Any thoughts on removing a preamp from your system


Hello guys

This is my first post and I have been on Audiogon for a number of years now.

My question to the group is, have any of you removed your preamp completely from your system? Run your front ends straight to your amp? And, what benefits have you noticed, if any.

And finally, if you have used a passive preamp in your system, what are your thoughts on the setup?

I understand one would need to have some sort of "pot" in the signal path to regulate volume.

Herb
hcalland
Hello Phusis.

Interesting synergy comments. I have not looked any further into simplifying my system other than the direct to amp configuration. I use two power conditioners mostly because I had experienced some low level hum, which has all but vanished with them in place. My mono amps are point-to-point wiring, and my speakers are a 3 way design. My speakers could, at 89db be more efficient for the low 20 watt Monoblocks, but I don't play my system at high volumes, so it all works.

The direct to amp did not work so well with my SS phono amp. I suspect the mono cartridge used in this configuration is the blame. It has always had very low level and tolerable hum. A condition common to the design according to the Japanese designer. But with the direct-to-amp setup the hum was remarkable. My preamp evidently helps control the noise level.

I did not try the SACD player because as you well know, digital signals will always need to be tamed. I figure the VTL preamp can only help in that setup.
Herb --

Thanks for your comments. Your findings on by-passing the VTL preamp are interesting, and overall are impressions I share with the direct-route in my own, albeit different setup. It goes to show there are sonically very worthwhile combinations without a preamp, and that neither dynamics nor the sense of body and vitality are necessarily sacrificed - or so I find myself. Nonetheless keeping your VTL seems like a good idea.

With regard to the synergy mentioned I believe in getting it in place, as an outset, via as few components as possible. My speakers are 2-way (w/2 units per side) with a very simple cross-over (6/12dB); my Class-A poweramp (sporting a relatively simple topology) is non-balanced and built with few by very high quality components; I use no powerstrip but instead connects my DIY power cables conductor-direct via screw terminals (though not on the component side); no connectors are used on the speaker cables (solid-core silver/gold round wire and copper foils in single-wire parallel), etc. To reiterate: simplicity not for the sake of simplicity, but as an outset and maintained where it is sonically superior or at least the equal.

How is the testing with named components proceeding?
After more than a decade of testing my system, I have now eliminated my de Havilland Mercury 2 preamp. My CD player - Audio Aero Capitole Ref SE seem to do a better job direct to my power amps. It is more natural, fluid, organic and delicate. The preamp added more liveliness, speed and scale but also made it more mechanical.
For a while I had the Promitheus Audio Reference Dual Box C-Core TVC in my system driving the Spectron mono-blocks. This was a fantastic unit. Totally transparent and free of artifacts. I have also tried the Benchmark DAC1 and the DAC2 HGC feeding the Spectron mono-blocks as well.

None of these units are a true contender to the Joule Electra LA-300 ME tube preamp. The 300 ME brings in perfect pitch definition and the correct weight to each instrument. I'm used to listening to live classical music, and these two qualities in audio playback is something that's missing in both, the Promitheus and the Benchmark units. Both of these units will sound amazing as far as hi-fi sound is concerned, but when you compare them to live music, they do fall short of making me believe that the musical performance is happening in front of me.

I recently just listened to the Benchmark DAC2 HGC going directly into the mono-blocks for a few weeks. This unit gets closer to my analog playback. Anything you would want in audio reproduction is there, except that it lacks the same pitch definition and weight that the Joule Electra brings in.

If I didn't have the Joule Electra, I could definitely live very happy with either the Promitheus or the Benchmark units. In the end, one decides to live with things we appreciate the most, and to me the accurate reproduction of live music is essential in audio playback.
Mapman --

YEs, but the question is, why?

I can see how the proper eletronic mating might be trickier with a passive, but I cant see a disadvantage if done right, other than that various active pres might provide more flavors of sound to please more people. Not everyone likes vanilla best.

