@almarg
I was referring to George and Ralph's technical discussion on the last page (3), and not the whole thread and topic.
I was referring to George and Ralph's technical discussion on the last page (3), and not the whole thread and topic.
Have Passive Preamps Finally Come of Age?
Back in the late 90s (eons ago) I tried a variety of passive preamps (PPs). The most musical was an autoformer, but back then my system was not balanced. For the last decade I have been using active preamps, both tube and solid state, but finding a quality balanced preamp under $4K is damn near impossible. Enter the Parasound P5 (2.1), which in addition to having balanced I/Os, it has a separate bass management circuit (MSRP $1095), and I was hoping it would provide better control over the built in class D plates incorporated into my 2 SVS powered subs, whose volume controls are STUPIDLY sensitive: when barely cracked from zero they overwhelm. Alas, no bueno.
Recently i watched a PS Audio YT video that was emphatic about NOT connecting powered subs with interconnects; instead he recommends speaker cables piggybacked off the main systems amp/s. I had a spare set of DIY flat copper cables, and was shocked how much better they sounded, but doing so did not change the volume control problem and unfortunately this id not bypass the SVS amps whose class D chips are now ancient. Thinking there could be an impedance problem led me to revisit PPs.
I sold my P5 and was using the XLR outs from my Oppo 105 (upgraded power supply and IEC/wiring to the power supply) direct to my Emerald Physics 100.2SEs (class D). The noise floor dropped tremendously, allowing me a much better view into the music. My Core Power Technologies 1800 PLC had more than a little to do with this, but...
Days of PP research later, I came across LDRs, which seem like the ultimate PP option, but XLR versions are ~ $2K and up, with the Tortuga coming in at $2700, seems like a true SOTA bargain, just not in my current budget. Scouring the' for sale' sites I came across a Hattor XLR (MSRP $995) which was in my price range. Hattor's www had links to 2 reviews both were extremely positive: one used it in combination with a class D amp. Bingo! I snapped it up.
It arrived late yesterday, although Hattor's www pictures look awesome, they do not compare to seeing and touching it. The metal carrying case was an indication of the designer's dedication. This is an etremely well made piece of kit, but how does it sound? Alas it came with no manual and Hattor's site does not have a PDF. How hard can it be to hook up? Well, after a couple scary minutes, I discovered that it would not light up until I connected the 105.
Stone cold, the first thing that shocked me was a further reduction in noise floor and an incredibly wide and deep sound stage, but as can be expected, it was dry. Fingers crossed, in about a half hour I began to be rewarded with texture as well. Tis only got better as the night wore on
I hope somebody chimes in with their Tortuga experience, or any other high quality PP information.that goes under the reporting radar.
Recently i watched a PS Audio YT video that was emphatic about NOT connecting powered subs with interconnects; instead he recommends speaker cables piggybacked off the main systems amp/s. I had a spare set of DIY flat copper cables, and was shocked how much better they sounded, but doing so did not change the volume control problem and unfortunately this id not bypass the SVS amps whose class D chips are now ancient. Thinking there could be an impedance problem led me to revisit PPs.
I sold my P5 and was using the XLR outs from my Oppo 105 (upgraded power supply and IEC/wiring to the power supply) direct to my Emerald Physics 100.2SEs (class D). The noise floor dropped tremendously, allowing me a much better view into the music. My Core Power Technologies 1800 PLC had more than a little to do with this, but...
Days of PP research later, I came across LDRs, which seem like the ultimate PP option, but XLR versions are ~ $2K and up, with the Tortuga coming in at $2700, seems like a true SOTA bargain, just not in my current budget. Scouring the' for sale' sites I came across a Hattor XLR (MSRP $995) which was in my price range. Hattor's www had links to 2 reviews both were extremely positive: one used it in combination with a class D amp. Bingo! I snapped it up.
It arrived late yesterday, although Hattor's www pictures look awesome, they do not compare to seeing and touching it. The metal carrying case was an indication of the designer's dedication. This is an etremely well made piece of kit, but how does it sound? Alas it came with no manual and Hattor's site does not have a PDF. How hard can it be to hook up? Well, after a couple scary minutes, I discovered that it would not light up until I connected the 105.
Stone cold, the first thing that shocked me was a further reduction in noise floor and an incredibly wide and deep sound stage, but as can be expected, it was dry. Fingers crossed, in about a half hour I began to be rewarded with texture as well. Tis only got better as the night wore on
I hope somebody chimes in with their Tortuga experience, or any other high quality PP information.that goes under the reporting radar.
