George, your info would be spot on IF the AA did not have 2 gain optionsYeah I saw the 2 x gain options specs, neither will give an input impedance to let your Hattor be good match with it, it just changes the gain.
Cheers George
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.
238 responses Add your response
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 |
george, while these are both good suggestions "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" I live in Florida so sending the Hattor back is not gonna happen (no telling how long before he turned it around), plus, having seen the insides, I don't think it is upgradeable. I bought the AA used, so no sending it back either Fortunately, the combination sounds damned good, certainly good enough to wait it out to get either the AA DCA/PRE (which must be a match) or the Tortuga, assuming it is compatible. |
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 |
I look at at this and see a serious bit of kit, if you like tube sound.George, thanks, as usual you bring the good 411. I just emailed Arik (Hattor) as to whether the opamp can be installed . He's some 8 hour time difference, so maybe tomorrow Ill know more My kit is 100% balanced, I would think any XLR tube buffer would be $$$$$ + another XLR interconnect + power cord, so $$$$$++ I might be able to borrow an AA DAC/Pre, which would let me know how much better a pre built specifically to go with my amp will sound. Be great if the price to upgrade and turnaround time were acceptable to hace theeDAC/Pre that long |
George,
Arik is on holiday, but I managed to score a AA Dac/Pre at a price that I can easily flip when/if I get the Hattor OpAmp upgraded. Arik thinks I can do the parts upgrade here, but Im not that inclined as I don't have a high heat iron, or silver solder. Maybe he will send some solder. I should have the AA by mid week to finally hear my system without impedance mismatches |
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 |
Hi tweak1 I am not sure if you referred to my review of the Nord Class D and Hattor preamp. I found the Hattor and Nord worked exceptionally well together. The Hattor can have a buffer amp added and even though mine has one I do not use it. I prefer the sound without it and the impedances all match anyway. I can plug it back in for those components where it does not match. The main Nord amps use the nCore modules and to my ears, they sound better than the other ICE module (not tried them all) but of course, your mileage may vary. In your position, I would move towards the Hattor/Nord. I use Audionote E silver signature speakers at 97db efficiency and even though on paper they look overpowered I find it gives a very relaxed sound and is always in control. It is clearly cruising with a bucketload in reserve. Try to always use balanced with the Nords. I have all sorts of RCA/XLR convertors and cables but it seem like going backwards to get a high resolution preamp/power amp and then use single ended. Anyway good luck in your endevaours and do not to forget to get off the upgrade cycle and listen to the music!! |
George Hi tweak1 I am not sure if you referred to my review of the Nord Class D and Hattor preamp. I
Yes, that review is where I first learned of you, it motivated me to get the Hattor. I thought I had posted this but, I decided against the Nord Two because of the monster power. Sometimes I change discs and the output is crazy different: than the new disc BLASTS out so loud it scares me, and I run for the remote//mute. Then I got a deal on the AA amp for about half the price of the Nord, which you said is an even worse impedance match than my prior EP 100.2SEs, which sounded glassy in my system. Prior to the Hattor I had a Parasound P5 and was not thrilled FYI: I went all in on XLR decades ago. I asked Arek about the OpAmp you suggested, but he is on holiday. He suggested sending me the board with OpAmp, which I hesitate to do, but... Then an AA DAC//Pre came up at a price I couldn't resist. Better not be an impedance mismatch there. I should have it Thursday. I will use until I get the Hattor sorted out. Thanks again |
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 |
@atmasphere FWIW dept: our MP-3 preamp can be ordered as a balanced tube buffer with no active gain stage.That is interesting Ralph, I wish I had heard the no-gain version back when - I may not have sold my MP-3. Now I have a great sounding SS unity-gain buffer by Steve McCormack so don’t have the need for another. You should get the word out. With today’s high output DACs, that might be just the ticket for many. |
I might be missing something, but for as long as I can remember, the dacs I have owned, the cd players I have owned, the tuners I have owned ( and some tape machines ), have all been 2 volts output, or more. I also remember early passive units from way back. So none of this is new, with maybe the buffer circuit being new. Of my hundreds of amplifiers passing through my doors, all could be driven to full output with 2 volts in ( I am not talking about the impedance here, just the output voltage ). I do understand the importance of impedance matching. Enjoy ! MrD. |
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 |
George said (7/15): 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. (How can I 'heed; when I don't know the right questions to ask? Impedance matching is new to me, and I am not a techie Now you confuse me by saying (7/25): 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. so, how can you know it is/isn't the best match? " not the best match for your Hattor passive." Morten Sensor of Tortuga sheds some light on the subject of Passive V active in an article he wrote. Link on his www. |