My thoughts as well. I'd wager most active preamps are inherently limited by a lack of transparency, or certainly an added sense of character, an issue that is revealed the more obviously when compared to a successful poweramp to DAC direct-coupling or a similarly well-integrated passive preamp, and of course also relative to the active preamp used. Moreover, where the synergy of a setup is "dialed in" around the use of an active preamp and its negation results in the overall sound falling by the wayside, so to speak, this is not necessarily indicative of the preamp's merits but could as well point to its colorations and/or a less than ideal in-/output impedance match in its stead.

To those considering skipping both an active and passive preamp, and go DAC/poweramp-direct: Digital volume controls in the 24-bit domain (or higher), preferably dithered and where the source is PC-based, are a brilliant solution. In practicality their use, even down to some -40dB attenuation, seem not to impede in any way noticable to my ear (going by JRiver MC19's volume control), and with the typical poweramp gain level and speaker sensitivity most would likely use digital volume leveling in the -10 to -25dB range, which is more or less inside the (theoretically) safe confines before bit stripping/truncation is said to occur. However, even outside this spectrum (i.e.: above ~-25dB ) I can't to the best of my hearing abilities hear any signal degradation with "normal" listening levels, or even lower, which in my case is typically an average ~65-75dB (measured via iPhone SPLnFFT v4.4 noise meter. Put more faith in thy ears than mere numbers and theoretical deductions..
For the same reason Phusis, that's why I called my product the "Lightspeed Attenuator", as it's a passive attenuator, as there is no preamplifying going on inside it.

Cheers George
My experience equals others in this thread. I would not say I have given up on "resolution", but for me also, "musicality" is even more central. Last year, I tested the Aesthetix Io phono stage direct and through preamps so much that I started to hate it. Why? Because the direct connection is indeed excellent, has outstanding clarity, and so on! It was only after awhile that I starting missing something. Gradually I learned what to listen for. Like a bit washed out sound. Big dynamics, but not timing. A friend summed it up: your speaker drivers aren't controlled in the right way. I recently managed to get a used Einstein The Tube Mk2 preamp for a fair price (here in Europe). It gives me much of what I was missing. Indeed, since it came into my system, I have not bothered with more of the tiresome with/without preamp testing. It just feels right.
Hi Phusis, Iike your analysis.

Yesterday I returned my Fosgate Phono amp to my VTL 5.5 preamp, and immediately noticed a lost in dynamics and transparency. Needless to say I switched back to the direct connection of my phono amp to my Audio Mirror power amp. The Audio Mirrors have pots.

I realize these results maybe due to "total" system synergy, which is why I am not throwing out my preamp just yet.

I have two other source components (Marantz SACD, and a solid state battery operated option PATHOS Phono amp), which I plan to test tonight.

Herb
I do it all the time when reviewing various pieces; results vary widely. If you can do so, try it. But there is no universal acceptance, nor performance guarantee when doing it.
Hi George

Thank you for your comments and corrective remarks on my use of the term 'preamp.' Not to appear too apologetic I'm guessing I intended to use the term as a means to address the effort made with the analog output stage of the BCA Roquefort, and that this in a sense pointed to its deliberate use as a "preamp" (where none is) simply by virtue of having a volume control in the digital domain and a collection of digital in- and analog outputs.

If it makes any difference, here's the link to a Danish review of the Roquefort (albeit a prototype) with a picture of the left backside:

http://nerds.dk/review/?rid=155
Hi Phusis, a well written self analysis of what you believe is happening, well done.

As for the BCA Roquefort using the word preamp, this is a bit of a misnomer, as it does the volume control in the digital domain before the digital to analogue conversion (dac) stage, and has also in the same section a switch ability for various digital inputs. "with 2 pcs. AES / EBU, 2 pcs. S / PDIF, 1. coaxial, 1. Toslink and 1. USB"

This can be very loosely called a "digital domain preamp" but shouldn't. The word preamp is to pre-amplify in the analogue domain, and there is no preamplifing done there, and I don't believe this unit has switchable analogue inputs without seeing the back, as then there would be no control over the volume, as that's done up river in the digital domain. It should just be called a digital domain volume control with digital input switching, like many others do, Wadia, ML, etc.

