[R-390] R-392 Power Connector

Roy Morgan roy.morgan at nist.gov
Tue Jun 14 11:20:13 EDT 2005 

At 07:26 PM 6/13/2005, Osamu Hazawa wrote:
>>you can run the R-392 at 24 with somewhat reduced performance while being 
>>more gentle on the tubes. ...
>24VDC power supply that I got from an auction is 24VDC version.
>So it won't whip the tubes. But I'll try to boost up to variable limit (25 
>or 26?)
>whether the perfomance changes or not.

Osamu,

The filament and plate connections at the power connector are separate (if 
I remember correctly).  So, you can increase the output of your supply to 
27.5 or 28 volts and apply this to the plate supply.  Then put some silicon 
diodes in series from there to the filament supply to drop the filament 
voltage down to the correct amount for the tubes for best tube life.  Make 
the diodes big enough to carry the filament current, whatever that 
is.  Figure 0.7 volts per diode.. using four as a test would be a good start.

Roy



>Osamu
>http://www4.ocn.ne.jp/~pomerol/MyPage/menu0.html
>----- Original Message ----- From: "Barry Hauser" <barry at hausernet.com>
>To: "Osamu Hazawa" <pomerol at mocha.ocn.ne.jp>; <R-390 at mailman.qth.net>; 
>"Tim Shoppa" <shoppa_r390a at trailing-edge.com>
>Sent: Monday, June 13, 2005 12:07 PM
>Subject: Re: [R-390] R-392 Power Connector
>
>
>>Hi Osamu
>>
>>Some follow-up -- see my comments:
>>
>>>Actually, I have some "Quick Disconnects" connectors in my junk box,
>>>and I was going to use them. But alas, they are naked, without any 
>>>insulation. So heat shrinkable tube
>>>work is needed (I hate it!).
>>
>>Well, the good news is that you can solder them.  If you don't want to 
>>use heat-shrink, you can "borrow" the insulation from some heavy wire and 
>>stretch it over the connector and lead.  I have also resorted to using 
>>pieces of plastic soda straw.  Regular ones might be too large in 
>>diameter, but the small ones that come glued to the side of those small 
>>drink cartons or the "little milk" cartons that don't have to be 
>>refrigerated -- might be the right size.  Of course, I don't know the 
>>dialectric/insulating properties of polyethylene soda straws, but ...
>>
>>You can also coat the connectors with silicone sealer which is flexibile 
>>when it cures so will expand with the connector.  Also very tough.
>>
>>>
>>>So, as Barry advised me, I'll try "Butt Splices/Connectors" or "Fully 
>>>Insulated Quick Disconnects". Any DIY stores might have them.
>>
>>Yes, they're pretty common.
>>
>>>
>>>Yes, after I confirmed that the R-392 is up and running, I eventually 
>>>have to buy "that" connector for safety purpose and  a finished look.
>>
>>Couple of other things.  Probably just as important as the connections 
>>themselves is to provide some kind of strain relief.  Loop the power 
>>supply wires below the connector and use a nylon wire tie or wire clamp 
>>(no doubt they are in your junk drawer/box, left over when you bought a 
>>packet of five and had 3 left over. ;-)  What you want to avoid any 
>>chance of is snagging the supply cable and causing it to pull off the 
>>R-392 and possibly shorting your power supply.
>>
>>I forgot the exact pinout on the R-392 for the DC supply -- nominal 24 
>>volts (24 v. vehicular power is just under 28 when the engine is running 
>>fast enough).  There are three relevant connections:  A single ground and 
>>two 28 v inputs -- one for filament and one for B+.  The usual practice 
>>is to strap the two together -- usually at the p/s end of the supply 
>>cable. However, it has been written that the R-392 is optimized with 
>>something higher than 28 on the B+ -- like 32 vdc as I recall, however 
>>the filaments are best run at no more than 24 to maximize tube life.  It 
>>may not be worth the bother to build a special P/S or use two supplies, 
>>but you can run the R-392 at 24 with somewhat reduced performance while 
>>being more gentle on the tubes.  I think I have conveyed this 
>>accurately.  If I'm wrong, someone please correct me.
>>
>>Barry
>>
>>
>>
>>>
>>>Regards,
>>>
>>>Osamu Hazawa
>>>http://www4.ocn.ne.jp/~pomerol/MyPage/menu0.html
>>>
>>>----- Original Message ----- From: "Barry Hauser" <barry at hausernet.com>
>>>To: "Osamu Hazawa" <pomerol at mocha.ocn.ne.jp>; <R-390 at mailman.qth.net>
>>>Sent: Monday, June 13, 2005 1:16 AM
>>>Subject: Re: [R-390] R-392 Power Connector
>>>
>>>
>>>>Hello Osamu
>>>>
>>>>There are two types of crimp-on connectors I've used and a possible 
>>>>third. One type is a "butt" connector.  This is the kind that is used 
>>>>to splice two wires together. You crimp the wire side and slip on the 
