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Quality tube sockets, and other parts?

Discussion in 'Tube Audio' started by Dale Murray, Oct 13, 2018.

  1. Dale Murray

    Dale Murray New Member

    Messages:
    7
    I am new to tube.
    My entry was building a VTA ST120 from a kit (based on Dyncao ST70); kit would be a proven design, I could get support, and I knew it would work if I did not mess up. So far so good, works and sounds great.

    *I want to rebuild it in a custom base for the following reasons:
    - Tubes are tightly packed. I'd like to offer a little more breathing room, especially if I start running KT120 tubes.
    - The Dynaco style base is ugly.
    - I want to include bias meters for the tubes.
    - I want to include VU meters because meters make the music sound better. <-- I'm joking.
    - I want to move the RCA jacks to the rear of the cabinet.
    - I want to move the power button to the front.

    I intend to transfer most of the expensive components from my existing amp to the new one. I am looking for advice on brands and sources for high quality components for the following:

    **8-pin octal sockets
    C24-X choke
    Quad Cap (80,40,30,20 Mfd)
    .022 Mfd 100 volt capacitor
    1000 ohm 1 watt resistors
    10 ohm 2 watt resistors
    4.7K ohm 3 watt resistors

    I do understand these are basic components but, if a type or brand is known to sound better than others, I would like to know.

    * I am a woodworker, have access to metal working machines, and handy with CAD if I want custom machines parts.


    ** I am really lost when it comes to tube sockets, seems like most cost about the same. do not know if there are any known to be better quality than others.
     

     

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  2. thorpej

    thorpej AK Subscriber Subscriber

    Messages:
    1,652
    Location:
    San Francisco, CA
    These micalex sockets by Belton are the gold standard, in my opinion: https://www.tubesandmore.com/products/socket-belton-micalex-8-pin-octal-mip

    As far as the C-24X choke is concerned, that's s standard Triad Magnetics part, so you can get it from any Triad distributor, but Mouser is always a good bet.

    As far as the resistors are concerned, you haven't specified where in the circuit those need to go, but I'm going to assume the 10 ohm resistors are for current sensing purposes, so you would want to use 1% tolerance parts there for measurement accuracy. For that application, I'm a big fan of the Vishay Dale CPF-series. The CPF210R000FHE14 is $0.98/ea at Mouser, and is a 50 PPM/C part. They stock the 100 PPM/C part as well (CPF210R000FKE14) for about half the price.

    I'm going to assume the 4.7K 3W resistor is for the power supply? Vishay Dale RS-series wire wound power resistors are always a good choice. RS02B4K700FE12 is the part number.

    What are the 1K 1W resistors for?

    What's the 0.22 µF 100V cap for?

    Here's a source for the 80/40/30/20 -- these CE twist-lock can caps are pretty decent: https://www.tubesandmore.com/products/capacitor-ce-mfg-525v-80403020-f
     
    Retrovert likes this.
  3. Dale Murray

    Dale Murray New Member

    Messages:
    7
    You are correct, I did not state where the resistors will be used; I was reading the parts list. My ignorance is showing - I have a lot to learn about this stuff.

    I'm going to trace all the wiring, etc this weekend. There is not a legit schematic for the amp that I am aware of, just very wordy instructions. When I complete that task I will come back with specifics.
     
  4. triode17

    triode17 Super Member

    Messages:
    1,250
    I understand the ergonomic reasons for doing this but you may be doing the design a mis service. The RCA's are in the front so that the signal has the least distance to travel from the jack to the first tube. Thus minimizing hum and noise pickup. The power switch is placed on the rear, so that the 60 cycle power has the shortest distance to travel to the power tx. and switch thus minimizing hum and noise pickup. I wouldn't do it, but its your call.
     
  5. thorpej

    thorpej AK Subscriber Subscriber

    Messages:
    1,652
    Location:
    San Francisco, CA
    It's pretty easy to avoid those problems:
    • Use shielded cable for the inputs, grounding the shield at one end only, running the cable down one side of the chassis.
    • Run the power switch leads down the opposite side of the chassis from the input cable.
     
    Retrovert and arts like this.
  6. Bob

    Bob AK Subscriber Subscriber

    Messages:
    2,147
    Location:
    West coast
    you have a wide variety of choices, design and parts, in this instance. you could go with film
    capacitors instead of that can capacitor (which uses electrolytics), be careful of the first cap
    if you are using a tube rectifier. Conrad Johnson uses film caps in their amps.

    try teflons, polypropylenes, paper in oil, etc everywhere else.

    while you're at it, think about other power tubes other than the el34/6CA7, you'll need
    to adjust the power specs, and worry about pin1-8 connections, then's the world's
    your oyster - 6l6, 6550, etc.

    i'd run stronger heaters in case you wish to go up to the KT120s.

    finally, think about running triode mode.
     

     

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  7. Dale Murray

    Dale Murray New Member

    Messages:
    7
    I am aware of why its setup this way and for the life of me, I cannot think of another amplifier I have ever seen IN THIS WORLD with the same sort of setup.

    I can use shielded cables, a remote power switch, or a number of other solutions.
     

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