Bottlehead Forum
Bottlehead Kits => Legacy Kit Products => Paramount => Topic started by: glynnw on December 27, 2013, 05:02:35 AM
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For several months I have had a problem with a crackling noise in 1 of my Paramounts. Following advice here I have replaced the hum pots (sorry Grainger, not the expensive model you used) and resoldered many of the connections, finding a broken wire that was still touching and carrying juice. But nothing worked. I started thinking about what I might have changed to start this problem and focused on the Yamamoto sockets I had installed a while back. Wiggling the 300B stopped the noise temporarily. I bent the pins (carefully) and again this worked for a short while. I used a small screw driver to bend in the contact points in the socket. Again, a temporary fix. So faced with replacing an expensive socket I decided to make a desperation move. Here's the instructions.
First, get a fire extinguisher and place it near the amp. Then remove the tube and carefully cut shims from a toothpick. Place them between the contacts and the teflon wall. Do test fittings until the tube will go into the socket. You need less wood than you'd first think. Check to make sure the fire extinguisher is fully charged. Turn on the amp. So far after 2 days it is working fine. I have yet to remove the tube to see if the wood has turned into cinders. Please note that neither I nor the Bottlehead company are responsible for you burning your house down. You'd think for what these sockets cost they'd have a way to adjust the tension on the contacts other than a banzai run at it.
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Sorry for your troubles! That's why I stick with the cheap sockets that you can adjust tension on.
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Man, that's rough! I have ~8 years on my factory Paramount tube sockets, and they still work nicely!
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After 2 ten-hour operating sessions, I removed the 300B and looked at the wood shims. Absolutely no signs of heat deterioration. I found a new product - "Yamamoto-style 4-pin Socket Shimming Kit". I think a razor blade, a set of tweezers and 10 toothpicks for $79.95? Extra toothpicks available at $1 ea. (It's special aged wood)
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I'd suggest a pair of Amphenol sockets.
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OK, it's been a while, buit I still do not have this solved. I finally decided to replace the Yamamoto sockets. I have purchased several sets of sockets, even had a pair shipped to me gratis by Queen Eileen, but none of them have fit. Apparently there was a design change to a larger socket in the later model Paramounts. My Paramounts were early models and the cutout for this socket is 1 1/8" with 1.5" screw hole spacing. Does anyone know where I can find a pair in this size? I am not about to try to enlarge the hole in the Paramount top plate. Would be ugly.
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I think PB is on the right track. If I remember correctly back when we put out the Afterglow we used to get a black Amphenol 4-pin socket that fit in an octal socket hole.
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These will also fit:
http://www.ebay.com/itm/2PC-4Pin-2A3-300B-274A-CMC-Ceramic-Gold-Tube-Socket-UX4-/260998771464?pt=Vintage_Electronics_R2&hash=item3cc4bd3308 (http://www.ebay.com/itm/2PC-4Pin-2A3-300B-274A-CMC-Ceramic-Gold-Tube-Socket-UX4-/260998771464?pt=Vintage_Electronics_R2&hash=item3cc4bd3308)
(4 pin ceramic socket with black retainer ring)
When we get older amps in that need new 4 pin sockets, these are what we use.
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Thanks, Paul, but this just adds to my confusion. The hole in the top plate on my Paramounts is a little over 28MM wide. The part you suggest says it requires a 30MM hole. I might order a pair just to experiment. Meanwhile, I could simply top mount 1 of the sets I have - the bottom of the socket is narrower than the top and will fit in the hole and is sturdy enough not to pull out when I try to remove a tube. I looked all over for Amphenol sockets, to no avail.
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Oops, try this one:
http://www.ebay.com/itm/1pc-4pin-CMC-Ceramic-Tube-Socket-Gold-Pin-300B-2A3-801-274A-/130674502821?pt=Vintage_Electronics_R2&hash=item1e6cceaca5 (http://www.ebay.com/itm/1pc-4pin-CMC-Ceramic-Tube-Socket-Gold-Pin-300B-2A3-801-274A-/130674502821?pt=Vintage_Electronics_R2&hash=item1e6cceaca5)
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Now that one looks perfect - I just ordered a couple. Thanks.
Love ordering from China - shipping notice gives a range of 1 month for when it will arrive. Sometimes I get things in less than a week and sometimes a full month, but the cost is ridiculously low. Their government must underwrite shipping costs.
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I use this type of socket in my Paramount 1.0 that I built back in '07 and have had no problems.
http://www.ebay.com/itm/Teflon-4Pin-300B-2A3-101-811-801-Tube-Valve-Gold-Pin-Socket-1PC-/260998766988?pt=Vintage_Electronics_R2&hash=item3cc4bd218c#ht_1189wt_1124 (http://www.ebay.com/itm/Teflon-4Pin-300B-2A3-101-811-801-Tube-Valve-Gold-Pin-Socket-1PC-/260998766988?pt=Vintage_Electronics_R2&hash=item3cc4bd218c#ht_1189wt_1124)
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Have you ever felt like you were living in a parallel, but slightly different, universe? I received the sockets Paul recommended, and while they indeed were small enough to fit in the hole, the retaining part was also so small it slipped up through hole as well. Strike 5. I finally have wound up top mounting a pair of sockets- they may not have been made to be used this way, but it works and looks fine - you barely see the metal bracket when the tube is installed. So thanks for all the tips, even if they weren't the answer. Just part of DIY life. I'm thinking of using the sockets left over in some kind of veneeered stand to display tubes. Now back to the music.
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Hmm, I am recalling that at certain points we may have also slipped an O-ring under these particular sockets to be sure they fit properly.
-PB