jtfoo 0 Report post Posted October 18, 2003 Finally completed the PPA project. i.e. giving meaning to the middle 'P' of the PPA. Actually doing up the battery board was much harder and health hazard than the amplifier board. Got myself cut in the process. But it's worth it. I also have to build a external power supply unit(PSU) to give the non-standard 27Vdc. The PSU is based on Wellborne PS1 layout. There's slight variation in parts and I added a 1uF reservoir cap. Another variation is I added 24Vdc so the PSU can power the Meta42 too. Some parts differences from the Wellborne are, Rectifier diodes - Schottky diodes (BYV10-60). They have very low forwarding voltage. I measured them to be about 0.18V to 0.2V. Snubber caps for diode, WIMA MKS3. 10nF ELCO- 3X Elna ToneREX(2200uF) and 1x Elna Silmic(100uF). Bypass - 0.1uF film cap from Rifa Evox, Reservoir cap - 1uF polyester cap from Rifa Evox. What made the PSU a audiophile PSU is the hot glue isolating the PSU board from the chassis. This reduce vibration and reacts with resonance in many good ways Share this post Link to post Share on other sites
Northern Oak 0 Report post Posted October 18, 2003 jtfoo, Was the Tonerex you've got rated at 42V? Share this post Link to post Share on other sites
jtfoo 0 Report post Posted October 18, 2003 The porn of the PPA with battery board.. Fast charging time suppose to be 2.3 hrs.. But initial fast charge took 3hrs 10 min to go into trickle mode. And here's the charging in process with all LED lighting up, Share this post Link to post Share on other sites
jtfoo 0 Report post Posted October 18, 2003 Yes, rated at 42V. Fromour friendly KOBA store.. You have them too? Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted October 18, 2003 Nice.... How's your buffer temperature at 24V. mines about 50C. Share this post Link to post Share on other sites
Northern Oak 0 Report post Posted October 18, 2003 I was about to buy them only to realise through ELNA's catologue that no such rating exists. Thus it got me wondering the genuity of the components. Share this post Link to post Share on other sites
jtfoo 0 Report post Posted October 18, 2003 (edited) I was about to buy them only to realise through ELNA's catologue that no such rating exists. Thus it got me wondering the genuity of the components. Jialat.. Hope the ELCO caps won't blow .... But I'll leave them there just yet. JAson, I don't have the means to measure temperature... I'll try and see if those thermometer from the SARs kit can do. Edited October 18, 2003 by jtfoo Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted October 18, 2003 I got 2 thermo from my SARS kit... Mine felt hot but touchable. Had add 3 heatsink at the buffer and looks pretty, too bad no camera... Share this post Link to post Share on other sites
N@Z 0 Report post Posted October 19, 2003 That's alot of AAs! Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted October 19, 2003 AAAs lah... Share this post Link to post Share on other sites
jtfoo 0 Report post Posted October 19, 2003 The PPA needs all those AAA to give a decent voltage for the opamps to work optimally. With 15 cells, that's about 18V nominal, but can reach 21V for freshly charged batteries. Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted October 19, 2003 Hmmmm, after I adjust the voltage to 15V and the buffer becomes luke warm. This is important for portability as the hotter it gets the faster the batt used it's power. It also ensures the working life of the component. Now doing some serious listening to determine whether the music becomes better or worse before I built the final power supply. This would take sometime around december before I can complete both the AD8210 and the OPA637 version. Share this post Link to post Share on other sites
jtfoo 0 Report post Posted October 20, 2003 Then you'll need 12 AAA batteries for 14.4V. A fully charged can reach 16.8V. Share this post Link to post Share on other sites
dvdweide 0 Report post Posted August 6, 2011 (edited) **MOD WARNING** Please don't try to post WTS any where. Edited August 7, 2011 by heady Share this post Link to post Share on other sites
