"New" vintage style 1/4 inch jacks

[Leo_Gnardo]

File under "what's old is new again."

Just got a flyer from Stew-Mac in via email. Worth a look and maybe a laugh. Who knows maybe these will turn out to actually be better than average. Double-contact phone jacks, similar to ones I've seen in some very old amps from the 1930's-40's. Price $4.20 - ha! what are they smokin? Gold plated option only a buck more. Well that's not an awful huge markup for gold. Despite the price I may have to give these a try. Unfortunately I don't see a version that has a shorting bar similar to the venerable Switchcraft 12A. Oh well.

Here's Stew-Mac's ad page:

https://www.stewmac.com/Pickups_and_...715_C_20180831

Disclaimer: I'm not an employee nor salesman for Stew-Mac. Sometimes I buy a couple things from them, so call me a satisfied customer.

[Helmholtz]

Also received the StewMac mail. I especially like the extra ground contacts. Decreased contact resistance is desirable for speaker outputs.

[Randall]

Not a bad idea, but did they really have to hype it with the Pure Tone moniker? Doesn't sell me.

[nevetslab]

Interesting mechanical design....at least for the Tip contact. The Ring contact.....well, not so much. The bend radius is way too tight & too short, I think. Think about the open frame Switchcraft jacks. They've folded those contacts so there's plenty of spring tension where it finally comes into contact with the plug. And, as Leo pointed out.....no switching provisions, so open circuit only. I do like the double-contact approach.

[g1]

Like Helmholtz said, increased surface area is great for higher power handling like speaker connections. Peavey used double contact jacks for some of their stuff on the speaker outs (plastic frame type).

[Leo_Gnardo]

Not a bad idea, but did they really have to hype it with the Pure Tone moniker? Doesn't sell me.

Reminds me of my fave oil filter, Purolator "Pure One." Well they had to call it something... And now that you remind me g1, I have seen a double contact jack in an old Peavey speaker cab.

[Helmholtz]

Like Helmholtz said, increased surface area is great for higher power handling like speaker connections. Peavey used double contact jacks for some of their stuff on the speaker outs (plastic frame type).

The weakpoint of Switchcraft type jacks is that they have no defined ground contact point and pressure even though there is a lot of of area. It is easy to measure a contact resistance of 0.5 Ohms or more. If the total contact resistance (including the cabinet jack) could be reduced by 0.8 Ohms , this would increase available output power by 10% @ 8Ohms.
Of course the result will depend on the contact material's quality (the best being phosphor bronze)/strength of the new jack.

[Leo_Gnardo]

The weakpoint of Switchcraft type jacks is that they have no defined ground contact point and pressure even though there is a lot of of area. It is easy to measure a contact resistance of 0.5 Ohms or more. If the total contact resistance (including the cabinet jack) could be reduced by 0.8 Ohms , this would increase available output power by 10% @ 8Ohms.
Of course the result will depend on the contact material's quality (the best being phosphor bronze)/strength of the new jack.

Indeed, Switchcraft jacks if I'm not mistaken are rated for 5A current max. It's definitely not wise to use them in high power applications. I was tasked with troubleshooting a JBL 18" subwoofer, cabaret series. No power amp was happy running it. Trouble turned out to be the wafers in its Switchcraft input jack had carbonized. I measured 1 ohm from common to hot with nothing else attached. New jack & everything ran OK after that. I cautioned the owner, no more than 200 watts please!

[rjb]

Gold plated option only a buck more. Well that's not an awful huge markup for gold.

Regarding gold contacts, what is your opinion on what I was told ages ago:

> Gold contacts are useful in preventing corrosion in connectors that stay connected all the time, e.g. computer backplane connectors.

> Gold contacts are NOT useful for instrument & speaker connectors that are repeatedly plugged & unplugged; the wiping action not only removes corrosion, but quickly wears off the gold plating.

Bored minds want to know,
-rb

[nosaj]

Indeed, Switchcraft jacks if I'm not mistaken are rated for 5A current max. It's definitely not wise to use them in high power applications. I was tasked with troubleshooting a JBL 18" subwoofer, cabaret series. No power amp was happy running it. Trouble turned out to be the wafers in its Switchcraft input jack had carbonized. I measured 1 ohm from common to hot with nothing else attached. New jack & everything ran OK after that. I cautioned the owner, no more than 200 watts please!

Well isn't that why speakon jacks were for?

Nosaj?

[Leo_Gnardo]

Well isn't that why speakon jacks were for?

Nosaj?

This was back in the days when dinosaurs strode the earth, before speakon jacks were marketed. Give the small metal contact area I see in Neutrik's product, I'm not exactly thrilled with them either. For high power application, I take a cue from Clair Brothers. At least what they were using in the 80's: "Australian Cannon" connectors. 30 amp rated, never a problem passing mondo high power. Expensive, yes. But they avoid the public embarrassment of failed speaker connections in the middle of a big big rock show. I've also seen 3 pin "Australian Cannon" used in old mic connector installations, in auditorium floors and aprons. Must have been from the days before "modern" XLR/Cannon plugs were the standard for mics. Plenty of contact area, no problem there.

[mozz]

First picture shows one color insulator, second picture shows another color insulator? For input jack, i don't think you need much more than a switchcraft.

[Enzo]

They are specifically called "output connectors", not really intended for input jack duty.

[drewl]

Bring back Banana Jacks!
Plenty of insulation and high current capability!

[SoulFetish]

I actually bought a couple of these and was going to start a thread about them. 1/4” jacks have been the weak part of the interconnect since the beginning, particularly when used for speaker connections. But we’re probably stuck with them at this point. The puretone jacks go a long way in improving the 1/4” jack design and they are so close. But they don’t offer any shorting option or switching jack! I actually modified one to get it to switch short when closed. I use shorting jacks on both inputs and speaker outputs in my amps so until they offer that, I’m probably out on them.