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Impendance taps setting on a tube amp

I have decided to try out the Rouge Audio Cronus Magnum integrated amp before I upgrade my speakers. Reading a Cronus review, I understand that the amp comes factory wired to the 8 Ohms taps. To switch to the 4 Ohms setting you actually have to remove the cover and fiddle with the wires a little. The 6-Moons reviewer suggested requesting that the amp be wired to match the owner's speakers' impedance to avoid having to do it yourself.

I currently have the Totem Hawks speakers, which have a nominal impedance of 6 ohms. Here's a quote I got from Totem: "The Hawk exhibits a nominal 6 ohm impedance that is very constant throughout the ban. The minimum is 5.2 ohms."

Given this information, what would be the optimal setting: 4 or 8 Ohms? Should I try both and see what works best? That's pretty much what RA recommended, but I wanted to see what others think or perhaps faced a similar dilemma.

Thank you.
actusreus
actusreus OP
733 posts
 
I settled for the 4 Ohm setting, but didn't listen long enough with the 8 Ohm setting to provide meaningful feedback. I started with the factory wired 8 Ohm setting and thought the volume wasn't loud enough so I assumed the 4 Ohm setting was going to be better. That was after about an hour of listening. The 4 Ohm tap sounds great so I didn't go back to comparing. The difference between volume levels is almost negligible but I think the 4 Ohms setting provides an overall optimal performance.
auxetophone
114 posts
 
You might want to swap back once you've lived with the amp for a while. I have always found that the choice is very important for sonic reasons, and the right choice is not possible to predict based on the stated impedance of the speaker - even for the same amplifier.

Before you buy another component, make sure you know how each tap sounds. You might have a free upgrade hiding under the amp's cover :)
actusreus OP
733 posts
 
All great points Auxetophone. But I must tell you changing the taps is a b.i.t.c.h. It's not so much that you have to unscrew 10 little screws and remove the top cover through the tubes; it is the fact that on one side there is virtually no space for the wrench to get a good hold of the female thread. I had to maneuver for quite a long time before I got the thread removed and fastened to my satisfaction on the 4 Ohm tap. I'm not looking forward to doing it over again (and possibly yet again if I end up preferring the 4 Ohm setting). Interestingly, only one wire on each channel needs to be switched, which I don't quite understand since with external taps it seems there are always two extra terminals per each channel for each setting.
auxetophone
114 posts
 
Wow - what a pain! Especially if you have to pull the thing out of the rack, take it apart, bust a knuckle, etc. and then put it back. Hopefully the trade-off for the pain-in-the-butt construction is really solid connections:)

Good thing it's just one wire. Actually, I've mostly seen the external taps with ground + one each hot tap for each speaker impedance, but there are many ways to hook it up I suppose.

Anyway, at least you won't have to do this more than a couple times, unless you're on a speaker merry-go-round. Your amp has a very convenient biasing arrangement from the looks of it, which is something you really should do from time to time.

I have one that needs to be flipped over and opened up, and the bias set with a voltmeter. Doesn't really bother me to stick my hands in there with 350 VDC, but not everyone feels the same:)
actusreus OP
733 posts
 
Wow, yeah, I guess I now appreciate the built-in meter and easy biasing process with the Cronus even more. In fact, I actually enjoyed doing it for the first time with the biasing tool provided with the amp. I also purchased the Cronus as a "temporary" amp before I can upgrade to a tube preamp and power amp combo; once that happens, I won't have to worry about the internal impedance taps, hopefully.

All that aside, the Cronus is a wonderful amp. It actually made it possible for me to listen to CDs again.
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