Is a preamp necessary to improve sound quality?

My DirectStream DAC feeds directly into the BHK 250 amp via balanced cables. With good recordings streaming on Qobuz, it produces the most live-like performances of any rig I’ve ever had.

I also have vinyl. My new generation Technics 1210 GR turntable with Ortofon 2M Black cartridge feeds the same DSD DAC via a Pro-ject Tube Box DS2 going into a very small $15 D to A converter, which supports a sampling rate of 48KHz. Switching between PC (USB) and vinyl (COAX) is done through the DSD DAC.

I have no interest in recording my vinyl. I have only two audio sources and simply want to avoid spending money on a preamp for switching purposes when the DSD DAC is capable of doing so, or to improve SQ if unwarranted.

Underlying this approach is the belief that unnecessary electronics are best left out of the signal path. Paul used to believe that as well until he heard the BHK preamp. He could not explain why the BHK preamp improved SQ and neither could Bascom when asked in a video.

When I originally posted that the SQ from my vinyl using this method was quite good, a commenter said he followed the same methodology with good results. Another said digitizing an analog signal then converting it back to analog with the DSD DAC did not make SQ sense,

At that time I did not have a preamp. However, I was curious to see if a preamp in the chain did indeed improve SQ. I could not get my hands on a BHK preamp but I invited audiophile friends to bring their preamps over to my home for a listen. Among the components were preamps from Benchmark, McIntosh and Mark Levinson.

With four pairs of ears listening, the SQ with any of those preamps in line did not improve the SQ from the DSD DAC going directly to the BHK 250 amp.

Many things beyond my pay grade could be at play. I wish Paul or Bascom could have an explanation for why a preamp in the chain (between the DSD DAC and the amp) improves sound.

Absent that, following my experiment I do not see any need to acquire a preamp to improve on SQ. The PS Audio DSD DAC, for some reason, can process the 48Khz sampled analog signal from my TT in such a way as to make the need for a preamp unnecessary. The PC originated signal also seems to be good enough not to require a preamp.

I suspect there may be many PS Audio customers doing the same thing that I am doing. Perhaps there is a silent majority out there. If there is, it would be nice to hear from them. I am fairly sure that the experiment will not convince those who doubt that digitizing an analog signal only to reconvert it to analog makes no SQ sense.

My purpose in doing the experiment was to determine if I needed to spend money on a preamp in order to improve SQ from my vinyl or my DSD DAC. I’m now convinced I do not. For me, that is all that matters.

Beyond that I do not want to generalize. I offer the results simply to inform others that spending $15 on a D to A test may, if their circumstances warrant it, help to avoid spending a few thousand on a preamp.

3 Likes

Not a owner of a PS audio DAC, but I do the same as you in my setup, if it sounds good, go with it.
Unless you really want to spend 6 k on a BHK preamp, and it sounds like you don’t, why not spend much less (but more than 15 dollars) on a better ADC?
The nuwave phono converter from PS gets a lot of love on here, second hand examples available, but there are many others if you look at the pro audio world, most significantly cheaper than a pre amp.
I use the ADC bit of a Behringer SRC2496, though that has recently (and disatrously) been discontinued, still available for 120 quid on eBay, but there are many others, then you can continue using the DS DAC as source switch / “preamp”, which given its rave reviews seems to make a lot of sense.
BTW my own personal opinion as to why the BHK changes (“improves”) the sound is the very subtle addition of harmonics to the signal. Not exactly harmonic distortion, more in the way an Aphex Aural Exciter used to be used in recording studios and live shows, although to a more subtle degree, but please note, this is not a particularly popular opinion around here, so others will probably disagree (which I have no problem with, what do I know?) :slight_smile:

If you’re not able to get at lease a BHK preamp, then forget it. Any lesser preamp will only muddle the sound. You have the same DAC and Power amp as my brother, and I can tell you, his system definitely sounds much better with his Conrad Johnson Gat preamp in than without it. The sound with the Gat has more body, more dimensional, more space between instruments and just more musical with the preamp in. Same in my case, but I am using an Esoteric A-02 power amp and an Esoteric C-02 preamp. The sound with the C-02 in is forget it, it is night and day. It is so much better it’s like a different DAC completely. You don’t know how good the DS DAC is until you hear it with a better preamp.

