I just advise to be very patient on delivery. Andrew Rothwell tends to use Royal Mail and the Russians hacked them in January. Andrew most likely won’t let you know that he posted them either. And I understand that the last entries on his Facebook page are from years ago. But they did eventually show! And they do sound good.
I have some temptation to borrow a tube pre-amp from a neighbour to see if I experience that “warming” effect folks mention for digital sources. But I have not gotten around to it. Since an offspring departed the basement, I moved my systems down there. And I think I have more of a reflective concrete walls and ceilings and floors problem!
My preamp is out for repair so I connected my MK II directly to my Cary 211 FE amps. I was pleasantly surprised by the sound without the preamp. On the plus side the bass was deeper and more accurate and the overall presentation was a little tighter. On the negative side I lost some height, width and depth on the soundstage. For comparison sake I would love to try a BHK preamp. Paul says that it sounds better than the MK II direct.
@vkennedy61 & Carousel ,my preamp is a Cary - SLP-05 with the ultimate upgrade, Synergistic Research fuses, 6F8G & Marconi BL63 tubes and a custom umbilical connection between the power supply and the preamp. Yes I did loose a little bit of warmth in addition to the previously mentioned changes to the soundstage.
I have the same problem when fishing a river ; always wondering what’s around the corner. Fishing however can be a lot less expensive than being an audiophile but both are great fun !
I just replaced the (pretty old) valves in my BHK Pre and was embarrassed to hear that they were way past due being replaced! What a difference. Agree that the Pre adds life, even to the Directstream Mk2. A reminder (to me) that everything in the chain counts.
I am confused. The preamp issue always bothered me if minimum interference with the signal is the goal. How is a preamp consistent with that goal.
Also the AirLens has an I2S connection, which is not available on the BHK preamp. So adding a XLR connection between the DAC and preamp seems incompatible with the goal of accurate reproduction of the signal.
Minimum interference “straight line with gain” is a goal or philosophy, but attaining that it another thing. The Directstream is a Digital to Analog converter, but the analog section is not the same as the analog section of the BHK Pre.
The AirLens provides a digital signal to a DAC. I’m not sure what you were getting at with saying the I2S is not available on the BHK Preamp which is a purely analog component? There has to be an analog connector (XLR or RCA) between the analog output of the DAC and the preamp, or direct from DAC to the power amp should you wish to skip the preamp section and control volume purely from the DAC.
Everyone has “different mileage” in their own systems. My recent observation was that I had delayed replacing the valves in my BHK Pre for too long and when I did, the SQ took a huge jump (better than DAC to BHK300 mono blocks).
The Airlens outputs only digital signals. You cannot connect it to a analog preamp like the BHK. You have to connect it to a DAC {digital to analog converter} or preamp with a DAC built in.
The DS MK2 can sound much better than running it straight to the amps. It depends on how good the preamp is. I have tried all kinds of preamps both tubes and SS and none of the preamps I tried sounds as flat as running it straight to the amps. All the preamps I tried are of a very high quality and are not cheap. If you use a lower quality preamp, it is most likely it will sound worse than without the preamp. The MK2 is very revealing, it will reveal the characteristic of the preamp. Put in a preamp at lease the quality of the BHK and see what I am talking about.
My curiosity is based on the point that there is an analog output from the DAC. How can another XLR cable and a preamp improve the analog output of DAC? How is it possible for a preamp to improve a signal? It seems everyone agrees that it does so, but how is that possible?
For me it’s what a preamp adds to the sound that makes putting in a good preamp better. A good preamp can add richness, better soundstage, and more 3D dimensionality to the sound. I don’t know if it’s more accurate, but it certainally sounds better. Here’s Paul take on the matter. https://youtu.be/cBgYBa0YXB0?si=ZmE62BvJsN9bz8mw
Mark I’ve gone through the journey of “less is better” to “my system sounds better with a pre-amp following the DS”, and I’m the sort of person who’s allergic to tubes and harmonic sweetening.
There are two things that I know the pre-amp can do better than the DAC by itself.
First, the pre-amp can attenuate the noise floor of the DAC, which is relevant not just in the audio band but also the ultrasonics which rise quite significantly (less so now in the MK2 with Massive until after 100kHz). How much this matters depends on your amplifier, speakers and ears. For me, it matters quite a lot.
Second, in terms of electronics and signal transfer a good pre-amp’s inputs and outputs are better optimised to interact with sources and amps respectively, compared to the interaction between a source and an amp directly. I can’t identify what those interactions are exactly but my experience and the reports of many others point to there being “something” that can be beneficial in this regard. But it is also going to depend on your specific equipment combination… some “DACs” have the equivalent of a high end pre-amp stage built in and so you’d probably get a net loss by adding something else before the power amp. This is not the case with the DS though.
Purely hypothetically you could imagine some characteristic where the DS output has a value of 1, the power amp input has a value of 11 and the sonic degradation relates to the square of the difference, so an impact factor of 100. Now image a pre-amp which has a value of 6 for both inputs and outputs. Now the degradation on input is 25 (five squared), and the degradation on output is also 25, for a total of 50 on that parameter.
I have no idea whether this relates to anything in reality. It’s just a vague mathematical shape which shows you can imagine an interaction where adding something in the middle of the chain could improve the result in a particular way. It would of course have other detrimental impacts, but that trade-off might be worth it.
Bottom line… I’m now using a Benchmark LA4 and I get the sense of “purity” I got with a direct connection but with a lower noise floor and without the closed-in, less-real film effect that the DS’s built-in attenuator suffered from in my system.
Ideally they have high input impedance and low output impedance. This will present a very easy load for your DAC to drive resulting in lower distortion and will better be able to cope with amplifiers that have lower input impedance. The lower your DAC output impedance and higher your amplifier impedance, the less impact a preamp will have in this regard.
We don’t typically listen at full volume and usually have some attenuation in the system. A preamp provides an analog volume control which will attenuate both the signal AND noise coming from the DAC. Assuming a low noise preamp, this will maintain a high signal to noise ratio (SNR) at low volume. At high volume (i.e. no attenuation), system SNR will be degraded by the preamp, again, hopefully the preamp has such low noise that this is negligible. Digital volume control can also provide a very high system SNR BUT it requires a very low noise DAC, as only the signal is attenuated, not noise. In a high noise DAC (for example an AVR DAC or DS Mk2), an analog volume control will provide much better system SNR than a digital volume control.
Finally, they usually provide a lot of input flexibility which allows you to integrate a variety of sources.
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