configure amp 4 or 8 ohm to drive 6 ohm speakers

Hi all, my push-pull vacuum tube power amp can be configured for 4 or 8 ohm load but is currently wired for 8 ohm. The spec on my speakers is 6 ohm. Should I switch the amp to 4 ohm, and if so why? Would it be for sonic reasons or to be safer for the amp? If better to switch, I need to get the info from Cary to change the transformer connections.

amp is Audio Electronic Supply AE-25 super amp with 6l6gc in triode mode.

speakers are Opera Platea's

thanks in advance for any input
If you already have the amp and speakers, just try it out and see what works best for your speakers and your taste in music.

Not sure if you have a frequency vs. impedance graph or not, but if you have one and see a big dip in impedance, I might give more thought to a 4 ohm tap if there isn't much sonic difference between the two.

But really, try each and go with what you prefer. If they sound the same, I'd go 4 ohm, since even with 6 ohm nominal impedance listed, there are often some dips in a freq vs. impedance plot.
I have a similar situation and use the 4 ohm taps as I have an amp that supplies a good amount of current if required. If I was in doubt of this, I might use the 8 ohm so as to not stress the power supply. Also, as I don't listen all that loud, I find the control offered on the 4 ohm tap better. If I listened at a higher level (requires more voltage usually) I again would choose the 8 ohm tap.
Thanks for the input. I just got through opening up the amp and did some re-wiring. I added some internal connectors so I can switch between 4 and 8 ohms a little more easily but you still have to take the bottom off to do it, so not a very quick thing.

Sonically, I'm not sure how the switch came out. I had been using it on the 8 ohm tap for the last couple of years on these speakers. It sounded great on the 8 ohm tap, and it sounds great on the 4 ohm tap. I wish my memory was better for comparisons like this but I have a hard time in that area. I do belive my volume control is higher now for the same speaker output. That sounds right, doesn't it? I am only going by what the seller told me to think it was on 8 ohm in the first place. What I encountered inside was the green wire taps were connected and I swapped to yellow, in case anyone is familar with these transformers.

I'll live with it this way (4 ohm) for now and maybe try a comparison back to 8 again someday.
I noted that despite the overall rating of 8 ohm impedance of my speakers, that the stated minimum was pretty low at 3.8. I tried the both 4 ohm and the 8 ohm taps anyway and liked what I heard with the 4 ohm tap. It made sense and my amps seem to be OK with it. Why else would they have a 4 ohm tap if it would damage the amp?
The impedance of those taps are not exact. Ask Cary what the actual impedance is on the outputs. It may be closer to 6 ohms than you think.
Rrog, I found one review online where the measured output imp with the 8 ohm tap was 4.4 @1khz. There was no measurement for the 4 ohm tap, maybe it would be around 2.2 or so.

Anyway, I've had 2 listening sessions since switching to the 4 ohm tap and midway through the 2nd I was convinced the soundstage was smaller and some dynamics were lost. OK, I'm no expert with these reviewer terms but to me it just didn't sounds as good. I powered the amp off and turned it on it's side, gee it's heavy, took off the bottom and switched it back to the 8 ohm tap. Just as I thought, I like the sound better.

It seems the more I read on the internet about audio equipment the less I know. In this case I believe I increased the damping factor when I tried the 4 ohm tap. It should have been basically doubling it, from 1.36 to 2.7. When I read certain articles this should have been goodness, and I should have found it superior. Why do I like the sound of the music better with a lower damping factor? And also, according so some things I have read either of these low damping factors is abysmal and should sound like crap. I suspect there are many complicated factors going on here and there may be others that outweighed the damping factor. And I do understand the impedance of my speakers may be all over the charts across the audio spectrum. I'll keep trying to learn this stuff. Nothing better to do.