. Lastly, 2 more things. I have heard a few systems, in which an active preamp was beneficial ( the added gain ), but, to my ears, some neutrality was lost. I also greatly believe ( besides the source needing to have the proper output voltage and matching impedance ), the source, whatever it would be ( let’s say a dac ), should have a very hefty, over designed, stiff and well regulated, power supply, as part of it’s analog output section, based on my listening ( many do not ). I am open to further discussions on this matter, invite questions, and share experiences. Enjoy, be well and stay safe. Always, MrD.
mrdecibel

Showing 10 responses by mrdecibel

BTW...some of the cable brands we listened to were Audioquest, Cardas, Silnote, Kimber, Transparent, WyWires, Shunyata, Belden ( home made ), and the Benchmark cables. 
@atmasphere Welcome to my post, and thank you for the feedback. My other cable is in fact another of the same cable, and of the same length. I like the sound of these cables. I am yet to hear a cable that does not have a sound ( after an extensive break in ( another topic I will discuss at some point, also ad nauseum ). If I like something I put in my system, I give it some break in time, but generally do not need much time to make my final judgements. My Yamaha amps ( and other pro amps ), with it's input attenuators, easily allows me to hear the quality of a preamp, or passive unit, because I can go source / dac direct into it. My currently enjoyed amp at this particular time, is an original Edge M8, by the 1st company of Tom Maker. It is single ended, only. His newer stuff, Maker Audio, is balanced, and I am familiar with balanced connections, and the benefits of use. I totally went over this amp, and it is a dream to listen through. As we have discussed before on other preamp / passive threads, we always differed in opinion on this subject. Georgehifi is another, who is in my camp. I am completely fine with this, as I know many prefer a preamp, but few, ime, actually need one. As far as cables are concerned, and I am speaking of balanced cables as well, they all have different SQ characteristics, from each other, and from the various levels within the same brand. Power cables ( I build my own ), that will be another discussion, also discussed ad nauseum. There is a YT video, from " The British Audiophile ", " Hi Fi Cables, Myths and Misconceptions ", which is very informative. He is intelligent, and speaks with etiquette, as I find most Brits. I am glad you stopped by. All is good with our differences of opinion. As you may know, since my beginnings here on the ' Gon, I have always stated what SQ characteristics I enjoy, and I understand more than most, the variety of listeners that there are. It is what makes our audio world go round and round. Enjoy, be well and stay safe. Always, MrD.
All good. I have heard the Benchmark gear ( at another listener’s home ), which I understand conforms 100%. We did a cable shoot out, and the sq differences between cables were quite apparent to me ( I brought over some 1 meter Silnote Audio balanced cables I purchased from Mark, at Silnote ). On another visit, I did bring over two self modified Yamaha amps for comparison, and found them to be quite competitive to the Benchmark, for neutrality. The Benchmark preamp is quite amazing, in it's neutrality. It surprised me. 
My passive is single ended, and I am fine with it. Given everything you say, which is quite informative, still leaves me with 2 conclusions. The 1st is, balanced lines are useful, and necessary, when the lines are long, and / or there is an abundance of electrical, magnetic, or rf noise, contaminating the area ( which is truly likely in most circumstances ), balanced has a lower noise floor, resulting in a blacker background while listening. The 2nd is, there are very apparent sonic differences between cable brands, and as I mentioned, those models within the brands line. Balanced cables, as well as single ended cables, all sound different, and matching them to systems, can create a better synergy between the components, and sound shape the presentation, for the listener. Should this be the case, I do not know. But keep in mind.....I am one, who hears improvements, with an upgraded fuse ( another discussion ). I put a brick ( from your local garden / home improvement store, covered in a small towel ( towel to protect the equipment ), on top of an amp, preamp, transport, etc., and it changes the sound........anyway, thank you again, for your information and involvement with the discussion. You seem to be the only one, thus far. Enjoy, be well and stay safe. Always, MrD.
I have gotten a few private emails concerning the Luminous passive products, and passive, as a whole. I wanted to update this thread, as to create more interest, and truth, as to passive driven systems. There is no question, that extra gain can give you more " oomph ", but when listening to a piece of music, that has " oomph ", you begin to notice, with a good passive such as the Luminous, that there is finite information on the recordings, that can be lost, with extra gain. A longer signal path, cannot retain " what goes in = comes out ", with the most purity and clarity of the signal, and this is with a system that matches on all levels, source to amp. I would love to hear other stories here, as to those who have followed the passive path, understanding it has been discussed many times prior. There is a lot of repetition and repeat threads here, so nothing new. Enjoy, be well and stay safe. Thank you, MrD.
I have listened to passive units with transformers and find them to be round and colorful, meaning they are warm and the frequency extremes seem rolled of. They are not as detailed to me. Being familiar with pro gear and balanced lines, I still suggest, based on my listening, cable brands sound significantly different to me, whether they are single ended or balanced. I am not an engineer, and the reasons for this are likely many, as discussed here and elsewhete. I appreciate the feedback.
@atmasphere I know you are big on balanced, as this is so very obvious. I AM familiar with balanced systems, for a very long time. As I mentioned recently, I spent some time with the recent Benchmark gear, where we did a shootout with several brands of balanced cables, and they all showed various attributes, weaknesses, colorings if you will, and this included cables made by Benchmark. I am not sure why your insistence of " cables do not sound different ", when they are used in a balanced configuration. Several of us have heard these differences, and easily.......getting back to transformers for a moment. I feel, they are necessary in many instances.....but as a listener, I do not like them, in a home playback system, whenever possible. This is exactly why, you follow your path of OTL amplifiers, as your designs. Yes, it limits their ( OTLs ) use, but imo, transformers are band aids, that are needed in many areas. McIntosh makes fabulous output transformers, and continues to use them in their SS gear. However ( and I might get some backlash from some folks reading this ), my description above in my previous post, is exactly how I hear their amplifiers. Round, rolled off at the frequency extremes, colored, lacking in finite details, and sluggish and slower bass, than most ( why I do not use tube amps )However, I know hundreds and hundreds of listeners who use Mc gear and tube gear, and understand, and respect their decision to use it. Just not my cup of tea, as many, who do not like passive, or horns, etc. So, cables do sound different, whether single ended or balanced, to these ears. Always, MrD.
@atmasphere I will never claim to be as smart as you, but I am sure betting my hearing is as good as yours, and I will leave it at that. Although this thread was about passive vs active, you are making it about single ended, balanced, and balanced standard, AES48. I understand passive has it's limitations, and why you brought all of this up. I do not want to argue with you ( how I miss Almarq ). The entire system used during our cable evaluation was new Benchmark products, from the source to the amps, which I understand to be ( prove me wrong ), the standard AES48. And if I am wrong, so be it. I have been wrong before. So, given the " cable differences might be greatly reduced ", which is your wording, are you suggesting, that differences in cables, under these conditions, are NOT audible at all ? As far as transformers....I understand all that. I still do not like them, in applications that I am speaking. 
@atmasphere As I said, I am nowhere as smart as you, and if I am wrong, which seems to be the case here, I am wrong, and I thank you for all of the tech stuff you teach me, and many others here. I obviously made assumptions, and you know what that makes me......lol.....Question : Are there many high end home audio companies whose products offer balanced only, conform to the AES48 standard. Back in the day when I was an AES member, much equipment did conform ( pro and studio gear particularly ). Thanks again for the tutorial, as I always appreciate learning. Always, MrD.
@atmasphere Ralph, great story. I am sure in my past life I had many instances of using and listening to a true balanced system. So, what can we all do, to get this type of balanced system into out listening rooms ?