What, if any, preamplifier do you use?

Other Audio Components
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I recently acquired a Discrete DAC, which I am absolutely loving. However, I sold my preamp (McIntosh C2700) as the Discrete sounded, frankly, not noticeably better than the C2700’s DA2 DAC board (which has an ES9028PRO chip that’s “quad balanced”). Going directly from the Discrete to my amplifier was a completely different story and I’m still blown away by how good it sounds. I was initially hesitant to get the Discrete as I’d have to go up to the Cascade or now discontinued Reference or Select to be able to accommodate any analog inputs from other sources (in my case the left and right channels from a home theater setup). I decided that for me it was worthwhile to just completely separate the two systems with a couple of bookshelf speakers and a subwoofer for home theater, and reserving my floor standers for two channel music from the Discrete.

I had asked Vince Galbo (MSB National Sales Manager) about this dilemma, and his response was as follows:

“Sometime around the early 30s RCA established in industry line level whose connector we still use today. A preamp takes industry line level and boosts it up one and usually more gain stages, using transistors or tubes to achieve full volume for the sole purpose of….. turning it down again! Our ladders put out full volume, and we consider that point in the design to have the absolute purest sound. Our volume controls simply attenuate the loudness down from there, with the signal then going straight to the output jacks. Therefore, a preamp of any kind is simply redundant, boosting the signal up to turn it down again violating the purity of the original design. I am not saying there are not good preamps out there, but it is hard to find one that matches the clarity and beauty of our direct volume attenuated outputs.”

Fair enough - I’m a reasonably educated person, now retired after a career in computer software development, but I have no education in Electrical Education so I don’t have the background to really have an opinion on this. However, I have certainly seen comments on this and other forums from people that prefer a preamplifier with their MSB DAC.

So my question is: If you have and prefer a preamplifier, which ones have you found that integrate well with your DAC without compromising its quality?

Thanks for any responses.

Brett

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I have a Discrere DAC as well. I believe the key to using any digital volume control is gain setup.

I ran my discrete directly into a pair of Pass Labs Class A monoblocks for about 5 years and was happy with the results. Those amps had 26db of gain and my speakers are 87db/1watt efficient. I configured my discreet for low output, which had the desired effect of me mostly using the upper part of its digital volume control range. Using high output would have resulted in excessive digital attenuation for my situation.

For other reasons, I replaced the large hot running monoblocks with a Benchmark AHB2 power amplifier. I added the Benchmark LA4 preamp at the same time. This power amp has selectable gain of 9.2, 17, or 23 db. I selected 9.2, the lowest setting, so I could have higher gain earlier in the signal path and therefore higher signal to noise ratios over the interconnects. My Discrete DAC is now configured for fixed high output.

Do I recommend the Benchmark LA4 preamp? Yes. It has impeccable specs and independently measured performance that make it a candidate for the quietest and most transparent separate preamp on the market at any price. One feature I really like is the ability to adjust the displayed volume level per input. I have mine adjusted so a full scale signal from the DAC at a displayed zero db would result in just shy of full power out of the power amp. This way I know clipping is not possible with a zero or negative db volume setting.

So what are my could be better thoughts on the LA4? The volume control is implemented with discrete resistors and some high end relays. Unfortunately you hear relay clicking sounds when you run the volume up/down. You get used to it, and it is some positive audible feedback that you are in fact changing the volume. Having used the really well functioning spinning wheel volume control on the MSB remote for a long time, going back to up/down buttons is a less satisfying user experience. The MSB remote just makes it so easy to rapidly make a big change and then quickly fine tune. There are only 2 balanced and 2 RCA inputs. There is no provision for an integrated phono amp. There are no tone controls. All things considered, this preamp functionality works for me and provides state of the art performance at a bargain price.

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Thanks for the reply. I’ve read good things about the Benchmark components.

When you got them, did you compare your Discrete directly into the AHB2 to running it through the LP4? My issue with my C2700 was that the sound signature was not as open and involving as when I go directly into my MC462 amp.

