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Post by nicholas on Nov 30, 2018 18:11:19 GMT -7
I don't quite understand the speaker impedance options on the Nova. I'm trying to decide between the head or combo and was pretty sure I'd go for the head. But it looks like it can only run an 8 ohm speaker. However it does have two speaker output jacks. Currently I only have multiple speaker cabs wired at 16 ohms.
I'm not really understanding it though. How do the two jacks work. I would think they are parallel? So you could run an 8 ohm cab, or two 16 ohm cabs? How does that work then in the combo with the included speaker?
I really wanted to use the head with my 16 ohm Marshall 1960 cab. My Zplus sounded great through it. But if that won't work the combo looks like the next best thing.
Any info is appreciated. I might be missing something obvious lol.
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Post by nicholas on Nov 30, 2018 18:49:05 GMT -7
I downloaded the manual from Z's site. Who would have thought there would be useful info in a manual? Lol. I still don't really understand it. As usually if they are parallel then plugging in another cab would require halving the impedance. But it says you can run two 8 ohm cabs. So if I flip the switch on my Marshall cab to stereo it splits it into two 8 ohm cabs. So I could then just use two speaker cables from the head to the cab? Maybe Z used a switching jack on the external out speaker? I don't get it. If the speaker outs are parallel, how can you run one 8, or two 8's? Curious overactive minds need to know!
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Post by detuned on Nov 30, 2018 19:14:24 GMT -7
If I'm reading that correctly, the Nova expects to see an 8 ohm load, but will tolerate a 4 ohm load fine. That's why you can add a second 8 ohm load. Lots of old Fenders are like that too. The tranny is pretty tough, within reason.
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Post by premiumplus (Dave) on Nov 30, 2018 19:17:22 GMT -7
That's right. It works fine with 8 ohm and 4 ohm loads. The two jacks are connected in parallel in the amp's chassis.
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Post by nicholas on Nov 30, 2018 19:56:16 GMT -7
Thanks guys. So I could just plug into the 4 ohm input on my cab to the internal soeaker jack on the Nova. I've never tried a miss match in that direction. How would it sound different? I've gone the other way and it is usually less output, smoother, and less defined. Somebody plug you Nova into a 412 and let it rip. Lemme know
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Post by premiumplus (Dave) on Dec 1, 2018 8:53:03 GMT -7
Thanks guys. So I could just plug into the 4 ohm input on my cab to the internal soeaker jack on the Nova. I've never tried a miss match in that direction. How would it sound different? I've gone the other way and it is usually less output, smoother, and less defined. Somebody plug you Nova into a 412 and let it rip. Lemme know If you set your 4x12 cab to 4 ohms, you should unplug the internal speaker in the Nova and you're good to go. Mine does NOT disconnect the internal speaker. My Nova doesn't have a switching jack, it connects in parallel whatever you plug into the external jack. Both speaker jacks are wired together in parallel.
So if you have the 8 ohm internal speaker connected and plug in a cab that is set to 4 ohms the impedance that the amp sees is going to be 2.66 ohms, and unless Doc says this is okay I would not do that. Doc, if you see this could you please elaborate?
Regarding the mismatch, if you had the 4x12 plugged in set at 16 ohms with the internal Nova speaker at 8 ohms, the impedance the amp sees would be 5.33 ohms. By Ohm's Law the single 8 ohm 12" would pull twice the current that the 4x12 does, making the Nova's speaker considerably louder than the 4x12...not what you're looking for, right?
If it were me, I'd use one or the other, not both.
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Post by nicholas on Dec 1, 2018 10:01:37 GMT -7
^ yeah, I was talking just about using the Nova head with a single cab. On the Marshall cabs you can plug in at 16 series/parallel, or 4 ohms all parallel. My wording was a bit confusing regarding the combo.
I was thinking there might be some internal switching that changed impedance taps if both jacks were used. But from what I gather it's set up as a straight 8 ohm load with standard parallel jacks, no impeadamce selection tap options. But it will tolerate a mismatch.
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Post by Chilly Gibbons (Todd T.) on Dec 1, 2018 11:15:55 GMT -7
If I’m reading this correctly, with a head, you should be able to use you cabinet in stereo mode with a cable from each jack to each side of the cab for a total 4 ohm load on the OT. Thank goodness for the switch on the cab, or you’d have to rewire it to all ||.
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Post by premiumplus (Dave) on Dec 1, 2018 17:24:37 GMT -7
Switching the cab to 4 ohms and using only one cable accomplishes the same thing. Unplug any other speaker output.
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Post by doctorice on Dec 2, 2018 7:33:30 GMT -7
Nick, you could check with Z or Don to be sure, but I suspect the OT has 8- and 4-ohm taps. That's what I infer from the instructions. I can't opine on how well or poorly the Nova's OT handles impedance mismatches.
