4 ohms vs. 16 ohms: any diff in tone?

[STRATDELUXER97]

Re: 4 ohms vs. 16 ohms: any diff in tone?

I think we're hearing or feeling the same thing, John. To me the tone is more relaxed. Rounder is the word that AJ used. I think both apply. But again: I could be wrong.

I doubt any of us are wrong pal...I still think it is really just something I feel,though just a change in incoming wall voltage could do the same thing,and just a different day etc.also....Wall voltage changes of just a little bit can make a significant change in bias current and overall voltages within the amp...Good techie conversation though and I Like this and reading people's opinions.

 

[ratherdashing]

Re: 4 ohms vs. 16 ohms: any diff in tone?

I actually don't hear a tonal difference Matt...It's more of a "feel" thing...Might be just me and not really an easy topic to discuss with 100% certainty.

Yes, good point. "Feel" is probably closer to what you'd actually experience difference-wise. Given that the OT is such an important part of the amp's responsiveness, it makes sense that you'd notice a difference between the three taps.

 

[STRATDELUXER97]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Yes, good point. "Feel" is probably closer to what you'd actually experience difference-wise. Given that the OT is such an important part of the amp's responsiveness, it makes sense that you'd notice a difference between the three taps.

:beerchug:

 

[dr.barlo]

Re: 4 ohms vs. 16 ohms: any diff in tone?

+1 to what John has been saying...

There is a bit difference, just a bit. 16Ohms from my 1960AV with my 1987 clone is sorta deeper and rounder. But, its nothing too pronounced... Still noticeable though...

B

 

[STRATDELUXER97]

Re: 4 ohms vs. 16 ohms: any diff in tone?

+1 to what John has been saying...

There is a bit difference, just a bit. 16Ohms from my 1960AV with my 1987 clone is sorta deeper and rounder. But, its nothing too pronounced... Still noticeable though...

B

Yep same setup....1973 Marshall NMV 50 watter into the AV Marshall 4x12...

 

[briggleman]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Okay, I will chime in here and only from a amps perspective....

Back in the day of great stereo receivers, the wattage rating was always specified against the ohms it had to push. A great receiver would actually go up in power when given a lower ohm load....

For example, at a 8 ohm load the receiver would produce 100 watts, at 4 ohms 120 watts, at 2 ohms a 160 watts.

So the ohm load was affecting the amplifier, not the speakers. NOW, in stereo receivers where the amp section was not that great, the power would go down and the amp would clip, it would run out of juice so to speak.

So to my thinking, what tonal difference you may be hearing is how much or less headroom your amp has and not a speaker induced tone effect.

Brad

 

[uOpt]

Re: 4 ohms vs. 16 ohms: any diff in tone?

If you switch your amp between 8 and 16 Ohms you use different parts of the output transformer. The 8 Ohm output uses only half the transformer.

If your sound is partially based on output transformer saturation then you would get a difference.

Another things is output impedance and "braking" speakers. When comparing solid state and tube power amps one large difference is that the output impedance of the SS amp pretty much shortcuts the speaker, and that makes when you remove the input signal the speaker abruptly stops. With a tube amp the speaker would swing back and forth more freely. This is definitely a major factor. Maybe the different output impedance between a tube amp for 8 Ohms and one for 16 Ohm also causes a difference here. Audible? Who knows.

It doesn't apply to this thread but there's also the question whether an 8 Ohm version of the same speaker really sounds the same as the 16 Ohm version. It's thinner wire with more winds, so...

I supposed I could test that first theory with my power soak...

 

[STRATDELUXER97]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Okay, I will chime in here and only from a amps perspective....

Back in the day of great stereo receivers, the wattage rating was always specified against the ohms it had to push. A great receiver would actually go up in power when given a lower ohm load....

For example, at a 8 ohm load the receiver would produce 100 watts, at 4 ohms 120 watts, at 2 ohms a 160 watts.

So the ohm load was affecting the amplifier, not the speakers. NOW, in stereo receivers where the amp section was not that great, the power would go down and the amp would clip, it would run out of juice so to speak.

So to my thinking, what tonal difference you may be hearing is how much or less headroom your amp has and not a speaker induced tone effect.

Brad

Same holds true in a guitar amp also..The amp could put out more wattage/power at the lower OT impedence taps and we also have to be careful about not over-saturating the OT by mis-matching impedences or running an amp lower than it's rated ohm impedence ratings..Kinda off track here I Know.. ;o) I'm still a collector of 70s Marantz,Pioneer receivers and I'd agree that maybe tonal differences(and definately power)changes more with the impedence changes..Not sure if it's a ss vs tube amp thing though?

Enjoyed your informative post.

 

[briggleman]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Just finished repairing a Pioneer SX-950, and not long before that had the pleasure of working on a Marantz 2285BD. Only about 280 of those ever made. They are works of art. Love the displays, switches, and knobs. I miss them!!!

 

[STRATDELUXER97]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Just finished repairing a Pioneer SX-950, and not long before that had the pleasure of working on a Marantz 2285BD. Only about 280 of those ever made. They are works of art. Love the displays, switches, and knobs. I miss them!!!

Very cool...I've done the same on 2 Pioneer SX 1010s, a 939,an 838,and a Marantz 2275...Still also have my Technics DD tables also...Love the Pioneer stuff.

 

[Dr. Vegetable]

Re: 4 ohms vs. 16 ohms: any diff in tone?

A lot of good points here. The winds on the output transformer could certainly play a part.

