Passive preamp


Hello. I wanted to learn more about running a preamp in passive mode versus active mode.  Am I correct in thinking that passive mode means it is not altering the audio signal?  My question relates to a Schiit Frida s that I am using in passive mode, using it essentially as a switching device.  Am I missing anything?.   

128x128grantgg

I would do more research. If you are looking for very high quality sound, then you will find it with a very high quality active preamp. The idea that a passive preamp will interfer less sound great in theory, but typically that is as far as it goes. Yes, it can be done.

 

The preamp takes really small signals and boosts it to an optimal output for an amp. The amp is rather unrefined brut as opposed to the amplification in a preamp. For most of us, the preamp is the heart and soul of our systems. It is the component that brings the magic.  A great preamp will make the rest of the system sound better… maintaining the sound quality you want with the choices you made before and after. I currently have a spectacular system, well balanced among components (see under my UserID). If I was going to do something to upgrade my system, it would be to replace my Audio Research Reference 6SE with an Audio Research Reference 10 preamp.

 

There are a number of people that employ passive preamps to good results, but these are definitely in the minority. Active preamps are main stream for a reason… achieving great sound is really hard and using a passive preamp to achieve great sound quality makes it much more difficult… in component choices and the knowledge level required… this is coming from someone with thousands and thousands of hours of pursuing great sound. You don’t want to make the journey harder.

But if this excites you. Go for it. I am sure there are folks here that will be happy to help guide you.

 

 

There’s more to it than just active vs. passive. It boils down to an overall design, quality of parts, power supply. There’s no such thing as a wire with gain. Anything in the signal chain will impart its sonic signature. A good property designed active preamp with beefy power supply always wins in my experience. Solid state or tubed. In case of tubes you have the added 2nd and 3rd order harmonic distortion that makes tubes sound pleasing (softer and fuller and in high end preamps no sacrifice in resolution and holographic soundstage). Personal preference, synergy and your perception of ideal sound is what will make it or break it. If you like your Schiit in passive mode, just enjoy it!

My worry is that your system is good as your weakest link.  Which might be the schiit.  I'm using a Starkrimson Ultra class D amp (which I just added), and Dynaudio Heritage Specials as well as Innous Zen mk3 and Bricasti M3 DAC. I was hoping that a 'budget' preamp might work in passive mode.  But I'm having second thoughts now.

Passive preamps can sound amazing, but it takes much more care in component matching. You can in essence relying on the output of your source (in my case, my DAC) to drive the amp (in my case Coincident Frankstein 300b). If the input sensitivity of the amp is high enough and the output of your source is high enough, then a passive preamp can sound absolutely glorious (keep in mind that you need to select cables very carefully as well and avoid any longer lengths). Get it wrong and it's going to sound flat and uninspiring.

 

On the other hand, a really good active preamp will remove most, if not all, of these constrictions and can very well make your entire system sound better.

Run your M3 directly into your amp and use its preamp which is awesome btw and may beat the schiit out of your freya s.

let us know!

depends on how many sources one wants to use in the system -- in the old days we needed phono stages, and then also listened to cd players, tape decks or radio tuners, which have line level outputs, so a switching preamp was a necessity

today things can be very different as a single digital streamer front end (dac output) allows a user to choose from many sources like internet radio, cd transport, tidal and so on

the truism is always that best pre is no pre, passive or active

an active pre aids the sound if there is a mismatch between the source output and the amp input, that is, the source output is too weak or has too narrow a range to drive the amp to desired volume levels

i had a bricasti m1 with remote volume control... the bricasti m1/m3 have robust, great sounding analog output stages -- if that is the sole source, i would say it is best to go without a linestage at all

OP, What do your ears tell you ? BTW, this topic has been discussed, ad nauseam. As some say, it can work, and as others say, it does not. As audphile 1 stated above, everything matters, and as he suggested, you can eliminate your Frida ( sorry, I had to ), and the use of an additional interconnect, going direct from your M3. People are very opinionated here, including myself, but I use my ears to determine what is enjoyable, and preferable, to me. My best, MrD.

If your system is passive friendly (and you can search here to see what that means) a passive line stage is your best bet. There is no need to throw away gain when it’s not needed, I’ve had some very good active preamps up to around 8k and all of them were shown the door by one or another passive device. If you truly need gain, then disregard the aforementioned and buy the best active preamp your budget will allow.

I have a Schiit Freya + I occasionally use (well worth the $800 I spent on it) and with my class A mono's I prefer it in the active mode using the LISST  Tubes. However the passive mode is very musical also. It will be system dependent and I like having a little gain. 

