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Series versus Parallel question

Lumpy_Bass

Lumpy_Bass

Jun 8, 2010
196
11
Hockessin, Delaware
www.instagram.com
#1
What's Up Everyone,

I know this has been addressed numerous times in this forum but I wanted to get TB feed back and opinions on my specific rig.

I have a Hartke ha2500 running into Hartke VX210 and 115XL cabs. I've always run them in series but recently I realized that I may be able to get a little more out of them in parallel.

The 2500 put out 250Watts @4 Ohms, 180 at 8 Ohms the vx210 is 250 watts at 8 ohm and the 115xl is 200watts at 8 Ohm.

Should I stay in series or could I safely get a little more in parallel?

Thanks in advance for all feedback.
 
#2
How are you running in series? Virtually all amp to speaker connections are parallel. Series makes no sense, since you would be doubling the impedance of your two cabs to 16 ohms (assuming they are 8ohm cabs), getting virtually no power out of your head.

You might be confusing the term 'series' with daisy chaining (running the head to one cab, and then connecting the two cabs). This is still parallel, and identical to running each cab from the two speaker outputs of the head.
 
#3
Unless you have a special cord, you're probably running in parallel now.

When you plug one cabinet into the head and the second cabinet into the first cabinet, you still have a parallel connection- same as plugging each cabinet into the head.

Series connections take a bit of custom wiring.

John
 
#4
john m said:
Unless you have a special cord, you're probably running in parallel now.

When you plug one cabinet into the head and the second cabinet into the first cabinet, you still have a parallel connection- same as plugging each cabinet into the head.

Series connections take a bit of custom wiring.

John
Click to expand...

I guess I am little confused about what series actually means.

So to simplify my question....currently I am using both speaker outputs on the amp one to the 210 and one to the 115. So am I already parallel and will it change anything if go just one output to the 210 and then run the extention connection (daisy chain) to the 115?

Thanks
 
#5
Lumpy_Bass said:
I guess I am little confused about what series actually means.

So to simplify my question....currently I am using both speaker outputs on the amp one to the 210 and one to the 115. So am I already parallel and will it change anything if go just one output to the 210 and then run the extention connection (daisy chain) to the 115?

Thanks
Click to expand...

Correct.........

Already in parallel, nothing to gain by changing the configuration.
 
#6
Lumpy_Bass said:
I guess I am little confused about what series actually means.

So to simplify my question....currently I am using both speaker outputs on the amp one to the 210 and one to the 115. So am I already parallel and will it change anything if go just one output to the 210 and then run the extention connection (daisy chain) to the 115?

Thanks
Click to expand...
No difference electrically between those two arrangements - in both cases the cabinets are connected to the amp in parallel (current will pass from the amp through each cab without passing through the second cab before returning to the amp). They may LOOK like different wiring arrangements, but they're not.

EDIT - Bass Puncher beat me to the pound. :D
 
#9
Lumpy_Bass said:
Cool. Thanks to everyone for all of your quick and knowledgeable replies.

So is Ohm stabilization the advantage of a series connection?
Click to expand...

Never heard of Ohm stabilization. I have been using, building and repairing amps and cabs for over 40 years and that is a new one on me.

A bit of maths

Speakers in parallel. (and resistors)

2 X 8 ohm speakers in parallel are equivalent to one 4 ohm speaker.

derived from the formulae 1/total = 1/R1 + 1/R2

which gives 1/total = 1/8 + 1/8 = 1/4

so 1/total = 1/4. transpose this gives total = 4

Speakers in series

Total = R1 + R2
= 8 + 8
= 16

So putting them in series will give you 16 ohms and for a (tranny) amp will give you approximately 1/4 of the power to putting them in parallel. Tube amps are a bit different but you should set your speaker impedance selector to match your speaker impedance or expect trouble. I have never experimented with putting the wrong impedance speaker on a tube amp as I don't want to have to buy a new output transformer.
 
#11
delta7fred said:
Never heard of Ohm stabilization. I have been using, building and repairing amps and cabs for over 40 years and that is a new one on me.

