Passive Pre-Amp into Integrated Amp to Prevent Clipping?


On my previous system (DAC -> active speakers), I had some serious issue with clipping, even at low volume (volume was controlled by the active speakers). So I solved that by sticking a passive pre-amp (Schiit Sys which is a pot-based passive attenuator) in between the DAC and the active speakers. I used a 0 dbFS 60 Hz sine wave test tone (60 Hz because I would be sure my Fluke TrueRMS multimeter would measure it accurately since the Fluke is mainly used for home AC power applications) from my PC into the DAC-Preamp chain and measured the RCA output level with the multimeter at the SYS outputs. Then I turned the SYS volume down from 100% (measured 2 Vrms) until the multimeter measurement matched the active speakers’ input sensitivity (750 mVrms). Never touched the SYS volume knob again (I used the active speakers’ volume knob for adjusting listening level) and never had any clipping issues afterwards. And as they say, the rest is history. (Actually, if anybody has any feedback on my methodology, that’d be great).

Not quite. I finally decided to upgrade my system to one with passive speakers. The system I decided to go with is a Yamaha R-S202 stereo receiver with ELAC Debut 2.0 B6.2 speakers. The DAC hasn’t changed. (It’s an old DIY Ross Martin 24-bit DAC I was gifted from a friend. I don’t think Ross Martin is in business anymore because his website is down.)

The Yamaha receiver, being an integrated amp, already has a built-in pre-amp (I do not know if it has an active pre-amp stage or simply a passive volume control upstream of the power-amp section - does anybody know?). The spec’ed input sensitivity is 500 mVrms. Given that I had clipping issues with the old active speakers, which had a sensitivity of 750 mVrms, I assume that my clipping issues would get worse if I go DAC -> Yamaha?

Do I need to stick the SYS in between DAC and Yamaha (calibrate SYS volume to 500 mVrms output and do not change so I can use the full range of the Yamaha’s volume knob for adjusting listening level without ever clipping)? Would there be any disadvantages with respect to sound quality?

I did check the chain for proper impedance bridging. The minimum damping factors I calculated would be SYS/DAC = 13.74 and Yamaha/SYS = 17.74 so I wouldn’t be running into many issues with frequency roll-of. I’ve frequently come across the statement that damping factors > 10 is a minimum and >20 is best. Would there be any issues with respect to sound quality using damping factors between 10 and 20?

Thanks.
carlosaudio51
I guess that’s what I get for being a cheap audiophile. I'll keep the SYS in the chain.

I’m already saving for a future system (<$2,000) with separates (DAC -> pre-amp -> power amp -> speakers). Hopefully the future system will be made of quality-designed components so I won’t have this issue.

Anyway, thanks for the responses.


A very nice system can be had for under $2000. If you enjoy the Elacs I would keep them and purchase an quality integrated amplifier and a more modern DAC. Both could be purchased as recent production models, however used.   

I also own a SYS and use it as a passive preamp with a NuForce STA 200 amplifier (currently selling for $400).  
Yeah, I'll definitively be looking at other forum posts for suggestions on the components for a $2000 system in the future.
2V is exactly the standard for DAC's into RCA's.

No modern receiver will have a problem with that.
OK. What do you think is happening on my system? If I go DAC -> receiver I have clipping even at low volumes (20/100). If I add the SYS before the receiver and reduce the volume to about 3 o'clock, the clipping is gone.