Have Passive Preamps Finally Come of Age?
George always leaves out the rest of Nelson's wordsBecause 90% of systems are a great match for passives, and are the most dynamic /transparent way of getting the source to the amp except for going direct if you can do it without "bit stripping". Here's Wadia take on going direct and Mark Levinson does the same. https://ibb.co/kc4OCo Cheers George |
The PPs suck dry musical dynamics, timing and related details. That could be true if you weren’t impedance matched. An active preamp can’t "make" these out of thin air, compared to a "impedance matched" passive preamp, it's already there in the music that comes from the source. Remember what Nelson Pass says about passive preamps
Cheers George |
These are two Hattor’s. Passive, which I believe you have, which what looks to be Kozmho switched volume control, which I believe is a fixed series resistor and variable ones to ground, which will vary it’s i/o impedance’s at different volume levels, best to me is ladder ones, where the series and shunt resistors work in opposites to each other to give a more constant I/O impedance https://www.audiocircle.com/index.php?topic=145833.0 And the active buffered Hattor which used an opamp. http://mockingbirddistribution.mockingbirddistr.netdna-cdn.com/wp-content/uploads/2018/03/Hattor-Min... Here are some different ways of doing a volume control, quad matched ldr is a ladder https://www.stereo.net.au/forums/uploads/monthly_2018_06/Capture.JPG.93bbd2ce49060300b06abfd1a62ce8f... Cheers George |
Just found their site, they have an extensive range, of what looks to be well made products, including a tube one http://www.hattor.com/index2.html#ultimate Cheers George |
Have Passive Preamps Finally Come of Age? Passive preamps are coming of age, not because of themselves, but because the sources today can do the job 90% of the time without the need of active preamps, and in many cases better, in some cases without the need of passives also if the source has it’s own volume control, which is becoming more and more the norm. I see active expensive pre’s as a bit of a dinosaur slowly becoming extinct, far cheaper more transparent/dynamic passives as an interim move, before all sources have their own volume control. But switching between sources will have to be worked out, but you definitely don’t need a mega dollar preamp to do a source switching job, a $100 dollar switch box can do that. Cheers George |
mrdecibel MrD you want a 10kohm passive, as that will serve most situations, as most s/s sources can drive 10kohm no problems, and a 10kohm pot has at worst around 2.5kohm output which will drive almost all poweramps >33kohm input. 1: For the cheapest option, you could go Schiit Sys, for $49 it’s 10kohm with 2 inputs one output. http://www.schiit.com/products/sys 2: Then there the Saga which is 10kohm passive with a better relay pot and it has output tube output select’able if desired 5 inputs two outputs. http://www.schiit.com/products/saga 3: There are a few LDR some passive including mine which mimics a 10kohm pot. I’m sure there are many others Cheers George |
When you they want to know several things about what you listen with, so the passive preamp can have its impedance matched to your particular system. If using a ladder network (no.2), the best, this is a bit of a sales gimmick, a 10kohm passive is what’s needed for most. EG: The only time I can see say a 50 or 100kohm passive being needed, is if the source has an output impedance of over 5kohm (yuck!) and the poweramp amp happens to be maybe a Rogue that has 1 megohm input impedance. If they use just a fixed series resistance and vary the shunt resistor (no.3) to ground, which is not as good as the ladder, then yes they can sort of tune it a bit better for different conditions, but this shunt series method varies wildly in it’s I/O impedance, unlike the ladder far more stable. I think you’d be better off just using an Alps Blue Velvet (RK27) or Alps Black Beauty (RK40) at 10kohm. See linked diagram. https://ibb.co/fXy008 Cheers George |
I think TVCs are the way to go passively and don't experience the loss of dynamics,TVC's are also great, but they do have their own colouration if you don't mind that, as that poor weak source signal has to go through a "mile" of very thin transformer wire winding and back out again, they are not as transparent to the source as other passives. Plus never get one with "gain" stay with unity, as they do have a tenancy to "ring" from the test we've seen. Cheers George |
1. I believe NPass is speaking to a perfect electronic interface world, which would necessitate building ones system around a PP, as opposed to trying to insert one into a active preamp system I believe it does, and that "perfect electronic interface" is available in systems much much more than not. 1: If the source has more output voltage than the amp has input sensitivity to give full output. This is maybe in 100% of cases. (I have yet to see a source with less output voltage than the amp needs input voltage to make it clip) 2: The ratio of output impedance to input impedance, of the source to passive and from the passive to the amps, are both 1:10 ratio or more, this also would be in at least 90% of cases. Then you have what you call, that "perfect electronic interface" for a passive to work as it should, which is getting the source signal to the amps in the most transparent, undistorted, uncoloured, unhindered way. Cheers George |
tweak1 OP Actually hate to say, your Emerald Phyics EP-100.2SE Class-D amps are not a great match for a passive pre, as their input impedance is "not typical" as they are very low at 19kohm, your passive preamp while working fine would sound even better if it had a unity gain buffer on it’s output. For a 10kohm passive to work it’s magic the input impedance of an amp/s should be 33kohm or higher. Cheers George |
tweak1 OP This will be great with your Hattor Passive Pre and much better. As the Nord is double the input impedance of the Emerald Phyics no need for a buffer then. I always say the best buffer is no buffer if possible. Cheers George |
Scratching my head as George said my Hattor is not compatible impedance wise It’s not the fault of your Hator, it’s the amp that is only 19kohm input impedance, even the Khozmo is not compatible. They (Hattor& Khozmo) would both have to be 1-2kohm pots to be compatible with 19kohm, then the source would have trouble driving into that 1-2kohms. Cheers George |
1graber2Yes I know, if you look at my posts going back for the last year, I think I'm probably the strongest promoter of the Freya for 3 in one preamp at a steel of a price. Cheers George |
