I just ordered an Axiom II.
How much do I need to spend to get a preamp that sounds better than no preamp?
Hello all.
I'm using an Audible Illusions L1 preamp and I think my system sounds better when I remove it from the signal path. Oppo BD105 directly to SMC Audio DNA1 Gold power amp. I have read that there is level of quality you need to hit before there will be an improvement in sound. I can't seem to find what that level is. Any ideas?
Thanks in advance,
Ben
I'm using an Audible Illusions L1 preamp and I think my system sounds better when I remove it from the signal path. Oppo BD105 directly to SMC Audio DNA1 Gold power amp. I have read that there is level of quality you need to hit before there will be an improvement in sound. I can't seem to find what that level is. Any ideas?
Thanks in advance,
Ben
403 responses Add your response
honashagen OP $49 closest thing to going direct with a only potentiometer in the way. http://www.schiit.com/products/sys Or if you like to change the sound 3 different ways $699. http://www.schiit.com/products/freya Cheers George |
honashhagen, Many years ago Adcom had a pass thru line stage, touted as no coloration. I tried it with many amps. It did not seem to impart any color to the sound, yet something imho was missing. Well, not just imho... something was missing. The dynamics seemed compressed, and while there seemed to be minimal if any serious coloration to the sound (the bane of some preamps), there was also a lack of texture, space and fine detail. You know how when everything comes to life in music, the actual physical distance between the guitar and drums, the bass player... that was missing when compared to a good preamp. In fact the last comparison was putting a Gryphon Preamp, (very, very expensive) with any and all of the amps, all areas of aforementioned subtleties came to life. The preamp seemed to take the amp, even an Adcom 60wpc, to another level. It was a great thought experiment that I still remember more than 20 years hence. So, I recommend a good preamp at whatever price you can afford... BUT experiment... you won't regret it. Best, Larry |
Hi Ben, from the responses, it seems the sound of a preamp is quite dependent on the system and personal preference. I tried something yesterday that I have tried at least 20 times previously, with the same result. I know, the definition of insanity, right? I replaced my unity gain buffered preamp with a Goldpoint passive. At first, I really enjoyed the quiet background, nice tone, clarity, and purity, but after about 5 - 6 songs, I had the familiar sense that something was missing. I reinstalled my active/buffered preamp and.....Technicolor! The preamp had the same attributes as the passive but added tremendous body, dimensionality, and tonal density that made the music sound more "real." Since you asked about what level of quality it takes to improve the sound over a passive, here are my thoughts.
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honashagen OP38 posts04-30-2018 8:02amLast night I think I talked myself into thinking my new pass preamp was sounding good. I was fooling myself. It still sounds too forward to me. I really want to like it. Your Oppo has an output impedance of 100ohms, it will drive the 100kohm input of the DNA-1 in it's sleep, and just about anything else. And the Oppo at 2.1v out for RCA and 4.2v out for XLR. It easily has enough v gain for your DNA-1 poweramp, which only needs 800mV (.8v) in to give it’s full output wattage!!!!. As you can see, you don’t need anymore gain from an active preamp. Just look at the maths? Here is what Nelson Pass regards as his best sounding preamp, he says he can’t belive it didn’t make him filthy rich, and yes it’s totally passive untill the volume control hits 3 o’clock, then it becomes active for those that need the extra gain, "most likely because many of his poweramps are very low gain" but he also does say you take a hit in sound quality when 3 o’clock and over are used when it becomes active. Yes your going to say, but he makes $$$$$$ preamps. He’s not a fool he likes to make money, passives don’t make money because you can’t sell them for $$$$K I prove that.
" Nelson Pass: The Aleph L is a single ended Class A audio preamplifier combining new design thought
Another quote from him Nelson Pass, "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. Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control. What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection. And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."