249 responses Add your response
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celander You shouting!!! never joke about having a beer to an Aussie, mate, he'll be on to you like a rat up a drain pipe. Sorry Tweak again with the off topics. |
Just looked at it tweak1 OP they missed the mark as nowhere does it say you can switch out the J-Fet buffer, that's a bummer. Nelson Pass kindly made a buffer for the Lightspeed Attenuator 10 years ago so his customers could drive a couple of models of his low impedance amps with the Lightspeed. I built one up and yes it sounded good and you needed it for those low impedance amps, but still, no buffer sounded better if it wasn’t needed. That’s why I say they missed the mark by not making it switchable. Here it is https://ibb.co/im8ZrK Cheers George |
atmasphere Really, you need a history lesson back to the 1970’s, your not worth the effort after that statement, you’ve really shown your ignorance now. tweak1 OPSomeone had to do buffered one, it’s been nagging at me to do it since Class-D came about with their very low input impedance, 10k many of them. But it really needs to be able to be switch out when not necessary into amps with high input impedance, as the best buffer is no buffer, just like the best coupling cap is no cap Cheers George |
@mitch2 "I mostly agree. For example, what does "finally come of age" mean?" I think this phrase mostly relates to Tweak1 having discovered a nice balanced stage passive preamp for use in his system having (at the time) a class D amplifier. He wanted to extend his discovery to a discussion about other passive preamps to this group. @tweak1 Thanks for posting this thread query. It's been a bit chippy at times (and continues to be--Lol), but I learned a lot from the contributors herein. |
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I auditioned their tubed buffer when it was on "tour" and thought it sounded pretty good for the price when in line with two different passives I have here (both resistor based). I am a little surprised they are not offering both tubed and JFET buffer sections in the active preamp since they already have the tubed buffer designed. I suspect the preamp will represent a relatively high value for a modest price. |
I will say, without a doubt, that I am much happier, without the preamps in my system. I have tried passives before, but never thought they " came of age " but it has all come together. I suppose I am one of the few lucky ones I don’t think Mr D that it’s a matter of passives coming of age as they are still basically what they used to be. More likely to me, that today’s sources have stronger output stages just as good as preamps in many cases, are dc coupled, have lower output impedances, as well as having twice (even more) the output voltage needed to fully drive poweramps to their full rated wattage output. So who needs more gain/noise and added electronics in the signal path from active preamps. Cheers George |
Hello A’gon members. I have had my Luminous Audio Axiom, Walker Mod, 3 in, 2 out, single ended remote unit for quite a while now. Without slighting the preamp manufacturers, nor those readers who might own the preamps I have been using ( I will not name them , I will say, without a doubt, that I am much happier, without the preamps in my system. I have tried passives before, but never thought they " came of age ". Maybe it is my amp’s high gain, or my efficient speakers, but it has all come together. I suppose I am one of the few lucky ones, as I am rediscovering recordings that I thought I knew so well. Lets all just get along. Enjoy ! MrD. |
If a listener likes the sound of a certain type of passive in their system, then that’s what matters. If they want to compare their passive with an active circuit, then they can simply connect a buffer to the passive and decide which sounds better. There are many on this site who enjoy the sound of their passive volume controls and many others who prefer their active preamps or buffers.All this is so true, and I’m sure tweak1 is glad we are back on topic. " Have Passive Preamps Finally Come of Age? " I believe so and some, but like the active preamp, it also is going to become a dinosaur, as all the volume control duties are best done at the source so long as "bit stripping" is held in check maybe with a loudest level gain preset like Wadia and ML did, also with output stage buffers that are as good or better than most active preamps it going to be a win win, also noise floor is as low as it can get with direct source to amp connection, and only one set of interconnects. Cheers George |
@celander
This back and forth is hilarious.I mostly agree. For example, what does "finally come of age" mean? The Hattor is simply a resistor based passive volume control, not unlike Goldpoint, Placette, and others that have come before, and not really unlike what is in Ralph's preamps except that those also provide buffering and gain. George wants us to believe the Lightspeed is "compatible" with most impedance and gain situations - and that may be true. However, just because something is "compatible" doesn't mean it is the best-sounding option. What's missing is that this is really about what one hears in their own system. If a listener likes the sound of a certain type of passive in their system, then that's what matters. If they want to compare their passive with an active circuit, then they can simply connect a buffer to the passive and decide which sounds better. There are many on this site who enjoy the sound of their passive volume controls and many others who prefer their active preamps or buffers. There are other options such as DACs by Empirical Audio and Metrum Acoustics that adjust volume by changing the reference voltage, which does not negatively affect the signal like DACs that throw away bits of information to reduce the volume level. This is really easy, try several options and stick with what you like best. |
