matbon0013 0 Report post Posted July 2, 2003 razerx, while you're at it try out the Plainview 9v Batteries maybe get it from JMT too, should be good! Reason discussed in length in the Plainview thread Share this post Link to post Share on other sites
N@Z 0 Report post Posted July 2, 2003 razerx, make sure you have a multimeter to check the output voltage as it might total more than 24V initially before it drops. Initially after charging my GP batteries read a little over 10V so 3x would equal over 30V. I point that out just in case it may cause problems with your op-amp. Good luck. Share this post Link to post Share on other sites
erickoh 0 Report post Posted July 3, 2003 Just a note to add, I believe the plainview default charger runs on 120V AC only. Your normal NiMH chargers may not work well on the plainview More Info Share this post Link to post Share on other sites
matbon0013 0 Report post Posted July 3, 2003 eric, is there any alternatives for 230v charger that you know for the Plainviews? Thanks! Share this post Link to post Share on other sites
razerx 0 Report post Posted July 3, 2003 JMT said he might need to rethink on the opamps to make this work. I am sure he has done this enough to make a sound (pun intended) judgement. Two 9v batteries would be under powered since rechargeables are only 8.4v and Plainviews are not available in Hong Kong. Three batteries should total around 25v but N@Z is correct that the opamps need to handle 30v just in case. Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted July 3, 2003 Use an opamp to maintain the voltage at 24V lol. The reference can be found at Gilmore amplifier design. Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted July 5, 2003 The circuit for the DC power supply is complete. Everything tested out ok and need to tune to +-12V. Now, where is that casing.... Share this post Link to post Share on other sites
Firefox 0 Report post Posted July 5, 2003 Correct. Building one good regulated power supply would be definately less than $50. Here is the cost: 1. transformer dual output $10.00 2. LM317 and LM327 $2 3. rectifier X 2 $1 4. Resistor $2 5. Cap $3 6. PCB $1 7. Connector $4 8. Metal box $10 Adding other Gilmore recommend part would add another estimate $50.00 I doubt it's that cheap. You'd want more caps on the input & output section. That would include film/foil & ceramic bypasses and relatively large E-caps (3300uF - 6800uF). Otherwise, the regulation won't be as good as a cheapo wallwart. Secondly, I think you meant LM317T (+Ve) + LM337 (-Ve). A design for a very good dual-voltage PSU would be the PS1 from Welborne Labs. You can scrimp and save on a few of the caps but the basic design is there. The LT regulators can be swapped for LM ones. Share this post Link to post Share on other sites
N@Z 0 Report post Posted July 5, 2003 Mat no problems getting the Stepdown converter. I was able to source them at Hua Ho Yayasan. They have 3 versions available. All automatically converts the frequency 50hz/60Hz. So if you wanna get the charger for the plainviews go ahead. Coincidently, the colour of the step down transformer matches the Plainview's charger too! The brand is the same as our current transformers. The shop also sold a regulated AC-DC transformer but expensive. Two is available $50 & $70 respectively. Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted July 5, 2003 Thanks for pointing the 337 out. Been days that I didn't notice I type wrongly. The input caps are ELNA 50V 3300uF and the output Panasonic 16V 4700uF with 0.033 uF bypass ceramic cap. The config is +-12V with the use of 2 regulator. Since voltage are relative, can be arrange as 0V & 24V. These are just good enough. If there is a need to add more better part, I would follow the Gilmore design where $50 extra is required. This is a cheapo power supply where 24V supply output can hardly be found in the market. The PS1 cost $140 (US?). If matbon don't like I still can use it for my upcoming PPA... Share this post Link to post Share on other sites
Firefox 0 Report post Posted July 5, 2003 Thanks for pointing the 337 out. Been days that I didn't notice I type wrongly. The input caps are ELNA 50V 3300uF and the output Panasonic 16V 4700uF with 0.033 uF bypass ceramic cap. The config is +-12V with the use of 2 regulator. Since voltage are relative, can be arrange as 0V & 24V. These are just good enough. If there is a need to add more better part, I would follow the Gilmore design where $50 extra is required. This is a cheapo power supply where 24V supply output can hardly be found in the market. The PS1 cost $140 (US?). If matbon don't like I still can use it for my upcoming PPA... I don't remember 50v, 3300uF Elna caps being so cheap.. At least not at $3.00 for 2 * Elna + 2 * Panasonic E-caps of those values. Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted July 5, 2003 It is a LP5 made from Thailand.. Share this post Link to post Share on other sites
Firefox 0 Report post Posted July 5, 2003 It is a LP5 made from Thailand.. Bought from SLT? I remember the cheap Elna's of that value priced at $2.00++ each. Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted July 5, 2003 Yes. Less than $1. You want I buy some, plan to go down on Monday. I think I saw some cerafine for less than 50 cents. Share this post Link to post Share on other sites
Firefox 0 Report post Posted July 5, 2003 I'm probably going down on Monday as well.. Just let me know what the shop's name is... hehe Share this post Link to post Share on other sites
