{"id":59,"date":"2011-06-10T05:22:42","date_gmt":"2011-06-10T05:22:42","guid":{"rendered":"https:\/\/peterklemperer.com\/blog\/?p=59"},"modified":"2016-11-27T04:26:10","modified_gmt":"2016-11-27T04:26:10","slug":"cmoy-headphone-amplifier-part-2","status":"publish","type":"post","link":"https:\/\/peterklemperer.com\/blog\/2011\/06\/10\/cmoy-headphone-amplifier-part-2\/","title":{"rendered":"Cmoy Headphone Amplifier, part 2"},"content":{"rendered":"

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Tonight I made significant progress on my Cmoy amplifier. It makes promising noises now but it’s noisy and generally is not super-awesome sauce. I think I’m going to lay out a PCB design for it and assume that most of my problems are due to my horrible assembly practices. \u00a0I’ve got enough parts for one more I think, so that should be ok to do without too much cost at Digikey.<\/p>\n

When I put it down I was having a problem with one ear working only intermittently. \u00a0Today I start checking the circuit for symmetry and I found that the IN+ on the right side was reading 100K ohm but the IN+ on the left side was only reading 80K ohm (to ground, spec is 100K). \u00a0I desoldered the connection between the resistor and the DIP connector and when I reconnected it was reading 99.7K. \u00a0Given how jankily this whole point-to-point setup is, I’m pretty satisfied. That fixed most of the balance issues. \u00a0It’s still got a bit of an issue. I think it’s due to the power supply resistors that split the 9V battery voltage for the floating ground are not terribly balanced (junk-drawer-specials).<\/p>\n

I also disconnected the volume adjustment pot. I think I smoked it’s case when I was hooking up the leads. \u00a0It just occurred to me that having something a 10K path to ground from the input will probably have a good effect on the pop and hiss even though I’ve decided that I don’t want volume control. \u00a0Better check out the junk drawer. EDIT: Yop, that was it.<\/p>\n

One other modification I’d make if I were doing this again would be to add some sort of soft-start. When I flip the power switch a loud pop occurs as the cap’s fill up. Sounds like ass and can’t be good for my headphones either.<\/p>\n

In conclusion, I want this project done, so I’m going to drill the front panel and mount this up. Hopefully I’ll revisit this again soon because I don’t think it’s going to perform very well at work with my nice headphones.<\/p>\n","protected":false},"excerpt":{"rendered":"

Tonight I made significant progress on my Cmoy amplifier. It makes promising noises now but it’s noisy and generally is not super-awesome sauce. I think I’m going to lay out a PCB design for it and assume that most of … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":false,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[21,6],"tags":[],"class_list":["post-59","post","type-post","status-publish","format-standard","hentry","category-cmoy-amplifier","category-projects"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_shortlink":"https:\/\/wp.me\/p1VqWo-X","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/posts\/59","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/comments?post=59"}],"version-history":[{"count":0,"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/posts\/59\/revisions"}],"wp:attachment":[{"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/media?parent=59"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/categories?post=59"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/peterklemperer.com\/blog\/wp-json\/wp\/v2\/tags?post=59"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}