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I did not connect the Discrete directly to the AHB2. I will say direct to the Pass Labs XA60.8s sounded the same as discreet→LP4→AHB2. I am sure I would have failed a blind test. All these components are very neutral, so I was not surprised they sounded the same.

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@BTHartman , this is a great discussion. Often, the biggest factor here is not which preamp works well with the DAC, but which preamp works well with the amp. If you have an amplifier that matches well with the DAC, you will get great results that can’t be beat. However, many amplifiers are designed to run with a specific preamp. Having the set will yield great results. All in all, there are a lot of factors to consider. Tricky to parse.

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I have a Premier DAC which I love and I have an analog set up, so I use a Backert Labs Rhumba Extreme (funny name, I know) preamp to allow me to select between the DAC and phono stage inputs. The Backert Labs is a very good sounding preamp and I don’t feel like I’m loosing much sound quality vs the DAC direct to amplifier (David Berning ZH230) with the gain of convenience of being able to select my sources.

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Indeed it’s all rather complicated, particularly for the average lay person without a background in electrical engineering, much less specific knowledge of the engineering behind audio components.

In my case my preamp was a McIntosh C2700 and my amp is a McIntosh MC462, so it definitely wasn’t a case of a mismatch between the preamp and amplifier.

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Having used MSB’s passive volume control implementation for analog sources (and the DAC module outputs) for several generations (Signature DAC III, Signature DAC IV, and Reference DAC) I am an advocate of the less is more approach to the analog signal path.

Why would one want to deviate from this approach and add an active linestage preamplifier?

  1. When the gain from a phono front end requires additional gain.
  2. When the partnering power amplifier has weird specs, e.g., really low gain/low input sensitivity.
  3. When one prefers a particular sonic colouration overlaid on every recording.

I remember swapping out a highly regarded linestage preamp in a friend’s system and replacing it with the “preamp” of the Reference DAC. It was like removing blankets from the speakers.

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I certainly understand the argument. The problem is that neither the Discrete nor the Premier DACs offer any sort of analog input whatsoever. Disregarding debates about the digital volume control in the Discrete and Premier, the inability to integrate analog sources with the Discrete and Premier is a disadvantage in a system that’s not entirely digital. As I don’t have a turntable but only wanted to integrate the front left and right channels for my home theater system I’ve accepted getting an additional set of speakers so I can completely separate my two channel (digital) system from my home theater.

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Agree completely re the Discrete and Premier DACs and the lack of analog inputs and the use of digital attenuation below a certain threshold. That is why I chose the Reference DAC, despite its much higher price. I figured it would cost me at least the price differential for a dedicated linestage preamplifier and associated power cable, shelf space, and a pair of interconnects.

I have used active crossover speakers for several decades, but if I were building a simpler system around passive speakers then a Discrete or Premier DAC partnered with a very capable integrated amplifier would make a lot of sense.

The Lagrange from Heed Audio appears to be the best bang for buck integrated amplifier with an extremely capable MM phono section, ready to match one’s MC cart and SUT of choice.

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What an interesting question of whether the MSB DACs should be considered hybrid preamp/DACs, like your C2700, or stick with the ‘single use’ DAC intent. Also, what compromises are inherent in adding preamp functionality to a DAC or DAC capabilities to a preamp! It looks like MSB decided to separate functionality in the more introductory product lines while extending capabilities in the higher end products.

I’ve not considered connecting my Discrete directly to my power amps mainly because I have both 1) analog inputs and 2) the desire for a home theater bypass (to also use my main speakers as Front L/R for theater, as you’ve been doing). So I haven’t run the comparison you did (i.e. Discrete-to-amps vs Discrete-to-preamp-to-amps) but find my Discrete playing through Pass XP-22/Pass X260.8 preamp/amps provides a significant upgrade for my digital sources (streamer and CD player), with sound that’s detailed, transparent, very musical and thoroughly enjoyable. So, if adding my preamp into the ‘chain’ is a compromise to be able to use my main speakers for theater as well as music, and to continue enjoying my analog sources, it’s one that’s worth it to me.

Thanks for the thought-provoking question.

