Can the speaker out ohms be easily changed?

George Kimery · Post by **George Kimery** » 7 Aug 2014 11:36 am

I am just exploring my options. My Valve King 112 is factory set at 16 ohms. I would like to try my Eminence EPS-12c in it, but the 16 ohm speaker output needs to be changed to 4 ohms. Is this minor or major surgery? The Valve King 212's have a 3 way switch that lets you select 4, 8, or 16 ohms, so it must not be that big of deal to change ohms.

Eminence will custom make an EPS 12 c in 16 ohms for $260.00. I don't want to spend that kind of money to just try it.

If I hook up my 4 ohm speaker to it, will I hurt the speaker or the amp and will the tone change going from a 16 ohm factory speaker to a 4 ohm Eminence? I am talking strickly the change in ohms affecting the tone, NOT the fact that there are different speakers involved.

If I just hook it up for a couple of minutes and keep the volume low, would that be safe? And most important, would I be hearing the same tone as if the amp was set for 4 ohms?

Lane Gray · Post by **Lane Gray** » 7 Aug 2014 12:00 pm

There are reports that the different coils will color the tone: that a 16 Ohm won't sound like an 8 or a 4.
As to the safety of a 4:1 mismatch, I couldn't say. I'd not bet on Peavey using the most robust transformers. Beefy costs money.

Curtis Alford · Post by **Curtis Alford** » 7 Aug 2014 6:01 pm

Your switch, you state, is tapped for 4,8,or 16 ohms.
If you select the 4 ohms position it should be for 4 ohm speaker. The transformer has 3 different taps for those ohm speakers

Lane Gray · Post by **Lane Gray** » 7 Aug 2014 6:05 pm

The 112 version lacks the switch. 16 ohm only.

Bobby Snell · Post by **Bobby Snell** » 7 Aug 2014 6:10 pm

Usually not a good idea to use an impedance mismatch.

The 212 has impedance switch but not the 112? Maybe a replacement transformer, one that has the variable switch, could be installed.

And the difference in tone from a variable transformer is very hard to discern.

Godfrey Arthur · Post by **Godfrey Arthur** » 8 Aug 2014 3:47 am

Not easily unless the stock tranny is set up for multi tap impedance where you'd get your amp tech to wire it for 4 ohms. Otherwise you'd need to swap the tranny that will give you 4 ohms. And then a different tranny will provide a different tone than the original.

Stephen Cowell · Post by **Stephen Cowell** » 8 Aug 2014 5:12 am

Weber makes a product just for this...

https://taweber.powweb.com/store/zmatch.htm

... it comes in 50 and 100W versions, so buy the one you need. Looks like the 100W is out of stock... popular, I guess... for only 20$ less, I don't see why folks would buy the 50w one anyway.

Jon Light · Post by **Jon Light** » 8 Aug 2014 5:40 am

FWIW, I have a 100W Z-Matcher, very lightly used in-house. It does what it's supposed to do.
Anyone needs it, I'll think about a price. Talk to me.

Sorry for the spam.

Bottom line---with an amp like an old Fender, I know from experience and reputation that it'll survive a mismatch between 4 & 8, 8 & 16. But even the Fender I would not test with a 4/16 mismatch.
I don't know of any other amps that has this same reputation for being so forgiving. Therefore I wouldn't test them.

Add to this the fact that trying the speaker at a low 'safe' volume is going to be so uninformative as to be hardly worth it. You will not at all learn what it really sounds like this way.

Tim Herbert · Post by **Tim Herbert** » 8 Aug 2014 6:15 am

Jon - PM sent.

Curtis Alford · Post by **Curtis Alford** » 8 Aug 2014 9:47 am

Did he not state his amp has 4,8,and 16 ohm selector switch. If so the tranny has three taps and is switchable.

Howard Parker · Post by **Howard Parker** » 8 Aug 2014 10:06 am

Nope.

George Kimery wrote: My Valve King 112 is factory set at 16 ohms.

h

Mitch Druckman · Post by **Mitch Druckman** » 8 Aug 2014 11:42 am

An additional $40 for a custom built 16 ohm version is not a bad deal.

Tim Marcus · Post by **Tim Marcus** » 8 Aug 2014 12:11 pm

putting a transformer after the output voids the warranty on my amps - not sure what Peaveys policy is, but I would advise against it.

The best way to change the output impedance is to replace the output transformer, and thats a BIG job on most amps.

Lane Gray · Post by **Lane Gray** » 8 Aug 2014 1:04 pm

Curtis Alford wrote:Did he not state his amp has 4,8,and 16 ohm selector switch. If so the tranny has three taps and is switchable.

Curtis, I downloaded the owner's manual and read it.
The 100W 212 version has the three taps, the 50W 112 is dedicated 16 ohm.

