Jumbo Sunshade - Blogpost

Using a 9-volt battery to check speaker polarity
It seems weird that strangers actually email me asking questions, but it's cool i guess.  Far and away the most common is somebody throwing amplifier/speaker specs at me and asking me to draw up a wiring diagram so i can email it to them.  Less than half the time they're polite about it.  A bit more often than not though, it's like this:

"i want to use ur 212 stero/mono wiring diagram i am not compltly getting your diagram tho as far as the input jacks go i under stand how a mono one works with the ground and the lead but im not understanding the stero switching pic that ur using in ur diagram do u think u can help out me undrstand it better maybe draw me something out that looks like the acualt input?"

I've been doing this long enough to know that i'm not gonna be able to help this guy out.

I knew this guy who worked on amps in a really busy repair shop in Van Nuys and he was telling me that at least twice a week somebody would come in and say "Ok like i already pretty much know all about how amps work with the tubes and stuff. Could you just show me how to bias it myself so i don't have to keep spending all this money on it?"
What do you say to something like that?  I mean it would definitely be funny the first 2 or 3 times, but after that i think most people would start getting obnoxiously sarcastic about it.

Anyway, i get alot of email asking if it's really ok to use a 9v battery to check speaker polarity and/or how to use a 9v battery to check polarity.  And i never respond to this because i'm afraid of somebody suing me after they put a 9v battery across the output from their amp/poweramp to their cabinet(s).

The 9 volt battery speaker polarity check is something i've known about since first getting into recording.  Engineers are so ridiculous because there is SO MUCH that they will never teach anybody, but then with things like the 9v battery "trick" they act like they're giving you this golden nugget from their sage cabinet of knowledge (or something like that).  haha

I still hear people telling other people to use a 9v battery to check the polarity on their typically $500+ monitors, even though almost everybody is using powered monitors these days.  Yea, go ahead and start putting 9v batteries across your powered speaker inputs and let me know how that turns out.
[Sarcasm! Don't actually do this with your powered monitors!]

Obviously you CAN use a 9v battery to check speaker polarity, and anybody who wants to know how to do this should go ahead and Google it!


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