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Another ohm question!

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Ben Moore (ben)
Username: ben

Registered: 06-2008
Posted on Friday, July 18, 2008 - 12:38 pm:   

I have a 210 HD-130 and know that both speakers are 8ohms. From the info I've gathered here, by itself, it should be running at 4 ohms.

I want to add an extension cabinet...I guess a
2x12. So I can add either a 4 or 8 ohm cabinet and just switch to the 8 ohm setting on the back of the amp?

Is there a way of really dumbing down this explanation for me? Thanks.
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Saturday, July 19, 2008 - 10:47 pm:   

Ben,number 1 :you can have 2 8 ohm speakers in a cab or i should say combo in your case and they still be running at 8 ohm,it matters how they are wired (series/parallel).But I will say i'd never run a 4 ohm extention cab on it .I'd say you get a 8ohm extention cab and flip the switch to 4 ohm you should be fine.I may be wrong here but I don't beleave musicman made any 4ohm guitar cabs.
Dave Gossett (davey)
Username: davey

Registered: 05-2006
Posted on Sunday, July 20, 2008 - 08:23 am:   

Hi Guys, this is how I understand it. You have two 8 ohm speakers wired in parallel in your amp, that makes it 4 ohms, put the switch on 4. The extension speaker jack in the back of your amp is wired in series, not parallel. So you want to add the ohms of the extension speaker cabinet you are going to use. So.. if you use a 4 ohm extension cab and your amp is at 4 ohms, 4+4=8 put the switch on 8. I'm pretty sure that's how it is with my 2/12/65 watt Music Man and I think yours is the same. Hope this helps, Good Luck.
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Sunday, July 20, 2008 - 09:07 pm:   

dave i've never owned a combo but are you sure the 2 speakers in that combo are not wired in series? This will make the speakers run at 8 ohms.Then running a extention cab at 8ohms will make the amp run at 4ohms.theres also no mention of possibly spliting one of the jacks or using 16 0hm speakers in parallel.but i do beleave the switch should be on the 4ohm setting ,running 2 4ohm speaker arangements will put the power section at a 2 ohm load not 8 ohm ,right?
its more a game of subtraction not addition,if a guy was crazy enough to run 4 4ohm speakers or speaker cabs,this would put the amp at full power load ,without proper cooling it would probally have a melt down .
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Sunday, July 20, 2008 - 09:33 pm:   

http://en.wikipedia.org/wiki/Ohm
Ben Moore (ben)
Username: ben

Registered: 06-2008
Posted on Monday, July 21, 2008 - 05:57 am:   

uh oh...now I'm really confused.
I was agreeing with Dave based on this information I found in another post from Steve Kennedy:
"The rule of thumb (assuming all speakers are the factory impedances) is:

Single and 4 speaker combos should be set for 8-ohms if used by themselves or to 4-ohms if used with an external 8-ohm cabinet.

Two speaker combos are set to 4-ohm if used by themselves or to 8-ohms if used with an external 4 or 8-ohm cabinet.

The difference is because the first group (singles and 4-speaker) have their two speaker output jacks wired in parallel. The two-speaker combos (and heads) have their jacks wired in series.

Factory Music Man speaker drivers were all 8-ohm.

I have seen exceptions but most of them are wired in this fashion.

Steve"

Since my amp is a combo with 2-8ohm speakers internally, I'd run it at 4 ohms? Two speakers = wired in series?
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Monday, July 21, 2008 - 08:46 pm:   

ok,Ben you are right in the begining,Single and 4 speaker combos should be set for 8-ohms if used by themselves or to 4-ohms if used with an external 8-ohm cabinet. but the Two speaker combos are set to 4-ohm if used by themselves or to 8-ohms if used with an external 4 or 8-ohm cabinet,has to be wrong.ohms are not a measure of power but of resistance,the more you chain together the less resistance you get .thats why a 16ohm speaker run at the same wattage as a 8ohm speaker is not as loud its the resistance,but run 2 16ohm speakers at he same wattage as one 8ohm speaker and the loudness should seam the same ,because the 2 16ohm speakers wired parralel become 8ohms.Ben one thing you can do to ease all nerves is use a multimeter,plug in the speakers the way you like then test the ohms,now understand theres a great chance that you are not going to get a even number so round to the nearest.also understand that musicman amps while set up to run at 8ohms should work also at 4ohms more power even,so if you make all the wrong moves what should happen is less output or even reduced tone,but i don't beleave it would hurt the amp.
Alex Herrlein (alex_h)
Username: alex_h

Registered: 07-2007
Posted on Wednesday, July 23, 2008 - 02:42 pm:   

I'm going to have to agree with Steve here. I have a 210-65 and it has two 8 ohm spkrs wired in parallel within the amp for a 4 ohm load. I believe the back of the amp says something about external speakers in series. Thus when I use a 12" extension cab, I flip the switch from 4 to 8.
Ben Moore (ben)
Username: ben

Registered: 06-2008
Posted on Friday, July 25, 2008 - 05:57 am:   

hmmm...
So I've been looking to add external speakers to my 210-hd130.
I'm looking at the Traynor YCX12 or the YCX212.
The YCX 12 is 8 ohms and 80 watts.
The YCX 212 is 4 ohms and 160 watts.
So by Steve's account, I could run either one?

Now, to get off track, Alex, how do you like the sound of that single 12? I'm wondering if 2-12s would be too much....
Alex Herrlein (alex_h)
Username: alex_h

Registered: 07-2007
Posted on Saturday, July 26, 2008 - 02:11 pm:   

I was just looking at the Traynor YCX212 for a friend who wants to expand the sound of his 210-65. I think it's a great visual match for the Music Man amps, and the speakers should be good enough(Celestions). Ideally, the 4 ohm 212 cabinet would be a better match for the 210 combo, since the two pairs of speakers will equal exactly 8 ohms. My 1x12 cabinet is 8 ohms and thus is 12 ohms when I run it along with the onboard speakers. Not a big deal, but the lower impedance of the 212 cab gives the full use of the speakers.
My 1x12 with a more efficient Eminence speaker is actually louder than the onboard 2x10's, so I stand closer to the amp and farther from the ext. cab. The 1x12 cab is fine sound-wise, but you can't stack the combo on it (too narrow). Since you already have a 210 combo, I'd go for the 2x12 cab since it can piggyback at home or in the studio, and it will be more powerful at a gig. Just my 2 cents.
Bill Traylor (bozzy369)
Username: bozzy369

Registered: 02-2008
Posted on Tuesday, August 26, 2008 - 03:24 am:   

I would like to clear up something about my posts,i guess i was thinking musicman kinda did most things on their amps the same ,i should have never thought that because i know better.I was baseing my comments on the setup my rd-100 has which is parallel jacks ,now by what i'm learning here the amp in question must have series jacks which does change things abit ,my comments i still hold as true if your amp has parallel jacks,but having a amp with series jacks and a 4 ohm speaker seems kinda messed up to me ,because when you add another 4 0hm and set it to 8 ohm setting you are using that setup more like a buffer,now not saying that won't work ,just i would think this would change the tone ,not for the better. maybe?