CMoy and PPA - diyAudio
Go Back   Home > Forums > Blogs > My DIY projects
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
I returned to DIY electronics in 2009 after a 20 year pause by building a few kits to get in shape. This blog is for me to keep track of my progress.
Rate this Entry

CMoy and PPA

Posted 13th August 2010 at 09:37 PM by alexcp
Updated 6th April 2011 at 01:35 PM by alexcp (Added pictures)

Of course I built the ubiquitous CMoy. It was a big improvement over various built-in headphone amps (e.g. in a TV) and added headphone capability to where it did not exist (e.g. to a Playstation).

Encouraged, I built the PPA project with a Young-Jung power supply. The enclosures for both the amplifier and its power supply are from modushop.

On first power-on the amp oscillated at 12 MHz when connected to headphones. The oscillation was inaudible but clearly visible on a scope. A quick look at head-fi.org showed that PPA instability is not a new problem. I reduced the value of R11 (see PPA's schematic), which eliminated the oscillation and improved the sound. I replaced the recommended OPA627 with LME49710.

PPA is positioned as a high-end DIY headphone amp, and it is in this project that I felt how subjective "high-end" is. PPA is a nice amp, but a true high-end device like Musical Fidelity X-CANv8 simply blows it away.
Attached Thumbnails
Click image for larger version

Name:	IMG_2029.jpg
Views:	908
Size:	51.1 KB
ID:	200   Click image for larger version

Name:	IMG_2031.jpg
Views:	2886
Size:	69.5 KB
ID:	201   Click image for larger version

Name:	IMG_2033.jpg
Views:	1228
Size:	66.2 KB
ID:	202   Click image for larger version

Name:	IMG_2034.jpg
Views:	1503
Size:	72.3 KB
ID:	203  
Posted in Headphone amps
Views 2985 Comments 0
« BantamDAC     Main     Creek with a tweak »
Total Comments 0

Comments

 
Hide this!Advertise here!

New To Site? Need Help?

All times are GMT. The time now is 03:49 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Copyright 1999-2016 diyAudio

Content Relevant URLs by vBSEO 3.3.2
Wiki