A bit of maths

Speakers in parallel. (and resistors)

2 X 8 ohm speakers in parallel are equivalent to one 4 ohm speaker.

derived from the formulae 1/total = 1/R1 + 1/R2

which gives 1/total = 1/8 + 1/8 = 1/4

so 1/total = 1/4. transpose this gives total = 4

Speakers in series

Total = R1 + R2
= 8 + 8
= 16

So putting them in series will give you 16 ohms and for a (tranny) amp will give you approximately 1/4 of the power to putting them in parallel. Tube amps are a bit different but you should set your speaker impedance selector to match your speaker impedance or expect trouble. I have never experimented with putting the wrong impedance speaker on a tube amp as I don't want to have to buy a new output transformer.
Click to expand...

Ok, perhaps not Ohm stabilization but how about Ohm doubling? IDK?? So am I understanding you correctly that the main function of series wiring is to correctly match up ohms from cab to amp?
 
#15
ok what about power distribution on serial connection?

for example, a 4ohm plus 8 ohm in parallel, the 4 ohm will get twice the power of the 8 ohm;

what kinda power will each cab gets if there were connect in serial?
 
#17
mulchor said:
In serial, the current through the two speakers will be the same. Consequently there'll be double the power at the 8 ohm than at the 4 ohm. Power is current squared times resistance.
Click to expand...
No - that ignores the fact that more current will flow through a lower impedance load.

Whatever power the amp is putting out will be dissipated half and half in each cab if they are the same resistance. So in parallel (1/8+1/8 = 1/4, so 4 ohm load total), each cab will get half the 250W output and in series (8 + 8 = 16 ohm load total) , each cab will get half of maybe only about 100 to 120W.
 
#18
bassybill said:
No - that ignores the fact that more current will flow through a lower impedance load.

Whatever power the amp is putting out will be dissipated half and half in each cab if they are the same resistance. So in parallel (1/8+1/8 = 1/4, so 4 ohm load total), each cab will get half the 250W output and in series (8 + 8 = 16 ohm load total) , each cab will get half of maybe only about 100 to 120W.
Click to expand...

I believe mulchor is answering a different question and he is right.

Ignoring power differences from the amp at different cabinet impedences,

When a 4 ohm and a 8 ohm cab are connected in parallel, the 4 ohm cab gets 2/3 of the power coming from the amp, the 8 ohm cab gets half as much (1/3 of the power).

When a 4 ohm and a 8 ohm cab are connected in series, the 4 ohm cab gets 1/3 of the power coming from the amp, the 8 ohm cab gets twice as much (2/3 of the power).
 
#19
Mulchor is correct on series connection, but keep in mind these are reactive loads with impedance curves. The curves of two different cabinets is going to change which frequency. Connecting them in series is going to change the power curve mainly at bass frequencies between the two cabinets.
If the cabinets were identical this wouldn't be a problem.
If they're different it's more of a gamble than just parallel connection. Parallel works more like a voltage source.

Parallel connecting two cabinets is also a gamble as you're essentially field designing a speaker system on the fly.
 
#20
I was actually going to ask a very similar question this morning.

I have an Ampeg SVT 2 Pro which only supports 2 or 4 Ohm loads. I have 2 Aguilar cabs that are each 8 Ohms. Normally, I connect each one directly to one of the 2 speaker jacks on the amp, and set the amp impedance selector switch to 4 Ohms.

But, I also have a Peavey Pro 410 cab, which is 4 Ohms.

I was thinking, if I want more volume than I get from just the two Aggie cabs, I can daisy chain the two Aggie cabs, so they're both being driven by one of the speaker output jacks from the amp, and then I can connect the Peavey cab to the other speaker jack on the amp. Then set the amp impedance selector switch to 2 Ohms.

Right? This should be "safe" as far as the rated specs of the amp and all 3 cabs, right? (All 3 cabs are rated for at least 300W, which is what the amp is rated at)
 

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