Excellent idea to try the M3 as the pre going directly to my amp.  I would at least have something to compare against the passive pre. Unfortunately, I do have more than the one source (turntable and other) otherwise I would stay with the M3.  Happy to notify in this thread what my results but but it'll be a couple of weeks before I have things set up.  Cheers!

As you have more than one source and are forced to use a preamp, you need something better than that piece of Schiit preamp. With that Schiit in front of Bricasti dac you pretty much wasted your money. You’ll know what I mean when you run M3 direct. 

How does the Freya sound when using in different modes? Passive, buffered , tubes. I use mine in a second system 90+% of the time in passive mode. I actually went as far as selling a Freya+ a while back as a substitute was found and said to be superior. Used the superior unit for a couple of months, then bought another Freya+. Sold the superior unit as it was inferior to the Freya+. The Freya+ is tough to beat unless one spends sizable piles of cash. Your mileage may vary. 

One of the finest passive preamps that I've found is Khozmo Acoustics. The shunt-zfoil volume control is superb. Only limitation is 3 inputs only (which is one more than I use, so not a limitation in my case).

 

Very reasonably priced as well!

Ive owned quite a lot of kit over the decades. I really loved the Khozmo dual mono preamp. Sadly, I had to sell it to fund another purchase

I run systems with both active and passive preamps. What works best depends on synergy with the amp, as other posters have emphasized. Categorical statements about which is better don’t really apply. If your amp is friendly enough to passives (and as others have pointed out, a search of these pages would educate you on how to determine this), then you have choices of topology. The three main ones are resistor, transformer, and autoformer. I’ve played with excellent examples of all three and the autoformer-based passive from Bent Audio is my personal favorite. YMMV. The only way to know is dig in, research, and experiment. Bent is no longer in business, btw, but used ones do come up.

When I hear passive preamp, I’m thinking of a unit that does not amplify the signal halves, but the quality of components, power supply type as in diodes or tube based rectification, in addition to capacitors, etc will leave its fingerprint on music. I have an Esoteric C-03X preamp that is able to add +6, +12 or +18 dB on the output side. If I choose the 0 dB setting, this is somewhat like a passive preamp as the signal halves do not pass through any amplification/processing. Next, the signal is influenced by the power supply quality as in transformer size, quality and selection of caps and resistors will influence the sound as it passes through the preamp so it is not just an attenuation nob with resistors linked to it. At the 0 dB setting, music seems less embellished, well at least not processed by an op amp or something similar; the music has an open and airy sound. When I choose +12 dB or the higher setting, bass extension and the transient snap is better, plus bass is deeper and denser; overall, the music seems to be faster, which I’m guessing the bit of processing increases decay. This would make sense as Esoteric’s output board has a brace of capacitors to give music that transient "snap." I choose the Goldilocks setting, meaning the middle setting. Although, Ottmar Liebert on the passive 0 dB gain setting is pretty amazing...

I went through this a few years ago. I think whether you want passive or active, depends more on the efficiency of the speakers and second the amp specs, input and output sensitity. I found a very good explanation of different types on the Goldmund website. I then kept seeing Khozmo in a lot of conversations. If you have your amp specs Arek will steer you. The volume control comes with different resistance options. I have heard people say resistors don’t have much to do with sound, but they do. I got two resistor upgrades with my Khozmo. I can achieve over 100 dB with 60% volume setting. My amp can achieve full output at 1.25 V and my Dac puts out 2V so that explains it. Bottom line is if you are not sure about all this get your specs together and talk to a vendor. Arek , for example, will tell you if a passive will work. In my situation, I don’t know what an active would do other than add gain and have an influence on what your system sounds like, for better or worse.

When I hear passive preamp, I’m thinking of a unit that does not amplify the signal halves, but the quality of components, power supply type as in diodes or tube based rectification, in addition to capacitors, etc will leave its fingerprint on music ...

You're describing an active preamplifier, not a passive one.

I did try using the Bricasti M3 as my preamp, and DAC and it worked a beautifully. The sound and dynamic range is really nice, don't have the remote control though.   Then I put my Freya S back in line running passive, and to tell you the truth, I cannot tell a difference at all.  Maybe I'm just getting too old to know.  I did get the solid state Freya S instead of the Freya + (tubes) since it was my intention to run this Passive anyway .  I may stick with the Schitt for the time being until something else comes up.

I did try using the Bricasti M3 as my preamp, and DAC and it worked a beautifully. The sound and dynamic range is really nice, don’t have the remote control though.

brian zollner at bricasti will be happy to sell you the remote kit with sensor, umbilical and handheld... it works well, if a little old school

@jjss49 I thought all MDX board M3 units are remote control ready. But verify with Bricasti.