I received some lovely speakers from the UK yesterday: Spendor SP3/1R2*

The output voltage from a tube amp decreases as the speakers voice coil impedance drops and on any tap.

 

And that has to do with what?

For a given power level, if the impedance of the voice coil drops the current will increase and the voltage will decrease.

A tap does not have anything to do with this. It is just Ohm's Law.

It also have nothing to do with my statement.

If you plug a speaker that was designed to operate at 8-Ohms into a 4-Ohm tap, the current running through the voice coil of that speaker will double.

That is all that I said.

This does not have to do with anything else.

Not sure why my post was quoted?

 

Actually, it doesn't work that way. The load (speaker) determines the current drawn. Changing taps does not change the amount of current the speaker will draw. The taps are to match the speaker load with the maximum voltage the amp can produce.
You will not hurt your speakers by using the 4 ohm tap on 8 ohm speakers. The sound will change though. Some tube amps simply produce more distortion on the 4 ohm taps. The frequency response will also change, the 4 ohm tap will have a lower output impedance than an 8 ohm tap, thus less affecting the frequency response. Some tube amps output impedance can run at 3-4 ohms. Frequency response can and will vary quite a bit into different speakers on these amps. The better modern amps are usually below one ohm, which is why they don't sound so much different than good solid state amps on balance.
Tube amps generally produce less power at lower taps than higher ones, so if you could end up with not enough power if you use a real 8 ohm speaker on a 4 ohm tap. You just have to try them, which is why you see amp manufacturers giving that recommendation.

That being said, you most likely will not run into power considerations with your very efficient Altecs. But, when those speakers were designed, pretty much all tube amps had high output impedances, so changing to the lower tap may throw off the frequency balance if the speaker was designed using 8 ohm taps.

I love the sound of tubes, but its not a plug and play method, unless you just get lucky.

 

How's it going with the Spendor and Fisher combo versus Rega Brio? Is one of them still driving the Spendors, or have you found a better preamp and amp match?

Your older posts have encouraged me to purchase a pair of Denton 80th and connect to my Lafayette LA-310 (PP 7189) amp. As the speakers further break in, this combo sounds better all the time.

Although, I am really curious about your Spendors (darn you!). Do you still think they are worth the premium over the Wharfedales? I must keep in mind this is a second system which has no real permanent location.

 

I keep going back and forth between the Fisher and Rega with the Spendors, trying to decide which I like best. Both have their own relative strengths/weaknesses.

Both have excellent mids. The Rega sounds tighter/clearer and has a very "natural" tonality, with very good imaging. The Fisher has a fuller, more prominent bottom end and slightly blurred top-end compared to the Rega, but the soundstage is more expanded/layered, as one would expect with tubes. At the moment I'm leaning in favor of the Rega.

The Dentons are an exceptional bargain.

I am going to hold off on responding to this, because I haven't done a proper A/B comparison, but I've been meaning to. I might be able to do it this evening, so stay tuned.

I'm curious myself to see how they compare.

 

Nice! Also dig the double lava action

 

Looking forward to your assessment. Having read all your comments during your Denton and SP3 posts, I have a feeling you and I prefer the same type of sound presentation.

 

I haven't yet done the Spendor/Wharfedale shoot-out, but I have concluded that the Rega sounds better with the Spendors than the Fisher X-100.

Both amps seem to have about an equal amount of grunt (50 watts solid state vs approx. 14 watts of tube!), but the Fisher sounds a little bit smeared compared to the Rega, and the Rega has a more accurate tonal balance, top to bottom.

I really wanted to like the Fisher better too...

 

I'm using the Fisher again today and am totally digging it now.

The thing is, both amps are terrific and both have their own unique strengths. It's not easy to determine which is "better."

 

Are you listening to both amps at the same volume? Loudness is a key factor in the perception of sound quality. The Rega should be able to drive your speakers to higher volume levels without clipping. Perhaps the "smearing" that you get with the Fisher is actually clipping.

I would guess that your Fisher would be more suited to speakers with a higher impedance, e.g. 11 or 15 ohm LS3/5as. Alternatively use speakers with a higher sensitivity, i.e. 88 or 90db or more. What's the sensitivity or your Dentons? 88db? If so, use your Fisher with them.

