my experience with preamp

[tesla2046]

I am using topping d90 dac and NAD M22 V2 amp now, bought after learned their good measurements from ASR. The problem for my setup is the speakers sounded too forward to me, with direct DAC to amp connection. So partly by curiosity, I added a class A, zero feedback preamp, knowing that I introduced distortion/coloration to the system. To my surprised, the change is very obvious:

1. Before adding the preamp, everything sounds flat or analytic. With the preamp, I have much enhanced contrast. Stronger bass, all background small details sound much higher in volume, maybe digital volume loses resolution or better impedance matching?
2. Distortions in a good way to me:
- a little recessed sound now which resolves my problem.
- higher orders of harmonic distortion adding very slight "ing-ing-ing", artificial headroom? even less noticeable when it fully warmed up.
- more textured sound, for example: voice "la-------" becomes "la^^^^^^", also instruments like cello have more vibrations
3. The biggest surprise to me is the phase change. Phase affects human ear to tell the source of direction. Now with the preamp, I can easily tell the moving of the source, not just left/right, but angles/rotation. For example, if someone uses a cellphone to record a saxophone player playing, and turns around, I can very easily tell he is turning around, with side or back to the player now. Or a trumpet is moving down to up or directly facing to you. No need for high quality recordings, just YouTube videos can easily demonstrate the phase improvement. Now the soundstage is more opened up in my system because of the phase change, more depth.

So distortion or no distortion, is a question. Also, I feel phase shift specs should be equally important to frequency distortion specs. Just my 2cents.

Sorry for my poor English...

 

[Koeitje]

Sounds like your speakers have an uneven response and somehow more distortion from your source masks it. This is 100% not an issue with your D90 or NAD. What is the rest of your setup?

 

[tesla2046]

Thanks. Good to know. It is also for nearfield listening at low volume. Probably problem exaggerated?

 

[tesla2046]

My speakers are ELAC CARINA BS243.4.
Stereophile has the measurements:
https://www.stereophile.com/content/elac-carina-bs2434-loudspeaker-measurements

 

[AnalogSteph]

Trying to solve speaker and room related issues by putting an effects box between your DAC and amp is inefficient and silly. (You can always get an effects VST, quite possibly free at that.) A measurement microphone would have made a better investment, then at least you could have gotten an idea of what may be wrong and tried to develop an EQ setting.

The Elacs seem to be fairly decent little bookshelves... maybe a hair too little low midrange and a hair too much mid-treble but nothing dramatic, a slight midrange dip as you move off-axis horizontally, and vertical dispersion in the treble is looking a bit bumpy (maybe the tweeter is seeing the woofer surround, plus top edge diffraction perhaps?) so I would rather keep these well away from desks or ceilings. Not sure how I feel about a little ribbon tweeter with a very shallow waveguide crossed over at just 2.7 kHz.. probably good for dispersion but I imagine there'll be a distortion peak in the low treble at higher levels.

There is nothing majorly wrong with the speakers per se but I wouldn't want the room to amplify their quirks even further.

Isn't the M22 V2 (a 300 W into 8 or 4 ohm amplifier) a bit oversized for "nearfield listening at low volume", even given a moderately efficient speaker at ca. 82.5 dB SPL / W / m? Especially when it retails for €3499, more than twice as much as the speakers and DAC combined? 4500€ for both amplifier and speakers could also have bought, say, some Genelec 8331s plus GLM kit.

 

[Jackpine]

Or maybe he bought a really good preamp.

 

[tesla2046]

Trying to solve speaker and room related issues by putting an effects box between your DAC and amp is inefficient and silly. (You can always get an effects VST, quite possibly free at that.) A measurement microphone would have made a better investment, then at least you could have gotten an idea of what may be wrong and tried to develop an EQ setting.

The Elacs seem to be fairly decent little bookshelves... maybe a hair too little low midrange and a hair too much mid-treble but nothing dramatic, a slight midrange dip as you move off-axis horizontally, and vertical dispersion in the treble is looking a bit bumpy (maybe the tweeter is seeing the woofer surround, plus top edge diffraction perhaps?) so I would rather keep these well away from desks or ceilings. Not sure how I feel about a little ribbon tweeter with a very shallow waveguide crossed over at just 2.7 kHz.. probably good for dispersion but I imagine there'll be a distortion peak in the low treble at higher levels.

There is nothing majorly wrong with the speakers per se but I wouldn't want the room to amplify their quirks even further.

Isn't the M22 V2 (a 300 W into 8 or 4 ohm amplifier) a bit oversized for "nearfield listening at low volume", even given a moderately efficient speaker at ca. 82.5 dB SPL / W / m? Especially when it retails for €3499, more than twice as much as the speakers and DAC combined? 4500€ for both amplifier and speakers could also have bought, say, some Genelec 8331s plus GLM kit.

Thanks for the education. I will try VST, sounds interesting. As for the ELAC speakers, I don have to raise it from the desk ~ 5 inches to have better sound. The vocal sounds a little thin though, but with very nice treble.
M22 V2 has adjustable low, mid and high gain, and I am using the low gain setting +19db. At this setting, volumewise I don't feel it is oversized. Probably not bad. With the preamp, I feel the timing and phase have been corrected or modified, so that better soundstage, and voice has realistic low/high slow/quick now. Slowness you can feel the slowness, punch you feel the punch, etc. It is not adding any information, but magnifying all the details, such as background sound, breathing etc. Maybe the digital volume in the DAC has something to do with the difference, loss of resolution at low, negative feedback interference with amp feedback?
All are there for DAC direct to amp configuration, but feel robotic/flat, though sound great, but with the preamp, it is like moving from 2d to 3d with sweetness and human emotion. Nice coloration, especially at low volume, so I keep it in the chain.

 

[righthookmike]

Can I ask what pre amp you are using?

 

[tesla2046]

It was a pretty risky blind buy. Since it is not cheap, without measurement I wouldn't recommend it and promote anything.