After the dac it seems it has the normal I/V (current to voltage) conversion stage, post dac filtering and output buffers. No analogue domain volume controled gain stages or analogue input switching.

https://translate.google.com.au/translate?sl=da&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.studiosound.dk%2Fcddac%2Froquefort%2F&edit-text=

Cheers George
An audio-friend of mine has always found it better not to use a separate hardware preamp in his setups, especially since his latest DAC/preamp (the Danish developed/manufactored Blue Cheese Audio Roquefort http://www.studiosound.dk/cddac/roquefort/) sports a dedicated preamp section with digital volume attenuation. The separate preamps he's tested against it have all failed to deliver equally overall, until a very expensive preamp entered the setup in the form of a Belles LA-01 (driving his Belles SA-100 poweramp). While the inclusion of this hardware preamp to his ears doesn't necessarily translate into a win-win sonic scenario in all respects compared to the stand-alone BCA DAC, he's smitten especially by the added sense of "drive, dynamics and transient abilities - as if the existing components are harnessed into a fuller, better controlled potential in many respects," as he'd more or less put it. This is an intesting observation to me, also insofar it would take such an expensive preamp to finally turn it into (again, in some respects) an even more satisfying sonic experience.

This example - among others, actually - tells me that separate hardware preamps are a potential blessing in some vital respects, but are at same time an added component in the audio chain where many variables combine to make it a challenge for it not to impose too much of a character of its own (read: the challenge of transparency, if you will). I guess for some the above mentioned traits coming in the wake of a hardware preamp overshadow an added layer of coloring/character, where it might be more pronounced, whereas others (like me, for instance) would find it a nuisance - depending of course not only on taste, but also and not least the setup where these evaluations are made.

The motivation behind above mentioned friend trying out a hardware preamp in his setup was essentially due to the planned investment of a turntable, one might add. To me, with a digital source only and a very successful mating of DAC and poweramp direct-coupling, the inclusion of a hardware preamp would have to be so utterly convincing (not least in light of its expected severe cost for it to make a real difference) to have me forget the other areas where the same or less amount of money could make a difference. I've heard many preamp-based setups, and most of them to my ears truly lack the coherency, truth of tone, and snap and power found through my own setup - using no separate hardware preamp. A hardware preamp is not necessarily a sonic blessing in and by itself, and a preamp-less setup is not necessarily marred by what is so generally found in above postings. Just saying..
When I first connected my CD player direct to amps, I though I discovered transparancy and detail. I didn't. I liked it until I realized I was lacking everything that made music musical. I think the preamp is the heart and the back bone.
I am currently breakin in the new PS Audio Direct Stream Dac and I am running it straight into my Pass Labs X350.5 Amp.

First listen was pretty rough, but today, 100 hours later, I am really liking the sound. Quite impressive.

This weekend after I have more than 200 hours on the Dac I will connect up my Preamp and compare.
There is a good argument for passive when the control itself is built into the amplifier, as in an integrated amp.

But when the control is in an external box, the problem is that you are totally subject to the whims of the interconnect cables.

One very common buggaboo is that a passive control will sound fine at full volume, but as you decrease the volume control the bass and overall impact will diminish. You will get better results with shorted cables. So a lot depends on setup.

Because of the lower output impedance of many active preamps, they tend to reduce the artifact of the interconnect cables. In fact this is one of the functions that an active preamp should do- ideally, eliminate the cable artifact entirely.

If the active preamp is good in this department and is also lacking coloration, the result is that it will sound better than a passive setup.

