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Author Topic: When did pin 2 get "hot"?  (Read 7046 times)

Bob Lee (QSC)

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Re: When did pin 2 get "hot"?
« Reply #10 on: January 18, 2008, 04:59:52 pm »

Yeah, that was 1990. The spinner was something that the AES LA section had made to poke fun but also plainly point out that no standard existed at the time.

It's an issue mainly with equipment that goes from balanced to unbalanced or vice-versa. Anything balanced-to-balanced with XLR ins and outs is okay as long as the polarity is consistent.
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Patrick Tracy

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Re: When did pin 2 get "hot"?
« Reply #11 on: January 18, 2008, 06:25:12 pm »

John Roberts  {JR} wrote on Fri, 18 January 2008 10:39

trace knight wrote on Fri, 18 January 2008 10:42

I remembr back in those dayz...........some amps, i think I saw it on a carver, and a crest had a recessed switch pin 2-3 swap on the back panel, they couldn't make up thier minds I guess!
tk


The pin hot selector switch was one way to support customers with predominantly pin 3 hot systems, while also working with pin 2 hot system.

I encountered customers who were extremely confused and sometimes over reacted to mixed standard situations. In some cases customers introduced a polarity reversal with their modified wiring "fix"  where there wasn't a problem, thanks to the symmetrical nature of differential in and differential out interfaces.

I'm glad this is mostly behind us.

JR




Do I recall you saying that Peavey had settled on pin3 hot well before there was an industry standard and retained it to maintain continuity for their customers?

Andy Peters

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Re: When did pin 2 get "hot"?
« Reply #12 on: January 18, 2008, 06:35:21 pm »

Lester Moran wrote on Fri, 18 January 2008 13:49

John Roberts  {JR} wrote on Fri, 18 January 2008 17:39


I encountered customers who were extremely confused and sometimes over reacted to mixed standard situations. In some cases customers introduced a polarity reversal with their modified wiring "fix"  where there wasn't a problem, thanks to the symmetrical nature of differential in and differential out interfaces.



My KT DN 360s are "pin 3 hot".  My Ramsa WRS 840 is "pin two hot", but more importantly, the individual send and return insert points on the mixes are tip=hot, ring=cold.  If I present the inserted EQs with the Ramsa's hot signal to pin 2 of the EQs, I get 6 db loss, as compared to presenting the Ramsa's hot signal to the EQs at pin 3 (which introduces no loss).  Do you know why this would happen?...  i.e. what might be peculiar to the DN 360 balancing scheme to make it "care" whether the hot signal ran through it at pin 3 as opposed to pin 2?


DN360s have unbalanced outputs unless fitted with the optional output transformers. In either case, Pin 3 is hot.

So if used in an unbalanced insert situation, a 6 dB loss is possible. I haven't seen the input section schematics but I assume that it's a diff amp with gain of 0.5 (6 dB loss).

-a
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John Roberts {JR}

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Re: When did pin 2 get "hot"?
« Reply #13 on: January 18, 2008, 07:09:53 pm »

Patrick Tracy wrote on Fri, 18 January 2008 17:25





Do I recall you saying that Peavey had settled on pin3 hot well before there was an industry standard and retained it to maintain continuity for their customers?


No, and I still have the scars on my ass from working there during that transition. I started working there in the mid '80s as a Pin 2 guy inside a pin 3 company. They had made the pin 3 decision a few decades before I showed up. I was a pretty lonely guy, arguing for pin 2 hot, and for a while the AMR recording products (my specific responsibility) were pin 2 hot with Peavey SR gear pin 3 hot. The publicity surrounding the AES pin 2 hot endorsement a few years later was very helpful in getting the rest of the organization on board. It took years for the transition to actually take place as product lines turned over.

And like I said elsewhere many customers were very confused. Old school Peavey customers and dealers didn't appreciate the change one bit, but my philosophy regarding this was that if customers had problems interfacing mixed pin 2/3 hot gear, I wanted to be the one that was correct. Pursuing a path of staying pin 3 hot because it was easy, means being wrong in those cases.

I'm sure that was only one of many times I was a burr under the saddle there...

JR

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Mark Meagher

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Re: When did pin 2 get "hot"?
« Reply #14 on: January 18, 2008, 11:28:31 pm »

My memory must have failed, but I remember the early 80's being pin 2 hot from the Brits and pin 3 elsewhere.
Maybe I'm just recalling the EQ as "British EQ". <----rhetorical, discussion not needed-> Very Happy


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Moby (Mike Diack)

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Re: When did pin 2 get "hot"?
« Reply #15 on: January 19, 2008, 05:18:37 am »

"Down Under" pin 3 hot was the standard well into the 80's, and it's relatively recently that we've been dragged kicking and screaming into a pin 2 hot world. We also used XLR3Ms as standard for amp outputs and speaker inputs (hence speaker cables were XLR3F->XLR3F) mind you this was before the rise of the speakon. There were variations as to which conductors were used for what in the amp->speaker connectors, giving real meaning to the "pin X hot" conundrum, especially with primitive amps with poor protection.
M
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