4 or 8 ohm connection for a 6 ohm speaker?


I have a pair of Thiel CS2’s that have a nominal impedance of 6 ohms. My mono blocks have output impedance connections for 4, 8 or 16 ohm speakers. Is it best to connect the speakers to the 4 ohm or 8 ohm connections? 
Thanks for your thoughts.

Bill from Nova Scotia
wgs57
Looking at the impedance curve for the CS2 measured by Stereophile I would’ve run the 8 ohm taps without thinking twice. The CS2 only hits a minimum of 6 ohms with a dip at about 170 hz whereas it’s at or above  8 ohms from 500 hz and up.  Below 170 hz it fluxuates between 10 and 6.5 ohms. Surprised it has a 6 ohm rating to be honest.

If you’re having better results on the 4 ohm taps then it’s all good...enjoy the music.
Yes, I normally spend my Summers fishing remote places in British Columbia- this year not possible, so I am missing the fish, beautiful country and charming Canadians.
"keeping a load on" is in reference to never switching taps while the amp is on.
Enjoy :-)

Avanti1960, when you say I need to test carefully you are speaking of the sound quality? Would I do any damage to the output transformers by keeping a rated 6 ohm speaker load on 4 ohm outputs? 
I have settled on the 4 ohm taps as the sound is more complete at the low and softer in the high end. As long as no harm is done then the sound is great. 
Next change will be to upgrade the input or line stage I think it is called but that is for another thread :)

Best to you,

Bill
8 ohm has taps have worked much better for me than 4 ohm taps when driving 6 ohm speakers-  and it wasn't even close. 
but this is just a reference point- you really need to test carefully.   
I have lived all over the world . There is no place more beautiful than
Nova Scotia or better people than Canadians or a Country better than Canada .
Americans should thank God we have such a great neighbor we tend to ignore .
Hi jrwaudio! Well anytime you can get back to Nova Scotia it is even more beautiful...

The gentleman I purchased the two tube mono blocks from told me to always keep a speaker load on it when turned on so I was worried about trying a 6 ohm load on a 4 ohm tap initially but it all worked out in the end...4 ohm taps it is! Just being over cautious lol. 
Love Novia Scotia!! Haven't been there for years
I have my Maggie's on the 4 ohm tap of my tube amp, and to me they sound great. Nominally there are a 4 ohm speaker though

Tomic601, that makes sense to me as well...thank you. So glad I made the change to the 4 ohm taps today on everyone's recommendation because all around I now have a very pleasing sound output with a boost in the bass and a less hot high end. 

Next change will be the input stage on both mono blocks. 

Bill from Nova Scotia
I suspect you will like the 8 Ohms more. 

Pay particular attention to the brightness/harshness and detail in the mid to treble region vs. bass.


Bill: 80% of the sound of a conventional tube amp is the quality and configuration of the output transformer... in essence you switched transformers and in essence amplifier so a change in sound makes sense.
Very interesting, that's exactly what I experienced. I am trying to listen again like I did when I was a teenager. I really like the midrange from the Thiel's as I really enjoy female voice and jazz. Listening to the beautiful soundtrack from Philip Glass "Tales from the Loop". 

On a side note, Harbeth and Rogue Audio equipment are definitely on my wish list...but I am very happy for the time being though with the budget I have.

Wishing you all a great Sunday and week ahead!

Bill from Nova Scotia
As others have said, try it and see what you like best.  My experience is similar to yours.  I have Harbeth Super HL5 Plus and with some recordings, they sounded a little hot on the top end, or as you put it, "shrill".  I knew they shouldn't sound like that and switching to the 4 ohm taps on my Rogue M-180 monoblocks did the trick of taming that, while not losing any of the luscious mid-range.  I use four subwoofers, so wasn't looking to gain anything in the bass department, but I did end up turning the volume down a little on the subs after making the change.
Thanks for everyone's input! Much appreciated!

Originally I had placed the speakers on the 8 ohm taps as recommended by the person who sold the pair to me...he had a tube stereo power amp. After listening to my setup at home on my Dynaco MK 3's I was never really satisfied. Is it possible that the bass was less than satisfactory and the highs were shrill? I still enjoyed listening to the speakers though and I did try positioning them slightly differently but left it that way until now. 

Today I moved the speakers to the 4 ohm tap and listening to the same music the bass was way way more full and the highs were less shrill...is that possible? I feel that is what I heard (my hearing isn't what it used to be). I do honestly think the music is better on the 4 ohm tap and I am sure I heard distortion when on the 8 ohm tap. My audio source was from a Bluesound Node 2i playing music from Tidal. 

I feel definitely more satisfied now and nothing blew up LOL. 

Bill from Nova Scotia


HI, 
Some tube amps behave better on 8ohm taps. As your speakers demand a little push the 4ohm tap would propably be better but you wouldn't know till you have tried.
As most have said already, try the lower option first. I have a pair of speakers that average around 12 ohms during play. I tried the 8 ohm posts first and was disappointed. I the 4 ohm post and the speakers sounded much better. 
Roger Modjeski ( music reference ) advocates light loading but also listening. Clipping is bad, so listen for that also. I light load my Vandersteen TreoCT ( an engineered easy load at 6 ohm nominal ) with the 2 ohm tap on my RM-9. Amp stays in class A longer and at the relatively low volume I listen at - sounds better.
have fun - enjoy those great speakers! And the music !
It makes sense to try the lower tap first, but there definitely have been cases of particular combinations of amp and speaker where the tap a little over the nominal impedance sounds better.  Of course, if you ever look at some measurements, nominal impedance can be a pretty fuzzy term.
Hi Bill, I would suggest the 4 ohm. Please report back your findings the differences.
Thank you Timo62 for the reply. I have them on the 8 ohm tap at present and will try the 4 ohm tap next. 
Bill,


You can try all 3 to find out which you prefer with your speakers. It will not hurt anything.  I would imagine the 4 , or 8 ohm tap would be in your range of preference for your speakers..