DIYAPASON-L Digest #377 - Saturday, September 1, 2001
Re: [Residence Organs]  Console progress
  by "Jane and Dave Whitmore" <>

(back) Subject: Re: [Residence Organs] Console progress From: "Jane and Dave Whitmore" <> Date: Sat, 01 Sep 2001 11:38:42 -0400   Hi Randall,   From your description it appears that you do not have a selenium = rectifier in your unit. A selenium "stack" is/was an early form of diode developed = in the 1920's to do what all diodes do. However, the technology at the time wasn't as good as it is today and selenium diodes were big and prone to failure. When they went they usually smelled like rotten eggs. They look like long stacks of disks or squares with spaces between the disks or squares. A typical rectifier might be 6" long with 2" diameter disks. They =   were often coated with some kind of enamel sealer.   The glass diodes you've seen are for small signal applications rather than =   for rectifying AC into high current DC. Small glass diodes won't handle very much current at all, probably a few ma at best. In your unit look for =   a diode that has a threaded connection on one end and is bolted onto the heat sink. That should be the baby!     >I have no idea what a "Selenium stack is" but I see no diodes of the type = I >am familiar with; the small clear glass deals on printed circuit boards. >There's 3 transformers, 2 long aluminum capacitors, a long coiled = resister >tube, 2 heavy aluminum heat sink plates with 2 diodes on each. >It is rated 120 VAC 8 AMP in , 5 AMPS cont, 10 AMPS max DC 10-15V >I have another rectifier from the Kilgen organ but it is a 220v jobbie = and >looks like it is from the 50s or earlier, less efficient as it says 12VAC = 10 >AMPS in. >I also have the one from the Moller which does work but the La Marche is = a >better unit and newer, it is putting out about 12, maybe 12-1/2 VDC with = the >voltage control tap on the 13V lug. >Seems to me a discussion on piporg-l a couple of years ago about the 90 = OHM >magnets and the voltages, that running 12 VDC stuff on 10 or 11 thinking = it >was better for the componet's life etc wasn't the case. >I'm wondering if I should run the voltage tap to the 14 V lug and see = what >the reading is and leave it there since I will be running more magnets = than >the Reuter organ this rectifier powered (thinking voltage drop and = additional >wire resistance)   I'm running my Wicks on 13.8 volts and the life of the magnets doesn't = seem to have been impaired. Response time with the Wicks DE magnets is better = at higher voltages but this may not be the case with your Moller action.   Good luck!   Dave in Vermont