Preamplifier needed?


#1

Hi
I’m thinking of buying some PS Audio audio reproduction components. In the manuel to the DirectStream DAC it says the signal “can be fed directly to a power amplifier or preamplifier”. My dealers (in Switzerland) says from experience he recommends feeding the signal to a preamplifier first; otherwise some noise could result. What do you recommend?


#2

There are several threads here on the forums easy to find with a quick look about this topic. Bottom line is: many feel that a very good preamplifier can improve the sound, others prefer the sound of the DS directly into a power amp. There are factors that could make either choice preferred. It’s a question best answered by oneself with components in their own system. . . .


#3

Welcome, Herbert!

It depends entirely on the particular system as to how well directly connecting the DAC works. My impression is that it works well for most (it does for me). If your dealer will allow it, bring the DAC home and try it out.


#4

In my system there’s no comparison. Preamp is so much better. Check out a good preamp and listen for yourself. You can always return it if it doesn’t work out.


#5

I ran the DSD directly into my BHK 300’s for a year and I thought that it sounded exemplary. I finally decided to move to a BHK Preamp when I found a good deal. I’ve never looked back. After the Toronto Audiofest a week ago, I had a few audiophile friends over. Both have multiple systems and they stretch into six digits. Both commented on the sound with the preamp being really good. Noticeably better than direct from the DAC which both had heard in the past.


#6

I did have a slight hiss in my speakers running the DS directly to my amps. It was very faint and the Attenuation (filter) button on the remote eliminated it altogether. However others with different speakers and amps have stated it was worse in their set ups.

After adding a BHK pre the faint hiss is gone and the sound quality went to another level. I was very happy with my system before adding the pre, but now I can’t imagine listening without it. Like Elk stated, it is system dependent. Ultimately you should trust your own ears. Hopefully your dealer will help you out.


#7

I ran a PS Audio DAC straight into a big balanced power amplifier. Worked fine. Did it for a couple of years. PSA has a superb volume control in the DAC.


#8

I agree completely. If a preamp changes the sound there is something up.


#9

Huh? Watch the BHK video on preamps.


#10

yeah, like an impedance mismatch between dac and amp.


#11

No problem there as the output transformer on the DAC is very low and the input impedance of the amp is very high. This is not a mismatch but an ideal situation. The advantage of the Directstream DAC is that it does not have an ACTIVE stage past the output of the video switch. most active circuity cannot keep up with the steep waveforms coming out of the DAC. Another set of interconnects and active stages are just more opportunities to screw up the signal. I MUCH prefer the sound of the DAC directly into my amp IN MY SYSTEM.


#12

It works fine - just doesn’t sound nearly as good. I’m using a Primaluna Dialogue Premium preamp and it sounds stunning with the DS Sr. I guess if I never heard it I’d be ok without it. Maybe something is up but who cares. You’ve got to at least try it before you pass judgement.


#13

…and I MUCH prefer the sound of the DSD when fed into my preamp first.

Why? The soundstage is narrower and shallower without the preamp. The music is also flatter sounding and less musical without the preamp. The difference is night and day.


#14

I have compare the sound with and with out, I would not make my choice unless I had.


#15

Consider trying a better preamp…


#16

That sums it up well - also more detail - images float within their own defined layered space - more transparent, refined - non fatiguing… I’d imagine a poor preamp would make things worse just don’t see how it’s possible that something like the PM or BHK wouldn’t be a big step up. For me it was a bigger improvement that the Power Plant - and that was a big step in the right direction.


#17

Running the signal through a valve active pre-amplification stage clearly colours the sound to your liking. That’s good for you, but if it was not ok before implies there was something wrong with the DS or your amplifier. I doubt it was the DS, never heard a bad word abou5 them.


#18

Multiple people are extrapolating their experience too broadly, as well some are clearly not understanding the kinds of situations where a preamp helps, (even with an ideal amp) and others don’t seem to understand that, at times, no preamp is the best for related reasons.

Two items:

Very capacitive cables (or very long cables - very roughly 1nF total for the whole cable) will interact with the leakage inductance of the output transformer. When the attenuator isn’t being used this will cause peaking (not drop off) around, say 30k, but possibly into the audio band. When the attenuator IS being used high cable capacitance can cause a HF drop off like you might expect.

The output level of DS vs input sensitivity, gain of amp, sensitivity of speakers and preferred listening levels may not match in some systems. With the DS the 20dB attenuator helps some non ideal situations, but a preamp is much better in that it allows matching levels with virtually arbitrary down stream components. This is more important with single bit DACs than PCM based DACs (or multibit SDM based DACs) since single bit DACs have a fixed analog noise floor. Most of the early SACDs were mixed or mastered using single bit DACs, but there’s always a preamp in those situations so there’s no level matching problem.

Of course the quality of the preamp matters.


#19

All I know is that in my 40 years of buying and listening to audio equipment, I have always preferred the sound of a quality active preamp to a passive preamp, or more recently, a DAC with a volume control.

Now maybe my experience is limited compared to some others, or maybe my equipment has not measured up to what others have used. But I do take exception to being told that don’t know what I am talking about and I am ignorant.

Thanks…


#20

It’s certainly not about coloring the sound no more than using a higher resolution component colors the sound. Think most of us here know the difference between a tone control and higher resolution. I also know output impedance and cables play a role – along with the quality of the preamp. There’s always objective facts to deal with this hobby. There are also occasions were performance enhancements can’t be completely explained with objective measurements

Check out a few you tube videos on using Preamps from Paul McGowan, BHK and Kevin Deal. You may not agree with their opinion but you might consider that they are all not wrong.

Ultimately its always subjective and if you’re convinced adding a preamp can only act as a tone control you’re probably better off anyway – your bank account will thank you in the long run.