Cheers George |
As George points out, suitable impedance matching and adequate voltage gain are critical to achieving good results with a passive. Other considerations, depending on the type of passive, are the potential for changes in impedance with changes in volume, and the effect of cables on impedance and capacitance. Passives seem to work best in situations where there are short cable runs after the passive. You can read a lot about this in these forums. Active buffering helps control impedance so that it stays low and consistent, and to help with consistent current delivery. One thing you should consider is that while the stock DNA-1 has an input impedance of 100K ohms, if Steve's upgrade of your amplifier included adding transformers the resulting input impedance was likely changed to only 10K ohms, which would significantly affect your compatibility equation for use with a passive. BTW, the amplifier I used for my passive comparison described below has input impedance of 100K ohms. |
I’ve done a blind A/B with 30 of our audio club members using a 10kohm passive preamp. A source with 2.5v at 100ohms output impedance. We had a power amp with 1.5v input sensitivity for full output, the amp had a special switchable input impedance’s on the fly 10 x from 100kohm down to 10kohm Nobody could tell the difference from 100kohm all the way down to 33kohm, when we got to 20kohm 5 of the 30 members though they heard something but weren’t sure, then it added up from there the lower we got. During the whole time we made sure the level was spot on within 1 mV from the amps output using a 1khz sine wave. Cheers George |
Honashagen, some questions: 1)Are you using balanced or unbalanced connections between the Oppo and the Pass? I suspect balanced would be preferable, as I alluded to earlier. 2)Have you tried both the 4 db and 14 db gain settings of the Pass? 3)Are you setting the Oppo’s volume control at or near max when the Pass is being used, which I would expect to provide better results than having that control at a lower setting? 4)If you are using an unbalanced connection to inputs 1 or 2 of the Pass, is a shorting plug or jumper connected between pins 1 and 3 of the corresponding XLR connectors? (See the second from the last paragraph on page 3 of the manual). Regards, -- Al |
George excerpted a quote from Nelson Pass's website. It makes it look like Nelson had a certain position on the subject, but if you read what follows, you might see that such is not the case. Here is that further text (I've included the end of the text that George quoted earlier):
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Ralph (atmasphere) is trying to counter my quote with other quotes. But it still doesn’t get around the fact, that a favourite sounding Pass preamp of Nelson’s is the Aleph L. And this preamp is a totally passive switched resistor attenuator as his statement shows, only becoming "active" after the volume control goes beyond 3 o’clock. This is a patented "active" circuit, that he introduced is for the use with a couple of his Aleph type ect low very gain power amplifiers, which have very little only <20db or so gain, so then the "active" part of this preamp has to make up for this low poweramp gain, but the sound does take a hit as he says when the active circuit comes in beyond 3 o’clock. Thankfully most power amps on the market are much more gain and the "active" circuit wouldn’t be used, and the Aleph L will stay totally passive. Nelson Pass:As far as impedance matching goes, over 90% of sources and amps have a fine match with passive attenuators. It’s only the very few tube output >1kohm dacs and very low input impedance <20kohm power amps that can take a slight sound quality hit. As for interconnects quality low capacitance which thankfully most are, at 2mt or less in length. And you have what Nelson Pass describes as the best way to get the sources signal to the poweramp/s, with control over the volume. Cheers George |
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It is a provisional patent, which has maybe been granted by now on this special circuit, he may not have given the secrete to how he bypasses the "active stage" in the the schematic so it runs totally passive, after all it is patented. I've seen other manufactures post schematics and leave out their special circuits. Why no Nelson. His words "The only component in the signal path is wire and switch contacts."This means nothing active in the signal path. Same goes for my Lightspeed Attenuator there is nothing active or any switch contacts in the signal path just a passive ldr, yet it is powered by the mains for the leds to function. Yet it is a passive preamp with no gain. Cheers George |