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I recently added a Premier DAC to my system, purchased from my great local dealer. My preamp is the Vitus SL102mk2 and my amp is the Vitus SS103. Speakers are PS Audio FR10. I only have two (digital) sources: TV and music streaming (source: EVO432 High End streamer), so I don’t have the analog input issue that the OP has.

I had read about a lot MSB users removing preamps with great results. I have also heard my dealer’s setup, which is the Cascade DAC into the MSB M500 monoblocks (if I am correct) into Magico speakers. My dealer’s setup sounds fantastic to my ears.

After inserting the Premier DAC, I bypassed my preamp. I had to use the High gain setting and ride the volume right at 100+ when i wanted to go loud for music and movies. The sound was pretty nice. I wanted to love it so badly, so that I could then sell my preamp and make more room in my rack. I listened for a week or so… but was never quite satisfied. I put the preamp back in and understood very quickly that, in my system, the preamp is a must. With the preamp, the music had a richer sound, and more organic, to my ears. It was meatier in every way: harmonic meatiness and also punchier and more heft in the bass. The music didn’t slow down - it was the same speed as far as I could tell. On the down side, the preamp, when compared to the DAC direct, slightly obscured some of the fine details, such as those subtle and nuanced sounds associated with some voices, instruments, and that can fill out and enhance a soundstage. But to hear these “limitations”, I had to focus intently and really listen for them… but, when I sat back and just listened to the music (though still actively listening in the audiophile sense), then I didn’t really notice them and have since forgotten about them.

So, it’s a (slight) trade-off to add the preamp, but - for me, in my system - the choice is clear.

Net net: I encourage every MSB DAC user to try both configurations, to see which one works best for you, in your system.

Enjoy! What a great hobby and passion we all share!

And thanks to MSB for building such amazing equipment!

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I would suggest experimenting by going directly into your X260.8 amp to compare the sound. It sounds like you have perhaps a turntable in addition to home theater? That is certainly an issue. Vince Galbo did suggest that other customers have commissioned a purpose built input switch to allow choice between a preamp and the DAC to the AMP input, but I decided that wasn’t an option I wanted to explore.

Another solution I tried was to send the optical output from my TV into the Discrete, which would work for me as I have downsized my home theater to just a stereo pair of speakers rather than surround sound. Marantz makes an HDMI switch (VS3003 3 8K HDMI in, 1 out) for $200 on Amazon. I decided I preferred to just use a AVR and 2 bookshelf speakers (plus a sub, which I don’t need/want for my music listening with my Wilson Sasha 2 floor standers).

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Exactly - it’s all about system integration and, of course, the subjective opinion of the listener. There’s an interesting column in the current Stereophile about system synergy and a complete system (even including the network switches and the ports for the ethernet cables to plugged into) from Fredrik Lejonklou. I obviously had a completely different reaction plugging my Discrete into my McIntosh C2700 vs directly into my MC462 amp. I don’t have any issue with the volume out of MC462 when plugged in directly, with both the Low and High output settings from the Discrete.

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I think I’ll give it a try, although with both turntable and tape analog inputs, plus the theater pre/pro as a bypass input, it would require a lot of change. But, who knows. Perhaps it will be worth it.

The theater gets maybe 30% of my attention and it’s built around Martin Logan electrostatics for all 3.2 speakers (CLX mains, Focus center, EFX surrounds) and a Descent i sub that has inputs for theater and 2 channel.

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Since I only had the one analog source, and one that I wasn’t overly concerned with musical sound quality for I went with the option of separating the two with my quality focus on the music side. In your case, certainly try the Discrete directly to your amp to decide if it’s enough of a difference (if any) to justify exploring options.

If you determine that it’s better to go directly to the amp you might also reach out to Vince Galbo about sourcing a high quality selector switch so you can switch between the Discrete and the preamp. As I recall he told me it was around $900-$1000 and that it was extremely transparent to the source. Of course you then also need additional high quality interconnects as well. I decided not to go that route, but I would have more seriously considered it if I had a turntable or R2R deck.

BTW - I considered getting into R2R but had a hard time justifying the high cost of good quality pre-recorded tapes, as 15 ips tapes from sources like The Tape Project were around $500 each.