4 ohms or 8 ohms

[Chris M]

I have a new Cary SLI-80 integrated amp and have Paradigm Studio Reference 100's. The speakers are rated at 'Nominal - 6 ohms/Minimal - 4 ohms'. I can run the amp at 4 or 8 ohms. Any suggestions on what I should run my amp at?

Chris

P.S. I like to crank it

[petzi]

Originally posted by Chris M
I have a new Cary SLI-80 integrated amp and have Paradigm Studio Reference 100's. The speakers are rated at 'Nominal - 6 ohms/Minimal - 4 ohms'. I can run the amp at 4 or 8 ohms. Any suggestions on what I should run my amp at?

Chris

P.S. I like to crank it

With 4 Ohms you are on the safe side. I won´t try to guess what might happen if you run the output at 8 Ohms and turn it up cause I don´t know anything about the power amp circuit in the Cary.

[Steve Hoffman]

Run the Cary at 8. Easier on the amps that way. More bass for you...

[petzi]

Originally posted by Steve Hoffman
Run the Cary at 8. Easier on the amps that way. More bass for you...

Huh ? Maybe I misunderstand the meaning of this 4/8 ohm switch on the Cary, but normally it should be better for an amp to drive an 8 ohm load when that amp is designed for 4 ohm load, than vice versa ?
:confused:

[Steve Hoffman]

Oh, I didn't read the part about the Amp being switchable. Sorry.

Cary's are happiest with an 8 ohm load.

Try them both and see which one sounds the best to you; the one with the most effortless dynamics, etc. I'm sure it will be the 8 tap.

[Dave]

Steve or anyone, would this also apply to my Classe' SS set-up? The reason I haven't hooked up to 8ohms is that my amp pushes out 75 a side at 8 and my 6ohm Castle's are only rated at 50 W each.

[petzi]

Originally posted by Dave
Steve or anyone, would this also apply to my Classe' SS set-up? The reason I haven't hooked up to 8ohms is that my amp pushes out 75 a side at 8 and my 6ohm Castle's are only rated at 50 W each.

Did you know that the combination of a speaker with 100 W connected to an amp with 50 W is more likely to damage the speaker than vice versa ?
Besides, the nominal impedance of a speaker (say, 4 or 8 Ohm) is a gross and inaccurate simplification, because almost all speakers have an impedance that greatly varies with the frequency.

[Metralla]

Originally posted by Dave
Steve or anyone, would this also apply to my Classe' SS set-up?
Swap the speaker leads to the 8 Ohm taps and give it a shot. You might like what you hear.

Regards,
Metralla

[Khorn]

Originally posted by Chris M
I have a new Cary SLI-80 integrated amp and have Paradigm Studio Reference 100's. The speakers are rated at 'Nominal - 6 ohms/Minimal - 4 ohms'. I can run the amp at 4 or 8 ohms. Any suggestions on what I should run my amp at?

Chris

P.S. I like to crank it

If possibe find a plot of the impedence curve of the speaker in question. You might get this from the manufacturer's liturature or a magazine test report. You should be able to then see the impedence load over the whole reproduced frequency range and that should help you make a decision as to what the 'nominal impedence' really is and, which output more closely matches it. If it dips really low for any appreciable portion of the spectrum you would go with the lower tap whereas if it remaines around the eight ohm mark or above for most of the frequency range (more likely given the mfg's nominal 6 ohm rating) then you would use the higher one.

[Todd Fredericks]

Now I'm getting confused (it's late here). My Meadowlark Herons are 4 ohm and I have them connected to my Dynaco ST-70 via 4 ohm tap. I always thought you shouldn't use the 8 ohm tap for 4 ohm speakers? Is there any risk going to the 8 ohm tap? I'm sorry but I'm a wee bit confused...

Todd

[Steve Hoffman]

Todd (or anyone),

Do you have the Beatles CD that has "I Feel Fine" on it? Past Masters volume 1...

OK, now play just the left channel (drums & bass side) for about one minute.

Listen on the four ohm tap and the eight. Which ever one sounds the best to you, and reproduces the bass and drums with the MOST dynamics, without sounding like it's huffing and puffing, is the tap to use.

You won't hurt anything....

[Todd Fredericks]

Do you have the Beatles CD that has "I Feel Fine" on it? Past Masters volume 1...

I'll try it tomorrow.

Todd

P.S. Thanks!

[Dave]

Thanks Steve and everyone,

I'll give that Past Masters vol.1 a spin. I was just concerned about possible damage. Now that that's no longer a concern, let the testing begin...

[Todd Fredericks]

Steve,

Okay, I spent two hours listening to 'I Feel Fine' (drums/bass side) and it does sound better on the 8 ohm tap. The bass & drums were a lot tighter/more defined and it had more punch. Each bass note had a nice roundedness to it compared to the 4 ohm tap which lacked the same kind of "life"/lack of dynamics (especially when the drum bit comes after the instrumental). The 4 Ohm tap use seemed a bit bland in comparason (kind of squeezed and not going anywhere/dificult to explain). I also listened to some other sources with both channels during the evaluation. Same results. I'm leaving the speakers feed from the 8 ohm tap (gee). Thank you very much for this tip and also a good demo piece to "hear" for myself. Now my question is why? Why is the 8 ohm tap providing better results for a speaker that is 4 ohm? Also, what is technically happening to the amp (my Dynaco ST-70) by using the 4 ohm or the 8 ohm. It's 35 watts per channel. Am I getting more or less wattage, etc.? Is the amp working harder or less? Why have I always heard it was wrong to do this and why the warning?

Thanks, again,
Todd

P.S. One thing's for sure, I'm learning a lot here...

[Steve Hoffman]

Todd,

Now that you've decided that the 8 tap brings out the dynamics in the lower regions, try listening to something that has some high freq. dynamics to it (not "I Feel Fine" :) ). Hmmm. Do you have that Donald Fagen disc (either one)? Listen to something on the 8 and on the 4. Hopefully, the 8 will STILL sound just as pleasing to you. If not, of course you will have to decide between bass dynamics and top end dynamics....Which ever is most important to you, leave it on that tap...

[Todd Fredericks]

Thanks, Steve! I'll try some more switching tests tomorrow night. So far everything I've been playing on the 8 ohm tap sounds very nice. What technically is happening with the amp & speakers when doing these switches? Also, I have my single cable run (not bi-wire) feeding the Tweeter/midrange (which says 8 ohm) feeding the bass drivers (4 ohm) with a jumper. Please explain some of the reasons behind all this I'm very interested...

Todd

[Doug Hess Jr.]

Steve,
Let's take this a step further. What if you have more choices. I've got an old Scott tube amp and it has several choices-- 4, 8, 16, etc. How would the taps compare? Would the variations you described between highs and dynamics continue as you included the other taps?
Doug

[Steve Hoffman]

Doug,

Unless you have a VERY old pair of speakers, the 8 and 4 taps are the only ones that should concern you.

Try the "I Feel Fine" test. That song is fairly compressed, so which ever tape makes your amp struggle, you will hear it right away...