Having played with several solutions I found the best is a 12 V 1 A switcher with the output voltage increased to 15 V, check the capacitors and if necessary replace with 25 V. I laid out a PC board that has a TC7662A inverter followed by a 79L12. Also on the board is a 7812 followed by a 7805. Putting them in series gives me good thermal distribution. In my opinion every thing else is an overkill. Working with very low noise PLL's I have found that getting rid of switcher noise is much easier than 60 Hz. There are other pin compatible alternatives to the TC7662A, even a 555 will work, just more components. Bert Kehren In a message dated 8/25/2012 8:10:07 P.M. Eastern Daylight Time, li...@rtty.us writes:
Hi The easy way to do a TBolt supply is to start with something between 15 and 18 volts. Regulate down to 12 and 5 with linear regulators. 7805's are fine for the +5. Something like a LT1764 might be better for the +12. The -12 supply is very low current and does not matter much. People have had good luck with voltage inversion chips off the +15 and then something like a 79L12. Bob On Aug 25, 2012, at 6:41 PM, Edgardo Molina <xe1...@amsat.org> wrote: > Dear Chris, > > Good afternoon. I am in the process of mounting my TBolt to a 2U 19" rack enclosure and was looking for a decent power supply. I found the Cisco unit and I am ordering a couple of them just in case. It would really be nice if I could have access to the diagram of the upgrade you did on yours to recreate the same performance from the Cisco unit. Please do not feel compromised if it is difficult to share. I didn't mean to be rude and if my note causes you any discomfort please kindly disregard it. I jumped into the thread because of experiencing the same doubts as the originator of it. > > Redondo Beach? I love visiting there whenever visiting my brother who lives in Rancho Palos Verdes. I would invite you lunch anytime just for the pleasure of meeting you in person. > > Thank you. > > Regards, > > > > > > Edgardo Molina > Dirección IPTEL > > www.iptel.net.mx > > T : 55 55 55202444 > M : 04455 20501854 > > Piensa en Bits SA de CV > > > > Información anexa: > > > > > CONFIDENCIALIDAD DE INFORMACION > > Este mensaje tiene carácter confidencial. Si usted no es el destinarario de este mensaje, le suplicamos se lo notifique al remitente mediante un correo electrónico y que borre el presente mensaje y sus anexos de su computadora sin retener una copia de los mismos. Queda estrictamente prohibido copiar este mensaje o hacer usode el para cualquier propósito o divulgar su en forma parcial o total su contenido. Gracias. > > > NON-DISCLOSURE OF INFORMATION > > This email is strictly confidential and may also be privileged. If you are not the intended recipient please immediately advise the sender by replying to this e-mail and then deleting the message and its attachments from your computer without keeping a copy. It is strictly forbidden to copy it or use it for any purpose or disclose its contents to any third party. Thank you. > > > > > > On Aug 25, 2012, at 3:26 PM, Chris Albertson <albertson.ch...@gmail.com> wrote: > >> On Sat, Aug 25, 2012 at 1:06 PM, Jerry <jster...@att.net> wrote: >> >>> I am using a Cisco supply 3 voltage supply for the T-bolt. Is there any >>> performance loss if the +12vdc rail and the -12vdc rail are off by a few % >>> in opposite directions, e,g +11.7 vdc and -12.3vdc ? >>> >>> The true nuts here on the time nuts list will tell you that the noise from >> a switching power supply is bad and that you need a regulated linear power >> supply. But for most practical purposes the Cisco supply is a good one. >> Being only slightly nuts myself. I use the Cisco supply but I built a >> small power adaptor board with matching connectors and some "pi" filters >> made with RF choke and capacitors. I realy don't thing the filters are >> needed but I wanted a connectorized installation and a small choke was as >> easy to solder in as a length of wire. >> >> -- >> >> Chris Albertson >> Redondo Beach, California >> _______________________________________________ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
