Should I eliminate my preamp?

Many owners have complained about the sound of the Oppo’s balanced or SE output I can’t remember which it was.
But technically the ESS dac chip having a balanced output, would say to me that balanced should be the superior output, as to have a SE output another summing opamp would have to be introduced to change balanced back into single ended.

Cheers George

marqmike529 posts04-09-2018 1:20amThat is real possible. Thanks

If you look at it technically, the VH 1st interconnect has not only capacitance, but resistance (very little, except for the Carbon they once had) and also inductance.
These three parameters "capacitance, resistance and inductance" are the three component (parameters)  that make up for the "crossover filters"  in speakers.
And by halving the length of your VH 1st to 1/2mt you've changed all three parameters from what they were at 1mt.

This could be the difference you heard??

Cheers George 

They do say the VH First has a sound of it's own, and is not neutral. Maybe what you heard is just that with the 1/2mt, less of it's house sound getting closer to neutral.

Cheers George

Looking at your very nice system
https://systems.audiogon.com/systems/2186

Your D100 dac is no problem at 2v and 100ohms into the Lightspeed. And that at 2.5kohms using the 1mt of VH First at  61pF/mt is -3db at 1mhz!!. And your Belles Ref 150A needs only 1.4v in for full output at 100kohm input impedance which is no problem.

Looking at all this you have a prefect match up I can't see how there can be a difference between 1m or 1/2m of the VH First???

Cheers George

Using a passive I know in my case that there is a real noticeable difference when I go from a 1 meter cable to a half of meter cable.

If you hear this difference in length, either your interconnects are high capacitance or your passive or source is high output impedance.

Cheers George

alfa10069 posts04-07-2018 8:01amI do not have a preamp. MSB DAC direct into Pass Labs power amp. Previously it was Wadia DAC direct into Pass Labs power amp. Tried many preamps and always preferred no preamp.

Yes if you have a great source/s as you have had, this always seems to be the outcome.

If your source is not so great and needs some sort of colouration’s (tonal changes) to make it listenable, then a band-aid fix with a preamp can make things better, but picking the preamp with the right tonal colouration’s to fix the source is always a mine field, as all preamps sound different.

In my view it’s best to fix the problem (source), not to throw a band-aid on it.

Cheers George

It also explains why some folks report that using different interconnects makes a big difference in sound quality while others don’t hear a difference.

You welcome, and correct, always use quality low capacitance interconnects, with passives and you’ll get the closest to the proverbial  "The best preamp should sound like a piece of wire" sound.

Cheers George

It's always been said by audio designers as a gauge of how good a preamp is since the mid 1900's, when separates (preamp & poweramp)  entered into audio, that saying is:
  
"The best preamp should sound like a piece of wire"
  
ie: a like a direct source to amp connection.  


Cheers George   

If you have a solid state source like a CD player, quite often it has a coupling cap at its output

What Ralph mentioned about coupling caps above is not relevant these days, as nearly all solid state sources have been direct-coupled for years, only tubed sources may have this problem as they have a caps on the output.
But below tubed preamps have this problem at the other end of the system with some of today's low input impedance amps.  

All is not good a match with 99% of tube preamps with  low input impedance amps these days, many Class-D's, some First Watt's, some Pass Lab's and many others.

The coupling cap that's needed on the output of 99% of tube preamps can be too small for these amps I mentioned, which can be as low as 10kohm input impedance. 

This is not a good match and will roll off the bass very early, to the point of owners saying this "tube pre has little or no bass".
  
To fix this one can change the cap for a much larger uF one which can be a fitting issue in itself or revert to a not so good sounding bi-polar electrolytic cap which will be small

Cheers George 

I like 10kohm pots as passives, as the can be driven by just about any solid state source, just some high impedance tube sources have trouble, and being 10kohm as a voltage divider passive they have the lowest output impedance at worst (mid possition) around 2.5kohm.

With 2mt of poor quality interconnect with high capacitance at (100pf picofarad per ft) that 2mt is approx 650pf total

6.28 (2 pie) x 2500ohms (2.5k) x 650 (650pF) ee to the -12 1/x = gives a very respectable -3db point at 98khz! and this is the worst interconnect at 2mt at the worst mid volume setting.

So as you can see driving the capacitance of poor quality 2mt interconnects with a 10kohm passive at worst volume mid position of 2.5kohm Z is not an issue at all as we are at only -3db at a still very high 98khz!

With one meter of that same interconnect, it becomes -3db at 196khz!!

With one meter of better quality interconnect which has only 50pf per foot then the -3db is at 392khz!!!!   

Cheers George

The OP was asking about getting rid of the preamp in the case when the DAC has a volume control. In that case, there is no downstream volume control, and no need to provide a low impedance buffer for the interconnect, as the amplifier will take care of that.

This is correct, and the source having a digital domain VC it will have a low impedance output, probably lower than many preamps especially tube ones, and it will drive any interconnect just as well if not better.
Besides, driving interconnects with a 10kohm passive is not an issue either, unless the interconnects are"low quality high capacitance" and are 3mt or more long. I can give you the maths if you want. 

Cheers George

However, since the OP has all the tools to do the test for himself, he is best to answer his own question.

+1
I have always found that if you have enough gain for the loudness level you want or need, then going direct (with no preamp) has always been the most transparent, dynamic, least coloured way of listening to the source.
So long as the source is not a tube output, which can be high impedance, then you may get a impedance mismatch to your amp.

Nelson Pass made a preamp he loved called the Aleph L, which is passive until the volume control get’s to 3 o’clock, after which an active stage come in if you need more level, but as he says at a detriment.

Nelson Pass: " At the 3 o’clock volume control position, the Aleph L offers a direct path from input to output.
The only component in the signal path is wire and switch contacts.
At positions below 3 o’clock, the volume control functions as a precision passive attenuator using discrete resistor ladders.
Above 3 o’clock, active gain is added to the output signal in 2 decibel increments, for amaximum of 10 dB.
As a result, you suffer the effects of active circuitry only when additional gain is necessary."

Also a Nelson Pass quote:
" We’ve got lots of gain in our electronics. More gain than some of us need or want. At least 10 db more.

Think of it this way: If you are running your volume control down around 9 o’clock, you are actually throwing away signal level so that a subsequent gain stage can make it back up.

Routinely DIYers opt to make themselves a “passive preamp” - just an input selector and a volume control.

What could be better? Hardly any noise or distortion added by these simple passive parts. No feedback, no worrying about what type of capacitors – just musical perfection.

And yet there are guys out there who don’t care for the result. “It sucks the life out of the music”, is a commonly heard refrain (really - I’m being serious here!). Maybe they are reacting psychologically to the need to turn the volume control up compared to an active preamp."

Cheers George