To Preamp or not to Preamp, THAT is the question


#1

I’ve acquired a new Directstream Jr on approval and have been enjoying it alot to say the least for the week or so that I’ve had it. The rest of the system is Aesthetix Janus & Aesthetix Calypso (presently unhooked from the system), a Pass Labs X150.8 and Thiel 2.8 speakers. I have been using the Janus which includes a phonostage and although I have a nice VPI turntable rig I find myself not using it much. SO, I finally switched the preamp out altogether and am running the Direcstream Jr directly into the Pass labs power amp and am finding I LIKE IT BETTER than running it through the VERY FINE Aesthetix preamp. One other reason (apart from the phonostage which I can probably do without as digital as gotten, well less digital) is the presence of tape loop on the Janus which is use to feed a fab Woo Audio headphone tube amp which then feeds my Beyerdynamic Tesla-1 headphones.

  1. Does anyone else find they prefer using the variable gain out of their directstream better than ANY PREAMP regardless of make or model?

  2. I can live without the phono stage but I can’t really without the headphone option (which I use primarily for late night listening). The tube headphone amp is single-ended, but I’ve read NOT to connect both single ended and balanced outputs on the direcstream simultaneously…IS THAT CORRECT? Is my only option to just disconnect the balanced connectors between the Direcstream and the power amp and reconnect the single ended cables to the Woo Audio piece when I elect to listen via headphones?

  3. Thoughts, ideas comments?


#2

This is a case of purely personal taste. I have the same amp and a BHK pre which replaced a Calypso that was damaged during a storm and a DSD Sr. The volume control in the dac sounds great but to my ears, there’s no contest. There’s a lot of discussion about this subject that can be found on this forum.


#3

Lot’s of discussion on this. Personally, my DSD to BHK sounds a world better with my pre. I have tried direct hook up again recently and the difference was very apparent. But that’s just me. Paul I believed used a Calypso as well. That is where I first heard about some preferring a pre vs not. But there are avid campers in both schools and of course both are right. Whatever sounds best to you.

#2. There is a thread on this topic as well. If I remember correctly you can use both outputs. (And I have BTW) but if you are using balanced and also using the RCA the XLR is no longer a true balanced connection as it shares a common connection with the RCA. However if you don’t have a noise issue , then no harm done. Currently, I just leave my RCAs (To a headphone amp) disconnected from the DSD till I want to use them which for me, is not that often and easy to connect. Hopefully you will get a few more responses.


#4

I’ll concur on the nod to a Preamp for improved sound in my case. I have the DSD Sr and a BHK Pre. I used the DSD Sr. with balanced outputs to the BHK 300’s and the single ended outputs to my Woo WA5-LE for headphone use, before I had the Preamp, This sounded very good. I used both outputs in the DSD simultaneously with no ill effects. If you want to be sure just disconnect the cables from the output that you aren’t using. In my case I had the device set up for easy access to the outputs. My beef about the BHK preamp was the lack of three outputs or a tape out. I now have to disconnect the Subwoofers from the RCA outputs and connect my headphone amp. Eventually I’ll deal with this. Fortunately my audio roon is far enough away from most of my family that I don’t need to use headphones for sound containment.


#5

I was in the “no pre” camp since updating with the DS kit, for about 4 years, that was my goal, but Paul reported that a pre was an improvement, then the BHK pre came out and even more favorable pre reports.

I was very content with the sound without a pre but needed to know if there actually was room for improvement.
I wanted to try a pre with not just volume gain but also out put level adjustment, fully balanced and tube based.
I set my sights on the new Decware ZTPre and managed to acquire one second hand.

Adding the ZTPre allowed me to run the DS with the -20 dB attenuator, which is quieter and also let me run my amps at 15 dB gain vs 23 dB gain, which also was quieter.

The result was much more musical, not that my system didn’t sound musical before, just much more musical to me, more dynamic and extended.

My gain path went from ;

DS set on high ( listening at 80 ) > Atma Sphere M60 OTL with high gain > Avantgarde Duo Omega 107 dB
To
DS set on low ( listening at 100 ) > ZTPre high gain settings > Atma Sphere M60 OTL with low gain > Avantgarde DUO Omega 107 dB

The system was very quiet without the ZTPre, after adding the ZTPre, the noise floor dropped even more.


#6

Great. I am using a ZTPRE as well and love it–and I too was in the “no preamp” camp til a Decware ZTPRE came along and let me use three balanced sources, and makes the DSD sound so so good. I’m also using a 25th Anniversary version of the Decware CSP3, as it has a special synergy with the 25th Anniversary SE84UFO3 Decware mono blocks I’m using, and also drives my headphones spectacularly.

I use a Decware ZBIT to feed the single-ended inputs of the CSP3. A dead quiet system despite two tubed preamps in the chain. . . and fantastic sound with lots of ways to “ride the gain.” I’ve never heard sound like this before, it’s addicting.


#7

Lon–So, you’re using the CSP3 only for headphones?