tweak1 OP Tweak1 It may sound good, but I don’t want to burst your bubble, you should have asked, if your still using your Hattor passive, you didn’t heed what I said about your EP 100.2 amp being only 19kohm input impedance, and not the best match for your Hattor passive. Now you bought the AA DPA-1 without looking at it’s input impedance, as it’s even lower and more difficult to drive than the EP was, at 17.0 kohm xlr and 10.7 kohms rca, this I hate to tell you it's a worse match for the Hattor than your EP was. You said you were looking at the Nord Two Stereo amp, and I said this was better than the EP, should have stayed with that. You have two options to get the best with what you have. 1:Send your Hattor back and get them to install the optional OPA2134 output buffer in into it, this will allow it then to drive the very low input impedance of the AA or the EP if you still have it. 2: Send the AA back and get a poweramp that has got higher input impedance 33kohm or higher. Cheers George |
tweak1 OP I believe you, as I said to you two posts back, " Tweak1 It may sound good". But your not hearing the best from it, with that kind of 17kohm input impedance of this amp. An active pre in this case would probably sound better. Cheers George |
Fortunately, the combination sounds damned good Later then you could if you want, try from the reports a very good external tube buffer that has a low 150ohm output impedance, that is the new iFi Micro iTube2 tube buffer. I look at at this and see a serious bit of kit, if you like tube sound. And it has it’s own passive volume control should you wish to use it instead, selectable in or out and selectable 0db or 6db gain settings, all done with the dip switches on the bottom. https://ifi-audio.com/portfolio-view/micro-itube2/ Cheers George |
tweak1 OPJust remember if this dac/pre has it's volume control operating in the digital domain like most do. So you don't loose resolution, "bit striping" it's volume control should be used at or above 75% of full volume, or you run the risk of only getting 14bit or even less resolution, depending who much below 75% you go. Cheers George |
Now we’re looking at what the Oppo can drive I don’t know the impedance of your Hattor or is attenuation method, series, ladder or shunt. For simplicity let’s say it’s ladder (the best one), And is say it’s a 17kohm ladder passive this impedance combined (paralleled) with the 17kohm impedance of your AA becomes half, at 8.5kohm that the Oppo will see, this to me a still good impedance for it to looking at. You can see "if" the Oppo is 100ohms from 20hz to 20khz then the ratio into the 8.5kohm combination Hattor/AA is 1:85. BUT!!! see that "if" the Oppo could have an output coupling cap, an if not large enough will make that 100ohm impedance rise in the bass and then your 1:85 ratio quickly diminishes which could roll off the bass to early. Cheers George |
Correct MrD, as Nelson Pass says, today we have way to much gain (voltage) with the sources we have. That’s why if you can do it with the source that has a volume control, go direct from source to poweramp. If no volume control put one there "a passive" so long as the impedance’s are right, and in most cases they are. Cheers George |
Now you confuse me by saying (7/25): Now we’re looking at what the Oppo can driveWe were before just taking about just about match between passives and amps. Now we are talking with the Oppo and what it is able to drive, and in a (non active) but passive situation that will be the paralleled combination of the passives input impedance and the amps input impedance together. As all the Oppo sees, is "like" two paralleled resistors to ground, one being the passive the other being the amp. Throw and active preamp into the mix and forget about the amps impedance, all the Oppo sees is the input resistance of the active, it can’t see the amp impedance. Cheers George |
If a power amp has an input sensitivity of say 1v input to make it reach full wattage output (eg: clipping) There is no need for the preceding stage (whether it be a preamp or direct from the source) to put out any more than say 2v so long as it's clean. Having the ability to put out 30v instead of the 2v, and said to sound better because of it!, is a total furphy by the one who said it. Cheers George |
I have no doubt that Ralph is just in protection mode for his product. Any source that has been designed to give out 2v has been done so to be done to do so in it's most linear state, you would be a fool to do otherwise, unlike what Ralph will have you believe. To use all this 2v, is better than shunting it to ground with the preamps volume control, and then having to make back up again with the gain stage of the active preamp which also will increase the noise factor by the gain amount of that gain stage. Nelson Pass: on active preamps. " We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more. Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up." So get rid of that output gain stage (you end up with a passive) and utilise all of what the source can give out, instead of throwing away half of it so the preamps output gain stage can make it back up. Cheers George |
George is consistently pushing these passive threads for that exact reason.And for someone who uses the same high gain Herron phono stage as this one. Here in case you missed it is this users report on utilising all the gain from the Herron source, instead of reducing with the AR Ref5se pre so it can just make it back up again with it’s gain stage. The owner of the Herron said the Lightspeed passive pre wins out over his Audio Research REF-5se and older Pass X1. He’s now getting a battery for the Lightspeed and will hopefully do an update here on that. "It sounds fantastic !! Gain structure he has. Lyra Etna SL 0.25mV > Herron 64db > Lightspeed 0db > Gryphon Antillion input sens. for full output 0.97v (30db) > Wilson Sasha 90db HisTurntable https://i.pinimg.com/originals/c5/da/d3/c5dad306fea0f6cdda772d0ed07c2425.jpg Cheers George |
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 |
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 |
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 |
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 |
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 |
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 |
Just stay on topic as
tweak1 OP asked, so I don't have to respond to your
“hilarious”
off topic remarks. Cheers George |
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 |
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. |
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. |
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 |
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 |
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 |
