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Smote
Posted on Tuesday, May 14, 2002 - 09:25 pm:   

I have a MM HD130 head and am looking to get some new speakers for it, any suggestions...maybe some orginal MM 4'10's if I can find em.
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Steve Kennedy
Posted on Wednesday, May 29, 2002 - 11:24 am:   

Are you going to use the amp for Bass or Guitar? How portable (size & weight) should the cabinet be?

If you want to stick with a Music Man cabinet, the most plentiful seem the to the RH series (Reflex Horn) of cabinets followed by the odd 410 & 412 bottoms (bass models have a "B" appended to the model number).

The smaller 1-10, 1-12 and 2-12 cabinets are relatively rare and I haven't seen many of those floating around.

What speakers are in the cabinet(s) you wind up with will be a crapshoot... stock, EV special order, JBL, etc.

Steve
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Jens
Posted on Thursday, May 30, 2002 - 06:45 am:   

Out of curiosity: I have a HD 130 reverb Head and two cabinets - a GS412 and a RH212.
What is the optimal way of setting this stack up ? Impedance setting on Head ? What cabinet should be on top ? Or does that not matter ?
(The head has a switch that toggles between 4 and 8 ohms)

Any comments are greatly appreciated
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Steve Kennedy
Posted on Thursday, May 30, 2002 - 10:11 am:   

Look at the rear of the head at the nomenclature surrounding the speaker jacks. Most Music Man heads have speaker jacks wired in series but this isn't cast in concrete. The only way to tell is to look at YOUR amp and see what it says on the dataplate surrounding the jacks.

The RH212 is a 4 ohm cab while the GS412 is an 8 ohm. If your amp head has series jacks (as expected) your total impedance is 12 ohms (4 + 8) and operating in the 8 ohm position would be correct (rule of thumb: up to 100% mismatch from the switch setting can be tolerated as long as you do not go lower than 4 ohms).

If your amp has parallel jacks (most of the combos are this way) then your total impedance would be 2.66 ohms (4 x 8 / 4 + 8) if both cabinets were plugged into the amp's jacks. In this case it would be safer to wire the cabinets in series than to run the amp at the 4 ohm position. Although I'm sure the amp would handle it, this would put more stress on the output transformer and tubes than operating in the 8 ohm position with a 12 ohm load.

Another thing to consider is that you might like the way the amp sounds one way versus the other! The match between the load and output stage will determine specific conditions (like dampening) that do effect the way a system sounds. All things being equal (or close), I personally try to stay on the conservative side to keep things as cool and safe as possible.

Do your cabinets have "through" jacks that allow cabinets to be strung together? If so, you could wire these to allow series operation in order to keep the amp as cool and unstressed as possible. This shouldn't be a concern if your amp's jacks are in series.

You could also rewire the RH cab to be a 16 ohm load. This would make a parallel total for both cabs about 5.3 ohms which could be use in either the 8 or 4 ohm switch positions.

As far as position goes, I would put the RH on the bottom as this cabinet will provide the majority of your low end while the GS412 will project better if elevated.

I hope this provides food for thought and doesn't get too confusing!

Steve


(Message edited by admin on May 30, 2002)
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Jens
Posted on Friday, May 31, 2002 - 02:38 am:   

Thanks for the input - that clarified a few things. Having checked the amp, the output jacks are connected in series, so I will follow your advice. I guess that connecting each cabinet to it's own output jack will work okay, even though, that the 412 cabinet has got, what I assume, is both an input and an output jack.

But thanks for the help, and have a nice weekend
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Steve Kennedy
Posted on Tuesday, June 04, 2002 - 11:35 am:   

It is better to connect each cabinet directly to its' own output jack on the amplifier. This makes a more direct connection with fewer points of potential connection failure!

Steve

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