Curtis Alford · Post by **Curtis Alford** » 8 Aug 2014 6:35 pm

Lane, my bad I read that wrong about the switch.
Wonder if placing the 212 tranny in the 112 would be probable.

Stephen Cowell · Post by **Stephen Cowell** » 8 Aug 2014 8:24 pm

Curtis Alford wrote:Lane, my bad I read that wrong about the switch.
Wonder if placing the 212 tranny in the 112 would be probable.

When you take away two tubes, you are 'un-paralleling' them... so the impedance goes up. This means that if you put the 100w four-tube transformer into the 50w two-tube amp your taps will be 32, 16, and 8, not 16, 8, and 4. Like if you put a Twin transformer into a blackface Bassman head it will have an 8ohm output impedance... or if you pull two tubes from a Twin Reverb (one from each side!) you'll be running a x2 mismatch unless you clip one speaker free (again, 8ohms result).

Curtis Alford · Post by **Curtis Alford** » 9 Aug 2014 9:50 am

Not sure about the primary voltage to the OT on this amp, but it may be 50w bassman4,6,8,tapped OT might work.
I did this with my DeVille 60w Hot Rod work great and tone was inproved and head room increased.

George Kimery · Post by **George Kimery** » 9 Aug 2014 1:42 pm

OK, I am leaving well enough alone on the 112 Valve King. Changing ohms is not a simple thing to do and I am not sure that I would be happy with the results. I will stay with the 16 ohm speaker that came in it.

Thanks for all the help. I was going to contact Mike Brown and see if Peavey would change it from 16 to 4 ohms, but I am not going to do that now.

Lane Gray · Post by **Lane Gray** » 9 Aug 2014 2:00 pm

It wouldn't hurt to make the call to inquire about cost/feasibility.

David Stilley · Post by **David Stilley** » 22 Aug 2014 10:36 pm

I'm not sure about the formulas, but I'm sure lots of others here are. You can wire multiple speakers (2, 3 or 4 or more) in different ways series/parallel to end up with a different ohm load on the speakers. Maybe you could just use a cab with 2 speakers wired together in a way that will match the rating of the 16 ohm amp. Of course you'd be hauling more stuff but you might like the sound you get with two speakers. And it might be cheaper than changing the electronics in the amp which you couldn't go backwards on easily if you didn't like it.

I guess what I'm saying is that it's easier to change the ohm rating of a speaker setup than it is to change the amplifier!

Lane Gray · Post by **Lane Gray** » 22 Aug 2014 10:52 pm

Indeed. Two 8s in series is 16, or 4 4s or one 8 and 2 4s (in series, you just add them).
But he has a 16 ohm amp and a 4 ohm speaker.
I think the phrase "you can't get there from here" fits.

George Kimery · Post by **George Kimery** » 23 Aug 2014 4:28 am

This whole issue is a can of worms that I don't want to open. I am sticking to the 16 ohm Valve King speaker that came in the amp.

At some point in the future, I want to get a Valve King 212 which has 100 watts amd tw0 12 inch speakers. I already have an Eminence EPS 12c speaker. I would like to get a Telonics to pair with it and see what happens. Since the 212 has a variable ohm switch for 4, 8, or 16 ohms, this will not be a problem.

i am thinking since speakers have different peaks and valleys in their response, the Eminence/Telonics combo might work out quite well. What one lacks, the other one might fill in. If this combo does not work out, then my option would to get either another Eminence or Telonics. I would try the Telonics in my Nashville 112. Then decide what speakers to put where. If I decide to go back to the two Valve King speakers in the 212, then I could sell off the extra speaker or speakers, and put one in my NV 112, or even go back to the original blue marvel.

All of this sounds nuts, I know. But I just love to experiment. I had a neighbor of John Hughey's tell me that John was constantly trying different combinations, so maybe I caught the disease from John.

Stephen Cowell · Post by **Stephen Cowell** » 23 Aug 2014 9:35 am

Be aware that when you mix and match speakers they need to be the same impedance... the lower impedance speaker will hog most of the power, and the resulting impedance will be somewhere between two settings.

George Kimery · Post by **George Kimery** » 24 Aug 2014 1:00 pm

Yes, Stephen, I am well aware that the ohms in both speakers would need to be the same. I believe the Eminence and the Telonics are both 4 ohms. Also, since Eminence makes the Telonics and I was talking to them about a custom made 4 ohm EPS 12c for my Valve King, i asked them if they thought that one of these two speakers would be louder than the other and that it was a bad idea to pair them. They didn't think it would be a problem, volume wise. But, like everything else, we really don't know how it is going to sound until we try it.

The Valve King 112 with the stock speaker sounds really good, but I just can't help wanting to know what a 212 would sound like with the Eminence and/or Telonics speakers. In my mind, it seems like it might be a killer amp.

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