#8

No, I’m using the ZTPRE as the input for my three sources (DSD, Oppo UDP-205 which I more often listen to through the DSD, Magnum Dnyalab 90T SE tuner) and have the output gain about 50 percent (about 18 db) and then run the balanced output of the ZTPRE into the ZBIT, and the single-ended output of the ZBIT into the CSP3 and the single-ended output of the CSP3 into the Monoblocks. I generally control the volume manually by the CSP3 but can and sometimes do use the remote on the ZTPRE. I do also use the CSP3 for headphones in this system.

Seems weird to have two preamps I guess, but the power supply mods for the CSP3 mirror the mods done to the Monoblocks and just add more spatial and tonal goodness… … The sound is the best I’ve had this way and I just get lost listening and watching day after day.


#9

Actually I realize this is inaccurate, I forgot to mention that I have a Decware ZROCk2 in between the ZBIT and the CSP3!

I used to be a “Keep it Simple Stupid” follower, but the DSD into my amps directly via single-ended just didn’t have enough “juice” for my system, and I needed to utilize the balanced output. That led me eventually to this route which has given me surprisingly great sound, and I tossed “KISS” out the window!


#10

In my system the BHK preamp to monoblock amps sounds much better, than the PSA DAC to the monoblock amps.


#11

That’s my system and I concur.


#12

I originally used my DS Sr. into various amps. Sounded Great. Didn’t really notice anything ‘missing’ when using the vol. control provided by the Sr. and honestly coming from my previous DAC, the Sr. was so much better that it was hard to imagine adding a pre doing much, but… Added a BHK Pre and for me, regardless of the amp used, there was no turning back. Def. a step forward with the BHk Pre in the chain.

Off-topic,… Hey @Mrderrick, I have been considering switching from my M-60’s to a Decware amp ( have owned a 34.2 and SE84 in the past) . Either Torii Jr., MkIV or possibly a ZMA. Have you ever had the chance to compare your M-60’s to any of these amps? Or any one else on here have any exp. with the aforementioned comparisons? Thanks all!


#13

To preamp, THAT is the answer :wink:


#14

I’ve tried running the DS Jr directly to the M700 amps but heard hissing background noise. Running through the BHK preamp, the background noise is mostly gone. Anyone notices this higher noise floor with no preamp?


#15

Just so readers know there are choices here… DS Sr direct into Musical Fidelity M8 500S power amp. Balanced all the way. I have zero interest in putting additional circuitry in the signal path.

Even the attenuator, though it does take the noise floor from being quiet to being close to inaudible, sucks some of the life from the music. A smaller number of well-matched components is how I get the sound that I like.


#16

The DSD output stage direct to an amp is, as far a I am concerned, very flat sounding when compared to active line stage/preamp. I don’t like the sound without some kind of quality active line stage/preamp.I especially like a tube line stage/preamp to tube amp.


#17

It depends on the amp and the interconnects. A power amp is a gain stage. A pre-amp is a variable gain stage (whether it’s actually variable gain or fixed gain with variable resistance). There’s nothing in principle that means a power amp can’t sound as good as a pre-amp, but there are good reasons why less circuitry often means better – or at least more accurate – sound.

Getting flat results from a direct connection many times comes down to an impedance mis-match. If the amp’s input impedance is too low you get HF roll-off and IIRC also poor dynamics. A good pre-amp usually has a high input impedance (good for matching with sources) and a low output impedance (good for matching with power amps). If your system sounds better to you with a pre-amp than without, the reason is usually either that one or it’s that you personally enjoy the additional colourations which the pre-amp provides.

Using just the single-ended specs my system is 100 Ohm output into 50 KOhm input. A DS -> BHKPre -> BHK250 system is 100 Ohms into 33 KOhms (worse) then “<100 Ohms” into 50KOhms (better). It may make a difference that I’m using a fully balanced topology rather than single-ended, but neither PS Audio nor Musical Fidelity publish full specs including balanced input/output impedances.


#18

Yet:


#19

Not the same comparison. Within the first 30 seconds we learn that the video is about “active” pre-amps vs “passive” pre-amps which are purely volume-reducing devices. I’ve tried passive pre-amps. I agree that they are a major compromise, and impedance is again most of the reason.

The DS Sr’s output stage is much more capable than the “line out” from most other DACs and sources. And the volume control is digital and lossless, as Ted has explained several times in detail. The compromise I’m living with is a higher noise floor. I don’t have the flatness caused by impedance mis-match, and I don’t have any colourations or fidelity loss caused by the extra components and signal path increase that a pre-amp involves.

I’m not saying that you would like my sound. I’m just saying that I do, which proves that at least some people will prefer a direct DAC-to-amp connection. It’s a valid option for people to explore. That’s all.

Oh PS – Other than a few special one-off experiences I have never been a fan of the sound of tubes. That you enjoy them shows we have quite different tastes. I’m OK with that and I hope you can be too.


#20

The DSD has a passive output stage. Very specifically it is stated in the video that they prefer an active preamp to the output stage of the DSD. I do too.