I’ve seen this mentioned years ago, but there doesn’t seem to have been a definitive answer.
My DAC outputs 2.2v and my Heed amp says it has a sensitivity of 250mv but I can barely get the volume control up more than one notch. I was wondering if digital volume control using a negative headroom of say -10db would be preferable to using a pair of attenuators of the same value? Years ago i did try these but I thought they robbed the sound of life, maybe it was my imagination!
Thanks @Nic that’s a great thread with loads of advice, loads of conflicting opinions as well! I’ve just dialled in around 15db of negative headroom (well I’ve got one band of DSP to remove a bass peak at 47Hz and that has a 2db reduction as it was clipping - so I actually set the headroom to -13db) and exactly like you I can now get the volume knob to just over 9 o’clock.
I’ve some 10db Rothwell attenuators I had for another system ages ago and I’ll try them in the morning (it’s a bit late now for playing with possibly loud volumes!) but like I said last time I used them I felt they sucked the life out of the music… maybe it was imagination?
Edit: Just tried them and I am sure they slightly dulled the treble, now my system is bright and I have been trying to tame it, now I’m just wondering if the brightness has been a result of preamp overload all the time? And that the perceived slight dimming of that brightness is actually the Rothwells working properly? Oh dear what fun! Also they can’t be left in place as there isn’t room at the back of my rack as they cause the cable to hit the wall - but I see they do a ‘for source’ version wired in reverse for that very issue - a sign maybe! Think I’ll order some anyway and see…
@Judelow yes I’m craving a tube amp, I’ll start some research!
Funny thing is I just tried the optical toslink input into the DAC (It’s a new DAC I’m just setting up) for the first time as it’s attached to the TV and I could get the volume up to nearly 10 o’clock without negative gain?
Different attenuators were tested here. I felt there was an impact on dynamics. And always send them back. Same feeling with headroom.
Until, I received a pair of 12dB DIY. The guy tested from 0 to 30khz with an analyser showing no impact at all on frequencies. With this pair, no issue on the music. I don’t use them any more, if you are interested feel free to mp(I still have the measurements results as well).
Thanks @Judelow I’ve ordered a pair of 15db Rothwell’s so I can make a proper comparison with none, headroom and attenuators - I’ll let you know if I don’t get on with them - thanks again!
Just to finish up here, the Rothwell -15dB attenuators are in place and I can’t hear any loss of dynamics or rounding off in the treble - and at last my volume knob can actually get to 11 o’clock!
(I hadn’t realised that 250mv input sensitivity was actually .25 of a volt!! What ridiculous input spec to release an amp with in these days of typical 2 volt outputs [I notice the latest V3 has upped this to 500mv] - even if it does sound so lovely as the Heed!)
I’ve just dialled in around 15db of negative headroom (well I’ve got one band of DSP to remove a bass peak at 47Hz and that has a 2db reduction as it was clipping - so I actually set the headroom to -13db) and exactly like you I can now get the volume knob to just over 9 o’clock.