 

Same volume.

I think the smearing that I was reacting to is the inherent difference in presentation between a modern solid state amp and a vintage tube amp. The Rega has a tighter, more controlled character and the Fisher has more of a rounder, plumper character.

Tonally, they are similar, although the Fisher has a fuller bottom, possibly due in part to the RCA small black plate 12AX7's and Mullard 5AR4 rectifier.

 

I edited my post whilst you were replying. Your Fisher will clip at higher volumes.

As you probably know, I've got the new Rega Brio which got total re-design. The reviews say it's even tighter and more controlled than its predecessor. There are a few appearing on the used market now. Well worth considering if you can afford it.

 

The Spendors are 88dB efficient and I do not often crank the volume, so I think I'm OK with this pairing re: clipping.

I would definitely like to hear it!

 

The 3/1R2s have a minumum impedance of 5.7 ohms. Most of their bandwidth has an impedance over 8 ohms - hardly a difficult load in that respect. They will also get a lot of gain from his small room.

 

Yeah, I once tried running them off the Fisher's 4 ohm taps and that sounded awful.

My current room is 11 x 13 (a welcome upgrade from the 8 x 12 closet I had a few months ago) and I have the speakers along the long wall, maybe two feet in, with OC703 panels behind them.

 

Interesting comment for me. A few months ago I purchased a Fisher KX90, kit version of X100-A. After recapping the power supply, I've been using it on and off for a month or so with a pair of 90db efficient speakers. I say on and off as I have also been using a Cairn 4808A solid state amp rated at 30 watts per side. My assessment of the sound is pretty much identical to yours. Jury's still out, but I'm leaning toward the Cairn.

 

Tough call, right? I keep wavering back and forth.

I've had the tubes glowing since about 8AM this morning (it's 2:30PM now) and the Fisher is warming my heart.

There is something undeniably intoxicating about the Fisher's midrange glow and holographic soundstage, but then again the impactful bass and overall tightness and clarity from a good solid state amp is also a very desirable trait. I'm lucky to have both available.

Maybe I'll keep the Fisher in place until the hot weather arrives, and then swap in the Rega. Yeah, that sounds like a plan.

 

I just spent the day listening to the Rega/Spendor combo, and now I've swapped in the Dentons.

The Spendors have the sweeter top-end and are probably pretty close to neutral, while the Dentons are warmer, with a fuller midrange/upper bass, and a slightly rolled-off top-end. Both are pretty wonderful.

The Spendors have the clear edge overall, as a pair of speakers retailing for $3,195 should, but $399-$499 for a new pair of Dentons is a remarkable bargain.

 

Very cool to hear that the modest Dentons are performing so well! Have you also compared other qualities than frequency response, such as their imaging capabilities, instrument separation, speed, or timbral resolution? Very interested in the Dentons.

 

The Spendors have the more accurate timbral representation, the Dentons have a more obvious coloration, which I don’t find unpleasant at all, but it is noticeable following the Spendors.

The Spendors have the more detailed top end, which gives them better overall clarity and insight.

The Dentons image effortlessly and might have a slight edge in that area, as it was one of the first things that got my attention. The Dentons also seemed a bit punchier than the Spendors.

If you can be happy with a warmer, fuller presentation, the Dentons are a tremendous bargain, worthy of pairing with a very good amp. They are especially good with tubes, running off the 4 ohm taps.

 

I should add that I didn’t notice the Dentons’ coloration when they were my only speakers, it was only apparent when directly comparing them to the Spendors.

 

Thanks!

 

I'd love to know how the new Denton 85th Anniversary speakers compare with 3/1s ...

I may be in the market for some fuller-sounding speakers at some point in the middle future ...

 

hey @action pact

just checking with you, how is the bass performance of the spendor classic 3/1? I have a pair of graham ls6 and they seem to be similar in design and dimensions.

I had quite a bit of problem with the ls6 bass port. so if the 3/1 has tight bass, that may be what I am upgrading to next.

 

No problems with bass performance per se, although they don't go especially low. Bass is tight and clean.

I've since augmented the Spendors with a small sub.