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Confused as fuck about impedance.

 
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Reece
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Joined: 14 Jan 2008
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PostPosted: Sun Feb 24, 2008 8:50 pm    Post subject: Confused as fuck about impedance. Reply with quote

I've been look at some small tube combos for when I go to uni, but I also want to be able to plug the combo into my PPC112 when I'm at home. The PPC112 is rated at 16 ohms.

After reading up about impedance, I am now completely and utterly confused about what I could safely plug into it, can someone explain impedance matching in thick terms, since I'm now worried I'm fucking up my TT?
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Sloan
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PostPosted: Sun Feb 24, 2008 11:29 pm    Post subject: Reply with quote

MAKE SURE THE RATING ON THE AMP IS EQUAL TO OR HIGHER THAN THE RATING ON THE CABINET.

ex:
16ohm amp > 16/8/4/2 ohm cab
8ohm amp > 8/4/2 ohm cab
4ohm amp > 4/2 ohm cab
2ohm amp > 2 ohm cab
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Sloan
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PostPosted: Sun Feb 24, 2008 11:31 pm    Post subject: Reply with quote

16ohm cab is weird to me.
I guess it's a Vintage 30 rated at 16ohms?
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Doog
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Joined: 24 Apr 2006
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PostPosted: Sun Feb 24, 2008 11:40 pm    Post subject: Reply with quote

Sloan wrote:
MAKE SURE THE RATING ON THE AMP IS EQUAL TO OR HIGHER THAN THE RATING ON THE CABINET.

ex:
16ohm amp > 16/8/4/2 ohm cab
8ohm amp > 8/4/2 ohm cab
4ohm amp > 4/2 ohm cab
2ohm amp > 2 ohm cab


NOOOOOOOOOO

The amp's impedance should me the same or LOWER than the cabinet's.
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Reece
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Joined: 14 Jan 2008
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Location: Kent, UK

PostPosted: Sun Feb 24, 2008 11:53 pm    Post subject: Reply with quote

Doog wrote:
Sloan wrote:
MAKE SURE THE RATING ON THE AMP IS EQUAL TO OR HIGHER THAN THE RATING ON THE CABINET.

ex:
16ohm amp > 16/8/4/2 ohm cab
8ohm amp > 8/4/2 ohm cab
4ohm amp > 4/2 ohm cab
2ohm amp > 2 ohm cab


NOOOOOOOOOO

The amp's impedance should me the same or LOWER than the cabinet's.

Does trust doog more than slon.

Means I haven't been fucking up my TT then, tis all good.
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mickie08
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PostPosted: Mon Feb 25, 2008 12:22 am    Post subject: Reply with quote

Doog wrote:
Sloan wrote:
MAKE SURE THE RATING ON THE AMP IS EQUAL TO OR HIGHER THAN THE RATING ON THE CABINET.

ex:
16ohm amp > 16/8/4/2 ohm cab
8ohm amp > 8/4/2 ohm cab
4ohm amp > 4/2 ohm cab
2ohm amp > 2 ohm cab


NOOOOOOOOOO

The amp's impedance should me the same or LOWER than the cabinet's.



+1
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Sloan
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PostPosted: Mon Feb 25, 2008 2:24 am    Post subject: Reply with quote

hhaha.

the post right after that i actually changed.
it originally stated that i probably fucked it up. lolz.
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Hugogamelas
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PostPosted: Mon Feb 25, 2008 4:07 am    Post subject: Reply with quote

Sloan wrote:
MAKE SURE THE RATING ON THE AMP IS EQUAL TO OR HIGHER THAN THE RATING ON THE CABINET.

ex:
16ohm amp > 16/8/4/2 ohm cab
8ohm amp > 8/4/2 ohm cab
4ohm amp > 4/2 ohm cab
2ohm amp > 2 ohm cab


This is wrong, its the other way round.
You should never plug into cabs with lower impedance than the minimum suported by the amp.
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Mike
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PostPosted: Mon Feb 25, 2008 8:48 am    Post subject: Reply with quote

Actually it's never really safe to mismatch impedance either way. I posted fucking SCIENCE everywhere the last time Doog said lower was OK and it was ignored.

http://www.shortscale.org/forum/viewtopic.php?t=13794

Match if you can.

If you mismatch you're basically stressing the transformer - good transformer means no worries, a cheap or poor one = problems.

Small mismatches are generally fine in either direction. For example 8 ohm cab // 16 ohm cab = 5.33 ohms. Use the 4 ohm socket.

Just use you TT 16 ohm output.
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Bacchus
Whatever's handiest


Joined: 20 Apr 2006
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PostPosted: Mon Feb 25, 2008 1:44 pm    Post subject: Reply with quote

Buy an epiphone valve junior head, and sell the TT to me.

Otherwise, it'll probably blow up, like.

It's the only sensible option.
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Doog
can i get uhhh


Joined: 24 Apr 2006
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PostPosted: Mon Feb 25, 2008 2:04 pm    Post subject: Reply with quote

Mike wrote:
Actually it's never really safe to mismatch impedance either way. I posted fucking SCIENCE everywhere the last time Doog said lower was OK and it was ignored.

http://www.shortscale.org/forum/viewtopic.php?t=13794


Pffffft. What do you know, with all your "electronics degrees", "applied learning", "fancy word books" and "sitdown brunches"..
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Mike
I like EL34s


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PostPosted: Mon Feb 25, 2008 2:16 pm    Post subject: Reply with quote

I thought you said "Sitdown wees" then for a second. I was all like HOW DOES HE KNOW?
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Doog
can i get uhhh


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PostPosted: Mon Feb 25, 2008 2:30 pm    Post subject: Reply with quote

HAHAHA

Luxury pisses ftw.
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Sloan
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PostPosted: Mon Feb 25, 2008 3:29 pm    Post subject: Reply with quote

I SIT DOWN WHEN I PEE
THERE AIN'T NOTHING THAT CRAZY BOUT ME
I'M JUST TAKIN A WHIZZ, MIND YOUR OWN BIZ
WHY IS EVERYBODY ALWAYS LOOKIN' AT ME?!!!

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