Speaker / Amp impedance mismatch...

[calling card]

Yeah balance, moderation etc...

[GrantB]

Don't mismatch - safest.

It's not really living life on the edge though, is it?!

[AiRdAd]

Don't mismatch - safest.

It's not really living life on the edge though, is it?!

instead of eadge of breakup sounds - it would be edge of breakdown sounds

[RectifiedAmps]

Remember that the impedance rating of any speaker is for a specific frequency and impedance will vary widely above and below that, so any impedance tap on an OT will have to handle a range of impedances anyways. That said, it’s still safest to match the speaker to the right tap.

I always subscribed to the view that a speaker should be the same or higher than what the OT asks for, but Merlin Blencowe gives solid reasons behind why the opposite may be safer (speaker equal or lower than requested impedance):
“Connecting a higher impedance speaker will cause the load line to rotate anti-clockwise around the bias point, possibly causing screen-grid failure due to passing below the knee of the grid curves (although if you're lucky, the screen resistor will fail open first). It can also cause arcing in the transformer due to much higher anode voltages being developed when the valve is overdriven. Connecting a lower impedance speaker will have the opposite effect; the load line will become more steep, pushing the valve into cold Class A operation which may or may not cause over dissipation of the anode (thankfully it usually doesn't). It is therefore always safer to plug in a lower impedance speaker than a higher one, if you have to.” (http://www.valvewizard.co.uk/se.html)

[MikeC]

Don't mismatch - safest.

It's not really living life on the edge though, is it?!

With my vintage Marshall cranked, yes.

[wavesofffear]

Fenders should be fine with the mismatch (Marshall less so).

I hope you didn't decide to replace the OT!

[Bg]

Fenders should be fine with the mismatch (Marshall less so).

I hope you didn't decide to replace the OT!

Words of wisdom and a very welcome to the forum if I haven't done that to any of your previous 20 posts

[wavesofffear]

Fenders should be fine with the mismatch (Marshall less so).

I hope you didn't decide to replace the OT!

Words of wisdom and a very welcome to the forum if I haven't done that to any of your previous 20 posts

Thanks Bg. Happy to be here!

[Miza]

Searching for an answer for this, but no luck.

Is there any way I can safely run an 8ohm amp into a 4ohm speaker? Like, is there a way of manipulating/convering the signal somehow without adding another speaker?

Only asking cos I've got an old 4ohm speaker in my new cab that I want to try but my only amp is 8ohm.

[Slowy]

Searching for an answer for this, but no luck.

Is there any way I can safely run an 8ohm amp into a 4ohm speaker? Like, is there a way of manipulating/convering the signal somehow without adding another speaker?

Only asking cos I've got an old 4ohm speaker in my new cab that I want to try but my only amp is 8ohm.

Any chance you have another 4 ohm speaker?

[MikeC]

Searching for an answer for this, but no luck.

Is there any way I can safely run an 8ohm amp into a 4ohm speaker? Like, is there a way of manipulating/convering the signal somehow without adding another speaker?

Only asking cos I've got an old 4ohm speaker in my new cab that I want to try but my only amp is 8ohm.

What kind of amp? What output wattage?

[Miza]

Searching for an answer for this, but no luck.

Is there any way I can safely run an 8ohm amp into a 4ohm speaker? Like, is there a way of manipulating/convering the signal somehow without adding another speaker?

Only asking cos I've got an old 4ohm speaker in my new cab that I want to try but my only amp is 8ohm.

Any chance you have another 4 ohm speaker?

No, the amp's speaker is 8ohm.

[Miza]

Searching for an answer for this, but no luck.

Is there any way I can safely run an 8ohm amp into a 4ohm speaker? Like, is there a way of manipulating/convering the signal somehow without adding another speaker?

Only asking cos I've got an old 4ohm speaker in my new cab that I want to try but my only amp is 8ohm.

What kind of amp? What output wattage?

Fender Pro Jr, 15W.
I'm not entirely sure what the wattage the speaker can handle. I used a DMM to work out the ohms, so hoping it's right.

[Miza]

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Theres some faded text on the back, could be 30W?

[robthemac]

Probably a dumb question, but what if you just jammed a high-current 4 Ohm resistor in series with the speaker's coil?