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Post by DRZ on Dec 2, 2018 17:06:36 GMT -7
I don't quite understand the speaker impedance options on the Nova. I'm trying to decide between the head or combo and was pretty sure I'd go for the head. But it looks like it can only run an 8 ohm speaker. However it does have two speaker output jacks. Currently I only have multiple speaker cabs wired at 16 ohms. I'm not really understanding it though. How do the two jacks work. I would think they are parallel? So you could run an 8 ohm cab, or two 16 ohm cabs? How does that work then in the combo with the included speaker? I really wanted to use the head with my 16 ohm Marshall 1960 cab. My Zplus sounded great through it. But if that won't work the combo looks like the next best thing. Any info is appreciated. I might be missing something obvious lol. OK I have seen this thread and thought I might shed some light on it. The NOVA uses an original Triad Tweed output transformer. As with all Tweed OT's they are, to use an industry term " Wound on a Stick ", paper former , non interweaved , single secondary impedance. The same as all original Blackface Fenders OT's that utilize full wound single output impedance designed for the combo amp of use. This is a very vintage way of building an Output Transformer and is responsible for there unique warm, rich, and thick overdriven tone. That is why I chose this design. So yes the NOVA has only one single 8 ohm out Internal , and a paralleled External speaker out. As with all Vintage Fender amps they will tolerate a mismatched load to some degree, as all Blackface amps do have a paralleled speaker jack, but only one true output impedance. So you can mismatch a NOVA head with two 8 ohm loads without damage, but two 16 ohm loads would be ideal if a dual speaker cab set is needed. Multi tapped Interweaved Output Transformers came into play with British designed amps , since most were designed a Heads for the most part, the multiple taps were a useful feature , but not always the most tone full answer. Nothing is free in design engineering , gain something lose something. Z
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Post by nmz on Dec 3, 2018 18:56:04 GMT -7
I ran two cabs both 8ohm last week and it was glorious!
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Post by nicholas on Dec 4, 2018 13:50:27 GMT -7
I don't quite understand the speaker impedance options on the Nova. I'm trying to decide between the head or combo and was pretty sure I'd go for the head. But it looks like it can only run an 8 ohm speaker. However it does have two speaker output jacks. Currently I only have multiple speaker cabs wired at 16 ohms. I'm not really understanding it though. How do the two jacks work. I would think they are parallel? So you could run an 8 ohm cab, or two 16 ohm cabs? How does that work then in the combo with the included speaker? I really wanted to use the head with my 16 ohm Marshall 1960 cab. My Zplus sounded great through it. But if that won't work the combo looks like the next best thing. Any info is appreciated. I might be missing something obvious lol. OK I have seen this thread and thought I might shed some light on it. The NOVA uses an original Triad Tweed output transformer. As with all Tweed OT's they are, to use an industry term " Wound on a Stick ", paper former , non interweaved , single secondary impedance. The same as all original Blackface Fenders OT's that utilize full wound single output impedance designed for the combo amp of use. This is a very vintage way of building an Output Transformer and is responsible for there unique warm, rich, and thick overdriven tone. That is why I chose this design. So yes the NOVA has only one single 8 ohm out Internal , and a paralleled External speaker out. As with all Vintage Fender amps they will tolerate a mismatched load to some degree, as all Blackface amps do have a paralleled speaker jack, but only one true output impedance. So you can mismatch a NOVA head with two 8 ohm loads without damage, but two 16 ohm loads would be ideal if a dual speaker cab set is needed. Multi tapped Interweaved Output Transformers came into play with British designed amps , since most were designed a Heads for the most part, the multiple taps were a useful feature , but not always the most tone full answer. Nothing is free in design engineering , gain something lose something. Z Thanks for the detailed information!
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Post by nicholas on Dec 4, 2018 13:58:15 GMT -7
I ran two cabs both 8ohm last week and it was glorious! Nice. If there was any difference could you put it into words? I'm actually thinking I might go with the combo over the head. I really like combo amps in general and only have one right now, my JAZ. I have a few heads I like already. Also because I currently only have 16/4 ohm cabinets my OCD would probably make me buy another cab wired to 8 ohms. Not looking to get into all that... Man that Lance demo. It's got my wallet twitching.
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Post by nmz on Dec 4, 2018 14:27:00 GMT -7
No “difference” other than what you would expect from adding another cab (I have a head). Just bigger, more air movement etc.
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Post by nicholas on Dec 4, 2018 14:55:36 GMT -7
No “difference” other than what you would expect from adding another cab (I have a head). Just bigger, more air movement etc. Nice. Thanks!
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