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Not to be too far off subject - there seems to be quite an emphasis on SE triode power amps in the marketplace - they can be beautiful but I'm not fully convinced that they're 'better' than push-pull triode (without loop negative feedback) for high efficiency speakers.My 85lb homemade parallel 2A3 amp using IT coupled 5842Q and multiple CLC filtered supplies is pretty decent but I've heard good stuff from my parallel push-pull 6BX7 mod Eico ST-70 too (6BX7 vak~300vdc)- plus better damping due to more usable primary L.
Freddy
Follow Ups:
Excuse me while I pick myself up off the floor from laughing! Freddyi obviously mean to post this on the SET forum and not one of the twelve responses even mentioned that this is the HIGH EFFICENCY SPEAKER FORUM! Yes, I understand that SET's often go with high efficiency speakers because of their low power output, but not necessarily. I use push-pull pentodes with negative feedback, not single-ended triodes.
Am I the only inmate out there who noticed this? Maybe I just need some more shock treatments. By the way, what is the best way to propagate Gazania's? I heard root division is the best way to go. Or should I just buy seedlings at my local Nursery? I would appreciate any help on this. U.W.
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nt
On the hillside below my terrace, these things just seem to spread and mulitply like crazy with no care at all. They're really beautiful, even though they seem to be used as "indestrucible" public area lanscape plants here in Los Angeles.
Thanks everyone - sorry to get tube toplogy debate going on this forum but I suspected a lot of tube users in general with the higher sensitiviy speakers.There appears a slight preference (or complete one for Rich) towards SE - also a tip of balance on mids even using UL or pentode 6BQ5. I'll make a blind stab that a push-pull triode amp with no diff-amps (SE input) and slightly unbalanced phase-inverter may close the gap a bit(?) - I like p-p simple. In either topology w/o nfb the speaker's Z and tap selection/reflected Z can have a lot of influence on tonal balance.
My ancient Edgarhorn system sounds fab on 'naked ladies' LP of Jimi's 'Electric Ladyland' using my 5842/417A IT coupled LCLC supply parallel 2A3 amp - guitar and mix are "alive" - in comparison when putting the so-called remastered CD on a solid state amp my immediate reaction is to turn the music off - its destroyed period. Have never made it hrough the CD without cringing.
FreddyPS - to align with Rich - I may give a stab again at SE soon and upgrade my 417A's IT
**I'll make a blind stab that a push-pull triode amp with no diff-amps (SE input) and slightly unbalanced phase-inverter may close the gap a bit**Yup. My 6B4G amp has a 5842 driver, autoformer phase splitter (as above).
Must admit tho, it does give up a bit to a good SE, system dependant, of course. It's all about compromises.
you need more shock treatment ;-)Best way to propagate gazinias? Easy - pair off one teenage boy gazinia with one teenage girl gazinia, set them in front of the TV, turn on MTV and give them some "safe sex" pamphlets.
Works great for propagating humans, should work for gazinias.
I like the set amps on the top. (300 up) They seem to be more open and offer more glitter and presence.My triode wired Curcio ST-70 has however taking it's place driving my bass horn 100-300 cycles over a pair of 300b mono's. It really kicks ass on them. Punchy as hell and LOTS of headroom!
Magnetar..Get Real. Get Horns!!
Freddy,I use a 6L6 monoblock pair in triode mode, push-pull with no feedback, interstage transformer coupling.
I like it much better than SET because:
- I get way better bass
- I get terrific clear detail
- I get a lovely midrange
- more dynamic and punchyThere is absolutely nothing wrong with PP no-NFB amps that are designed well - but I believe that with this topology, choke power supply and the use of interstage transformers is mandatory to get really great sound - and the quality of the transformers is critical.
The cost of that, however, makes a good PP amp not a great commercial proposition. SET is more popular among the US makers because (and here come the flames) is is cheaper to get good sound from in a production piece.
Also, SET is for some reason, probably marketing, more fashionable.
Very often the differences come down to perception, if buyers think it's cooler, more underground or exclusive, the claims of better sound follow. NOT to say SET is bad, far from it - nor is PP superior - but both are very valid and I believe it would be very wrong to say one is universally better than the other.
Is there a amp available (either kit or assembled) that is designed the same as your amp?
Of course! Mine is the Sun Audio SV-6L6PE, which is quite simple to convert from pentode connection to triode connection ( going from 20 wpc to about 6 wpc).
Well Fred, My wacky opinion is I like both. I think a nice simple P-P with interstage phase splitter(even a cheap one that makes it over 20khz) can sound great. My main thought is simplicity and power. Simple and safe DHT amps are mostly limited to 10 watts. 845, 211, SV572 amps can produce more than 20 watts but at higher B+ and they require more experience to build and own. IT coupled P-P can be easily and safely built to over 30 watts. The IT provides many of the quilties of SE, the P-P provides power. The combination has very good potential but isn't practiced nearly as much as SE or tube phase splitters.I've been working with both designs but have to say even though I like both I like SE a little better. I also don't miss the loss of the bottom octive as many report and I measure good output below 30hz on all the SE designs I've undertaken 70%=-1.5db. The JBL 2226H only goes to 50hz. But for balls to the walls rockin jams with 95db or less speakers that can produce sub 50hz with output, P-P is the winner.
Like so much here it's down to taste, simplicity and synergy. But no NFB is a common point that does make a positive differance in both design types.
Don't be afraid to use either designs.
***I'm not fully convinced that they're 'better' than push-pull triode (without loop negative feedback) for high efficiency speakers.***I am.
It is a matter of taste. The music you listen to will dictate the amps you will finally end-up with. SET for very refined listeners,PP for people with a need for an entertainment. You want both? Have a both amps on hand!!!( My situation anyway...)
