Author Topic: Ohm question about Model T and concert head  (Read 4970 times)

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Offline e1ixirpatr0lman

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Ohm question about Model T and concert head
« on: June 17, 2011, 09:49:52 am »
I have a question(s) about the Ohm output on my Model T. If I have the knob set to, say 4 Ohms, does EACH speaker output (1 & 2) push out 4 Ohms? In other words, can I connect two 4 Ohm cabs? Or do I need two 8 Ohm cabs?

Another similar question about a sunn concert head. From what I gather, this is a 4 Ohm head. Again, does each speaker output push out 4 Ohms? Can I connect two 4 Ohm cabs? Or do I need two 8 Ohm cabs?

Thanks in advance for any insight provided.

Cheers.

Offline EdBass

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Re: Ohm question about Model T and concert head
« Reply #1 on: June 17, 2011, 10:35:16 am »
Amps don't "push out" ohms. They can't; nothing can. Ohms are a measure of resistance/impedance to current flow, ohms isn't a measure of power or anything that you can "push out" of anything.

Although a speaker (which unlike an amplifier IS rated in ohms) can actually "push back", but that's another story altogether.

Amps don't have ohms, not in the manner of which you are referring anyway, speaker cabinets have ohms.
The ratings on the amps that you are referring to is what impedance load the amp should be connected to for the best, safe performance.

There are numerous threads on connecting speakers to amps, impedance, jacks, etc.; use the handy dandy search function and all of your questions should be answered, and give you an idea of how that all works. It's good information, and easy to understand reading, also.

Good luck with your search!  :wink:

Offline e1ixirpatr0lman

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Re: Ohm question about Model T and concert head
« Reply #2 on: June 17, 2011, 11:35:34 am »
excuse me for my misuse of the word Ohm (or push); clearly you (and presumably other readers) understood my question...yet no real answer provided. I have been looking on this and other forums all week, and been having trouble finding the answer I am looking for, but thanks for pointing out the search feature.
If you happen to know the answer, know of a thread that contains the answer, or even better if you could just copy/paste from some existing thread, that would all be very helpful.
Unfortunately your first reply was not...thanks for trying

Offline CLD

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Re: Ohm question about Model T and concert head
« Reply #3 on: June 17, 2011, 11:51:29 am »
There really are a LOT of threads on this subject. Just use the search feature and you'll find plenty of answers.

This forum is a great resource but understandably the experts should not have to answer the same questions over and over again every time a new person joins.

If you use the search feature, chances are you'll find exactly what you want. You can do that with a lot less time and effort than someone can do it for you. It's been a great tool for me since I joined several years ago.
Sunn since June 1971!
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1970 200S; 1974 Coliseum 880

Offline e1ixirpatr0lman

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Re: Ohm question about Model T and concert head
« Reply #4 on: June 17, 2011, 11:55:44 am »
as I said, I have been SEARCHING the forum all week. Have not been able to find the answer to my question(s). Thus the resulting post for help.
I just tried a couple searches again, and only my post with my questions pops up, so if anybody has the answer, please help. PLEASE PLEASE PLEASE...

Offline e1ixirpatr0lman

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Re: Ohm question about Model T and concert head
« Reply #5 on: June 17, 2011, 12:23:32 pm »
I found this in another post:

"So you could run one cabinet rated at either 8Ω or 4Ω (full power) using one output jack...  or you could run two 8Ω cabs using both output jacks"

this would lead me to believe hooking up two 4 Ohm cabs would be bad, can anyone confirm?

Offline Walt-Dogg

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Re: Ohm question about Model T and concert head
« Reply #6 on: June 17, 2011, 01:36:33 pm »
Oh for chrissake. When the Model T is set for 4 ohms, you will need two 8 ohm extension cabinets, one connected to each of the speaker out on the Model T in order to get a 4 ohm load with the cabs. That's series-parallel I believe.
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Offline Walt-Dogg

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Re: Ohm question about Model T and concert head
« Reply #7 on: June 17, 2011, 03:18:30 pm »
No worries. I just don't understand why no one with a Model T or experience with one//solid state Sunns posted in this thread when that's what the question the OP asked pertains to.

Also, OP, what kind of Concert do you have (Lead, Bass, silver-face, red knob)? That also dictates at what ohm load the head is stable at. And a note with the T, it's easier to use two 16 ohm cabs and setting the head for 8 ohms.
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Offline Isaac

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Re: Ohm question about Model T and concert head
« Reply #8 on: June 18, 2011, 08:14:36 am »
Oh for chrissake. When the Model T is set for 4 ohms, you will need two 8 ohm extension cabinets, one connected to each of the speaker out on the Model T in order to get a 4 ohm load with the cabs. That's series-parallel I believe.
You're right about the two 8 ohm cabinets having a combined 4 ohm load, but it's not series parallel. It's just two cabinets in parallel.

And yes, e1ixirpatr0lman, running two 4 ohm cabinets from the Concert head is probably a bad idea. If it's a silver and black Concert head, it's definitely a bad idea.
Isaac

Offline pickinatit

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Re: Ohm question about Model T and concert head
« Reply #9 on: June 21, 2011, 07:37:43 am »
I have the red knob concert bass amp and have seen it advised many times on this forum to NOT expose it to a 2 ohm load.  The amp is supposed to be rated for that but the actual (I'm just going to say electronics) of the amp don't really support that. Someone else can give a more technical reason then that, but that's the advice I see over and over again.

Offline Isaac

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Re: Ohm question about Model T and concert head
« Reply #10 on: June 25, 2011, 07:44:08 am »
The technical explanation is that it doesn't have enough output devices (power transistors) to put out the current required for full power into a 4 ohm load indefinitely without burning up.
Isaac

Offline OR120

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Re: Ohm question about Model T and concert head
« Reply #11 on: July 01, 2011, 07:42:51 pm »
R1xR2 divided by R1+R2.  8x8 (64) divided but 8+8 (16). Works for figuring out impedance for parallel loads. I have made series cables though for using 2 8 ohm cabs and making a 16 ohm load- I hate proprietary stuff though. If it broke you'd be screwed.
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