Keep your DHT socket pins tight and clean

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Vinnie R.

Keep your DHT socket pins tight and clean
« on: 17 Oct 2017, 04:02 pm »

I posted this sometime last year, but I think it is wise to start a new thread on the topic of the importance of keeping your DHT sockets clean, and making sure the pins are making a tight connection.

I receive LIOs from customers for upgrade, and I am kind of surprised by how dirty the DHT sockets are when I clean them.  I wish I took pictures of how black the Q-tips were.  :o

Regarding tube pins and tube sockets, it is very important to make sure you are getting a secure, clean connection. I have found DHT tubes have some level variation in the diameter of the tube pins (even from batch to batch of the same tube... it's not *that* uncommon it seems). 

So if you use a tube that has a slightly larger pin diameter, it can stretch the tube socket pins to accommodate the tube pin.  However, when you go back to use a tube with pin(s) of a slightly smaller diameter, the connection might not be as good as it was previously due to the stretched out socket pin. 

No problem - here is what you do about it:

The Yammamoto Teflon UX4 tube sockets used in the DHT PRE have female pins with a slit in the middle, and  this allows you to push the two halves of the socket pin together (closing the diameter of the female socket and making a better connection with the tube pin).  See:

If you use a very small flat head screwdriver (e.g. google "jewlers screwdriver," or "eyeglass screwdriver"), you can easily tighten them up if/as needed.  Just be careful as you work on each socket pin.

- Does this need to be done often?   

Not necessarily, unless you are rolling tubes often.  If you are getting an intermittent connection (could be noise, popping, crackling, or any noise that was not there before) with a particular tube, doing what I mention above will take care of it.  It's good to do this if you are tube rolling often, and as I mention in the DHT PRE Owner's Manual, you want to make sure the pins of the tubes that you install are clean *before* installing them!  This is especially important with NOS tubes that might have dirt and oxidation on them.  And you want to make sure your tube socket pins are also clean and free of dust and other contaminants.   

A clean, secure connection is going to provide best results (best sound, lowest noise). 

Try Caig DeOxit spray for cleaning.

Overall, this adjusting of the tightness of the socket pins and cleaning them and the tube pins are all part of "normal maintenance" that goes along with owning a component with tubes, and tube rolling.  If you confirm a tight connection and don't tube roll often, you probably won't need to do this that often.

Now... apply these same good habits above to your speaker posts, cable connectors, etc. :whip:

Best regards,

« Last Edit: 2 Jul 2020, 08:37 pm by Vinnie R. »


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Re: Keep your DHT socket pins tight and clean
« Reply #1 on: 17 Oct 2017, 09:39 pm »
People are getting an upgrade and "tune-up" at the same time.   :thumb:


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Re: Keep your DHT socket pins tight and clean
« Reply #2 on: 17 Oct 2017, 09:58 pm »
Couldn't agree more about cleaning.  Also be aware - I have purchased some pricey sockets (Yamamoto) only to find they wouldn't retain the tension necessary to grip the tube pins. In one case, a tube fell out of the socket when unit was inverted (OK, I know this is a stupid thing to do). At one time I was shaving toothpicks to get small slivers I could put between the contacts and the socket body to tighten them when a tube is inserted.  So I have switched to the cheaper sockets that let you tighten the contacts underneath the socket. Which I still clean regularly.

Vinnie R.

Re: Keep your DHT socket pins tight and clean
« Reply #3 on: 20 Oct 2017, 06:08 pm »

Hi glynnw,

I really like the Yammamoto Teflon 4-pin sockets, and they can easily be tightened from the top with a small flat-head screwdriver.  Once this is done, the tube makes a snug connection...

But not sure we are talking about the same model socket?