Series and Parallel help

bassclef216 · #1 01-18-2011, 09:16 PM

I'm sure I'll be told that I should have used the search but I did. I searched "series", "parallel" and "series vs parallel" and found nothing. Here is my question...

1. Head has 1 speaker output and I plug one 1/4" speaker cable into it and then run it to 1 cab.....That is simple.

2. Head has 1 speaker output and I run one speaker cable to one cab with two 1/4" input/output jacks. Then take another speaker cable from the second jack into a second cab. What is that? Series or parallel?

3. Head has two 1/4" speaker output jacks. I do the same as I did in #2...any different?

4. Head has two 1/4" speaker output jacks. I take one cable from one jack and plug it into one cab. Then I take a second speaker cable and go from the head's other output jack and go into a second cab....is that series or parallel?

5. If the head has two speaker out jacks should I use them both if I have two cabs? or is it the same thing to use one output jack from the head and just go from one cab to the next. Is one better than the other?

I heard one guy on here say that he saw a guitar center sales guy plug a head with two outputs into one cab via both cab inputs using two cables. What would that do?

bassclef216 · #2 01-18-2011, 09:43 PM

I'm so confused...

This is from the Hartke site:

"Here is the tricky, yet simple rule of impedance: When two speakers, of equal impedance
are wired in "Parallel", the total impedance is cut in half and when two speakers are wired in “Series”, the total impedance is the sum of the speakers individual impedance."

Then they go on to diagram what I used in example 2 and call that parallel. So if I run a cable from each output from the head into two 8 ohm cabs is that now 16 ohms of resistance?

christw · #3 01-18-2011, 09:48 PM

Okay, let me give this a shot. prd004 has daisy chaining mixed up with series wiring.

#2 There is a 99% chance that this is parallel. Input/Output jacks on cabinets are like using both speaker jacks on the back of your amp. You have two cabinets in parallel. This use of input/output is called daisy chaining and people tend to do this so that you can hook up 3+ cabinets to an amp with 2 outputs.

#3 Same as #2 and parallel. It is NOT series unless the head explicitly states on it's power section or in the manual that the speaker jacks are in series.

#4 Again, this is in parallel unless the head or its manual explicitly states otherwise.

#5 It's the same as daisy chaining. Do whatever you want to.

ia02 · #4 01-18-2011, 09:49 PM

Quote:

Originally Posted by prd004

#2 Series
#3 No different than #2
#4 Paralell
#5 If the cabs are both the same ohm, no difference

Series is anything in a continual chain ie one unit plugged into another, plugged into another etc.
Paralell is two (or more) seperate chains

I believe all this to be correct, if not I'm sure someone will correct me!

Sorry to say but are incorrect. The OP's questions depend entirely on what particular cab and amp he/she is using.

For example, if the OP were using a Markbass LM2 head and two Markbass cabs the answer to #2, #3, #4 would all be parallel. This is because the output jacks on the amp are parallel output jacks and the input jacks on the cabs are wired in parallel as well. No matter how you hooked them up the cabs would still be wired in parallel.

However this is not a rule of thumb. It is possible that the output jacks on the amp or the input jacks on the cab could be wired in series (not common but possible in theory).

It is important to understand how the cabs and amp outputs are wired so that you can calculate impedance to ensure your particular combo of cabs will not exceed your amps specified range.

The only general rule of thumb here is that #5 is both pointless and probably not a good idea. Unless the head and cab are a biamp setup but that is a whole different animal.

Check out http://www.bcae1.com/spkrmlti.htm for basic series/parallel info.

christw · #5 01-18-2011, 09:51 PM

Quote:

Originally Posted by bassclef216

I'm so confused...

This is from the Hartke site:

"Here is the tricky, yet simple rule of impedance: When two speakers, of equal impedance
are wired in "Parallel", the total impedance is cut in half and when two speakers are wired in “Series”, the total impedance is the sum of the speakers individual impedance."

Then they go on to diagram what I used in example 2 and call that parallel. So if I run a cable from each output from the head into two 8 ohm cabs is that now 16 ohms of resistance?

Addressing this now... No. If you daisy chain the two cabinets, they are running in parallel and your total impedance will be 4 ohms.

billfitzmaurice · #6 01-18-2011, 09:59 PM

Unless specifically noted otherwise in the owner's manual amps have parallel outputs, cabs have parallel inputs. Series connections usually can only be realized with specially made series cables. Eden Nemesis combos are one example of an amp with series output jacks. It's an exception to the rule.

prd004 · #7 01-18-2011, 10:03 PM

Since I was incorrect I deleted my posts, not because my butt hurt from being wrong, LOL!

