Do I Need a Preamp?

0 Members and 1 Guest are viewing this topic. Read 964 times.

DZetye

  • Full Member
  • Posts: 386
Do I Need a Preamp?
« on: 20 Dec 2017, 03:17 am »
I have been using my Chord Dave Dac directly into my amp but it doesn't have any sort of explosive dynamics or anything close.  I tried an Auralic Vega in place of the Chord and dynamics were quite a bit better.  Would using a good preamp help me to regain my lost dynamics with the Chord Dac?

Mag

Re: Do I Need a Preamp?
« Reply #1 on: 20 Dec 2017, 04:05 am »
You can use something like a mixer as a pre-amp, I have the Yamaha MG-10. You have to be extremely careful with the settings like gain, line in, and master volume as you could easily damage speakers.

The drawback is mine doesn't have a remote so I run my pre-amp processor to mixer for remote control and refinement in sound. But the mixer by itself can sound very good if you can find the right setting preferences for your likes.

jseymour

Re: Do I Need a Preamp?
« Reply #2 on: 20 Dec 2017, 04:15 am »
Buy a Schiit Freya. You will get 3 different modes: passive, ss and tube.

PMAT

Re: Do I Need a Preamp?
« Reply #3 on: 20 Dec 2017, 04:33 am »
A good preamp will work wonders.

richidoo

Re: Do I Need a Preamp?
« Reply #4 on: 20 Dec 2017, 05:54 am »
A preamp circuit changes the gain, but doesn't affect signal dynamics at all. Loud and soft signals are amplified the same amount.

An expander is an audio effect that increases dynamics. If you have computer audio you could use a dynamics effect plugin to try expander effect. But I doubt it will help. Chord will say it has very low THD, and the dynamic distortion is part of that spec. If you compared input to output levels you would find there is no compression to speak of.

IMO, it's not dynamic compression you are objecting to, it's just the "voicing" or the sound of the analog output stage. Probably an opamp current buffer used in a way that dumbs down the transient response to make a gentler, warmer sound, the traditional British hifi sound. Bad transient response or phase problems can ruin the openness and aliveness of the buffer circuit, making it sound closed in, stuffy, slow, boring, dull, etc. Every opamp is different and each has it's preferred way of being used to sound best. Best is in the eye of the beholder and any opamp can be tuned to sound sharp or softer according to what the marketing people want to sell.

In contrast to the British sound, the Vega has very strong, discreet transistor direct coupled balanced output stage that doesn't round over the edges at all. Cables and components downstream are forced to obey. It can be pretty merciless sometimes on lesser quality recordings, but it sounds alive and strong and clear. It's kinda the opposite of the popular TI LM49000 series opamps in unity gain with no phase compensation. My amps (Mod86) use that same opamp LM49710, but with 10dB of gain and with excellent phase compensation in the feedback loop and they sound crystal clear and "dynamic." With Vega as source it can be too much sometimes!! It's all in how you use the opamp, it's just another color on the palette. In your case I think they use it to soften the sound, or they use something else in the output stage to soften up the sound and that's not your preference.
« Last Edit: 20 Dec 2017, 02:19 pm by richidoo »

S Clark

  • Full Member
  • Posts: 5253
  • Measurements don't make your toes tap
Re: Do I Need a Preamp?
« Reply #5 on: 20 Dec 2017, 06:43 am »
A preamp circuit changes the gain, but doesn't affect signal dynamics at all. Loud and soft signals are amplified the same amount.
In theory, Rich is right. However, my experience is that an active preamp does affect perceived dynamics.
So, my free advice is, yes, look for  a quality active preamp. 

Big Red Machine

Re: Do I Need a Preamp?
« Reply #6 on: 20 Dec 2017, 11:20 am »
You need a preamp if you are serious about audiophile playback. Start reading reviews or forum questions on Audiogon and other sites and you will see to a man that when adding back in a preamp it added life and energy to their music. For any of us who have tried it w/o like DZ did, you'll quickly find it flat and disengaging.

And remember, the preamp is second most important to the DAC/source so don't skimp and just throw something in the mix. Choose wisely. 8)

JLM

  • Full Member
  • Posts: 8496
  • The elephant normally IS the room
Re: Do I Need a Preamp?
« Reply #7 on: 20 Dec 2017, 12:51 pm »
Agree with Rich, it's a matter of GIGO.  If anything is lost in the signal chain, it's lost period.  His suggestion of an expander is probably the only solution for loss of dynamics. 

But your experience goes against all the superlative reviews I read of the Dave.  Wasn't aware that Dave had a preamp section per se.  That could be a weak link, but at that price point I'd hope there were no weak links.  Sometimes loss of certain distortions can be mistaken for loss of dynamics.  Those minor, even subconscious distortions can irritate enough to make everything, especially peaks, sound louder. 