Now if you happen to use balanced lines, the whole idea behind the balanced system is to eliminate cable artifact. It is quite successful at this; without it the Golden Age of Stereo (1954 to 1963) would not have occurred. Not all high end balanced preamps and passive controls support the balanced standard (in fact, no passive control does and only a handful of actives do) so you do still read about people hearing differences between balanced cables. That isn't actually supposed to happen, if it does its a sign that the preamp you are playing does not support the standard.
Hi John,
Very nice post concerning your individual encounters with various system
configurations. My experiences parallel yours but I disagree on one point
you made.You aren't hearing more transparency with direct or passive
alternatives, just leaner and diluted sound that lacking vital music
information. The full body and tone you realize was missing is abundantly
present with live music. Listen to a live cello, saxaphone, piano, trumpet
etc. The colors, harmonics, richness and vibrancy of tone is crucial to
music. Any audio component that strips way those natural characteristics
is doing a disservice to the complete musical true. A tenor sax heard live is
so rich and full you could can its tone "fat"(I just heard one 3
days ago in a club, he was unmiked, pure and natural). IMO this so called
transparency you mentioned is fake. You'll never hear this from live
acoustic instruments. They possess big tone, fullness and dramatic
dynamic energy. In the past 3 months I've attended 14 live jazz
performances and these essential qualities are clearly evident and make for
a devine and emotional experience every time. John your active preamp
does a superior job of "retaining" those realistic cues although it still won't
match the live sound. It will get you closer than if you eliminate it from your
system.
Charles,
Herb, several times during my passive experimentation days, I too heard greater transparency when using a passive unit or going direct to amp. I am familiar with this feeling. The key is will this feeling last? I've found that after a period of time listening to this newly found transparency, when switching back to an active preamp, I rediscover the weight, body and soul of the music which had been lost during the switch, and was not initially realized during my enthusiasm for the gained transparency.

Overall, not just with preamps, I've learned that musicality is more important to me than transparency. If tonal accuracy is not true, I do not care how clean the signal is. This is the same reason I've given up on Nordost cables. Their transparency and revealing qualities can be very enticing in the beginning, but I've found, over time, that they cause me to listen less often and for shorter periods of time as listening fatigue sets in sooner and sooner. I still say that Nordost cables are great for demos, they will impress your friends, but I just don't care to live with them over the long haul.

Obviously, others will have different goals, but my days of chasing after the ultimate in resolution are over. I'm more about listening to what sounds musical or natural to me these days. My system is not as resolving as it was years ago, but it's much more enjoyable to listen to. I wouldn't say that you are imagining the increased transparency, I would just say be cautious, as this new sound may turn on you down the road.

Cheers,
John
Hcalland, if your phono stage has enough gain by itself by comming out of aux and bypassing the preamps tube line output stage, then yes you are getting rid of an unnecessary tube gain stage and the result will be more transparency.

Todays sources (phono,cdp,dacs) all have enough gain by themselves to drive most amps to full output, why add another preamp gain stage, only to knock the gain of the source back down with the volume control and creating more noise.

Just read what Nelson Pass has to say about it here.
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1400932591&openflup&6&4#6

Cheers George
Guys, It seems most of you favor a nice preamp in the path.

Well I made what I believe is a new discovery over the weekend, which maybe you can help me with.

Here's my situation.

I am running two turntables and their respective phono amps thru my VTL 5.5 preamp.

One is on the RCA input marked Phono, the other on an AUX input. I direct connected (i.e., by_passed the preamp) the one on the the AUX input and immediately liked the sound. I am still loving it. The direct to power amp connection just sounds more transparent and immediate to me.

1. Could I be imagining this increased transparency?

2. Could it be the AUX input is not suited for a phono amp connection and only the phono RCA connection is appropriate for phono? (The table running through this connection sounds great, albeit a mono cartridge setup.)

