Sgt. Posted January 11, 2013 Share Posted January 11, 2013 jan. 10/2013 i run two single 8ohm 1x12 cabs in stereo (one 30watt alnico and the other 80 watt ceramic) from a 15watt tube head, which has inputs for two 8ohm speakers. in stereo do you add the speaker wattage together, for example, 30+80 = 110 watts output total. it seems that the 80 watt in mono sounds louder. also i sometimes forget and plug one 8ohm speaker into the 1x16ohm input and the other into the 1x8ohm input. is this just cutting the power going to one 8ohm speaker or is it dangerous. just trying to understand the load when running two single 1x12's. i kind of understand when speakers are wired in series and parallel that the impedance either is divided in two for example, two 8ohm speakers wired in series delivers a 16ohm load to the amp, and the opposite with parallel, delivering 4ohm load to amp. what happens with stereo 8ohm speakers (seperate single 12" speaker cabs) going to an amp that has inputs for 1x4, 1x8, 2x8, 1x16, and 2x16? I don't know exactly what impedance the amp is. i figure it must be 4 ohm because it can handle a single 4ohm speaker, and 8ohm speakers with a 4ohm amp deliver half power, and a 16ohm speaker delivers a quarter power. it would be dangerous to go the other way and load a 2 ohm speaker load into a 4 ohm amp. Oh and while on this topic, another question: considering the description of the amp and it's various speaker inputs, could I plug one 8ohm speaker and another 16ohm speaker in stereo? would it balance the load? The owner's manual just doesn't go into depth on this topic. Ibanez TSA15h Celestion 70/80 8ohm 80 watt speaker Weber Classic Alnico 8ohm 30 watt speaker (optional) Eminence Lady Luck 16ohm 70 watt speaker What would happen if I plugged in all three? Link to comment Share on other sites More sharing options...
stein Posted January 11, 2013 Share Posted January 11, 2013 I'm not totally kmowledgeable on technical aspects, but here is a few pointers as simple as I can explain. The amps power is always the same. The connection between the amp and speaker is through the output transformer. The output transformer will have different "taps" for different loads. Think of electricity like a water tank. Water does not flow if the faucet is off. Changing impedence affects the faucet, not the total water available. So if a power amp has to "push" harder depending on how the faucet is set, the result isn't more or less power available, it's a matter of how much damage you can do when making it push it's power through. This is why a different tap on the tranformer might seem more or less in power. When the valve at one end is more shut, you increase it at the other end (that would be the volume control). When comparing speakers, it's a lot different. "Sensitivity" is the measurement of efficiency. A more efficient speaker will make more volume per watt. Higher wattage speakers almost always are more efficient. When 2 speakers are hooked up together, if the sensitivity of one is a lot different than the other, it will be different in volume. It is perfectly safe to mix impedences of speakers, so long as the total of the two together are within the range of what if safe for the particular amp. Different amps have different tolerances. THAT info as to what the tolerances are, you have to get that from someone who knows the amp, because there aren't rules for it. Example: most Fender amps can handle a 100% mismatch, such as a 4 ohm speaker on an 8 ohm tranny. A marshall usually can not. So, in short, don't worry about mixing un-like speakers, worry about the totals being within safe for the particualr amp. And for different percieved volumes coming from different speakers, look at the sensitivity ratings. Link to comment Share on other sites More sharing options...
