When mating tube amps to cones...
Does the difference in tube amp physics V solid state render a different set of parameters?
Does the difference in tube amp physics V solid state render a different set of parameters?
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The valve amp makes up for its high impedance by using the correct output transformer to match that impedance to the correct speakers.
Just remember not to power up the valve amp with no load.
Just remember not to power up the valve amp with no load.
Tube amplifiers often have higher output impedance (Zout) than typical SS amps. Often moreso for SE amps.
If this is so, then you want a speaker tha has a flattish impedance curve. Otherwise a portion of the speaker impedance is convolved with the FR (as measured by an amp w low Zout.
This is not unique to SS amps and is not universal — there are SS amps with high Zout, and tube amps with fairly low Zout. For instance the Pass ACA has fairy high output impedance especially if being run bridged.
And as Nigel points out, the output transformer of a tube amp (ignoring OTLs) has taps to provide a better match from the high impedance outoput of the tubes to the much lower impedance of the speakers.
Note that damping factor is a bastardized version of Zout (ie speaker nominal impedance divided by Zout). And unfortunately many tube amp manufacturers will not provide Zout or even know what it is.
What kind of speaker.
dave
If this is so, then you want a speaker tha has a flattish impedance curve. Otherwise a portion of the speaker impedance is convolved with the FR (as measured by an amp w low Zout.
This is not unique to SS amps and is not universal — there are SS amps with high Zout, and tube amps with fairly low Zout. For instance the Pass ACA has fairy high output impedance especially if being run bridged.
And as Nigel points out, the output transformer of a tube amp (ignoring OTLs) has taps to provide a better match from the high impedance outoput of the tubes to the much lower impedance of the speakers.
Note that damping factor is a bastardized version of Zout (ie speaker nominal impedance divided by Zout). And unfortunately many tube amp manufacturers will not provide Zout or even know what it is.
What kind of speaker.
dave
The Harman-Kardon Citation II and McIntosh MC275 have quite respectable damping factors and will do just fine with AR3s and AR9s. However, even those fine units are in way over their heads trying to deal with big Thiel speakers whose nominal impedance is 4 Ω and exhibit nasty dips down to 1 Ω.
You obtain max. performance from those big Thiel speakers by employing tubed preamplification connected to 1st rate SS power amplification. Mass market guano SS equipment is frequently damaged by connection to the difficult Theil load.
You obtain max. performance from those big Thiel speakers by employing tubed preamplification connected to 1st rate SS power amplification. Mass market guano SS equipment is frequently damaged by connection to the difficult Theil load.
That advice was one of the first things Grampa drummed into me. IIRC the high voltage developed could overwhelm the winding insulation and arc through.
Rogue's Mark O'Brien was kind enough to talk with me when I called their CS five years ago about my Atlas. He claimed that's not a worry with that amp. I still avoid running a power amp without a load, especially if an input signal is present. If my memory of that conversation is correct, what might make the conventional advice not always true? Better dielectrics, winding technique, or protective circuitry?
Rogue's Mark O'Brien was kind enough to talk with me when I called their CS five years ago about my Atlas. He claimed that's not a worry with that amp. I still avoid running a power amp without a load, especially if an input signal is present. If my memory of that conversation is correct, what might make the conventional advice not always true? Better dielectrics, winding technique, or protective circuitry?
^this^ was my concern-
IMO- tubes are voltage amps while solid state are current amps. Seems voice coils which do best mated to tube amps are higher impedance??
^again^
It has been my suspicion that pinnacle audiophile designs employ hybrid tech- I say that cuz they keep their designs close to the vest.
What matters is the impedance curve, not the nominal impedance. Many tube amps have multiple nominal impedance taps on the O/P transformers. Significant dips in the impedance curve, particularly in the deep bass region, are a warning for poor candidates to be mated to tubed power amplification.
Magneplanar speakers are not particularly sensitive, but they exhibit a "flat" 4 Ω impedance, which makes them good candidates for mating to tube equipment. As is always the case, avoid "constantly" driving the amp into clipping. Power appropriate to the listening venue and speakers must be acquired.