3. Or should I re-tube my preamp?

Herb
I used to have creek 4340 integrated amp that had passive line stage. Once I've acquired Bryston .5b pre and connected into the chain instead of passive, I immediately noticed what was missing!
From what a member has sent me O_holter, I don't think the 34A has an active preamp in it.
Both the Ming Da MC34A and MC34B are very similar and are poweramps with a 100kohm passive volume control and input switching on the input.
The B costs $100 more as it has triode switchability and uses 6L6 instead of EL34. See the circuit diagram with just the 100kohm passive pot on the input tube to the poweramp input tube.

http://www.pastisch.se/EF/Ming%20Da%20MC34B%20schematic%20mod%201.gif

Cheers George
Could be right Czarivey. Or the back bone, I am thinking, since I have a prolapsis now. Whatever the analogy, it is central. Listening now to the integrated Ming Da Mc-34a amp and Aurum Cantus speakers at my cottage. It can't compare to my main rig, but it does very well, at its level, and one reason is that there is no preamp problem. The preamp is integrated, well-tuned to the main amp, in one box. When we go for bigger, more specialized systems, we have to work out more of the system synergy ourselves.
Very interesting thread. I am temporarily without a pre and have my Oppo 105 feeding directly to my Classe mono blocks. Will use it this way until my VAC pre arrives in a few weeks thus I will have a good understanding of the differences. Will provide feedback once this happens.
O_holter, It seems to me that preamp is stomach rather than heart. No stomach, you can only use intestine:-)
I think Charles1dad put it right:
"over time and continued listening it's
apparent that the sound is leaner and lacking the complete sonic picture"
My experience too, even with the Aesthetix Io upgraded to Eclipse status. Very clear, but a bit washed out - my speakers sounded slow, until I got a good preamp.
Why? The preamp is "the heart of the system" isn't it?
I think Charles1dad put it right:
"over time and continued listening it's
apparent that the sound is leaner and lacking the complete sonic picture"
My experience too, even with a a top class Aesthetix Io upgraded to Eclipse status. Very clear, but a bit washed out - my speakers sounded slow, until I got a good preamp.
Wow - this is good stuff.

Based on your comments I connected my VPI Classic TT thru my Fosgate Phono amp directly into my Audio Mirror mono blocks. The blocks have two RCA connectors with a toggle switch between the two. Up until now, I had no idea why the builder of these amps included two RCA connectors. The amps have a pot on the front for setting the gain I assume, so it appears I can run a source directly into the mono blocks.

It sounds wonderful for now, I just have to switch the toggle to the Fosgate source cables when I want to listen to my VPI table.

I am running my 5.5 VTL preamp into the other RCA inputs. I feed a Pathos InTheGroove phono amp and Marantz SACD player into the preamp.

The Pathos Phono is fed by a Miyajima Mono Cartridge for my second TT, a Nottingham Space Deck. I am using balanced interconnects between the Pathos and preamp with good results. I have a low level hum, but I am told that is common for the cartridge.

Anyway, if I don't add anymore source components, I believe I can live with this setup for now. I don't know if the maker of the Audio Mirrors intended his amps to be used in this fashion, but I like the sound with the direct feed. I was thinking a passive preamp would allow me to get rid of my VTL, but based on your comments I think I will hang on to it.

Thanks
I was preampless for years and recently added a preamp and am in heaven. I was under the impression the preamp was like adding "steroids" but it was more like adding vitamins.
Stewie hi, you have no problems as far a I can see with these impedances.

Interconnect capacitance is the more important factor to you as you are bi-amped.
From the Carnary to your amps, because you are (bi-amped) and using two x interconnects per channel, I would use interconnects of 2mts or less, and of less than <50pf (picofarad) capacitance per ft. If only using 1mt lengths, then 100pf per ft is fine. This is so you will maintain proper high frequency extension.
Any decent interconect maufacturer should know this and should have it on their specs

Cheers George
Hi George,
Tube tops have 470k ohm input impedance; ss bottom has a 50k input impedance. Passive pre is a Canary CA-200. Thanks.
06-05-14: Stewie
I have a passive pre in my system right now and the music sounds great: tubes on the top end, ss on the bottom, and I have no idea whether impedance matches or doesn't match


Hi Stewie, if you tell me the input impedance of both your tube and SS amps, and the output impedance of your source. I can let you know if your bi-amped system is passive friendly and with what value passive pot.