DiamondJig Posted January 11, 2013 Share Posted January 11, 2013 The TSA15H is not a stereo amp, it a mono amp. You can't use the different ohm taps at the same time. You want to use the 2x8 ohms, this is for connecting 2 8ohm cabs total load 4ohms, you connect one speaker to the 2x8 ohm output and the other to the 1x4ohm output, they are wired in parrallel. The 2x16 is for 2 16 ohm cabs one in the 2x16 the other in the 1x8ohm, and the single at what they are. You add the watt ratting together so if you connect your 30watt 8 ohm and 80 watt 8 ohm they will handle 110watts and they will be 4 ohms to the amp. You can't mix any of the outputs. Link to comment Share on other sites More sharing options...
rct Posted January 12, 2013 Share Posted January 12, 2013 This will be brief, mainly because you think you are doing something you are not doing, so you need to rethink this. Your amp is not stereo. Using two outs does not make stereo, it just means you are using two outs. 1x4, 1x8, all that, it's all just 4, 8, 16 ohm taps off the output transformer. Ohms are a measure of impedance, that is resistance, not power. Your speaker(s) provide x impedance to the output transformer, in ohms. If the transformer has a 16 ohm tap and you show it 4 ohms of resistance, you could have a problem. And vice versa. Degraded sound, too much "distortion", outright blowing up the amp, these are the things that impedance mismatch can do. You can also play forever with mismatched impedance and never have a problem. I've done it. SS amps are better at impedance mismatch than tube amps. The wattage rating of the speakers is nothing more than approximate maximum power, in watts, they can handle, for some vague amount of time. They do not get added together, they do not equal output, they do not mean anything like that. Yer amp can maybe push 15 watts for some specified time, little over, little under most of the time. Yer amp doesn't care about the power ratings of your speakers, only the impedance. If your speakers show the wrong load to the amp for too long a time the amp will complain or die, usually spectacularly as any 70's Marshall user can testify. Your speakers don't care about the power rating of your amp unless it delivers too much heat for too long a time, then they don't work anymore. Stop what you are doing, get a book or two about basic electricity as it applies to sound reproduction, and above all, stop with the stereo stuff. Yer nowhere near anything remotely resembling stereo. rct Link to comment Share on other sites More sharing options...
Sgt. Posted January 13, 2013 Author Share Posted January 13, 2013 jan. 10/2013 i run two single 8ohm 1x12 cabs in stereo (one 30watt alnico and the other 80 watt ceramic) from a 15watt tube head, which has inputs for two 8ohm speakers. in stereo do you add the speaker wattage together, for example, 30+80 = 110 watts output total. it seems that the 80 watt in mono sounds louder. also i sometimes forget and plug one 8ohm speaker into the 1x16ohm input and the other into the 1x8ohm input. is this just cutting the power going to one 8ohm speaker or is it dangerous. just trying to understand the load when running two single 1x12's. i kind of understand when speakers are wired in series and parallel that the impedance either is divided in two for example, two 8ohm speakers wired in series delivers a 16ohm load to the amp, and the opposite with parallel, delivering 4ohm load to amp. what happens with stereo 8ohm speakers (seperate single 12" speaker cabs) going to an amp that has inputs for 1x4, 1x8, 2x8, 1x16, and 2x16? I don't know exactly what impedance the amp is. i figure it must be 4 ohm because it can handle a single 4ohm speaker, and 8ohm speakers with a 4ohm amp deliver half power, and a 16ohm speaker delivers a quarter power. it would be dangerous to go the other way and load a 2 ohm speaker load into a 4 ohm amp. Oh and while on this topic, another question: considering the description of the amp and it's various speaker inputs, could I plug one 8ohm speaker and another 16ohm speaker in stereo? would it balance the load? The owner's manual just doesn't go into depth on this topic. Ibanez TSA15h Celestion 70/80 8ohm 80 watt speaker Weber Classic Alnico 8ohm 30 watt speaker (optional) Eminence Lady Luck 16ohm 70 watt speaker What would happen if I plugged in all three? Yes, i am off the mark a bit ... the tsa15 is not a 'stereo' amp so it's not sending a stereo signal. maybe two tsa15's together ... it's just a mono signal with two speakers out and two separate 1x12 8ohm cabs are not stereo but parallel, making a 4 ohm load. there's many variables that make up the tone of the rig and that's why i ask questions for clarification. i don't know everything, but i learn ... ! are there 'stereo' amplifiers and 'stereo' cabinets? just curious would the cables be identifiable like a TRS, with an extra band around the 1/4" plug? yeah it can be confusing a litte, since i use pedals with 'stereo' outs and i've split the signal that way between the tsa15 and a smaller 5w combo. To think of an example of what 'stereo' is cool for is delay, the echo bounces back and forth from amp to amp. you may be able to clarify this further ... i am not using trs (stereo) cables with the 'stereo' pedals. maybe that's an equipment question for the sales guy at the music store. reference Wikipedia "guitar speakers" Link to comment Share on other sites More sharing options...