>>>>other. They usually come with insulation which extends beyond the 
>>>>metal. The receiver side needs to have that trimmed.  At first it will 
>>>>be loose, so you use the crimpers to make it a little smaller and 
>>>>test-fit until it is snug enough. The insulation on the butt connector 
>>>>prevents shorting to the other pins in the R-392 panel connector.
>>>>
>>>>The second kind is a round "snap" connector that comes in mail and 
>>>>female, often used in automotive installations.  The male version has a 
>>>>taper to it -- a narrow spot that snaps and holds in the female one. 
>>>>They usually have blue or yellow transparent insulation. You'd need the female.
>>>>
>>>>I haven't tried this, but you might also be able to use modified 
>>>>"Molex" connectors.  These are the nylon multi connectors also used in 
>>>>automotive applications, but most familiar as the 4-conductor versions 
>>>>used in computers to supply power to the hard drives, CD-Rom drives, 
>>>>etc.  If you have some of these around, you can try cutting them 
>>>>lengthwise to separate them into individual units.  You can also pick 
>>>>up two-conductor Molex connectors and, it might be that the spacing 
>>>>will allow connection to two of the pins in the R-392 jack.  Or you can 
>>>>remove the metal terminals inside (they float around a bit), solder 
>>>>them onto the supply leads and use heat shrink tubing to insulate them.
>>>>
>>>>First step is to look around in your junk box.
>>>>
>>>>Of course, another approach is to use alligator clips with the 
>>>>insulating boots, making sure that the boots are pushed forward.  Then 
>>>>use tape to keep them from accidentally getting pulled off.  This is 
>>>>the messiest.
>>>>
>>>>You'll probably want to go for the connector eventually to keep things 
>>>>solid and professional looking.  Have you checked with William Perry? 
>>>>His prices are supposed to be reasonable, but it could be expensive 
>>>>with the shipping to Japan.
>>>>
>>>>To make things clearer, here are the links to the terminal types on the 
>>>>Radio Shack web site
>>>>
>>>>Butt connectors:
>>>>http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=64-3037
>>>>
>>>>These are the round crimp on terminals:
>>>>http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=64-3086
>>>>
>>>>Here is a two conductor female "molex" -- Radio Shack calls them 
>>>>"interlocking" connectors:
>>>>http://www.radioshack.com/product.asp?catalog%5Fname=CTLG&product%5Fid=274-154
>>>>
>>>>You probably have other electronics stores that carry these.  Probably 
>>>>all are also carried by auto parts stores.  If you have one of those 
>>>>Check the diameter of the R-392 power connector pins.
>>>>
>>>>Sometimes you can find a plastic bottle cap that will fit over the 
>>>>outside of a mil connector -- maybe even a green one ;-).  Then you can 
>>>>use that to provide a finished look to it.  Of course, if you're 
>>>>concerned about that, even after the creativity, you'll probably go and 
>>>>order that $30 connector.
>>>>
>>>>Hope this helps
>>>>Barry
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>----- Original Message ----- From: "Osamu Hazawa" <pomerol at mocha.ocn.ne.jp>
>>>>To: <R-390 at mailman.qth.net>
>>>>Sent: Sunday, June 12, 2005 3:54 AM
>>>>Subject: [R-390] R-392 Power Connector
>>>>
>>>>
>>>>>Hello All,
>>>>>
>>>>>I'm still thinking about how to do with the power connector ( 164-4FS).
>>>>>A source ask me $30 for the connector, so "making" the connector by
>>>>>myself would be the best.
>>>>>
>>>>>If so, what receptacle contacts would suit for the pins?
>>>>>I recall someone advised it before but I lost it after I drunk some 
>>>>>shots of
>>>>>"Wild Turkey"(Rare Breed) :-)
>>>>>
>>>>>Osamu Hazawa
>>>>>
>>>>>_____________________________________________________________
>>>>>R-390 mailing list
>>>>>Home: http://mailman.qth.net/mailman/listinfo/r-390
>>>>>Help: http://mailman.qth.net/faq.htm
>>>>>Post: mailto:R-390 at mailman.qth.net
>>>>>Unsubscribe: http://mailman.qth.net/mailman/options/r-390
>>>>
>>>>
>>>
>>>
>>
>>
>
>
>_____________________________________________________________
>R-390 mailing list
>Home: http://mailman.qth.net/mailman/listinfo/r-390
>Help: http://mailman.qth.net/faq.htm
>Post: mailto:R-390 at mailman.qth.net
>Unsubscribe: http://mailman.qth.net/mailman/options/r-390

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
Home: 301-330-8828 Cell 301-928-7794
Work: Voice: 301-975-3254,  Fax: 301-948-6213
roy.morgan at nist.gov --

More information about the R-390 mailing list