Cheeers George
I have a passive pre in my system right now and the music sounds great: tubes on the top end, ss on the bottom, and I have no idea whether impedance matches or doesn't match.

That said, when I get my active pre (tube) back from being repaired, I'll put it back in my system, not b/c of a difference in sound but b/c I like my active pre-amp. Yes, that's audio insanity for you, but it's my own.

The point is, this an audio equipment forum for people--the vast majority of whom are males, who are either wired for it (pardon the pun) or culturally conditioned for it, or both--for people who are interested in equipment, in stuff. The more cool stuff the better. So no one should be surprised that the majority opinion falls in favor of pre-amps, and active ones at that. As others have said, let your own ears--which in this case necessarily means your own psychology--be the judge.
AL, thanks for that.

Yes, I suppose I'm back to my original post. Passive appears an attractive option for cost, small size, and simplicity, inc cases where those things matter, like mine, and perhaps other reasons, but you never know or sure what will work best until you try.

I'll probably stick with the various pre-amp options at my disposal already for now, in that these are working out quite well already, but I am thinking this is something I would like to give a go someday when the time is right, like if my trusty old NAD decides to finally give it up. OR maybe just something to toy with in comparison to the ARC sp16 in my main rig just for kicks, if I get a few extra bucks I don't know what to do with (ha!).
Mapman, thank you kindly for the nice words.

I haven't ever experimented with any kind of passive preamp, or with direct drive from a source component, because in my case it would pretty much be a non-starter functionally. I have five sources, having widely differing output impedances and levels; and my preamp supplies outputs to three destinations (I could readily do without one of them, the record out to my tape deck, but I definitely need outputs to my headphone amp (which I drive from a second tape out) and of course to my power amp). Also, the cable length from preamp to power amp is long enough to be something of a concern with many passives.

Regarding your question about why some people who've tried both approaches report better results with actives, even if cable lengths, cable capacitances, and impedances are all ostensibly suitable for a passive, I would speculate that one reason is that discerning listeners having resolving systems can hear effects attributable to those parameters to a degree that is somewhat greater than would be expected on the basis of conventional analysis.

A speculative and hypothetical example, to illustrate my point: If the combination of cable capacitance and the output impedance of a passive preamp (which will depend on the setting of its volume control as well as on the output impedance of the source component which drives it) results in a bandwidth of say 50 or 100 kHz, that would ostensibly seem likely to be sufficient. But perhaps in combination with bandwidth limitations elsewhere in the system the result might be phase shifts in the audible upper treble region that are sufficient to produce time domain misalignment of those frequencies relative to lower frequencies, to a degree that may be perceptible under some circumstances. In other words, more bandwidth margin may be necessary in some circumstances than is commonly recognized.

I'd imagine also that a contributing factor in some cases is along the lines of the point George has made in a number of threads, that active circuitry may be introducing colorations that are euphonic. Not that there's **necessarily** anything wrong with that, IMO.

Another reason may derive from the combination of the facts that it seems clear that not all cable effects are technically explainable or predictable, and passive preamps (or at least resistance-based passive preamps) can be expected to magnify cable effects as a consequence of their relatively high impedance levels.

The point that was made earlier about sonic degradations being introduced by the parts in a passive preamp probably also has some validity in many cases, but FWIW my own instinct is that if those parts are chosen to a high standard interface effects are likely to be more significant. Others may disagree.

And in situations where digital volume controls in source components are being used in lieu of having any preamp, presumably "bit-stripping" would be a factor in some cases.

So I think that the answer to your question of "why" is multi-faceted. And I certainly wouldn't rule out that in at least a few cases the "why" might simply be user error in configuring the application.