Can you output Dave without using it's preamp/volume features (to find out if it's the DAC or the preamp/volume control)?  I've not read of such issues on 'lesser' combined DAC/preamps like Benchmark, Mytek, or Oppo. 

mg8

  • Jr. Member
  • Posts: 106
Re: Do I Need a Preamp?
« Reply #8 on: 20 Dec 2017, 01:01 pm »
The high cost of electronics compels me to always A/B my new purchases against my old favorites.  This comparison has evolved my thoughts that a preamp is largely an input selector.  I firmly believe the preamp is the "heart" of the system.  Other components get "more ink" largely because of rapidly changing digital tech (e.g. DAC's) but I apply the "weakest link" philosophy to my audio signal. An expensive DAC and cheap preamp is a constraint for the DAC.  I have run various sources direct into an Amplifier, always balanced XLR, to ensure the max voltage potential.  Including the Auralic Vega (cited above) direct to the Meraks as well as through the discontinued Taurus Pre.  The  added Taurus Pre contributed less than in other examples but it still made a direct contribution to the "drive" and ultimate feeling of emotion and engagement.  I was disappointed that Auralic dropped the preamp.  I do know there are theoretical arguments for noise and distortion whenever a signal is interrupted (in this case a preamp between the source and amp) but I have never experienced an improvement in sound quality by excluding a preamp.  I have in most occasions experienced an improvement when a good preamp was added.

Elizabeth

  • Full Member
  • Posts: 1738
  • Love is all there is....
Re: Do I Need a Preamp?
« Reply #9 on: 20 Dec 2017, 06:04 pm »
The one area where skipping a preamp may matter is right impedance matching.

It is a VERY common problem with leaving out a preamp to have either a lack of dynamics, or a lean sound.. kind of 'skimpy' sound with no preamp, or a passive preamp.
The problem is pretty much the lack of drive in the source electronics.

Some sources do not have this flaw.
But to find which do or don't.. you need to hear for yourself..

I like preamps.

Rusty Jefferson

Re: Do I Need a Preamp?
« Reply #10 on: 20 Dec 2017, 08:19 pm »
^ Spot on. I was about to make the same point.

jules

Re: Do I Need a Preamp?
« Reply #11 on: 20 Dec 2017, 08:44 pm »
Some great posts above and I thought Rich's comments on different voicing related to national origin were very true. The same applies to speakers I think and there's a whole topic for discussion right there.

Overall though, I agree with Elizabeth and Rusty that the most likely cause of the problem comes down to what's generally described as impedance mismatching. The solution is some form of buffering and probably a little gain which adds up to a pre-amp. As an alternative you might find that something like a Burson buffer would do the trick.

Classic approach I guess but personally I think a pre-amp is a great  place to insert a hint of tube flavour to your system. The added advantage is that choice of tube brand gives you a subtle range of voicing options.

roscoe65

  • Full Member
  • Posts: 615
Re: Do I Need a Preamp?
« Reply #12 on: 20 Dec 2017, 09:23 pm »
I don't know anything about the rest of your system (hint: it would be helpful), but the output stage of the Chord Dave should be able to drive most amps at 6.8V.  I own a Chord Mojo with a considerably less beefy output stage and I have no problem using it as a preamp into my SET (full disclosure:  the amp has a 0.65v sensitivity).

That being said, when I swapped out the Chord Mojo for my Bimby, the sound became more rhythmically powerful but also became less forgiving of source material.  The Chord voicing tends toward warmth and inner detail but seems to sacrifice a lot of the high end energy.  I suppose that sound could be viewed as more analog like.  The Schiit just sounded a lot more dynamic, despite outputting 2V vs. 3V for the Chord.  IMO, the difference is almost purely due to voicing.

poseidonsvoice

  • Full Member
  • Posts: 3368
  • Science is not a democracy - Earl Geddes
    • 2 channel/7 channel setup
Re: Do I Need a Preamp?
« Reply #13 on: 20 Dec 2017, 09:44 pm »
AC'ers,

FWIW, the output impedance of the Chord Dave is: 0.0055 ohms. Yes, that's where the decimal point is! So unless you're interconnect is several miles long, I don't suspect an impedance mismatch! With a 6.8V RMS output, you should be able to drive anything.

I suspect the actual issues for why the OP feels that his Chord is less 'dynamic' than the Auralic Vega go beyond the issues of impedance matching, and given the paucity of info we have on the OP's actual components, room, speaker and overall setup, it will be anybody's conjecture as how to solve the OP's sonic woes.  :rules:

https://chordelectronics.co.uk/wp-content/uploads/2016/09/Dave-User-Manual.pdf

Best,
Anand.

Rusty Jefferson

Re: Do I Need a Preamp?
« Reply #14 on: 21 Dec 2017, 02:36 am »
Okay, that's seriously low output impedance.  Looks like the Vega also has very low output impedance.  Difference?   Perhaps the digital volume controls. Many are problematic particularly with dynamics. Perhaps the power supplies. I don't know.

If the OP simply tries putting a quality preamplifier with low output impedance in the system with Dave and dynamics return.....he's answered the question. I have yet to hear a system that sounds MORE dynamic with a volume controlled dac than with a quality preamplifier, especially if using solid state amp(s) with low input impedance.

cnguyen

  • Jr. Member
  • Posts: 6
Re: Do I Need a Preamp?
« Reply #15 on: 31 Dec 2017, 03:52 pm »
I would try without a preamp first and see how you like it.

Telstar

  • Jr. Member
  • Posts: 280
Re: Do I Need a Preamp?
« Reply #16 on: 3 Jan 2018, 11:01 pm »
Some third harmonic will give the illusion of dynamics. Therefore find a SS preamp, not single-ended.
To add real dynamics you would need faster speakers ;)