One subtle factor that has not been mentioned yet is the frequency response of the speaker circuit. The speaker cable and the speaker coil together form an R-C circuit that will behave like a high-pass filter. If all other factors were the same (and they usually aren't) a higher speaker resistance will cause a lower corner frequency. So the 16-ohm setup should have slightly better reproduction of very low frequencies. This effect should occur well below the musical range, but would cause subtle coloration of the tone.

 

[Lewguitar]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Regarding the Night Train, I wonder if the negative feedback circuit operates differently on the 8 ohm vs. 16 ohm tap. I think it does on old Marshalls.

Could be wrong.

I'm still not convinced it's all in the amp and output transformer. Could be the speakers.

 

[ItsaBass]

Re: 4 ohms vs. 16 ohms: any diff in tone?

You are talking about two different amps; there's no way to even pretend to come to any conclusions based on that. You'd need an amp that has both 4 ohm and 16 ohm settings on the back to make any sort of useful comparison.

The closest I could get to trying that out is with my V-4, which lets you pick 2, 4, or 8 ohms. I also have an Ampeg 2x15 cab that came with a stock series/parallel switch on the back. I can get 4 or 16 ohms from the same cabinet by just sliding the switch. However, none of my amps have both 4 ohm and 16 ohm settings. I could easily test it out if I had two 4 ohm speakers in that cab...but I don't. If anyone wants to donate two 4 ohm 15's to me, I'd gladly test it out.

 

[Lewguitar]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Well I talked to Bruce at Mission Amps about this and he said: "That's not surprising. EL-84 tubes sound better at 8 ohms than they do at 4 ohms. But they sound best at 16 ohms."

Then he went off as to why, and left me behind in the dust.

 

[uOpt]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Well I talked to Bruce at Mission Amps about this and he said: "That's not surprising. EL-84 tubes sound better at 8 ohms than they do at 4 ohms. But they sound best at 16 ohms."

Then he went off as to why, and left me behind in the dust.

Is he aware that there is such a thing as an output transformer?

 

[Lewguitar]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Is he aware that there is such a thing as an output transformer?

I'll assume you're joking.

I think Bruce might be right, BTW.

My Vox AC-30 was an EL84 amp and came with two 8 ohm speakers wired for 16 ohms and sounded great.

But I sold it and bought a hand wired Matchless SC-30 that had a single 8 ohm speaker and it always sounded rough to me. Never bonded with it.

The Night Train is also an EL84 amp and it sounded rough but good with an 8 ohm speaker plugged into the 8 ohm output. But sounded much different and much better with a 16 ohm cab plugged into the 16 ohm output.

There's a pattern there and it may be very simple.

Perhaps EL84's really do sound there very best with a 16 ohm speaker load plugged into the 16 ohm output.

Like Bruce said.

 

[uOpt]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Perhaps EL84's really do sound there very best with a 16 ohm speaker load plugged into the 16 ohm output.

Like Bruce said.

How so? The cab load is selected in the output transformer. Has nothing to do with the tubes.

 

[JB6464]

Re: 4 ohms vs. 16 ohms: any diff in tone?

To me there is a big difference between the two.
My 4X12 cabinets are loaded with EVM12L (16ohm) speakers , and with my Marshall's and Soldano 100w amps loaded at 4 , 8 or 16 ohm , there is a difference i can hear and feel between them .
When my 4X12's are wired at 16 ohm my amps feel softer with a slightly compressed attack and it sounds like the amps has more mid-low tones being dominate when i drive them hard at live perfromances levels .
And when they are wired at 4 ohm they feel alot tighter and sound more evenly focused without any frequincies being dominate much like a bass rig. What you put into it is what you get back with no extra colorization , no resistance . You hit a chord quickly on the guitar and it responds quickly with no lag or loss of definition .
Is one better than the other , no just slightly different.
With the Marshall amps i prefer the 16 or 8 ohm load since they are a bright mid-high dominate sounding amp. But with the Soldano amps i prefer them on a 8 or 4 ohm load to keep them more evenly balanced since they already have plenty of compression and gain and they are not overly bright sounding like a Marshall .
And when i run them in stereo it really makes a difference as well , i actually prefer a 4 ohm loaded cabinet on each amp since i don't need to play the amps as loud in stereo , lol.

 

[Lewguitar]

Re: 4 ohms vs. 16 ohms: any diff in tone?

Cool! Glad another person thinks they hear (or "feels" ) a difference between 4 ohms cabs, 8 ohm cabs and 16 ohm cabs.

At this point I am confused as to why!

I never mismatch the output impedance of an amp by using a cabinet with a different impedance. I always try to use the 4 ohm out with a 4 ohm cabinet, 8 ohm out with an 8 ohm cabinet and 16 ohm out with a 16 ohm cabinet.

With the three EL84 amps I've had (Vox AC30, Matchless SC30 and NightTrain) speakers wired for 16 ohms and used with the 16 ohm out sounded quite a bit better (oops...I mean "felt quite a bit better..." ) than 4 ohm speakers used with the 4 ohm out and 8 ohm speakers used with the 8 ohm out.

Bruce says he's noticed that too, especially in amps using EL84 tubes.

I'm not a tech and his explanation (which contained more math and electrical theory than my unedumacated mind can hold ) went right over my head.

 

[JB6464]

Re: 4 ohms vs. 16 ohms: any diff in tone?

My theory is that there is less resistance at 8 or 4 ohms so the output section of the tube amp does'nt have to work as hard to put out the goods.
Therefor the amp will sound and feel different .