I would say in case speakers are tube friendly there is no point of having an SS amp unless hassle of tube gear maintenance is not OK (output tubes wear off cathodes and have to be replaced, bias adjustment etc).
Based on my 30+ years of audiophile experience I would say tube gear tends to produce cleaner sound primely because of HiEnd passive components the good tube amp is implementing.
However modern wide band ICs are getting very close if treated right.
I liked Wadia+GRAAF sound. Graaf is out of production unfortunately. Never owned Atma-Sphere tube gear but there are opinions that Atma is on a par with Graaf if not better.
Agreed - I'm not looking to generalize. I'm testing specific combinations in my specific system. Even then, there are too many variables to draw firm conclusions.
That said, I'm planning to try a variety of tube preamps with solid-state power amps and solid-state preamps with tube power amps. If there's anything useful there, I'll say so - and expect to be flamed by those who disagree
My expectation (to be proven or refuted), is that: With my speakers, in my room, at the volumes that I listen at, and to my ears: One combination will sound consistently better than the other. If I'm wrong, then I've wasted my time & money. If I'm right, then I know something that I didn't previously.
My "knowledge" probably won't be worth a darn to any of youse guys (too many variables), but there may be value in hearing about the trials.
Cheers - Boomzilla
Not true based on many pre and amps compared in level matched double blind test. Those that do sound different are the result of poor design or unusually high distortion which often is the result of poor design.
The exception is single ended amp with high amount of even order harmonics, especially the 2nd order.
Suggestion: Active bi-amp (SET tube amp for mid-high, P-P amp for woofer) and let your sub fill the lowest 2 or 3 octaves. You will need a separate active crossover and do some tweaking around but once done, it's unbeatable.
Klipsch La Scala? Oh, that is a whole 'nuther story... Those are very efficient. Lots of sound out for little watts in. The only problem is that the La Scala's have wicked impedance peaks and dips. An SET amp with no NFB will gack on that.
OK, my opinion, FWIW -- which is probably not much, but just for fun...
I'd make a nice push-pull triode amp and choose an OPT with high-ish primary impedance for the chosen output tubes. For instance, a push-pull 2A3 amp with something like a 5k p-p primary impedance to 4 ohm secondary. Or maybe push-pull EL84's or 6V6's in triode, into a 10k p-p primary. Go for high-ish current through the output tubes, class A biasing, to reduce the tubes' plate resistance. You won't get as much output power, but you'll get better damping factor (I think...). If you choose a good enough OPT, you might get away without the need for global NFB.
Without NFB, it will be easy to make the amp sensitive enough that you won't need a line stage/preamp with gain. Try a good input selector switch and as good a volume control as you can get. That way you can forget about preamps, except for the RIAA amp. A line level preamp's not needed, really.
There's a guy who makes new design crossovers for the big Klipsch speakers. He claims that they have much nicer impedance curves than the stock designs. That would make them more tube friendly. Not cheap, but maybe worth it. ALK Engineering -- I have no experience with them, but I found the ideas interesting, maybe you will too.
I have a pair of KG 4.5 that I'm pretty pleased with for the little money I paid. I'd like to have a pair of La Scala's. I guess you like them?
--
Spend the big bucks on a first rate pair of OPT's. I heard an amp based on a pair of Hashimoto that was excellent, and measured spectacularly well. Quite good looking 10kHz square waves with no global NFG at all. I hear Electra-Print transformers are very good too. I'm lucky to have a pair of 1990s Tango XE-45-5's. The difference between those and something like a Dyna A470 is day and night, respectively. There are many really good amp circuits. Choose a good circuit and the OPT you choose will dictate the sound quality more than anything else.
OK, my opinion, FWIW -- which is probably not much, but just for fun...
I'd make a nice push-pull triode amp and choose an OPT with high-ish primary impedance for the chosen output tubes. For instance, a push-pull 2A3 amp with something like a 5k p-p primary impedance to 4 ohm secondary. Or maybe push-pull EL84's or 6V6's in triode, into a 10k p-p primary. Go for high-ish current through the output tubes, class A biasing, to reduce the tubes' plate resistance. You won't get as much output power, but you'll get better damping factor (I think...). If you choose a good enough OPT, you might get away without the need for global NFB.
Without NFB, it will be easy to make the amp sensitive enough that you won't need a line stage/preamp with gain. Try a good input selector switch and as good a volume control as you can get. That way you can forget about preamps, except for the RIAA amp. A line level preamp's not needed, really.
There's a guy who makes new design crossovers for the big Klipsch speakers. He claims that they have much nicer impedance curves than the stock designs. That would make them more tube friendly. Not cheap, but maybe worth it. ALK Engineering -- I have no experience with them, but I found the ideas interesting, maybe you will too.
I have a pair of KG 4.5 that I'm pretty pleased with for the little money I paid. I'd like to have a pair of La Scala's. I guess you like them?
--
Spend the big bucks on a first rate pair of OPT's. I heard an amp based on a pair of Hashimoto that was excellent, and measured spectacularly well. Quite good looking 10kHz square waves with no global NFG at all. I hear Electra-Print transformers are very good too. I'm lucky to have a pair of 1990s Tango XE-45-5's. The difference between those and something like a Dyna A470 is day and night, respectively. There are many really good amp circuits. Choose a good circuit and the OPT you choose will dictate the sound quality more than anything else.