2 Likes

I use a really nice Don Sachs 70 WPC KT88-based tube amp and have tried using the DirectStream for volume control and my Don Sachs 6SN7-based tube preamp for volume control. Using just the DirectStream sounds really. But, using the tube preamp sounds even better. The soundstage is more 3D and the sound is fuller and more musical. It is a noticeable improvement that I would not want to give up.

1 Like

I’m curious, is it the preservation of harmonics? Or the addition of good sounding harmonics that weren’t there?

good question, I would say if impedance matching (i.e. avoiding roll-off etc.) is happening, then the former, if not, then the latter, or somewhere in between. This would require someone with extremely sensitive test equipment and very clean methodology to find out, but I don’t think many with such kit and know-how have the will or interest (or need) to find out.

As ever, whatever sounds good is best * - there are folks out there who actually use Aphex (and other such) kit in their HiFi to just tweak it until they like it, and “purity” be damned. I have some sympathy with that view although I personally wouldn’t go that far, I do like the idea of purity, and do not use a preamp at all (usually).

  • but, as was the case with graphic eqs etc. in the 80s in particular, adding e.g. upper harmonics, or just “turning up the treble” can end up with adding more and more over time until the end result is far, far from HiFi, so I think not including tone controls and eq on amplifiers is a good thing, if folks seek or feel they need it, there are add on boxes (DEQ, or harmonic enhancers) available to add to the chain, others do it with expensive cables with (allegedly) different sonic characteristics. There are many ways to skin a (proverbial) cat…
2 Likes
2 Likes

Thanks, speed-racer. This is the video I had referred to in my post. To paraphrase, what I have sounds good but not as convincing as if a preamp was inline.

I tried some very good preamps, but there are so many and I take previous reply posters at their word that their preamp additions were worthwhile. I did not try any of the preamps they mentioned.

If we take Bascom at his word, it becomes a matter of which preamp and at what price? I can’t afford a BHK preamp, so is there a preamp, tube or solid state, up to $2,000, that can convincingly improve the SQ of my chain?

At the same time, the suggestion in a previous reply post of a professional quality A to D, is worth exploring. Would a better unit than my $15 budget basement A to D be more convincing, or does the process of a double conversion, A to D and D to A, degrade the signal to the point where improving the quality of the A to D conversion cannot be convincing in the same way that adding a preamp can?

I wish there was a BHK preamp, a very simple one, with just a couple of inputs, USB and phono preamp for example, but of the same quality as the larger BHK preamp, that could be manufactured and sold for less than $2,000?

Damn, I love this hobby. Thanks again!

1 Like

I remember all the typing back and forth with @Gary_M, and another time @sixpack1, on this subject!

Sixpack 1 was pretty much adamant the introduction of a preamp, any preamp, would be a retrograde. John’s system was sounding excellent with the DS straight to BHK250, how he didn’t want to screw with the music. I said to John I felt the exact same way until I tried a good preamp - then there’s no going back. Both Gary and John now use the BHK preamp between their DS DACS and BHK250s and they’ve never been happier.

It isn’t some euphonic change thing that simply ‘pretty’s up the music’…no, it’s a fundamental improvement across the board. ‘Makes Music’, it becomes 3D, sounds much more realistic…

Back when I used BHK amplifiers: I couldn’t go back to playing music with the DS DAC straight into the BHK300s without the BHK preamp.

6 Likes

I felt that way for years, after trying several high-end preamps and discovering that they only diminished the sound quality. I did however come across two exceptions. One was a 20K Accuphase preamp that I tried many years ago that a dealer loaned to me to prove that a good preamp does in fact improve the sound. Well that was great, except I wasn’t about to drop 20K on a preamp that cost more than my system at the time. The second exception to the rule is the preamp I currently own, the PSA BHK pre, which when fully broken-in blew me away.

1 Like

Thanks for sharing. You shed light on a world I know very little about. If the Behringer is not available, is there one you’ve seen that is worth exploring? And are the pros available for preferably under $2,000 but no more than $3,000?