rct Posted January 13, 2013 Share Posted January 13, 2013 Yes, i am off the mark a bit ... the tsa15 is not a 'stereo' amp so it's not sending a stereo signal. maybe two tsa15's together ... it's just a mono signal with two speakers out and two separate 1x12 8ohm cabs are not stereo but parallel, making a 4 ohm load. there's many variables that make up the tone of the rig and that's why i ask questions for clarification. i don't know everything, but i learn ... ! are there 'stereo' amplifiers and 'stereo' cabinets? just curious would the cables be identifiable like a TRS, with an extra band around the 1/4" plug? yeah it can be confusing a litte, since i use pedals with 'stereo' outs and i've split the signal that way between the tsa15 and a smaller 5w combo. To think of an example of what 'stereo' is cool for is delay, the echo bounces back and forth from amp to amp. you may be able to clarify this further ... i am not using trs (stereo) cables with the 'stereo' pedals. maybe that's an equipment question for the sales guy at the music store. k. hmmm... There are stereo amps, Roland JCs come to mind, and in the glorious 80's we used racks of stereo pre and power amps. Others will come along with other amps, I didn't and don't dabble in that much. TRS, tip ring sleeve, will carry stereo signals, or one signal one way and one the other. For consistency and no doubts, I use all TRS in my studio for anything that is not a speaker cable, or my one main guitar cable that I use for everything. If I want to what you are talking about, I do this: Guitar to A/B box. I use ART CoolSwitch. Two outs from the A/B, one goes to one amp, usually Princeton Recording. That stays there, that amp is used straight as it is, clean or dirty. OR, that out goes over to the rack, to some digital thingy or other, Behringer, Line6 thing, a digital modeler, something like that. The other out leaves the A/B and goes to another A/B box, another ART Cool Switch. The two outs from the second A/B go one to Prosonic, and one to old Marshall DSL 401. You with me? Now I have three lines out to three different things. At the two amps, Prosonic and DSL, I go out the effects loop of each. Marshall is on the left, Prosonic is on the right. These outs I send via TRS over to the Rack Of Doom, to usually a TCElectronics GMajor. It has a left and a right in. Marshall goes in left, Prosonic goes in right. It also has right and left returns, and I send them via TRS back to the two amps to their respective returns. Still there? So I have two amps, each effect loop send and return to and from a stereo device that creates stereo field delays and verbs and stuff. The stereo work is done by the digital device and he happily sends it out to whatever is at the other end. The two amps make gloriously fun huge stereo fields of Green Grass and High Tides, and it's a damn hoot and I'm seventeen again and sucking on a bottlea beer but not choking any Marlbls and it sounds heavenly. Recording it, however, is another matter altogether. But I have the stereo field to start trying to capture the best I can, along with a third out that can be left clean and dry but loud. Start mixing the three up with pans and fades and you can start making some pretty cool things happen. Then you take a break for lunch and can't remember how you did it and you start over again. You can do what you want to do, definitely. It just isn't as simple as it might seem at first. There are other ways to do it, and if I don't feel like it I just use the simulation boxes in the recording rack to get them delays side to side and pick slides from left to right and all that 70s tomfoolery. If you have a stereo pedal, it probably wants you to send the outs to two amps. I do not use pedals, others will tell you about that stuff. Yeesh. Way too much information. Feel free to ask, I'll try to be less confusing. rct Link to comment Share on other sites More sharing options...
