Speakers for tube amps

[pointy]

PPS...............how is most not a generalization

 

[disco]

Dave, that's exactly the lesson learnt from the 1954 article by D.J. Tomcik. When building your own stack it's wise to see speakers and amplifier(s) as a whole.

 

[planet10]

Dave, that's exactly the lesson learnt from the 1954 article by D.J. Tomcik. When building your own stack it's wise to see speakers and amplifier(s) as a whole.

Indeed. I've been pushing that message forever. You need to include the speaker cables in there too.

dave

 

[newtube]

Pointy. . . . i have to disagree fella. .

The amount of power the amp has makes bugger all difference to how it drives speakers in real world terms, i'll explain why. . .

I have had a 150w p/c yamaha monster ss amp, running with acoustic energy speakers rated at 8ohm with power rating 50 - 150 watts, 90.5db rated so not the most sensitive things.

I run the same speakers with an 8w push-pull tube amp thats far from the best and the little 8w tube amp can play just as loud as is comfortable, the yamaha would go louder and hold its composure at higher levels but whats the point in that when its too loud to listen to?

A tube amp made with good components will power most things without trouble, from dance to metal/rock and a bit of classical in the mix i don't know how fella, but they just do.

 

[pointy]

I will just let you know were I get my information from.
In the 1940s and 50s if you walked out of the door of my fathers work shop and then walked down the corridor two doors on the right the name on the door would be Mr wise.
Mr wise designed the leak ribbon and electrostatic speakers.

<http://44bx.com/leak/ribbon.html>

<http://44bx.com/leak/esl.html>

 

[tinitus]

Re: Re: Some things to keep in mind.

So much misinformation!!

I'm happily using a 3.8 W amp with 90 dB speakers.

dave

And fixed attenuator, could be just a couple of resistors

 

[Wavebourn]

To drive hard speakers I use local feedback by voltage in output stage and sometimes a positive feedback by current.

However, to drive ideal speakers that do not exist nothing is needed, just one triode and a gapped transformer...

 

[tinitus]

A Promitheus site they claim that the output trafo they sell fore SS amps makes the speaker a much easier load

Why doesnt that happen with a tube amp, or is it plain rubbish in the first place

Why does varying speaker impedance have so much influense on a tubeamp when the tubes "play" through a output trafo
I mean, the tube curcuit sees a constant impedanse, or ?

Would it be possible to limit bandwidth by adapted output transformer design to do the crossover function in a multiway speaker
Or just like say a woofer amp with superiour lowend but limited highs, and tweeter amp with limited lowend but superiour highs

 

[kuroguy]

Why does varying speaker impedance have so much influense on a tubeamp when the tubes "play" through a output trafo
I mean, the tube curcuit sees a constant impedanse, or ?

No, The load impedance is reflected from the secondary back to the primary. changing the speaker impedance changes the slope of the load line which effects the THD and powerproduced by the final tube stage. simple as that. There is a reason we use a specific impedance output transformer with a particular tube. It is all tied together.

That particular lack of understanding of how a tube amp works leads to a lack of understanding of how speaker impedance effects the quality of the sound and the amount of power that can be transferred from the final tube stage to the speakers

 

[kevinkr]

Indeed. I've been pushing that message forever. You need to include the speaker cables in there too.

dave

Right On! Designing my Onkens, the X-O design and all driver choices were all predicated on the typical output impedances of the amplifiers I design and build, and I ain't talking about the taps on the OPTS when I say that!

Nothing like direct experience, designing and learning by doing. I do like (read prefer) high efficiency speakers for the lack of dynamic compression they generally exhibit because you are not significantly heating the VCs at normal listening levels. I started out with high powered SS amplifiers and acoustic suspension speakers, switched to relatively high powered tube amplifiers, went to Magnepans, and even higher powered tube amplifiers, and then to SE and high efficiency JBLs followed finally by the Onkens with horn mids and highs.

 

[Wavebourn]

Why does varying speaker impedance have so much influense on a tubeamp when the tubes "play" through a output trafo
I mean, the tube curcuit sees a constant impedanse, or ?

Nothing sees a constant and linear impedance. And nothing has constant and linear impedance. Even amps with 12 pairs of output MOSFETs have non-linear and frequency dependent output impedances. Far the more, trying to damp EMF of speaker coils they force them to generate extra harmonics.

 

[duderduderini]

I got my asbestos suit on to help with the possible flaming but in my experience I have found that 8 ohm sounds better and I generally run a 12 inch woofer of good sensitivity (90 or above) with 2 mids in 8 ohm config with a tweeter of around 92db
I just use a 6db 1st order crossover with a decent inductor for the low pass for the bass. By decent I mean at least 2mm wire for a lowish dcr.. Even the erse superQ inductors sound good. I use mundorf Whitge mkp caps.. a bargain for the price. I then use 10w resistors to get the sound levels right between the mid/high and woofer.. I use them in series and I dont mind the results I get....
I have found my valve amps (p-p 6550 and se 6550) dont like complicated xovers
Speakers? Paper cone mids (kevlar at a stretch) SIlk tweeters and paper or kevlar woofer.
One accidental discovery I made with my current diy setup is I placed the woofer in its own ported box and then on top my 2 mids and tweeter onto a flat panel.. no box for them and the results for me where spectacular.. a real airy sound with good soundstage.
Dont waste your money on scan speak revelators I tried some mids and was bitterly dissapointed...very harsh sounding.
I tried some fostex single cone drivers.. again a let down... harsh in the mids...
I dont believe you have to spend big dollars to get decent sound try an open baffle for your mids/highs and use a 12 inch woofer(in a ported Box).. nothing like cubic inches fpr real bass
Good luck

 

[Hylle]

I seems to be a difficult qustion, since most do not have a direct answer, is high impedance better than high sensitivity. At least most people that tryes to answer this quistion is mostly for high and constant impedance.
I guess as always it is a balance of many parameters.

My speakers are 4 ohm 85dB sensitivity, and bas for sure gets more tight and transparent with my GamuT DI150 SS amp, but I miss my tube amp in the midrange. I guess it is a story heard before...

But we must admidt the peak current capacity of the amp is important since speakers are current driven, even that some seems to forget...

 

[disco]

The one answer to your question is that speakers (& cables) must be fitted to your amplifier. Or, the other way around if you can design an amplifier. They form an unseperable reproduction system.