This back and forth is hilarious. Let us distill it to its simplest form. 1. atmosphere considers George’s Lightspeed unit to be a fine passive preamp device, albeit limited in its design (1 input and 1 output) and clearly not as good as what atmosphere has auditioned by way of active preamp devices (hint, hint: atmosphere’s own company’s devices.) 2. George feels butt-hurt because atmosphere views his Lightspeed passive preamp as being inferior to atmosphere’s active preamps. 3. The causal observer of this banter would conclude that: (a) atmosphere is entitled to opine about comparisons between his company’s active preamps and George’s Lightspeed passive preamp, because the forum thread is entitled, “Have passive preamps finally come of age?” Atmosphere concludes that the answer to that question is “No,” at least with respect to the Lightspeed passive preamp. (b) George is entitled to take the opposite view of atmosphere’s opinion, notwithstanding his disappointment in atmosphere’s conclusion. |
I don’t remember which customer lent us the LightspeedYou attack my product and you tell me to keep calm, conveniently not remembering who it was. With a 3 foot high quality cable (which would have 300pf) in such cases you would have a roll-off that is very real world.Then you present this BS, and then try to back peddle after I’ve shown the truth with the math. Clearly it’s you in damage control, after all this is a Passive Preamp thread and all you present is negatives. Stick to the active preamp threads and stop putting **** on passives at every opportunity. |
Hmm. George, I'm not worried about it- I simply acknowledged that you were correct yet you're still going off. If anyone seems in damage control mode, its you right now. Just calm down. You'd have to imagine that I'm well aware of what our amps can and can't do; our amps don't use feedback, so speaker choice is important. But the flip side of that has consistently been that if the speaker requires the amp to have feedback, it also has no chance of sounding like real music (I can outline exactly why easily enough). So I just vet each sale to make sure the customer is going to have a success. Works pretty well- that's why we're one of the older manufacturers in high end audio- 42 years in about 10 days. I don't remember which customer lent us the Lightspeed, but we had it for a week. As passives go, it was one of the better ones we checked out. If you are on a budget and have only high level sources, its not a bad way to go. IOW like any passive it can do well but not state of the art; plain and simple. That's why I'm not worried; passives are just a little too simple to do everything correctly (the better your system gets, the easier this is to hear). Cable control and buffering the source to prevent distortion are two example of why and I can name more. Now that's not an insult, its just a statement of fact. State of the art nearly always costs more and that shouldn't bother you. BTW, your comment about headroom in preamplifier and source design is still false and no amount of remonstration on your part will change that. I chose not to continue that bit but you insist on attacks. Just calm down and it will be OK. |
Most good interconnects are 100pf per foot or less your citing of 300pf for a mt, is for a reasonable low capacitance interconnect and all my figures above in my last post are correct, and I have always stated so from the first Lightspeed built, and to use good quality interconnects that are 100pF per foot or less. What you stated is a total falsehood and misleading. With a 3 foot high quality cable (which would have 300pf) in such cases you would have a roll-off that is very real world. Apparently you had either clone or a faulty one or just BS’ing, and if your going to start on my product then you’ll receive the same. As for impedance matching, I have also always stated from the first one built that an output to input (Lightspeed to amp) impedance ratio should be 1:10 or higher, and have never said that it or any other 10kohm passive would be happy into a 10kohm amp input impedance. And that sources should have a low output impedance <500 ohms, not like most tubes sources have, very few like the Herron phono stage are fine. As I still believe these falsehoods are of someone in product protection mode, and to be honest I don’t blame you, threads like these cheap passives are a killer for $$$K preamp sales, and OTL’s can only drive so much, unless aided by Zero band-aids, of which I’m also anti. |