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About $3500 if buying used. Or about 5-6K if you insist on buying new. Always active (unless you get singularly lucky with the amp match) and almost always go with tubed preamps (unless you want to spend the big bucks). Almost everyone tries to do without one and convincing themselves for the longest time that they don't need one and fighting wars on this point. You need a good preamp and they are rare. If your budget is under 8K for amp/preamp, a good integrated is always the way to go. My dealer told me this when I started my audio journey, I didn't listen, now 10 years later, I realise his wisdom. I am using DAC direct as well, it beats most cheap preamps, but it still sucks, I am waiting to snatch the right used preamp : Shindo (Masseto or above), Coincident, Convergent etc. |
I’ve looked at most of the schematics Pass has posted or published. Typically when he means to leave something out he posts a "simplified" Please post a link to this latest Aleph L schematic of his, not Milan’s early version mod’d interpretation of it. As I can’t believe Nelson would say one thing and yet mean another. As we’ve conversed quite a bit, as he designed a buffer for my Lightspeed Attenuator many years ago (later to be know as the B1 buffer) so it could drive his customers low input impedance amps <20kohms This is "simplified", yet not stated as so by him. https://ibb.co/choBZS Nelson Pass quotes on the Aleph L "At positions below 3 o’clock, the volume control functions as a precision passive attenuator using discrete resistor ladders." "At the 3 o’clock volume control position, the Aleph L offers a direct path from input to output. The only component in the signal path is wire and switch contacts." https://ibb.co/iVXKon "The only component in the signal path is wire and switch contacts. At positions below 3 o’clock, the volume control functions as a precision passive attenuator using discrete resistor ladders." "Above 3 o’clock, active gain is ADDED to the output signal in 2 decibel increments, for a maximum of 10 dB As a result, you suffer the effects of active circuitry only when additional gain is necessary." Cheers George |
And for those interested, the manual of the Aleph L passive/active preamp. https://www.passlabs.com/sites/default/files/alman.pdf Cheers George |
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As you can see, I’ve highlighted in red from input to output, if the volume is kept below 3 o’clock it is totally passive and the signal only runs through the source selector and the switched resistor ladder volume control. https://ibb.co/j8uwJn Nelson is right when he said: "The only component in the signal path is wire and switch contacts. At positions below 3 o’clock, the volume control functions as a precision passive attenuator using discrete resistor ladders." "Above 3 o’clock, active gain is ADDED to the output signal in 2 decibel increments, for a maximum of 10 dB,As a result, you suffer the effects of active circuitry only when additional gain is necessary." If anyone want to get one of these Pass Labs masterpieces that he loves himself, good luck as they are very rare and if they do come up used go for quite a bit of money. Cheers George |
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An interesting circuit- the output of the follower drives the top of the control; its output (running wide open gain) is thus mixed with the incoming signal. While Nelson's comments are essentially true, they are not the whole story by any means. One weakness of this circuit is the extremely low impedance the source must drive, which in this case is less than 2000 ohms if the schematic George linked is correct. Most sources can't drive such a load at all. |
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Believe Nelson Pass, his creds far outweigh anyones here. I believe he says below the input impedance is 20kohm, and states it in the specs, also 99% of sources will drive that, just some silly (pitiful as he says) dac’s ect that have high output impedance, tube buffer stages may not. Pass Quote: " Input impedance, the Aleph L is a nominal 20 Kohms. From the standpoint of input impedance, I can only say that it is a very pitiful source that cannot come up with the 100 micro-amps of current needed to drive this input." Cheers George |
Source output impedances in the typical range of about 100 - 500 ohms should easily drive preamps with input impedances of 10K or up....as long as the cables are kept reasonably short. However, it must then be considered what happens between the passive preamp and the amplifier, how long are the cables, and what is the input impedance of the amplifier? All of these are factors contributing to the successful use of a passive preamp IMO. I believe it is to simplistic to simply say that if you have enough voltage and reasonable impedances, then a passive will sound good. I have heard it go the other way too many times. Based on comparisons between passives and my unity gain buffered preamp, the active buffering (but not necessarily gain) does lead to improved dynamics and bass, even when voltage and impedance rules are met between partnering equipment. |
