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

[olds1959special]

I have a tube pre-amp and tonight I hooked up my DAC direct to my power amps bypassing the pre-amp. I'm using the digital volume control. Right now it is set at 40 to get moderately low volume levels, as it is late and I can't test higher volumes right now, but I'm enjoying the improved clarity. I'm not really sure why I thought I needed a pre-amp. The consensus is SMSL digital volume controls are reliable.

 

[boxerfan88]

By removing the pre-amp, one removes one more source of distortion & noise.

Pre-amp is only needed if one needs source switching feature, gain matching/volume control function, tonal distortion from the circuits used (eg. tube) or tone control.

 

[dualazmak]

I can easily do the both, I mean with or without pre-amp (integrated-amp) in my setup.

Nowadays, however, I prefer using HiFi grade pre-amp/integrated-amp after the multichannel DAC in my PC-DSP-based multichannel multi-SP-driver multi-amplifier fully active stereo audio setup; you would please find details of the latest system setup here #931 on my project thread.

In that post #931, I wrote as follows;
...., please let me emphasize again about the pros and merits of relative gain (i.e. tone) control not only in digital domain but also in analog domain using pre-amplifiers or integrated-amplifiers (in my setup). I recently wrote again in my post #56 on a remote thread like these;

Yes, as for safe and flexible tone controls (or I can say "relative gain controls among the multiple SP drivers"), my stance (policy) at least, is that we are encouraged to utilize the "best combination" of "DSP configuration in digital domain" and "analog domain tone controls using HiFi-grade preamplifiers and/or integrated amplifiers".

We need to note (and to respect for) that analog domain tone controls (relative gain controls among the multiple SP drivers) give no effect nor influence at all on the upstream DSP configuration (XO/EQ/Gain/Phase/Polarity/Group-Delay). I believe that this is a great merit of flexible tone controls in analog domain. We know well, on the other hand, in case if we would like to do the "tone/gain controls" only within DSP configurations, such DSP gain controls always affect more-or-less on "XO" "EQ" "phase" and "delay" of the DSP settings which will leads you to possible endless DSP tuning spirals every time; within DSP configurations, XO EQ Gain Phase and Delay are always not independent with each other, but they are always interdependent/on-interaction.

Just for your possible reference, my DSP-based multichannel multi-SP-driver multi-amplifier active system has flexible and safe analog level on-the-fly relative gain controls (in addition to upstream on-the-fly DSP gain controls) for L&R subwoofers, woofers, midrange-squawkers, tweeters, and super-tweeters, all independently and remotely. My post here shows you a typical example case for such safe and flexible on-the-fly analog-level tone controls. This my post (as well as this post) would be also of your interest.

Of course, I know well that I (we) can also perform such relative gain control using DAC8PRO’s 8-channel output gain controllers (and/or in upstream DSP "EKIO"). I do not like, however, to change the DAC8PRO’s output levels frequently on-the-fly (while listening to music) due to safety and inconvenience concerns; I like to keep DAC8PRO’s analog out gain level always at constant -4 dB which should remain to be usually “untouchable” in my case.

One of the very unique aspects/features of my multichannel audio rig is that I fully utilize four HiFi-grade “integrated amplifiers” plus L&R active subwoofers, each of them have its own gain (volume) controller for safe and flexible relative gain (tone) control in analog domain even on-the-fly i.e. while listening to music.

In this perspective, my posts #438 and #643 should also give you better understandings. Furthermore, my posts #317(remote thread), #313(remote thread) would be also of your reference and interest.

 

[Mnyb]

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 .

 

[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 .

I've never had either of SMSL DAC's act unreliably with the volume. The volume is displayed upon start up. I'm not sure adding attenuators would help the sound or hurt it? It's around 50% volume when it's at the loudest I need, and 25% when at low volume.

Maybe I should use two amps instead of four and cut my power in half, then the DAC could be much louder.

 

[Sokel]

Maybe I should use two amps instead of four and cut my power in half, then the DAC could be much louder.

In the case you bi-wiring nothing will be louder for 2 vs 4 amps.

 

[Mnyb]

Some had Topping DAC's to go full volume .

That said i used this strategy with active speakers from DAC's and streamers . I Just adjust the active speakers volume/sensitivitey so that 100% volume on the DAC is as loud as i ever want to go , for best signal to noise ratio. I test with a quit recording.

But with the incredible performance of modern DAC's it's probabaly a bit overkill , it's a risk of overthinking this .

 

[Willem]

I am using an RME ADI-2 DAC as a modern preamp, into a Quad 606-2 power amp and three subwoofers. I have an attenuation cable between the ADI-2 and the Quad because the latter has an old fashioned very senstitive input. I guess a modern low gain power amp would be better, but I doubt I will hear the difference.

 

[DSJR]

My regular preamps have a stereo chip (or two mono chips) with a minimum of extras in the signal path. As my power amps have gain controls on them, it was easy at the time to set overall gain and play the CD player directly. The preamps appear to make no subjective difference at all and, as I need input switching and a phono stage, I keep with their use. I suspect not many here have legacy analogue inputs, so a dac or streamer with variable output may be all that's needed.

 

[BeeKay]

Some HPA (DAC/HPA combos) come with a pre option (even XLR). If you need to drive headphones anyway this could be an option.

 

[Willem]

Some HPA (DAC/HPA combos) come with a pre option (even XLR). If you need to drive headphones anyway this could be an option.

Conversely, the REM ADI-2 DAC is an excellent HFA.

 

[Joe Smith]

I'm willing to trade a bit of noise/distortion for added safety. While most of my amps have integrated volume control, I would never use a digital source direct to an amp without some intermediary v/c.

 

[Willem]

Why would there be any difference between a DAC With volume control and a traditional preamp with analogue sources?

 

[olds1959special]

going direct from DAC to power amps sounds better (more clear) on my bookshelf system, bypassing the preamp I was using. If the volume was maxed it would destroy my speakers and my hearing, but I'm not sure why I should be worried about that. Turning up 1/3 on the DAC results in moderate volume. I'm going to try a passive volume control with Alps RK16, though.

 

[Joe Smith]

going direct from DAC to power amps sounds better (more clear) on my bookshelf system, bypassing the preamp I was using. If the volume was maxed it would destroy my speakers and my hearing, but I'm not sure why I should be worried about that. Turning up 1/3 on the DAC results in moderate volume.

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.

 

[olds1959special]

Sound quality is great going direct, but it doesn't sound as good at the lowest volumes. At 40 - 50 on the volume, the loudest I need, the sound is good. Considering that, I'm not sure I need a passive volume control, provided I trust my DAC to be reliable.

 

[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 the volume at 40-50 is that okay? 50 seems to be the loudest I need, and I feel the quality is good. I am going to try 12db attenuators too.

 

[LGD_]

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

 

[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 Sanaui 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 will try this. Thanks

 

[Mnyb]

If I play the volume at 40-50 is that okay? 50 seems to be the loudest I need, and I feel the quality is good. I am going to try 12db attenuators too.

Yes passive inline attenuators works tried them in the past . Fit and forget 10dB or 6dB migth have better tolerances .