Remus_Redbone · #8 01-18-2011, 10:19 PM

#2 still parallel.

#3. still parallel

4. Still parallel

5. Does not matter. Dual jacks in amps and speaker cabinets are wired in parallel 99.99% of the time.

Series requires that you connect one "pole" (+ or -) of the amp to the opposite pole on the speaker and continue connecting opposite poles until you return to the amp. That requires splitting a speaker cable.

Here's an attempt at a series schematic using an IPOD touch.
•• = wire. You have to imagine there's only one amp with a + and - terminal even though the word is shown twice.

-amp+•••••-speaker+•••••-speaker+•••••-amp+

bowtieman427 · #9 01-18-2011, 10:21 PM

How is your AMP rated ? You want to match amp impeadance to Speaker impeadance.
Parallel 1 / ((1/R1) +....+ (1/Rx)) = Rtp
Series R1 +...+ Rx = Rts
lets do some examples
2 x 4 ohm speakers
Parallel 1/(( 1/4+1/4)) = 2 ohms
series 4+4 = 8 ohms

ErnieD · #10 01-19-2011, 01:28 AM

"I heard one guy on here say that he saw a guitar center sales guy plug a head with two outputs into one cab via both cab inputs using two cables. What would that do?"

Your last query shown above did not have a # to it. But I feel its the most important one you should know. If I understand what your writing here, then NO, you don't want to plug two cables from the back of the head into the two inputs on back of a single cab.

Then again, I've not seen where you've posted what kinda gear you're using. But typically this, no es bueno.

Brendan5 · #11 01-19-2011, 02:17 AM

Two cables from one amp to one cab in parallel should be fine, it is just redundant. It doesn't change the impedance of either.

Wes Whitmore · #12 01-19-2011, 05:58 AM

I think I was the one who posted that about seeing a sales guy at guitar center plug two 1/4" speaker cables out of the back of a Ampeg micro VR into both 1/4" inputs of a 410HLF. If they are the same length, then it should be the same as just using a bigger wire since both outputs of the amp are parallel, and both inputs on the crossover are parallel. Regardless, it's not needed.
W

billfitzmaurice · #13 01-19-2011, 06:32 AM

Quote:

Originally Posted by Wes Whitmore

I think I was the one who posted that about seeing a sales guy at guitar center plug two 1/4" speaker cables out of the back of a Ampeg micro VR into both 1/4" inputs of a 410HLF. Regardless, it's not needed.

It is, however, potentially dangerous if somehow one of the cords has the polarity flipped, which would create a dead short.

Wes Whitmore · #14 01-19-2011, 06:54 AM

Quote:

Originally Posted by billfitzmaurice

It is, however, potentially dangerous if somehow one of the cords has the polarity flipped, which would create a dead short.

Very true. I dont know how many cables come with the polarity flipped on one end, but it would only take one...I will remember to tell the sales guy the next time I am in there.

bassclef216 · #15 01-19-2011, 07:13 AM

Thaks everyone. That was very helpful. As far as what equipment I was using I was basing this off of something like a Gk goldline head (4 ohms) which has two speaker outputs, and going into something like one or two 8 ohm gk cabs with dual 1/4 inch I/O jacks. And as I am realizing the two output jacks on the head would be so that you can use 2 cabs if each cabs only had one input jack. I am also getting that if the cabs have two I/O jacks it does not matter if you run a line to each from the head or if you daisy chain them.

ia02 · #16 01-19-2011, 07:34 AM

Quote:

Originally Posted by bassclef216

Thaks everyone. That was very helpful. As far as what equipment I was using I was basing this off of something like a Gk goldline head (4 ohms) which has two speaker outputs, and going into something like one or two 8 ohm gk cabs with dual 1/4 inch I/O jacks. And as I am realizing the two output jacks on the head would be so that you can use 2 cabs if each cabs only had one input jack. I am also getting that if the cabs have two I/O jacks it does not matter if you run a line to each from the head or if you daisy chain them.

you are correct

JTE · #17 01-19-2011, 07:47 AM

MOST amps and cabinets have the jacks wired in parallel, and THAT is what determines how the electrons flow. The physical layout can be different but the way the jacks are wired is the only thing that matters. But some few do have series wiring (e.g. the original Music Man amps from the '70s, at least one Eden/Nemesis combo amp) so it's important to know YOUR gear.

John