Umbilical cords?

Discussion in 'Tube Audio' started by Selmerdave, Jun 10, 2018.

  1. Selmerdave

    Selmerdave Well-Known Member

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    Are there any ready-made options for umbilicals? I know the DIY market is small but seems like something that would have some customers if not stratospherically priced...
     

     

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  2. primosounds

    primosounds Parallel single ended EL84 ,EDCOR OPT

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    Not really, unless you are looking to replace something in an organ. Most DIYer will be using connectors of their choice and not many builder make a 2 chassis amp with a separate power supply.
     
  3. knockbill

    knockbill Addicted Member

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    Seems they would be pretty much custom, and priced accordingly... They are easy to make,,, I use octal type, usually to connect pre amp projects to PS... Sockets and plugs are easy to find for next to nothing at Hamfests, in my experience... I use a suitable size cable insulation, and fill it with conductors to match the circuits...

    This one feeds a pair of mono pre amps...
     

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  4. Tom Bavis

    Tom Bavis Audiophool Subscriber

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    And sockets should be used for power supply end, amps can have plugs with exposed pins (since there's no power there when unplugged). There are octal plugs with a chassis flange for the amp's power input.
     
  5. knockbill

    knockbill Addicted Member

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    Correct,,, these match the one preamp's socket,,, I didn't change it out yet...
     
  6. Selmerdave

    Selmerdave Well-Known Member

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    True but wouldn't something like two heater runs, a B+, B- and ground cover a good percentage of amps? Something like an 8-wire bundle with octal connectors would cover a lot of situations, for those of us without frequent access to hamfests...
     

     

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  7. knockbill

    knockbill Addicted Member

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    Probably... but I'm a DIYer,,, they are easy to make, a lot quicker and cheaper than ordering... More wire size and insulation choices also... Plus it seems new ones aren't available from a jobber...
    Octal plugs/sockets are most likely available from suppliers, (not sure if they still make 9 to 11 pin devices, tho) if you want to order new ones...
    Hamfests and radio shows are my suppliers, other than caps and resistors!!! Guy gave me a box full of them at the last meet I went to...
     
  8. Selmerdave

    Selmerdave Well-Known Member

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  9. knockbill

    knockbill Addicted Member

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    That's the Male plug for the octal sockets... Pins are hollow, conductors slide in and get soldered, the housing is required to cover them, and provides strain relief.... Look at the pics in post 3...
     
  10. Palustris

    Palustris Well-Known Member

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    745
    A year or so ago I decided that it was ridiculous to have to build a new power supply every time I built a new amp. So I decided to build two supplies and power all my projects from them. So I built a 550V @ 350mA supply and a 350V @ 250mA supply. Both these supplies are low impedance and choke input and provide the B+ only: the amp chassis carries the filament transformers since these could be different depending on the application.

    So I standardized on the connectors. One end of the power supply umbilical is fixed to the power supply chassis and has an Amphenol Industrial MS3106F10SL-3S female connector using Kimber Kable PBJ as the wire. The amplifier chassis has male connector Amphenol Industrial MS3102A10SL-3P. The Amphenol catalog is difficult to decipher, but these two connectors work well. Note that they are only three conductors since I use one for the positive and two for the ground, but a slight adjustment to the part number can change the number of contacts in the connectors.
     
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  11. primosounds

    primosounds Parallel single ended EL84 ,EDCOR OPT

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    Those are nice connectors. Quite expensive tho. It would be over a hundred just for the hardware for the 2 chassis and 1 umbilical. But that is the type the military uses.
     

     

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  12. Palustris

    Palustris Well-Known Member

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    I paid:

    MS3106F10SL-3S - $26.41

    MS3102A10SL-3P - $9.08

    I don't know what Kimber goes for since I have miles of it from previous projects and any 16 gauge wire can be used. You can buy a spool of 16 gauge for $5.

    Also the MS3102A10SL-3P is the male part on the amp chassis, so you only need one MS3106F10SL-3S for the power supply and each additional amp chassis can be done for $9.08. In other words, since I am only building one power supply for a range of amps, each new amp only needs the $9.08 part.
     
  13. Selmerdave

    Selmerdave Well-Known Member

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    I guess I don't see how to solder them with no access to the soldering surface, hold the iron to the outside of the pin and try to get the wire and some solder inside it? Or melt some solder into the pin and then keep it heated from the outside while inserting the wire? That's why I asked.
     
  14. gadget73

    gadget73 junk junkie Subscriber

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    Basically yes. Insert the wire through the end, hold the iron on the pin near the end and flow solder in along the bit of wire sticking out. Trim the end with cutters so it looks neat and clean. They're surprisingly easy to do, though they kind of suck to de-solder. Usually involves heating and flicking the socket to get the solder to come out enough to get the wire extracted.
     
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  15. Selmerdave

    Selmerdave Well-Known Member

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    Great, seems like that's the ticket then. Thanks!
     
  16. primosounds

    primosounds Parallel single ended EL84 ,EDCOR OPT

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    It is easiest to use solid core wire, not stranded. IF you use stranded wire, you need to pre tin the wire with solder to keep the strands together. Sometimes this makes the diameter of the wire too large to fit thru the hole on the bottom of the socket pin. Also a big tip soldering iron works best so that you can heat up the pin well and not make a cold solder joint.
     

     

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  17. triode17

    triode17 Well-Known Member

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    This is what we were required to do in military work. No exposed voltage.
     
  18. Selmerdave

    Selmerdave Well-Known Member

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    Sure, I like Palustris's approach with fixed cable on one end. With something like that one from Angela I'd fix the cable and connector to the amp side with an octal socket on the power supply side.
     
  19. triode17

    triode17 Well-Known Member

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  20. gadget73

    gadget73 junk junkie Subscriber

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