| Author |
Topic: Can I replace a 16 ohm speaker with a 4 ohm? |
George Kimery
From:
Limestone, TN, USA
|
Posted 2 Jul 2014 7:02 am |
|
I picked up a Peavey Valve King 112 tube amp yesterday. It has the stock, VK speaker in it, which is 16 ohms. I have an Eminence EPS 12c that I believe is a 4 ohm speaker that I would like to try in the VK. Are these two speakers interchangeable? If I install the EPS-12c, will I damage the speaker or the amp, or will the EPS 12c just not sound the way it should.
Late breaking news: I just checked the rear panel and the only reference to ohms is on the external speaker jack and it says a minium of 16 ohms. So I am assuming I should stay away from a speaker less than 16 ohms.
Last edited by George Kimery on 2 Jul 2014 7:25 am; edited 1 time in total |
|
|
|
Lane Gray
From:
Topeka, KS
|
Posted 2 Jul 2014 7:16 am
|
|
That amp wants to see 16 ohms minimum. I just checked the owner's manual, which you can download as a PDF.
I don't recall whether the tubes or output transformer have problems with running out of spec, but you're talking a quarter of the desired load.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
|
|
|
Bill Duncan
From:
Lenoir, North Carolina, USA
|
Posted 2 Jul 2014 7:24 am
|
|
Lane, I am running 8 ohms in mine. On the back panel of the amp at the speaker jacks it says 4 ohms minimum.
_________________
You can observe a lot just by looking |
|
|
|
George Kimery
From:
Limestone, TN, USA
|
Posted 2 Jul 2014 7:29 am Can I replace a 16 ohm speaker with a 4 ohm?
|
|
| Lane, I just edited my post to the effect that on the back panel of the amp, the only reference to ohms is on the external speaker out and it says a minimum of 16 ohms. Perhaps my amp is an older or newer model than Bills when Peavey changed what is written on the back of the amp concerning minimum ohms. |
|
|
|
Bill Duncan
From:
Lenoir, North Carolina, USA
|
Posted 2 Jul 2014 7:38 am Re: Can I replace a 16 ohm speaker with a 4 ohm?
|
|
| George Kimery wrote: |
| Lane, I just edited my post to the effect that on the back panel of the amp, the only reference to ohms is on the external speaker out and it says a minimum of 16 ohms. Perhaps my amp is an older or newer model than Bills when Peavey changed what is written on the back of the amp concerning minimum ohms. |
George, in that case please disregard what I said. My VK says 4 ohms minimum, so evidently ours are of different series. Bill
_________________
You can observe a lot just by looking |
|
|
|
Lane Gray
From:
Topeka, KS
|
Posted 2 Jul 2014 7:57 am
|
|
George,.if you google valve king owner's manual, you can download it.
The internal speaker is 16, and the external jack disconnects the internal speaker.
Bill, are you sure yours is the 112?
The other Valve Kings have different specs.
George, if you're playing country pedal steel through it, leave it on AB. If you play sacred steel, rock and roll or blues, especially lap steel, experiment with more towards the A. The class A will give you more breakup and tubey compression.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects
Last edited by Lane Gray on 2 Jul 2014 8:14 am; edited 1 time in total |
|
|
|
Bill Duncan
From:
Lenoir, North Carolina, USA
|
Posted 2 Jul 2014 8:07 am
|
|
Lane, Yes, I have both the 112 - 50 watt, and the 212 - 100 watt amps. However, Peavey reissued and updated the Valve Kings recently. I am using using single 8 ohm speakers in both of my Valve Kings. A 12" in the 50 watt and a 15" in the 100 watt.
_________________
You can observe a lot just by looking |
|
|
|
Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
|
Posted 2 Jul 2014 10:24 am
|
|
The Valve King is a tube amp with an output transformer. If the original speaker is 16 Ohms, it means that the output transformer was designed for a 16 Ohm load, and that's what it prefers to see.