If the passive has a 10K impedance maximum George's statement is true. Apparently not all Lightspeed controls have such a low impedance; we had one here that was much higher. So the model you get can have a big effect. Also, 300pf is a low value even for a 3 foot interconnect (A 6 foot cable will double that capacitance), although low capacitance cables are available that are much lower. Its my recommendation that such cables (such as are used for phono cartridges) be used unless a lower value of passive control (such as 10K) is employed. Keep in mind though that not all sources are happy driving a 10K load (which may well be in parallel with the input of a solid state amp, resulting in an even lower impedance) so its best also to check with the manufacturer of the source component to insure that it can drive such a load successfully. |
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With a 3 foot high quality cable (which would have 300pf) in such cases you would have a roll-off that is very real world.Totally false and misleading. A 10kohm passive pre which the Lightspeed is also, has a worst scenario output impedance of 2.5kohm. This together with Ralph’s example of 300pf for a meter of interconnect, will give a high frequency -3db roll off point of 212kHz!!!! (bat hearing territory) With 2mts of the same interconnect (which btw is not low capacitance) the -3db is still 106kHz!!!! faster than any transformer output tube amp. You are kidding yourself calling this "very real world". (Just product protection mode from what I see with these sorts of comments) Cheers George |
Hence the statement I quoted above appears to me to be incorrect, and George’s statement that "interconnects are the determining factor here" is likely to be correct.@almarg This seems to me a bit of a catch-22, as the very high impedance of the LDR at certain settings pretty well means that any cable is going to impose a bandwidth limit so in effect you could never have full bandwidth. With a 3 foot high quality cable (which would have 300pf) in such cases you would have a roll-off that is very real world. Another issue is that a high impedance thus imposed could have negative HF bandwidth effects due to Miller capacitance in the amplifier. The latter is one topic that rarely gets mention in these passive/active debates but its very real. |
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Just stay on topic as
tweak1 OP asked, so I don't have to respond to your
“hilarious”
off topic remarks. Cheers George |
@georgehifi I think you protest a bit too much. It is you that continues to get off topic, most recently with your negative comment (or three) about another equipment designer/manufacturer’s website content. You then get all defensive when I point out another website having inaccurate content about its product specifications. (I did say “hilarious” in my post, which you opted to take as being a serious comment other than for what it is.) If one stays on topic and perhaps one won’t generate additional commentary. |
Sorry again
tweak1 OP some just don't stay on topic, rather complain about the wording of my product instead, as you can see even Al gets sucked off topic by them.. Cheers George |
perhaps just as easily as their products can be dismissed?And so can you sunshine, big time Specs "Frequency response: 0hz – to almost Infinity. (Lightspeed) (interconnects are the determining factor here)" ALMOST!! being the operative word here, interconnects are the limiting factor as Almarg stated, the interconnects are the determining HF factor. Cheers George |
Notwithstanding the hilarious frequency response claim, I’m pretty sure the internal wiring to and from the internal portions of the RCA input and output jacks of the attenuator is likely going to be more bandwidth limiting than any external RCA interconnect(s). While I’m not familiar with the internal construction of George’s Lightspeed attenuator, I would expect that what limits high frequency bandwidth is the low pass filter formed by the interaction of the impedance "looking back" from the junction between the series and shunt LDRs and the capacitance "looking forward" from that point. Given the far greater length of an interconnect that would be usually be connected to the output of the Lightspeed, compared to the length of the wiring between the LDRs and the output of the device, that capacitance will almost invariably be dominated by the capacitance of the interconnect. Hence the statement I quoted above appears to me to be incorrect, and George’s statement that "interconnects are the determining factor here" is likely to be correct. Perhaps, though, the statement I quoted above was intended to refer to the bandwidth of the interconnect in itself. If so, under any reasonable circumstances involving a home audio system I would expect that number to be so high as to be irrelevant to the bandwidth limitation imposed by the interaction of the capacitance of the interconnect and the Lightspeed’s impedance that I referred to. Regards, -- Al |
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Notwithstanding the hilarious frequency response claim, Did you or your kids ever term the phrase?????? Or maybe you don't get out enough??? It was meant as a bit of a joke, Infinity and beyond (Buzz Lightyear/Lightspeed!!) I think everyone here can see it’s a "exaggeration" in reference to the name Lightspeed v Infinity, except for you maybe. As for it’s actual "measured HF speed", when you can’t detect not even 1/10th of a dB drop with a 500mhz Tektronix scope, I think that can give me the "exaggerated" use of "infinity" in reference to the name Lightspeed, even if it is in jest. Cheers George |