Correct MrD, as Nelson Pass says, today we have way to much gain (voltage) with the sources we have.He's not the only one to say that- its been a beef of mine for years. Whoever came up with the Redbook specs at Phillips and Sony blew it on this one, since any amplifier made will be clipped by a source that supports the Redbook spec. IMO it would be better if they dropped the output voltage, even by a little bit, since the less you have to knock down the signal to make it useful for an amplifier the better. |
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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 |
@mrdecibel He doesn't know what he's talking about. No good amp designer builds an amp that really peters out at it's rated power. You overbuild the amp, set the gain conservatively, and then brag how your amp gets .00X% distortion at "rated power" with 1.5V input. That's what Nelson Pass does all the time! It takes WAY more than 2 volts to break down a typical small signal audio JFET. |
Many amplifiers overloaded with 2 volts ? Are we talking about power amplifiers being overloaded, or preamplifier sections being overloaded ? 30 volts output ? Now I am confused.I haven’t read most of this thread, but regarding your comment I’ve seen preamp output voltage specs confuse a number of people here in the past. The 30 volt number Ralph referred to, and other preamp output voltage specs that are greater than a few volts, represent their maximum output voltage **capability.** Everything else being equal, the higher that number is the better (within reason of course), as a higher number will provide more margin relative to the output voltages that are actually required from the preamp in normal use. Actual output voltages higher than a few volts (in many cases something like 2 volts) will not occur in normal use, as they would drive nearly all amplifiers into clipping, and perhaps damage the speakers as well. Not to mention driving the listener out of his or her chair and toward either the volume control or the nearest exit :-) The actual output voltage provided by a preamp will correspond to the input voltage the source provides to it at any instant of time (which will vary with the volume of the music, of course), multiplied by the gain of the preamp (expressed as the ratio of output voltage to input voltage), and reduced by the amount of attenuation the volume control provides at the setting being used (relative to its maximum possible setting). Regards, -- Al |
Huh.... looks like the Aleph L runs runs 30 volt rails to get upwards of 10 volts output. With...... MOSFETs! If no amp ever made required more than 2 volts to utilize it's full power, why's Nelson Pass build nothing but pre-amps that give you at least 9.5 dB and at least 5 volts output? He certainly isn't the only one. All kinds of reasons why, too. |
All kinds of reasons why, too. I would think that one reason, in addition to providing overload margin per se, is that if a preamp’s output stage is just operating over a small fraction of the voltage range it is capable of operating over, the result in many and perhaps most cases will be that linearity and hence distortion are a bit better than if it were operating closer to its limits. Regards, -- Al |
Very true, Unsound. For example most and perhaps all Pass Labs amps have the same gain (26 db), which means that as the power capability of the various models progressively increases progressively more input voltage is required for them to reach their rated maximum power. Consequently the X600.8, for example, has a specified sensitivity for full power of 3.46 volts. Although if a Redbook source provides balanced outputs, those outputs may provide maximum voltages in the area of 4 to 5 volts (i.e., 2 to 2.5 volts or so for each signal in the balanced pair of signals), which would still be enough to clip that amp. Best regards, -- Al |
Many amplifiers overloaded with 2 volts ? Are we talking about power amplifiers being overloaded, or preamplifier sections being overloaded ? 30 volts output ?Al did answer this, I hope its now clear. Simply: With the sources feeding them, preamps active or passive giving out UP TO a clean 2v to an amp that only needs 1v in to give it’s rated output before clipping, there NO USE at all for those same preamps active or passive to be able to give 10v 20v or 30v output.George's statement here is clearly false; it doesn't appear that he's trying to mislead so much as he seems to have no idea of what he's talking about. As I said before, active preamps are often built to produce far more output than is asked of them so that distortion at their normal operating range of less than 2 volts will be devoid of distortion. Most sources like CD players have a similar overload margin built in to them as well for the same reason, despite the maximum output being the Redbook spec. The amount of overload margin used in a vinyl cutting system is even higher, to insure that its impossible to overload the cutter or the cutter amps. IOW, the inclusion of overload margin in audio products is a common practice among competent designers. |
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 |
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.George's confirmation of his earlier comments leaves no doubt that he's clueless on this topic! Any competent engineer knows this. Any linear circuit has distortion that increases with output. If the circuit only has to do 2 volts but can make much more, its distortion can thus be kept extremely low- to the point that its difficult to measure. This is why many active preamps have such low distortion, because they are operated well below their limits. This is just good engineering. |
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 |