Here's the blurb from the manual on the VK 112:
| Quote: |
EXTERNAL SPEAKER JACK
Provided for connection of external speaker cabinet(s). Minimum external speaker impedance is 16 Ω on the ValveKing112. This disconnects the internal speaker in the ValveKing 112. Load Impedance is selectable via the IMPEDANCE SELECTOR (25) on the ValveKing 212 and ValveKing 100 Head. |
This is telling you that the amp wants a 16 Ohm load, period. That's Peavey's 'party line' on this - don't mismatch impedances. My guess: likely if you do and something bad happens and they know you've messed with the load impedance, it will void your warranty.
All that said, if an output transformer is fairly robust (like on an old handwired Fender silverface amp), some (but not all) tube amps can handle a mismatched impedance of up to 100% in the lower impedance direction. For a 16 Ohm speaker load amp, that would imply not less than an 8 Ohm speaker load. I would not do a higher impedance, as this can result in what is known as a high flyback voltage to the transformer - a significant voltage is not dropped at the load, and a high voltage can get reflected back to the output transformer. This can result in arcing at the transformer and premature failure. Again, it depends on the transformer and circuit design. But unless you think you know more than the manufacturer, I just wouldn't use a higher impedance load than expected, no matter what.
But here they're telling you to use the correct impedance load. I would just do that - perhaps it's just a CYA thing, but perhaps Peavey is saying something here about what works and what doesn't. For example, I would never mismatch impedances on, let's say, an old Marshall. Part of it is that the circuit/transformer is more sensitive, and part of it is that higher-distortion amp signals have a longer duty cycle, which is harder on the system.
No matter what, I would absolutely not use a 4 Ohm load for a 16 Ohm system, period. 8 Ohms maybe, but that is as low as I would ever go, no matter what. |
|
|
|
Billy Henderson
From:
Portland, AR, USA
|
Posted 2 Jul 2014 5:27 pm Valveking
|
|
| I called the Peavey tech he said I could run an 8ohm speaker in place of the 16 ohm. Now I want to play a tele through it. So please tell me which speaker is best for the classic country and blues. Thanks |
|
|
|
Lane Gray
From:
Topeka, KS
|
Posted 2 Jul 2014 5:49 pm
|
|
I'd choose a clean steel-friendly speaker like an 8 ohm BW, JBL, EPS.12, et c. If you want grit for the blues, run that knob over to class A.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
|
|
|
George Kimery
From:
Limestone, TN, USA
|
Posted 2 Jul 2014 6:47 pm Can I replace a 16 ohm speaker with a 4 ohm?
|
|
I downloaded the owner's manual and they are showing a control on the back of the amp to select 16, 8, or 4 ohm. Evidently, the used amp I bought is an earlier model without this feature, darn it.
Thanks for the help. I am not going to put another speaker in it except a 16 or 8 ohm. I think I would be asking for trouble, big time. |
|
|
|
Dave Mudgett
From:
Central Pennsylvania and Gallatin, Tennessee
|
Posted 2 Jul 2014 7:46 pm
|
|
As the blurb I quoted above says, the impedance selector switch is only on the VK 212 combo and 100-watt head. The VK 112 never had this switch - I got one of these from Bobbe Seymour when they first came out several years back - no impedance selector switch on the 112 all the way back to its inception.
I think you're probably safe with an 8 Ohm speaker, but if you have a problem, I'd say "mum's the word".  |
|
|
|
George Kimery
From:
Limestone, TN, USA
|
Posted 3 Jul 2014 5:51 am Can I replaced a 16 ohm speaker with a 4 ohm?
|
|
| Dave, thank you for straightening me out. Now I feel better. Perhaps the amp is a later model, not that makes it better. A lot of the time, the older models on a lot of things were the best before the cost cutting gremlin got involved. |
|
|
|
Lane Gray
From:
Topeka, KS
|
Posted 3 Jul 2014 6:58 am
|
|
George, the manual requires careful reading, as it covers all the VK models, and the 112 has several different specs.
It sounds like a good amp, provided you can get a good midrange tone in the absence of a Shift knob.
_________________
2 pedal steels, a lapStrat, and an 8-string Dobro (and 3 ukes)
More amps than guitars, and not many effects |
|
|
|
