Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Ed_Chambley on June 11, 2012, 09:56:54 pm
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Does anyone know where to get Loctal sockets. I have searched and cannot find any state side. I would like to get a couple. I am sure someone makes a adapter, but I would prefer the ceramic socket. The 6v6 and 7c5 are the same tube, just different pinouts and sockets. What are the drawbacks to loctal and why are they not in fashion any more?
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http://www.vacuumtubesinc.com/Products/SocketsAdaptersParts/NewOldStockTubeSockets.aspx (http://www.vacuumtubesinc.com/Products/SocketsAdaptersParts/NewOldStockTubeSockets.aspx)
scroll down about 2/3 of the way.
http://www.ebay.com/itm/8-PIN-AMPHENOL-USA-LOKTAL-LOCTAL-TUBE-SOCKET-NOS-Mica-Military-Spec-B8B-/200721106707?pt=Vintage_Electronics_R2&hash=item2ebbe90713#ht_740wt_1163 (http://www.ebay.com/itm/8-PIN-AMPHENOL-USA-LOKTAL-LOCTAL-TUBE-SOCKET-NOS-Mica-Military-Spec-B8B-/200721106707?pt=Vintage_Electronics_R2&hash=item2ebbe90713#ht_740wt_1163)
not in the conUS, but at least in the same hemisphere.
http://www.ebay.com/itm/8-Pin-Loctal-Ceramic-Bodied-Chassis-Tube-Socket-For-6N7-BARGAIN-PRICED-/370594918988?pt=Vintage_Electronics_R2&hash=item56492db24c#ht_500wt_1413 (http://www.ebay.com/itm/8-Pin-Loctal-Ceramic-Bodied-Chassis-Tube-Socket-For-6N7-BARGAIN-PRICED-/370594918988?pt=Vintage_Electronics_R2&hash=item56492db24c#ht_500wt_1413)
made in china, but stocked and shipped from maryland...
http://www.ebay.com/itm/NOS-Loctal-Loktal-Tube-Socket-/270977929435?pt=Vintage_Electronics_R2&hash=item3f178b10db#ht_500wt_1180 (http://www.ebay.com/itm/NOS-Loctal-Loktal-Tube-Socket-/270977929435?pt=Vintage_Electronics_R2&hash=item3f178b10db#ht_500wt_1180)
those would be my last choice.
if you still have difficulty, PM me - i can sell you a couple, assuming of course that doug doesn't stock them.
--DL
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eBay
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> why are they not in fashion any more?
They seemed like a good idea at the time. My brother's 1941 Plymouth radio is full of them. They don't fall out. They were widely used in WWII-era military gear. But they and their sockets cost more to make, I suspect there was a license fee, there were not enough types to build an all-Loctal anything except a table radio, and then came the new Miniature tubes which soon covered every type sold in Loctal..... all in all it was just easier to use Mini for everything except over 12W, then big-Mini for anything up to 20W, and good old Octal above that.
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I read the data sheets (been reading lots of them) and it seems this tube is the same as a 6v6 but NOS RCA are cheap. I noticed the pinouts are slightly different. Are they the same? I saw the chinese version of the loctak cermac for $4.50. That seems like a cheap way to install a 6v6. Even the new JJ6v6 cost more than the 7c5 NOS RCA. Whats the catch? I have never seen anyone do it and I am not that smart where one of you guys haven't discovered this first. There has got to be a Pain in the butt factor, or the tube is not really the same. For instance, 5 new ones in a box sleeve for $50 or 10 bucks each. That is awful cheap for a RCA 6V6.
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I read the data sheets (been reading lots of them) and it seems this tube is the same as a 6v6 but NOS RCA are cheap. I noticed the pinouts are slightly different. Are they the same?
the 7C5 and 6V6 do have different pinouts, but the 7C5 is indeed is a 6V6 in the locktal form factor. Like sluckey said, ebay is the best. the new production sockets (white ceramic) are pretty cheap quality wise. on ebay, you'll find some NOS sockets that run $5-$7 ea, but they much better quality.
I built a Deluxe 6G3 using 7C5s instead of 6v6s and it sounds great. Its not exactly a perfect A/B test, but it sounds good enough for me to believe all the data sheets and tube manuals that say "refer to 6V6 for specs".
All the 7C5s I have are Sylvanias. I think they developed, or helped developed, the locktal.
