VK Music  Elekit & Triode Japan Forum Welcome! Need support, you got it. Or share your ideas and experiences. 

In Reply to: RE: TU882R Headphone Amp  Possible Mods posted by Tweaker456 on April 11, 2016 at 23:49:03:
Hi,
Simply remove R1 and R2.
The two input caps have to be replaced by a link.
I left all PSU caps as standard including C12 and C13 but I may replace these with good quality Panasonic.
You must have made an error in the calculation  we've all done it! :)
Z = 1/ (2 x pi x F x C) where F is the frequency and C is capacitance.
Rearrange to:
F = 1 / (2 x pi x C x Z) where Z is the impedance.
At low frequencies we can totally ignore the small filter cap C7 and the miller capacitance of the output valve, so the load is just R13.
When the impedance of the coupling cap equals the load R13 (1 megohm), half the signal will be lost across the cap and half will appear across R13 (look on it as a potential divider). This gives  3 dB.
So use C = 0.047 / 1 000 000
Z = 1 000 000
and you'll get F = 3 Hz near as dammit and that's ideal.
RC coupling give phase shifts, roughly speaking these affect only up to about 10 x the 3db frequency, so there will be no appreciable effect above 30Hz (and nothing much to worry about above 15Hz).
Hope this helps; do ask about anything you are not sure about.
"The only silly question is the one that should have been asked but wasn't". :)
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
 RE: TU882R Headphone Amp  Possible Mods  Mike C 17:18:23 04/12/16 (6)
 RE: TU882R Headphone Amp  Possible Mods  Tweaker456 12:36:40 04/15/16 (3)
 RE: TU882R Headphone Amp  Possible Mods  Mike C 15:49:04 04/15/16 (2)
 RE: TU882R Headphone Amp  Possible Mods  Tweaker456 16:17:53 04/15/16 (0)
 RE: TU882R Headphone Amp  Possible Mods  Tweaker456 16:12:23 04/15/16 (0)
 RE: TU882R Headphone Amp  Possible Mods  Tweaker456 21:57:51 04/12/16 (0)
 RE: TU882R Headphone Amp  Possible Mods  Tweaker456 21:41:49 04/12/16 (0)