justinsweber Posted May 29, 2014 Share Posted May 29, 2014 Months after building my 1st dedicated headphone amp I was plagued… yes I mean a pelage! with hum/noise issues… I think we tore the amp down 5 times trying simpler and more complex grounding sure that was the issue. Although the amp was on the website I didn’t have for sale until it was right. After consultation failed, I sent the amp out to friends much smarter than I… Seems the problem was solved by replacing 4 caps. The Kenzie headphone amp is based on the Darling circuit, offering no feedback, SET yuminess. Trying to bring this same sound I used the same power supply values… Normally this is where I go to town and make all sorts of crazy changes to get lower noise floors, and significant sonic improvements. We are not sure if the headphone specific transformers just needed more power supply filtering or we had a bad cap, but going from 47uf x4 to 100uf x4 with lower ESR has fixed the issue… We now have a headphone amp which is silent with even the most sensitive of phones. J Happy day. The amount of time and worry this caused was silly. $10 worth of caps…. Fudge…. I have a 300b project that haunted me like this. I discovered then that the caps were bad in the power supply. Lesson learned… assume nothing and always start with grounding or power supply. Quote Link to comment Share on other sites More sharing options...
CECAA850 Posted May 29, 2014 Share Posted May 29, 2014 Glad you figured it out. How does it sound? Spent much time with it? Quote Link to comment Share on other sites More sharing options...
joessportster Posted May 29, 2014 Share Posted May 29, 2014 Thats a pretty rare amp that can drive larger hard to drive cans and still be silent with IEM's I see lots of posts on Head-Fi concerning this issue, they are under the general impression that a tube amp will not work with IEM for tube noise reasons Glad you got it all figured out and it turned out to be a minor issue (not so minor figuring it out apparently) Now you have to take some time and post some listening impressions I am emailing you something for thought Joe Quote Link to comment Share on other sites More sharing options...
justinsweber Posted May 29, 2014 Author Share Posted May 29, 2014 Thanx everyone... I will have to put in on my own equipment... but I trust the work of who I sent it too... (Much smarter than I). Ill be needing to send it out to a few people for a listen. I do liek the purpose built nature of it. Quote Link to comment Share on other sites More sharing options...
Schu Posted May 29, 2014 Share Posted May 29, 2014 that is the Frequency Response on that unit? just curious. Quote Link to comment Share on other sites More sharing options...
justinsweber Posted June 1, 2014 Author Share Posted June 1, 2014 If memory serves me... it was ~ 12hz to 35khz @ 1db but I don't have my bech results... its in transit back... As soon as I get back... Ill put back on the bench. Quote Link to comment Share on other sites More sharing options...
joessportster Posted June 1, 2014 Share Posted June 1, 2014 Impressive......................It will be interesting to hear some of the reviews, I know Dean is in line with his B-5 Right ? Quote Link to comment Share on other sites More sharing options...
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