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I would have zero reservations about using an Amphenol or Cinch phenolic socket, rather than ceramic. As said, most commonly available ceramic sockets seem kinda low quality. I actually wish I'd used phenolic sockets instead of the ceramic ones I have in my current build.
And I'm pretty sure billcreller built an amp or two not long ago using loctals. Most folks would go out of their way to build such an amp, but the price difference on tubes is tempting. Guys usually do this because they have some loctal tubes hanging around they'd like to use up.
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I would be sure any 7C5 _is_ vintage-6V6 guts on a different base. Octal and Loktal are so similar there would be no reason to re-tool the inside bits. There's no recent market for 7C5, so any you find _are_ very-vintage. As you say, the price is so low it would hardly be worth testing and sorting used 7C5, the main supply is warehouse crates and dead service shops.
There IS the modest PITA-factor of re-socketing, and not being able to pick-up a new 7C5 late on a rainy Saturday night. So socket adaptors "might" be wise, so you could yank the adaptor and shove a Banjo-World "6V6" in there to get you through the night. OTOH a 5-pack of 7C5 would get you though a lot of bad nights.
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http://www.vacuumtubesinc.com/Products/SocketsAdaptersParts/NewOldStockTubeSockets.aspx (http://www.vacuumtubesinc.com/Products/SocketsAdaptersParts/NewOldStockTubeSockets.aspx)
scroll down about 2/3 of the way.
http://www.ebay.com/itm/8-PIN-AMPHENOL-USA-LOKTAL-LOCTAL-TUBE-SOCKET-NOS-Mica-Military-Spec-B8B-/200721106707?pt=Vintage_Electronics_R2&hash=item2ebbe90713#ht_740wt_1163 (http://www.ebay.com/itm/8-PIN-AMPHENOL-USA-LOKTAL-LOCTAL-TUBE-SOCKET-NOS-Mica-Military-Spec-B8B-/200721106707?pt=Vintage_Electronics_R2&hash=item2ebbe90713#ht_740wt_1163)
not in the conUS, but at least in the same hemisphere.
http://www.ebay.com/itm/8-Pin-Loctal-Ceramic-Bodied-Chassis-Tube-Socket-For-6N7-BARGAIN-PRICED-/370594918988?pt=Vintage_Electronics_R2&hash=item56492db24c#ht_500wt_1413 (http://www.ebay.com/itm/8-Pin-Loctal-Ceramic-Bodied-Chassis-Tube-Socket-For-6N7-BARGAIN-PRICED-/370594918988?pt=Vintage_Electronics_R2&hash=item56492db24c#ht_500wt_1413)
made in china, but stocked and shipped from maryland...
http://www.ebay.com/itm/NOS-Loctal-Loktal-Tube-Socket-/270977929435?pt=Vintage_Electronics_R2&hash=item3f178b10db#ht_500wt_1180 (http://www.ebay.com/itm/NOS-Loctal-Loktal-Tube-Socket-/270977929435?pt=Vintage_Electronics_R2&hash=item3f178b10db#ht_500wt_1180)
those would be my last choice.
if you still have difficulty, PM me - i can sell you a couple, assuming of course that doug doesn't stock them.
--DL
Thanks for the links and info. I found NOS AMPHENOL 8 PIN LOCTAL LOKTAL SILVER PIN TUBE SOCKET on ebay at $7. I bought the other day 10 NOS RCA 7C5 for $50. Five bucks each. My only concern is will they handle the plate voltage.
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Sure they will, if they're not dirty or crusted with gunk. They'll almost certainly have a dielectric rating exceeding any loctal tube's plate voltage rating.
For all tube sockets, the real enemy is solder flux, dust and dirt providing a leakage path that could eventually lead to arcing. Once there's an arc, the dust/dirt gets burned leaving a carbon tack which lends itself to further arcing.
But just about any clean tube socket of any material is good for well over 400v.
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Thanks for the help. The 10 I bought are new in the box RCA. @ rows of 5 and are still in the 5 pack carton. The carton tops were not even bent until I opened them. They look exactly like some RCA 6v6 I've got sept they have metal bases. They are really NOS. I got the sockets from a guy on ebay. Amphenol which he sells for $7 each. The photos of them look real nice. He said they are like new. If they are I think I will get about 6 more.