About designers/manufacturers nixing the website content of other designers/manufacturers, there is a lot of puffery to go around. To wit, take the following quote about the specifications of an attenuator from an Australian website: “Frequency response: 0hz – to almost Infinity. (Lightspeed) (interconnects are the determining factor here)” Notwithstanding the hilarious frequency response claim, I’m pretty sure the internal wiring to and from the internal portions of the RCA input and output jacks of the attenuator is likely going to be more bandwidth limiting than any external RCA interconnect(s). Reminds me of glass house owners being stone throwers. |
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To whom it may apply: "I" started THIS thread, NOT George. Sorry Tweak, it’s hard not to respond to others that are asking off topic questions. For $350 I would just go the Hattor mod with opamp, you have the Hattor and it’s very nicely made, the OPA2134 has a very nice musical sound not etched and sterile. It’s part of Texas Instruments/BB "Sound Plus" range which have always been good. As is my favourite dac chip, the PCM1704 Cheers George |
To whom it may apply: "I" started THIS thread, NOT George. The impedance issue between my recently acquired Hattor XLR and my EP amps/ Audio Alchemy stereo amp has turned out to be a blessing. To get to the bottom of the impedance issues, I bought a AA Dac/Pre, not for the dac, but for the pre. I thought I was satisfied with my Oppo 105s internal dac for redbook. LOL My intention was to use it while I got my Hattor XLR fitted with the OpAmp George suggested, which was going to take some time and additional cost $350 + shipping, if I attempted it myself. AA: after 24 hours and the standard wall plug for power I was hearing music that finally combined detail with warmth. Late on day 2, I decided to connect my WireWorld Toslink cable (which I used between my Pioneer PD 65 (inverted platter), modded by Musical Concepts, with outboard PS as a transport to some dac, and I still have it!) so I could listen to SACD/DVD-A discs, but first I compared the AA redbook dac to my 105, which was spinning Tony Bennett Duets. WOW, warm, texturally rich music,bordering on 3D, at least when the music was easy, less so when the music is complex. I reread the Absolute Sounds review, which tried the wall wart briefly, then inserted the PS 5 outboard power supply to complete the review.. So Im on a quest to locate one Back to my Hattor: If I move forward (and I might as it is dual mono wit better separation) it means I also need to add a dac and another power cord and use the Oppo as a transport, or use the 105 for SACD/DVDs only and my Pioneer to the AA internal DAC. Of course all that takes money, and by the time I add it up I am within reach of the Tortuga XLR.. FYI Morten says he will have a ss opamp soon Will someone please make me an offer I can't refuse for my Hattor?. |
I also tried TEO s overpriced passiveYes over priced for just 24 switched resistor position, do you know what value it was? 10 20 50 or 100k, and if it was a series, ladder or shunt switch resistor passive? As of yet I can’t find out, I’ll look harder tomorrow. This sort of thing leaves me https://www.emojirequest.com/images/CrossEyedEmoji.jpg " Judciously placed vibration control materials are located within the case of the Liquid Pre for the purpose of tuning, as the performance of the Liquid Pre is so refined that everything matters. In fact the center foot on the bottom of the unit is interchangeable for the purpose of voicing the system in which it is used: soft to hard. Even placing a thin item such as a business card under the center foot can tailor the sound. Similarly, one does not want to place anything on top of the Liquid Pre such as a book, as it will be detrimental to the performance." This tech page of theirs might is no better might as well have been written by a tech word bot. http://www.teoaudio.com/technical/ Cheers George |
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analogluvr589 posts07-28-2018 11:01amBut as I mentioned previously I tried a passive with the Herron but preferred the activeYes you did, but you said you tried it with a TVC (a transformer based passive), this you needed to say. As if TVC ’s have problems, you outlined what they were when you explained what was missing. What do you think would happen to the Herron’s phono stage output signal if it had to travel through such a thin Transformer wire hundreds of mts long.? Unscathed? I don't think so. Cheers George |
Jay23 7-27-2018 As I mentioned earlier I haven't taken the time to read the first couple of pages of this thread. And my usual tendency is to not take sides in traditional debate topics such as active vs. passive, tubes vs. solid state, vinyl vs. digital, R2R vs. delta-sigma DACs, etc., because it seems clear to me that any of these alternatives can work very well or very poorly depending on the specific designs, system matching, and user preferences. In other words, I consider myself to be a pragmatist. In case it's not clear, though, all of the comments I have provided in this thread have been entirely consistent with what Ralph has said on the same issues. And in fact I rarely disagree with Ralph about anything. Regarding George, I have both agreed and disagreed with him on numerous occasions in these forums, but always in a mutually respectful manner. One of the disagreements occurred in the recent thread where the Herron/Lightspeed/Gryphon combo he referred to above was discussed. Regards, -- Al |
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