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I don't like to "voice" systems or paying tons of money for a tube dac/amp with 10% distortion above 1khz.
In my opinion, amplifiers should be neutral and powerful, I like balanced solid states designs, pure class A with no feedback, like Gryphon amps for example.
For example "009 sounds harsh", solution: get 007 or another headphone, the problem is 009 not the partnering equipment.
That's my opinion of course, not the universal truth.
The BHSE (and I presume DIY T2) has extremely low distortion across the audio band. Justin published some BHSE (though a tube/SS hybrid) distortion numbers a while back -- even without comparison to other amps, they were extremely impressive numbers; no 10% THD in sight. Very impressive especially considering the 54-60dB of gain in an electrostatic amp:
Originally Posted by justin w.
I have measured the first BHSE produced in the current batch (not under test in the photo)
Equipment for THD testing: Tektronix TS-4353/U distortion test set (SG505 MOD WQ, SG505 MOD WR, AA501A MOD WQ)
Results @ 100Vrms w/ SR-404 load, RCA input to amp w/ 1.55Vrms sine wave
the 30khz low pass filter was enabled, the 400hz high pass filter was not enabled, which would have improved the results
Don't remember if this was the left or right channel however both were near identical
100hz - .003%
1khz - .0032%
5khz - .0058%
7.5khz - .007%
10khz - .0078%
15khz - .0049%
20khz - .0051%
20khz - .015% (with 30khz low pass filter disabled)
Results not comparable to any other amp measured by any other equipment at any other time.
And I've found that I do much prefer to have tube amplification somewhere in my 009 chain. And no harshness in the BHSE/009 with British/Mullard EL34 tubes. But I have heard harshness w/ the 009 in certain other all-SS amps, which I'm pretty sure would measure higher in THD than the BHSE.