1 Like

I have little doubt the Conrad Johnson or the Esoteric can do what you claim. At over $20,000 either one of them should. The question then becomes, not will a preamp inline improve the sound, but can an affordable preamp below the cost of a BHK preamp do it?

If it is not possible, then compromise beckons and looking towards the pro world using a much better A to D converter might have to be the ticket, if indeed a better one improves what I already have. Judging by price alone it should be possible, but we all know that price alone does not buy performance.

I wish there was a BHK preamp Jr., or that Bascom could answer Paul’s question as to why a preamp improves SQ. I would think you have to know something about the secret recipe before an affordable unit, much scaled back in functionality (connectors, etc) but not on SQ performance, could be designed.

1 Like

Do you need a pre-amp? - NO

I had a PS Audio DAC and plugged it straight into my amplifier. That was before the BHK pre-amp came out and Paul was saying that the volume control in my PS Audio DAC was the best thing since sliced bread.

I also have a system that does A/D conversion of vinyl with no issues at all.

Of course when the BHK pre-amp came out Paul says it’s the best thing since sliced bread and improves the sound, but can’t say why. Well, he’s selling products and fair enough. But the immutable logic is that adding something in the signal path either is fully transparent and adds nothing or adds distortion of one form or another.

So what is a pre-amp? Three things: a switch, a gain stage and an attenuator. If you need any of those things, you might need a pre-amp. It sounds like you don’t because you don’t need extra gain, the DSD DAC has an excellent volume control an you’ve solved the switching issue by using A/D conversion.

I would look at A/D converters from RME, they do a wide range of products at may prices.

2 Likes

Thanks for the tip, Steven. Given the price of a preamp that would enhance the sound between the DSD DAC and the BHK 250, it seems like looking for a high quality A/D conversion might be the more affordable alternative for me. I appreciate the suggestion of RME. Having purchased the DAC, amp and a power plant pretty much took most of my budget.

An added consideration is that most preamps have far more functionality in terms of ports, etc. than I need. I simply desire to easily switch between my PC originated streams or ripped CDs, or my vinyl analog output. Paul in his videos speaks of the expense inherent in adding ports for those who have asked for them. I believe it does add cost which, for me, is unnecessary.

Before the Esoteric, I was Using a tubed Bruce Moore Companion III ($4000) and it was fuller and more musical than straight in the power amp, but not to to same degree as the more expensive preamp. But with the Bruce Moore it was much closer to straight in, still it was better. I don’t think going below $4000 is any good though and would probably hurt the sound.

This preamp is awesome!:

http://www.dsachsconsulting.com/custom%20line%20stage.html

How can you expound on something you have zero knowledge, you’ve never owned BHK amplifiers. Your logic on paper appears logical, that’s until one actually tries a BHK preamp between the DS and BHK power amplifiers. Because until you listen to said combination - you are just pissing up a tree.

6 Likes

I think a very cheap A to D converter will introduce a lot of jitter so it’s worth getting something better. I have an RME UCX that I bought years ago simply to act as a digital volume control (that was before I had Directstream volume control and was using a Behringer DCX2496 that doesn’t have a remote volume control). Now I have an ADC within my DEQX digital crossover and when I play vinyl it sounds excellent, so, a good ADC and the DS straight into a BHK will be great.

Update - I should mention that there are lots of preamps on the market that are line stages, i.e. they do not have a gain stage but can be used to reduce volume. A lot of these will be tube based.

I’ll also add that switching analogue can be easily accomplished with a manual switch box. Some switch boxes can even have a remote control facility and incorporate a volume control pot.

3 Likes

Forgive me for interjecting, Dirk, but Steven is addressing the sequence of Paul’s “conversion” to supporting preamps between the DAC and the amp. That is factual and I wondered the same even if I did not mention it.

Paul is a merchant and if indeed it was a conversion that benefitted his bottom line I don’t object to it and I believe Steven said likewise. I want PS Audio to thrive.

Steven was not being critical of BHK components or their performance, but paraphrasing what I had said about my functional needs. At least that is how I read his post.

1 Like

Looks intriguing. I’ll look into it. Thanks for the recommendation.