I would certainly hesitate to generalise on the basis of my own experience, since mine have an output impedance of over an ohm, and my speakers are medium-sized ported boxes, which as a species tend to have subjectively under-damped bass.
I can't think of a reason why a particular type of triode would generically have a particular kind of bass, independent of circuit topology.
Alex
Topologies, opt ratios, feedback etc obviously effect subjective bass quality but I'm no the only one to make that observation. I've tried mine at between 3k to 6k load to see if changing the damping helped to no avail.
Don't get me wrong for vocals I've yet to better a 300b amplifier. Personally I'd keep them for mid/treble use.
Don't get me wrong for vocals I've yet to better a 300b amplifier. Personally I'd keep them for mid/treble use.
This is a very good topic.We can speculate all we like about amp/speaker synergy but hearing real world experience is always going to be interesting.
I have had a love/hate relationship with SET amps and never found the ideal speaker for them.Perhaps the Audio Note speakers like an AN/E are the safest pick.I have heard them sound good with a range of SET amps.
My Almarro 318B worked well with vintage Tannoys.300B SETs were much less convincing.The old Toshiba SS30 speakers can sound fantastic with lowish powered SETs.
If you don't do the homework, it's all a crapshoot really. Flat impedance, closed box it is. Nothing else works quite so well.
Arpeggio Loudspeaker - diyAudio
Morgan Jones pretty much wrote the textbook on SET amplifier construction, so is worth reading.
The Icon Audio Classic 40 amplifier may have me reaching for my wallet soon, as soon as I get settled. Icon Audio Stereo 40 MkIV Integrated Amplifier | Hi-Fi News
Does all the valve modes. That and high Qms speaker construction and we should be there: TQWT-
Arpeggio Loudspeaker - diyAudio
Morgan Jones pretty much wrote the textbook on SET amplifier construction, so is worth reading.
The Icon Audio Classic 40 amplifier may have me reaching for my wallet soon, as soon as I get settled. Icon Audio Stereo 40 MkIV Integrated Amplifier | Hi-Fi News
Does all the valve modes. That and high Qms speaker construction and we should be there: TQWT-
You'll probably find this interesting then:
High Efficiency Speakers
Some discussion of Audio Note and similar styles.
The efficient SEAS CA21REX project ends up in much the same place. Version 4 has the impedance flattening conjugate we mentioned. I wouldn't have thought some of SEAS's current 8" basses are wildly dissimilar.
High Efficiency Speakers
Some discussion of Audio Note and similar styles.
The efficient SEAS CA21REX project ends up in much the same place. Version 4 has the impedance flattening conjugate we mentioned. I wouldn't have thought some of SEAS's current 8" basses are wildly dissimilar.
I saw that a few years ago 
he does some impressive work!
The foam on one of my AN/ed has fallen apart, must get around to fixing them. I'm sure he's right the efficiency quoted is ' optimistic ' . My axioms were more efficient, think they are spec'd at ~96db/w.
I've fooled around with vintage pioneer stuff too, pax coaxials, they have good efficiency.
he does some impressive work!The foam on one of my AN/ed has fallen apart, must get around to fixing them. I'm sure he's right the efficiency quoted is ' optimistic ' . My axioms were more efficient, think they are spec'd at ~96db/w.
I've fooled around with vintage pioneer stuff too, pax coaxials, they have good efficiency.
Hey Bonzo, I have multi-channel SET amps running large 6 way predominantly horn speakers. DHT and IDHT tubes in use such as 45/2A3/UO186/RE604 etc. and 6C33C, 6E5p, 6E6p. System is basically 110dB/w/m apart from subs which are circa 100dB/w/m, but they are still run with a 9w, low output impedance SET with a giant specially wound OPT.
A lot of work to get setup...but well worth it if you are persistent.
A lot of work to get setup...but well worth it if you are persistent.
This WLM LA Scala seems to interest a lot of people. Famously cheap Visaton drivers, but very high-end in it's aspirations.
Should be very SET friendly with a little adjustment. Biggish 30L closed box and a conjugate impedance flattening:
You can model it easily with a TW70 tweeter and a W200S bass in 4 or 8 ohms. Software | Visaton
Any old well-behaved 8" 90dB woofer IMO. And I quite like the Monacor HT22 cone tweeter. In fact Tony Gee has done that in what he calls the Twenty Five:
Humble Homemade Hifi - Twenty Five
Very nice impedance, just needing a 1.8kHz LCR conjugate for SET friendliness, IMO. And closed box possibly.
Should be very SET friendly with a little adjustment. Biggish 30L closed box and a conjugate impedance flattening:
You can model it easily with a TW70 tweeter and a W200S bass in 4 or 8 ohms. Software | Visaton
Any old well-behaved 8" 90dB woofer IMO. And I quite like the Monacor HT22 cone tweeter. In fact Tony Gee has done that in what he calls the Twenty Five:
Humble Homemade Hifi - Twenty Five
Very nice impedance, just needing a 1.8kHz LCR conjugate for SET friendliness, IMO. And closed box possibly.
I have only read the 1st post, but the overriding requirement for typically high output impedance amplifiers is either a flat impedance or is such trgat the amplifier output impedance/speaker impedance interaction just happen to complement FR anomalies as measured by a voltage amp).
We have been going thru a good siscussion of this here: Do tubes actually sound like anything?
Efficincy itself is not the deciding factor, i see many (far too many) speakers that claim high efficiency that have ugly impedance curves that make them really iffy with a typical SET (ie most of the Klipsch i have seen people recommend).
For a typical SET (or other amp with high output impedance) a good FR with complementary impedance6 such as the Fostex FExx6 series in one of their matching horns, or something with flat impedance such as Elsinore Mk6..
Here is an example of a set of 3 simple BR boxes using the same driver designed for for varous ranges of amplifier output impedance.
http://wodendesign.com/downloads/King-of-Swingers.pdf
dave
Speakers/amp (and the cables that hook them together) have to be considered as a system.
This becomes much less of an issue if you restrict yourself with low output impedance amps & typical multi-way loudspeakers where most people play (even more so in the comercial space). But as soon as the amplifier’s output impedance starts to rise one has to take more care.
dave
Morgan did s good job illustrating the process of designeing a reflex for a high output impedance amplifier. The FE166e (w low output impedance amp) is not a very suitable enclosure.
My one nit is that he instsisted on puttin gthe vertical brace dead centre.
dave
What speakers ar eyou using. It could be a system mismatch and not an issue with the amp or the speaker.
Bass too fat and bloated or MIA?
dave
That answers my question. The impedance rise at the bass resonance is interacting with your amp’s output impedance to produce that bass.
A quick fix might well be as simple as adding damping the vent to push the box more toward aperiodic (and lowering the resonant peaks in the bass).
dave
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