Last edited:
Essentially, I already do this by routing the full range (variable, preamp-level) signal to both the power amp and to the sub. The sub's internal crossover cuts it in below the roll-off of the main speakers.
This isn't as elegant as having an upstream crossover that prevents the power amp from trying to drive subsonics to the the main speakers that can't reproduce them, but it does keep another active circuit out of the signal path. Overall, I find little difference.
Finally, may I say that in my juggling of electronics what I'm searching for is "synergy." This is something that you can NOT get from reading specifications. It is, instead, something that can only be identified by listening.
I can tell you that Klipsch La Scala speakers and VTL Compact 100 tube monoblocks are highly synergistic.
I can also tell you that Thiel 1.6 and 3.6 loudspeakers are highly synergistic with Emotiva power amplifiers (specifically, their XPA-2).
And finally, I can tell you that that Emotiva XPA-2 power amp that sounds so good with the Thiels sounds absolutely flat with the La Scalas. Why? I don't know, but I know what I hear.
For those of you with Thiel speakers who are in the market for a power amp, try the Emotiva products. They're sold ONLY over the internet with a free return period if you don't like them.
I don't work for Emotiva nor do I have any financial affiliation with them at all. Just saying that my Thiels never sounded better...
Again, synergy: I've heard La Scalas in homes where they profoundly suuuuuuuuuuuuucked! They sounded like exactly what they were - A big, horn-loaded, honkin' PA speaker with no bass and utterly terrible frequency response.
Then, in my room, with those VTL compact 100 tubes driving them, they transcend what I know them to be and disappear - MAGIC! I'd never have thought that they could have done this (despite OWNING a pair for a few years back in the late '70s). Of course, having the DefTech Trinity sub under them adds a complete other dimension to their sound, but what impresses me isn't the bass (well, it is, but that's not the La Scalas talking). It's the way the La Scalas energize the room, disappear as point sources, throw a soundstage that is wide AND deep, and put on a show that I've previously only heard with mini-monitors. Plus, the La Scalas have dynamics that make music sound absolutely alive! No mini-monitor has EVER done that in my room.
In short, yeah, I like them but that doesn't mean that you will...
Well, since I also live exactly above the center of the earth, you can bring your La Scala's over and try them with a tube preamp, op amp mixer, solid state amp, and tube ST70 before mods.
Or I could bring the amps over. Lots of words about La Scala's around, never heard them. Or try them and the amps in my room, 14"wx9'hx30' long with hard plaster walls. My speakers are also tube friendly, but have adequate bass for everything except 32' organ stop and earthquake movies.
The last hifi boutique store closed here 25 years ago. That is how I ended up with PA equipment, you can try before you buy.
Or I could bring the amps over. Lots of words about La Scala's around, never heard them. Or try them and the amps in my room, 14"wx9'hx30' long with hard plaster walls. My speakers are also tube friendly, but have adequate bass for everything except 32' organ stop and earthquake movies.
The last hifi boutique store closed here 25 years ago. That is how I ended up with PA equipment, you can try before you buy.
Last edited:
Hi Wave -
I'm confused...A not unusual condition
If I understand you correctly, you're suggesting that I insert diode tubes into the feedback loop of op-amps. By varying the filament voltage of the diodes, I change the dynamic output of the op-amp? This works by modifying op-amp gain dynamically based on the amplification (or lack thereof) of the diode tube?
If we're trying to modify the gain, why not use a small triode instead of the diode? The amplification circuits I've seen previously use triodes rather than diodes. What advantage is there to running a diode rather than a (more conventional) triode?
Pardon my ignorance here, but I'd like to learn something, and you sound like you've tried this before.
Thanks - Boomzilla
Hi Wave -
I'm confused...A not unusual condition
If I understand you correctly, you're suggesting that I insert diode tubes into the feedback loop of op-amps. By varying the filament voltage of the diodes, I change the dynamic output of the op-amp? This works by modifying op-amp gain dynamically based on the amplification (or lack thereof) of the diode tube?
If we're trying to modify the gain, why not use a small triode instead of the diode? The amplification circuits I've seen previously use triodes rather than diodes. What advantage is there to running a diode rather than a (more conventional) triode?
Pardon my ignorance here, but I'd like to learn something, and you sound like you've tried this before.
Thanks - Boomzilla
The advantage is, you are getting soft, well controlled "tube" clipping, without need for high voltage to power the stage. Connect filaments of both tubes in series, and power them from emitter follower after potentiometer.
To resume some of the (unspoken) conclusions here:
- pre amplifiers modify reproduction (possibly only by changing impedance), which is either done good or bad ;
- pre amplifiers which don't modify anything serve no goal ;
- best tube driven installation has separated frequency domains, powered by more amplifiers;
- immitating tube properties in ss confuses people, at least ;
Glad I know what I'm doing here: enjoying my home build gear while accepting it's not the latest and GREATEST. Cheers!
- pre amplifiers modify reproduction (possibly only by changing impedance), which is either done good or bad ;
- pre amplifiers which don't modify anything serve no goal
;- best tube driven installation has separated frequency domains, powered by more amplifiers;
- immitating tube properties in ss confuses people, at least ;
Glad I know what I'm doing here: enjoying my home build gear while accepting it's not the latest and GREATEST. Cheers!
Technically, that's active x-over but what I was referring to was a full blown active system. When you apply such system that covers the mid-range frequency, which our ears are most sensitive to, it will be something you won't want to leave.
If you think active crossover is disturbing, I wonder what passive crossover will do to you...
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.