Libor
I'm using PP 6B4G's, and am quite happy with the sound. My SE 45 has a bit more clarity, that elusive definative attack and decay (usually absent in digital, anyway) - but the PP amp comes close. And with a LCLC filter and fixed bias, I get that bottom octave.
Good post. It drives me a little bats, everybody is ga-ga over SET's these days. OK, I have high efficiency horns at 108 dB, its time to try the SET thing. 2A3? Nope, while there is new mfg available for a good price and performance, the tube nuts have driven the price of NOS into the stratosphere. 45? Nope, new mfg is 400$ (too rich for my tube allowance), and old stock is scarce and expensive. Well, I settled on the 71A, at .7W max. This might be best anyhow, since the 45 and above have way more power than I need. 71A's are hard to find, but they haven't been hit as hard yet.I haven't owned a quality PP myself, so I'm also planning on designing/building one too. I like to take a design, and push it to its extreme to see what it can do. The SET has been so, cobalt parafeed EXO-145's, teflon caps, etc. I want to do the same for a PP and then see what happens. I also love OTL's, and pushed that design to extremes, and got amazing results. I eventually gave up on it because it was too difficult to live with. Too hot, too much electricity.
So I don't think PP, or OTL should take the back of the bus. Well, not yet :)
Dan
I would be shot for this over in SET, but for me, it's primarily psychological.The sensation of having the fewest "parts" between source and your ears as possible.
OK, I haven't gone to single driver crossoverless speakers yet, but lordy lordy lordy those Laurel's playing through Khorns are as close to heaven as I've ever been.
Now if I could only reproduce the bottom octave, I'd be happy.
For a while.
Hi Freddy,I'm not so sure that it is a matter of one toplogy being better than another, or the best in all respects. Different approaches have their strengths and weaknesses. After I finally got my bass horns assembled and installed in my system, I mostly used a solid state amp for the first couple of weeks. It had the bass extension and slam that I could never hope for from my SE 45 amp, and was perfect for playing "Oh yeah" by Yello at 110dB.
What I've found is that, over time, I keep returning to the components and technologies that give me the most realistic lights-out listening experience overall. The transformer coupled SE triode amp is a mainstay, despite frequent experimentation. I believe that SE triodes deliver more low level detail than PP amps, all the subtle chair squeaks and reverberant tails that place the listener at the recording venue. The best explanation I've heard is that microvolt signals represent tiny variations in the constant flux in the transformer core and are passed easily, whereas they have to survive the most nonlinear portion of the push pull transformer's operation, where the fields are collapsing and reforming. I also like the argument that the SE amp maintains a natural mix of even and odd harmonic distortion products, which the ear accepts easily, whereas the PP amp cancels the even ordered harmonics, leaving only the odd ordered harmonics, which the brain recognizes as the sound of a chain saw (just kidding!).
Certainly a DHT PP amp will offer a very convincing sound, probably the best that PP has to offer. I still think there's something to this SE business, however. My first SE listening experience, back in 1986, was with a cheap integrated amp I had found on the sidewalk. A friend and I listened to it for hours on end, amazed at the sound. It used 6BQ5s in the output, running in SE ultralinear mode with screen taps in the output transformer primaries. Hey, wait a minute; that amp is still over at my friend's house!
The humble 6BQ5 is a sonic marvel- cheap, better sounding than the EL34 to me, and very nice in triode mode. Much fun can be had with these little pentodes.I like your explanation of the SE mystique- there is definitely a level of detail in them that I have yet to hear from other topologies.
That's what my Bogen db 230 runs. And sweet it is. TC
I compared several SET amplifiers driving a pair of AG Trios. They sounded wonderful. Hugely entertaining and involving and some of the most luscious music I'd ever heard. Midrange to die for and with vinyl, out of this World.
I then hooked up my then current amp (s'cuse the pun), a BAT VK-60, expecting it to be shot down in flames. Instead the music sounded somewhat less 'warm' but at the same time more realistic with that 'live music' fullness, dynamics, drive and presence. The music was more solid, especially in the bass, with greater intensity and inertia.If the SET was a candle-lit dinner, the BAT was life in the fast lane. Since then I've installed the BAT VK-75SE and never looked back.
The PP solution is however less tolerant of wayward front ends, poor cable matches or any set-up mistakes. A live trumpet for example walks right up to the edge of harshness while never crossing the line. I could best decribe the sound as 'thrilling'. It is however a thin line between thrilling and excrutiating and poorly selected matching components can easily push a system to the wrong side.
Ever see your favorite Italian Restaurant in broad daylight? If so, you know what I mean
I remember reading an article where Mike Sanders of Quicksilver audio recounted his attempts to compare SE with PP by building test amps in the two topologies...He finally settled on the PP configuration and said he would probably never produce a SE amp for the Quicksilver line...He was not negative about SE but felt that the PP came out better overall...He, of course, recognized (and said he heard) that the SE had less "smear", a purity, audible especially in the mid range that the PP could not match...
> > He was not negative about SE but felt that the PP came out
> > better overall...I think you're refering to the Stereophile interview by Sam Tellig.
My reading was different. It seems Mike Sanders complained about the high distortion in SET amps, and concluded that his 15wpc Mini Horn was better overall. SET amp distortion is non-linear; it's hideous at full power. If his speakers need a 15wpc amp, then a 3wpc SET amp won't do, at least not as good as his Mini Horn.If he indeed never used very high efficiency speakers in his 1-year-or-so experiment on SET (as I recall correctly from the article), then the story might be quite different when he needed very little power at much lower distortion and with all the juiciness of SET.
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