However, it must then be considered what happens between the passive preamp and the amplifier, how long are the cables, and what is the input impedance of the amplifier? All of these are factors contributing to the successful use of a passive preamp IMO. Nelson Pass addresses this also, as I have always said with the Lightspeed Attenuator passive, interconnect to the amp should be good quality low capacitance, which nearly all are, use <100pf per foot at 2mts or less. Nelson Pass quote: "The output impedance needs to be low enough to drive the capacitance of a reasonably long cable. How low does it need to be? I would say that it should be able to drive a 1000 pF load out to 100 KHz. The worst case output impedance of the Aleph L will drive 1000 pF with a -3dB rolloff at 225 KHz!!." Cheers George |
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Please give the man a break, he’s earn’t his dues and his credibility, more than you, I, Ralph and everyone else here put together. No wonder he doesn’t come here. Nelson Pass on the Aleph L preamp. "Less than <0.1% at full volume" (with active gain in the signal path). This is minuscule and it’s probably 2hd. Knowing Nelson it’s the nice (tube like) distortion . And it’s only when the active circuit is fully in over 3 o’clock. All active circuits have some small distortion. At below 3 o’clock when it’s passive it’s probably zero %. Pass Labs: Printed SPECIFICATIONS Aleph L (volume control full clockwise) Maximum Gain 10 dB Freq. Response +0, -1 dB @ 10 Hz and 100 kHz Distortion < .1 % THD Give it a rest. Cheers George |
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Like so many things he’s designed, it’s a quirky component with a narrow appeal.It’s one of his pride and joys as he’s stated, and said it’s a wonder it hasn’t made him filthy rich, not that he’s not already. Give him a break? You’re banging on as if this thing is audio divinity.Your searching for anything to put it and him down, and nothing is correct, as I have to post what he says and has measured in published in specs, to counter now 3 times what **** you’ve said. The reason you don't like it and keep putting *** on it, is because your F5 only has 15db of gain and you need a preamp or source with huge voltage gain, and this is not it. I WOULD RATHER BELIEVE HIM THAN YOU, AND THAT’S A FACT! Cheers George |
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To me the real benefit of a good active preamp is better dynamics, increased soundstage dimensions, better imaging, and (if tube based) having the ability to match tube choices that best mate with the speakers. It was mentioned earlier in this thread, but +1 for LTA MZ2 preamp. It does all of the above running dead quiet. Its price and simple looks makes many think its a toy, but smile all the way to bank. |
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kosst, he has many followers......geez,,,you are one of them. He never designed a product where someone could not use it. He caters to a wide variety of listeners, which is interesting because he almost designs for himself, going after his holy grail in design. As I see it, to listeners wanting the virtues of tubes, but want solid state, and has accomplished that. You just seem to be making fun of him and not giving the man any credit. Who is bigger than he in the diy world, and so generous with his knowledge. This is how I see it. |
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kosst, go away, where ever you go angst follows. The same goes for this Aleph L preamp it’s one of his favourites, and it came to us audiophiles when it was needed, as he said "we way to much gain in our sources and amps" so it’s not needed at all in the preamps. And as you can see in the link the Aleph L in red, it’s a direct path from input to output with nothing but input switch and resistors ladder switch in the signal path, only when the head of the volume arrow goes to the left of resistor marked RV6 does this passive become active. https://ibb.co/j8uwJn And as he states in the specs of the user manual https://www.passlabs.com/sites/default/files/alman.pdf "It’s Distortion at full is < 0.1 % THD," and below 3’oclock it becomes passive. "The sound is as pure as you can get. The distortion and noise figures you will get at this position are not easily measured." He also asks you to perform an experiment to see if you can hear the differences the active stage makes when it comes into the signal path above 3 o’clock from being a passive state below 3o’clock. Cheers George |
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I’m over you. Go back to your F5 with high gain active preamp and keep pushing it, because you can’t use this Aleph L when it’s at it’s best in passive mode, only maybe after 3 o’clock, and as Nelson says you’ll take a sound quality hit. And please stop putting **** on the man, your not his **** ****, and never will be. Cheers George |
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kosst, when you design and implement the manufacture of an amp that is competitive with FW, maybe, and only then, maybe, will I ever take what you say seriously and worthwhile to read. So, like many other posts of yours on various threads, keep convincing yourself of how smart and wonderful you are. Enjoy ! MrD |
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