bruce108
Head-Fier
- Joined
- Sep 19, 2006
- Posts
- 91
- Likes
- 10
Thanks, Tom, that helps.
Tomb,
Some time ago, there was a discussion between you and dsavitsk (I think) about low impedance cans and you mentioned the output impedance of the millet mosfet. I found it once and now, no matter what I search, I cannot seem to find it! What is the output impedance of the millet mosfet?
The important focus of the discussion was that Dsavitsk and I do not necessarily agree with the drive to super-low output impedance in an amplifier. It's one of the things that can cause Grado's to sound harsh, for instance. Dsavitsk thinks it has to do with some headphones having a high inherent damping. Apply such a headphone to an amp with very low output impedance and the result could be over-damping, which can lead to more distortion, not less. That may be the key to why everyone seems to think Grado's need tube amps (inherently higher output impedance). It has certainly proved out empirically for both of us.
In particular, this reminds me of the claims regarding the O2, and makes me really curious if those claims hold water given real-world, low-impedance cans. BUT, this thread is probably not the place for those considerations.
Regarding the Millett MOFSET-MAX amp, RA2L/R and RA4L/R call for a 1Kohm Metal Film Resistor. Is this a requirement, or can a 10Kohm Metal Film Resistor be placed here? What about a 1Kohm Carbon Film Resistor instead of Metal Film?
My next step in building my MOSFET-MAX is installing the VitQ caps I picked up from Beezar (http://beezar.com/catalog/product_info.php?cPath=24&products_id=68).
(1) My 1st question is: Do the VitQ caps have a polarity? I don't see any markings on the cap case nor have I been able to detect that either lead is connected to the cap case as suggested by other forums online. Does it matter which direction they are installed?
Also, on the subject of boutique components, my build is as follows:
CA2/CA7 = Elna Silmic II 1000uF 35V
CA8 = VitQ .22uF 100V
CA9 = Wima .22uF 250V
(2) My 2nd question is: Should I leave CA9 blank with my setup or go ahead and populate with the Wima cap?