speaker mismatch

[jestaudio]

anyone see any problems in running a 10.6 load on a 8 ohm tap, i have a chance at some unusual 5.3 ohm vintage 30,s from the 80's

[Phil_S]

Theoretically, it raises your 8K primary to 10,600 (or something else if I guessed wrong about the 8K). If that's in the relevant range for the power tubes, it's probably fine. To be sure, you really should consult the tube data sheet and draw the load line. To do the latter, you need to know operating parameters.

[pdf64]

5.3 ohms is very unusual; how do you know that's what they are?

[Bob Simpson]

Isn't 5.3 ohms about the usual DC resistance of an nominal 8 ohm speaker voice coil?

Bob

[jestaudio]

5.3 ohms is very unusual; how do you know that's what they are?

The 5.3 ohms printed on the back may be a giveaway lol, i gather they are customs jobs for a 3x12 to give a 16ohm load

[Phil_S]

A speaker's DCR is generally about 75% of its rated impedance. 5.3/.75=7. Chances are, they are 8 ohm speakers. Bring your meter when you look at them. If you get 5.3, they are probably 8.

[renshen1957]

anyone see any problems in running a 10.6 load on a 8 ohm tap, i have a chance at some unusual 5.3 ohm vintage 30,s from the 80's

Hi,

Speakers are rated for nominal loads, that is the resistance varies with pitch and volume, very low notes on a speaker can measure 1.2 ohms, and so forth.

The question is how well built is your OT? Undersized, "adequate," or something with full bandwidth (overbuilt, Hi-Fi, or oversized)?

Best Regards,

Steve

[husky]

You really need to do an impedance plot. DC resistance is not very accurate and basically tells you if the coil is broken or the ballpark of the lowest impedance.
Here is a VET 30 I just did an impedance curve on. The DCR read with probes 0'd out on a Fluke 87V is 6.8 ohms, as you can see the impedance curve never gets that low, close but at 20hz which this speaker really isn't going to produce.
https://www.dropbox.com/s/wfon1pflrn73jva/Vet30.pdf

Yeah the bottom line though is no problem even though what they inherently sound like even at the correct impedance is anyones guess. That will be a bigger factor than a slight mismatch.

[chief mushroom cloud]

I think you're all overthinking it.....