Bypassing pre-amp (direct from DAC to power amps)

[olds1959special]

In my case at least, there's a clearly audible SQ improvement when going direct into my Power Amp.
But I would strongly advise against using just your DAC's volume control ! One mistake, and you've blown your speakers - and maybe your ears, lol.
This is what I'm doing:

I use a totally passive volume control, at my listening chair, between my DAC and the power amp input of my Sansui AU-9900. (bypassing it's switching and tone controls)
It is just a dual 50K ohm pot - no electronics in it.
I feed the the DAC's output to and back from the vol control through approx 15ft of Canare cables that I made up for this.

It works fine, there is no audible SQ degradation at all from cables length , and it's so nice to just reach over from my chair to adjust volume.

https://www.amazon.com/dp/B07GRLV7XG?ref=ppx_yo2ov_dt_b_fed_asin_title

I got a Mackie Big Knob passive for this purpose and it seems to be working.

 

[olds1959special]

Revisiting this: I wasn't happy with the sound quality using the Mackie Big Knob, or my THX AAA 789 as a preamp. I decided to try direct again. I use a pair of splitters to send to my subwoofer also. Right now I'm listening at the level of 40 and I think the sound is actually better than ever before. It's an SMSL DAC which has never been unreliable with the volume control so I think I can keep using it this way without any issues.

 

[Chrispy]

Revisiting this: I wasn't happy with the sound quality using the Mackie Big Knob, or my THX AAA 789 as a preamp. I decided to try direct again. I use a pair of splitters to send to my subwoofer also. Right now I'm listening at the level of 40 and I think the sound is actually better than ever before. It's an SMSL DAC which has never been unreliable with the volume control so I think I can keep using it this way without any issues.

Makes me wonder more about your definition of "sound quality" than anything else.

 

[olds1959special]

Makes me wonder more about your definition of "sound quality" than anything else.

I guess that's something you have to use your ears for. If it sounds better, that's sound quality! Maybe it’s subjective though.

After listening for a few hours going direct, I really like the clarity.

Since I listen at 50% most of the time, I don't think the volume setting is unreasonably low. Also, in the case of running the DAC at full output accidentally, I'm not sure it would be enough to damage my speakers (or ears?) realistically. The Elac Debut 2.0 B6.2 are rated for 120 watts, and my amps are 100 watts.

I pretty much trust the reliability of my SMSL DAC's, I have two of them and they always remember the volume setting. They also display the volume upon startup.

 

[olds1959special]

my DAC started buzzing in the right side just like in my other system, or I just noticed it, so I'm using my headphone amp as a pre amp again.

 

[olds1959special]

I am no longer hearing the buzz. Not sure what caused it. After trying my headphone amp as a preamp again, I went back to direct from DAC. Nominal volume is at about 50% and the sound is better.

 

[olds1959special]

Beware of a proper gain scaling so that the volume makes sense from the DAC . power amp or speakers with adjustable gain is a big help or inline attenuators if needed .

Also software volume can go very wrong depending on implementation ( we all heard things go full volume for no apparent reason ) , so many users have a preamp for the sole purpose of having a dumb pot protecting the speakers .

If I play around at around 50% volume on average, does that make sense?

 

[Mnyb]

If I play around at around 50% volume on average, does that make sense?

What’s the signal chain , which DAC model and what power amp ?

 

[olds1959special]

What’s the signal chain , which DAC model and what power amp ?

SMSL DL200 to Kenwood L-05M mono blocks. I use splitters going to a subwoofer too. Elac Debut 2.0 B6.2 speakers and SUB1010.

 

[Luvchampagne]

SMSL DL200 to Kenwood L-05M mono blocks. I use splitters going to a subwoofer too. Elac Debut 2.0 B6.2 speakers and SUB1010.

Might be your splitters. I also removed my Krell preamp when I saw the measurement differences using REW. But, I was using a RME ADI2 DAC FS which has a great volume control and auto adjustment system to maximize S/N as volume adjusts. Tried doing this with my SMSL SU9 and the measurements were not the same. Should have been but were not. I did have to experiment with cabling to get rid of hum as I was splitting the signal to subs and amps.

 

[olds1959special]

As long as you're sure your DAC can't accidentally/electronically revert to 100%...you'll be ok. It just depends on how the DAC is designed. As noted above, some Topping owners have fried their speakers when the DAC accidentally got reset to deliver full volume.

The other option is to get a cheap pre with very low noise (example: Fosi P4), or to just use a fully passive preamp between them (v/c with resistors). I have a small custom built passive that works well that I spent about $100 on. They are found as cheap as $30 and of course, go up from there to whatever you want to pay for additional gold and fairy dust.

I recently added both the Fosi P4 and the Schiit Saga 2 preamps to my kit, and they both well as low noise and lost cost preamps, and give me the advantage of source selection and a remote. The Fosi is the better value, but the Saga has a much more precise volume control, especially for lower volumes.

I just ordered a P4. I plan to roll the op-amp.