What songs are you hearing the bass distortion on?
I'm amping my T90's with a bottlehead crack and I've heard some distortion in the bass and high end on a few songs at super loud volumes. I don't usually listen super loud but hey.. new headphones you gotta see just how clear and loud they can be :)
Specifically I can hear distortion in the beginning of Daft Punk's "Give life back to music" every time the kick hits in the first 16 seconds . Not sure if the distortion is being caused by overdriving the T90's or if they're just so revealing I'm hearing digital clipping in the recording.
Anyone else wanna run a little test with this track and lemme know if you get the same results?
What tubes are you using for the 12AU7 and 6080 or 6as7? Where is the volume knob set using an analog clock face as a reference from 7 o'clock to 5 o'clock? What DAC?
T90 on my Crack, RCA clear top 12AU7, Osram A1834, Daft Punk GLBtM first 16 seconds measures as follows:
8:00 78 dBC 68 dBA - this is where I would normally listen
9:00 90 dBC 80 dBA - this was as loud as I could handle
11:00 98 dBC 88 dBA - really LOUD
Now the above is only part of the information. To compare you also need to know the signal level sent by the DAC to the amp when either a 440 or 1000 Hz, 0 dBFS sine is played. In my case that has been set as follows:
All three mean the same thing but are different ways to represent the signal level.
I only listen to DP a little, and usually with the volume much lower than others listen.
Here are some screen shots from the Digital Audio Workstation for the first 20 seconds of DP GLBtM:
Above you can see the kick hitting near the digital limits
Zoom in to see how much time is at the digital limits
Zooming in again and the left channel, while technically a few samples below the limit, does have multiple samples that are flatline. This is self imposed clipping just below the digital limits so an analysis will show no clipped samples, which indeed the DAW stats showed no clipped samples. But there is clipping below the digital limits.
Edited by atomicbob - 2/14/14 at 4:38pm