Sgt. Posted January 13, 2013 Author Share Posted January 13, 2013 k. hmmm... There are stereo amps, Roland JCs come to mind, and in the glorious 80's we used racks of stereo pre and power amps. Others will come along with other amps, I didn't and don't dabble in that much. TRS, tip ring sleeve, will carry stereo signals, or one signal one way and one the other. For consistency and no doubts, I use all TRS in my studio for anything that is not a speaker cable, or my one main guitar cable that I use for everything. If I want to what you are talking about, I do this: Guitar to A/B box. I use ART CoolSwitch. Two outs from the A/B, one goes to one amp, usually Princeton Recording. That stays there, that amp is used straight as it is, clean or dirty. OR, that out goes over to the rack, to some digital thingy or other, Behringer, Line6 thing, a digital modeler, something like that. The other out leaves the A/B and goes to another A/B box, another ART Cool Switch. The two outs from the second A/B go one to Prosonic, and one to old Marshall DSL 401. You with me? Now I have three lines out to three different things. At the two amps, Prosonic and DSL, I go out the effects loop of each. Marshall is on the left, Prosonic is on the right. These outs I send via TRS over to the Rack Of Doom, to usually a TCElectronics GMajor. It has a left and a right in. Marshall goes in left, Prosonic goes in right. It also has right and left returns, and I send them via TRS back to the two amps to their respective returns. Still there? So I have two amps, each effect loop send and return to and from a stereo device that creates stereo field delays and verbs and stuff. The stereo work is done by the digital device and he happily sends it out to whatever is at the other end. The two amps make gloriously fun huge stereo fields of Green Grass and High Tides, and it's a damn hoot and I'm seventeen again and sucking on a bottlea beer but not choking any Marlbls and it sounds heavenly. Recording it, however, is another matter altogether. But I have the stereo field to start trying to capture the best I can, along with a third out that can be left clean and dry but loud. Start mixing the three up with pans and fades and you can start making some pretty cool things happen. Then you take a break for lunch and can't remember how you did it and you start over again. You can do what you want to do, definitely. It just isn't as simple as it might seem at first. There are other ways to do it, and if I don't feel like it I just use the simulation boxes in the recording rack to get them delays side to side and pick slides from left to right and all that 70s tomfoolery. If you have a stereo pedal, it probably wants you to send the outs to two amps. I do not use pedals, others will tell you about that stuff. Yeesh. Way too much information. Feel free to ask, I'll try to be less confusing. rct WOW!!! yeah i like the side to side l to r delay! Link to comment Share on other sites More sharing options...
Sgt. Posted January 13, 2013 Author Share Posted January 13, 2013 Yes, i am off the mark a bit ... the tsa15 is not a 'stereo' amp so it's not sending a stereo signal. maybe two tsa15's together ... it's just a mono signal with two speakers out and two separate 1x12 8ohm cabs are not stereo but parallel, making a 4 ohm load. there's many variables that make up the tone of the rig and that's why i ask questions for clarification. i don't know everything, but i learn ... ! are there 'stereo' amplifiers and 'stereo' cabinets? just curious would the cables be identifiable like a TRS, with an extra band around the 1/4" plug? yeah it can be confusing a litte, since i use pedals with 'stereo' outs and i've split the signal that way between the tsa15 and a smaller 5w combo. To think of an example of what 'stereo' is cool for is delay, the echo bounces back and forth from amp to amp. you may be able to clarify this further ... i am not using trs (stereo) cables with the 'stereo' pedals. maybe that's an equipment question for the sales guy at the music store. reference Wikipedia "guitar speakers" http://www.ehow.com/facts_5865197_stereo-vs_-mono-guitar-amplifiers.html EHOW: Stereo Vs. Mono Guitar Amplifiers Link to comment Share on other sites More sharing options...
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