On Tue, 17 Feb 2009 08:00:24 +0200, Geoffrey S. Mendelson wrote: >The PS-7 is rated 25 amps continous power ouput. Note that it is split, >the output for the control electronics is very well regulated, the >output for the finals is not.
You must be looking at a different PS-7 than I am. :) It is a very well designed supply using the 723 regulator IC. Indeed, the reference supply for the 723 is a seperate source derived from it's own transformer winding, if that's what you mean. This is a plus. It also uses remote sensing at the output terminal of the high current series pass transistors for improved regulation. This is a very good design, reliable and robust. The only negative point is that the high and low current rails are not split up in the cable to the radio, as has been addressed by GW4ALG and others. Clearly the radio was designed this way, I guess the engineer in charge of the PS-7 missed that memo. If you really wanted to do it right, the remote sense feature of the regulator circuit could be extended to the radio end of the cable. Ripple spec is 3 mV RMS at 25 A load, not bad at all. GW4ALG's notes state that the PS-7 overcurrent trip point is 31 to 32 amps, this would suggest a peak rating of 30 A for the PS-7. The TR7 is specified to draw 3A RX, 25A TX. FWIW, I ran my TR7 for years from a SAY Electronics SPS-30, which is a super-cheapo supply (not 723-based, IIRC). Four pass transistors, very much like similar Astrons, with one fair-sized main filter. The rig ran fine, especially after I built my "premium" power cable. No complaints, although I did have to replace the main filter cap after many years of continuous use (it ran other stuff in my shack in parallel with the TR7). 73 -Jim -- Ham Radio NU0C TR7/RV7/R7A/L7, TR6/RV6, T4XC/R4C/L4B, NCL2000, SB104A, R390A, GT550A/RV550A, HyGain 3750, IBM PS/2 - all vintage, all the time! HyGain 3750 User's Group - http://groups.yahoo.com/group/HyGain_3750/ http://radiojim.exofire.net http://incolor.inetnebr.com/jshorney http://www.nebraskaghosts.org _______________________________________________ Drakelist mailing list [email protected] http://mailman.zerobeat.net/mailman/listinfo/drakelist