A lot of experienced based opinions have already been expressed in this thread, from many whose opinions I have great respect for. As you said initially, there is no single right and wrong answer, that will be optimal in all circumstances. But FWIW mine own instinct (based, as I said, on having no experience with passives) is that Brownsfan's particularly nuanced post rings especially true.

Best,
-- Al
"I admire Al's technical knowledge as well but what do you expect him to say? "

A purely technical analysis/comparison as only a good EE might concoct.

Understanding the technology is always the key to making good decisions. Of course, you never know for sure how it will sound until you hear it in your situation, but I always like to go in as technically informed as possible.

My own assessment is that if the mating from a volt and impedance perspective looks good on paper, a simple high quality circuit behind it is all that is needed for optimal results. The there is the technology behind the volume control, a different and perhaps more complex story, but not Rocket science still.

Of course optimal results technically does not assure a winner soundwise in the end, given all the other things that factor into any good sound, but its a darn good place to start.
I admire Al's technical knowledge as well but what do you expect him to say? This is strictly an individual case by case situation. A number of people have auditioned the Lightspeed, some love it and some preferred their active preamplifier. It comes down to what you hear and choose as better. There's no technical explanation to account for the variance in choice. If Al uses/ prefers passive or active it's still his personal decision based on actually listening, not some technical theory. I find tubes better sounding than solid state in general. I don't require a theory to decide, I just listen. The same is true of those listeners who prefer transistors.
Charles,
Whenever Al chimes in, i just skip to the bottom of his post and try to understand his conclusion. I thought I was somewhat smart until I started coming around here, haha!

I really love my Lightspeed Attenuator. It definately removed that last layer of haze I had at the time. I think it has incredible transparency and dynamics and it was $500. I think you'd have to spend 3 to 4 times that much to even begin to make an improvement, probably at the cost of some transparency.
In my second system (the one in the vertical cabinets in my system photos), I have 6 sources:

1) phono
2) Squeezebox Touch
3) DVD
4) tuner
5) VHS tape
6) cable box

The last 4 feed into an old Radio Shack/Realistic unpowered "passive" 4 source switching box gadget I have had for years. This was a $20-$30 gadget as I recall many years back.

Then the "passive" source switching device runs into tape in on an old NAD 7020 receiver that I use for pre-amp only that feeds the TAD Hibachi monoblocks that drive my smaller OHM speakers and my Stax phones.

SB Touch runs direct into the NADs aux input and phono to NAD phono input.

This works quite well. None of the sources I am feeding into the passive Realistic box are SOTA certainly, but the performance is quite suitable. I have heard these devices running directly as well in the past, and if there is a difference, it does not seem to matter much.

That makes me think a true good quality passive pre-amp with a good quality volume control might work quite well. Definitely something worth considering if needed.

I need Almarg to chirp in and offer up his usual well informed and no nonsense assessment this time about good passive versus good active pre-amps!

Tortuga is one line that has caught my eye recently. LEt's use that as a test case for comparison perhaps.

Almarg, where are you?
Jaxwired,
Try Mytek 192 DAC-Preamp which is mostly DAC.
It's the best volume control I've ever used. It combines advantages of passive and active amplification. If your amp is sensitive, you can adjust gain to unity to have maximum transparency. You can also boost it to have better dynamics and bass control.
Prior to that I used DIY passive pre, Classe, Bryston and McCormack preamplification. In all cases I liked minimal preamplification gain figuring that minimalistic preamp is just as good as passive but better.
"Trust your own ears."

No doubt that is the main key, but I also find that most things that really matter in good sound can be explained at least in theory. WHether the theory is then supported by the facts during listening or not is another story.

That's how science works without in fact ever 100% proving anything. Without theory or hypotheses at a minimum, there can be no roadmap for making informed decisions. Chaos would rule. Chaos is not a very efficient mechanism for getting anywhere. :^)
06-04-14: Mapman
YEs, but the question is, why?

