tropicalrips 0 Report post Posted March 19, 2004 (edited) my first attempt at building a regulated power supply it has dual 9v regulated output, the Cmoys sound great with this thing having 9v regulated power per rail does make them sound better i'm just happy it did not blow up when i turn the power on more update when i fit the whole thing into a case, i'm also planning an AC power version of either a buffered Cmoy or clone Edited March 21, 2004 by tropicalrips Share this post Link to post Share on other sites
hacknet 0 Report post Posted March 19, 2004 wow... looks cool... what chip did you use?LM7809/7909? Share this post Link to post Share on other sites
tropicalrips 0 Report post Posted March 19, 2004 nope, its some cheap generic chip AN7809 & AN7909 the big caps are Panasonic FC 50v 2200uF the small caps on the DC side are also panasonic there's 2 more diodes under the board connected to the DC output side Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted March 20, 2004 (edited) Post mine too... Using LM317 and 337, configure as slow start up voltage. Measured the noise is about 30mV pk-pk. Edited March 20, 2004 by jasonhanjk Share this post Link to post Share on other sites
tropicalrips 0 Report post Posted March 20, 2004 anyone else with other DIY power supply? all are welcome to post in this tread how much does the LM317 & LM337 cost jason? how to do a slow start-up Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted March 20, 2004 $1 each for the LM. In the pdf file for LM spec have the slow start up circuit diagram. Uses 2 transistor for the slow startup, good for audio as it doesn't pop when power up. Share this post Link to post Share on other sites
jtfoo 0 Report post Posted March 20, 2004 (edited) anyone else with other DIY power supply? all are welcome to post in this tread how much does the LM317 & LM337 cost jason? how to do a slow start-up I made a PSU for my PPA and MEtA42. It's switchable between 27Vdc and 24Vdc, for powering (meta @24VDC) and charging charging the batteries on the PPA(@27Vdc). I posted it back some while ago here, http://www.sgheadphones.com/index.php?showtopic=1297 Here's a pic Edited March 20, 2004 by jtfoo Share this post Link to post Share on other sites
jtfoo 0 Report post Posted March 20, 2004 Just a question,tropicarips, Can you still get 9Vdc after you loaded your PSU? I'm just speculating that with only 9-0-9 tranny, you probably get slightly above 12V after rectified. But taking to account of voltage drop across rectifier diodes, roughly 1.4V, you're left with around 11V. To regulate to 9V, there's a delta of only 2V or so, pretty low margin. A LDO regulator might do the job, but the normal regulator might find it tough. Share this post Link to post Share on other sites
tropicalrips 0 Report post Posted March 20, 2004 i measured the output of the PSU at 8.7 - 9v per rail, rail-to-rail is slighty over 18v. the readings remain the same with a basic Cmoy connected. i hav bought another transformer thats 12-0-12 @ 1amp, this should do the job better i hav also rewired my 634 buffered cmoy to run from this new configuration. this amp has 4 op-amps, 2x opa627 + 2x buf634 and it shuts down when a single 9v batt drops to below 8.4v. with the new PSU, its running happily now i just need to find a case tall enough to fit the transformer & board Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted March 20, 2004 How much is that torroidal? Share this post Link to post Share on other sites
tropicalrips 0 Report post Posted March 20, 2004 i was thinking of using the DAGNALL ELECTRONICS transformers, anyone tried this? will those encapsulated Toroidal transformers be better? Share this post Link to post Share on other sites
jtfoo 0 Report post Posted March 20, 2004 (edited) How much is that torroidal? Can't remember the exact cost, it's above $30 from Farnell. Actually I wouldn't need a toroidal, since the PSU is built on a separate enclosure. Toroid has low hum field which it good for for amps that has their PSU built in. But then kiasu, all good amps has them, so I got one. Edited March 21, 2004 by jtfoo Share this post Link to post Share on other sites
hacknet 0 Report post Posted March 22, 2004 are those blue blocks toroidals? i thought they we EI cores... but never mind, its said that toroidals are better as they don`t saturate so easily, thus better regulation and hopefully less heat. but becareful, many sub standard toroials blow up much faster than EI as the heat from the core doesn`t get out. Share this post Link to post Share on other sites
tropicalrips 0 Report post Posted March 22, 2004 (edited) finally fitted my PSU into a case most of the smaller cases were too low to fit the transformer, so had to settle for a bigger plastic case the 2 ultra bright leds are connected on the 2 seperate rails, so i can see it if one of them fails seen here with my lastest amp, the power connector is a 4 pin type mini din, looks like a S-video connector internal pics to come later Edited March 22, 2004 by tropicalrips Share this post Link to post Share on other sites
tropicalrips 0 Report post Posted March 22, 2004 internal shots of the PSU with a new 12-0-12v transformer Share this post Link to post Share on other sites