I can see how the proper eletronic mating might be trickier with a passive, but I cant see a disadvantage if done right

I can't see sound waves either, yet they are there. My ears tell me the difference, not my eyes. I can't explain why anymore than I can explain why a power cord can make a difference, or tubes sound better to me than solid state.

I'm sure that someone can probably come up with some techno-marketing buzz words that may help you understand why, but in the end, all the proof you should need is in the listening. Trust your own ears.
A few thoughts based on my experience, which over the last 25 years has followed a convoluted path, from integrated amp, to no preamp with no volume attenuation, to passive with buffer, to another passive with buffer, to endler resistor based volume control, to Promethius Ref 4 TVC, to Promethius Signature TVC, and finally to Coincident Statement Line Stage.

Based on my experience, one can certainly go without a preamp if one is single sourced. If the source has a digital volume control, that is good. No ability to attenuate the volume gets old pretty quickly. My path was driven by economics more than anything else. I think you can do very well in a carefully built system pretty cheaply using passive volume control, particularly transformer volume control designs. I would still prefer an excellent passive to an average active.

I don't think you can get to the ultimate level without a top notch active preamp. It is more than just volume control and source switching. You need the active pre to drive the amps. Most sources just can't do that well. There could be other issues at work, but the results in my system were undeniable. Everything--- dynamics, image, resolution, you name it. Every aspect of musical reproduction was improved by adding the Coincident CSL to my system.

It is my opinion that a top notch active preamp should be the ultimate goal in every system, money permitting. But one does have some pretty good relatively inexpensive options while on that path.
Hello guys

This is my first post and I have been on Audiogon for a number of years now.

My question to the group is, have any of you removed your preamp completely from your system? Run your front ends straight to your amp? And, what benefits have you noticed, if any.

And finally, if you have used a passive preamp in your system, what are your thoughts on the setup?

I understand one would need to have some sort of "pot" in the signal path to regulate volume.

Herb


Hi Herb, look at this thread, it will explain most of all you need to know. And look at what Nelson Pass has to say about passive preamps in the 7th post.

http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1400932591&&&/Passive-preamp-w-Rogue-Medusa-and-Rega-D

And keep an eye on this thread for results for direct in observations on the sound when he does it.
http://forum.audiogon.com/cgi-bin/fr.pl?aamps&1401842543&&&/Mark-Levinson-no-20-monoblocks

Cheers George
I had a good experience some years ago in my sunroom system.

I ran a Mark Levinson 390s cd player directly into a Pass Aleph 3 amp, driving a pair of ProAc 1SCs. Supplemented at the low end with a REL subwoofer. Cardas Golden Cross interconnects and biwire speaker wire. The system sounded great.

The ML 390s had an analog volume control that preserved the detail of the music and it also had a digital input for another component that could be switched in. No preamp needed.

Another combo that worked for me was a bedroom system. My sources were a SAE 8000 fm tuner and a Sony disc player. I used a passive Promethius preamp that used a transformer for volume control, and this fed a Carver M-500t amp connected to a pair of Thiel 3.6s. Not expecting too much, I was surprised at the smoothness and dynamics of the setup. Not having an active preamp did not seem a problem.

One thing I have noticed is that most of my line level sources have more than enough voltage to play quite loudly through my amps. Most of the time, my active preamps are just attenuating the signal. Very rarely do I ever play music so loudly that I feel the preamp is actually amplifying the signal. If I lived in an apartment or someplace close to neighbors, I would never play so loudly.
passives have components that can also change the sound such as pots, resistors, transformers, internal wiring. Also except for transformer type passives there impedance changes with volumn setting. As I said before the Sonic Euphoria autotransformer based passive was the best passive I ever used but it had no where near the resolving power of my Shindo. You simply have to try with your own equipment
Alan
YEs, but the question is, why?

I can see how the proper eletronic mating might be trickier with a passive, but I cant see a disadvantage if done right, other than that various active pres might provide more flavors of sound to please more people. Not everyone likes vanilla best.