greg928gts Posted February 5, 2009 Share Posted February 5, 2009 I finally got a chance to try out the Jubilees with my SET amplifiers. Klipsch Jubilees, passive networks, 2A3 Horus monobloc SET amps in my 16 x 22 x 9 living room (where my Khorns normally reside). Just switched from the Scott 299A. The results were not good. The bass was bloated and the amps ran out of steam very easily. I'm disappointed because I was hopeful that the passive networks would bring the speaker system together into an efficient load that I could run with my amps, but it just didn't work. I assumed that the higher efficiency of the Jubilees would work at least as well as my Khorns do with my amps, and I have my suspicions about why it didn't work out so well. I really don't want this to get into a Jubilee bashing thread, so I'm not going to say much more. Mostly I just wanted to report my experience here for others that might be interested in this combination. BTW - I did use my SET amps on just the K69/K402 a few months ago when I had these biamped with the EV DX38 with very good results (usual complaints about the k/69402 aside). I had one of the Crown amps on the bass bins. Greg Quote Link to comment Share on other sites More sharing options...
Guest " " Posted February 5, 2009 Share Posted February 5, 2009 There's a product that increases the apparent load SET amps see. The link is below. http://www.enjoythemusic.com/magazine/equipment/0603/midmonth/zeroautoformer.htm Basically, the zero autoformer is an exotic version of the T2A transformer. Quote Link to comment Share on other sites More sharing options...
mikebse2a3 Posted February 5, 2009 Share Posted February 5, 2009 A cathode bias 2A3 amp with Jub/passive crossover would run out of current I would suspect for many users. I've heard Jub/passive crossover with 300B se amps and they reproduced IMHO very good sound reproduction. There are a couple of Jub owners in europe that I take from our conversations that seem to enjoy this combination also. I have used EV DX38 active crossover with 2A3 push/pull amp for Jub LF and 2A3 se amp for K402/K69-A with very pleasing results. Note: When using Jub/active crossover and tube amps I recommend the Tube amp for the Jub LF should perform best on the 4 ohm tap and I would recommend the Tube Amp for the K402/K69A be used on the 8 ohm tap. When Jub/passive crossover is used with Tube amp both 4 ohm tap and 8 ohm tap should be auditioned for preference. Anyway these are my experiences but as always every situation is unique to some extent as well as individual taste so results/opinions will vary no doubt. mike tn Quote Link to comment Share on other sites More sharing options...
PrestonTom Posted February 6, 2009 Share Posted February 6, 2009 Although the Jubilee bass bin is quite efficient, the two drivers are in parallel. The impedance can drop to about 3 Ohms. The K-horn is a different story, so the comparison is not an apt one. The biggest differences I have heard between amplifiers, involves speakers that present a low impedance. Not all amps can provide sufficient current, especially for transients and crescendos. So I am not surprised by your results. The good news is that there are plenty of other amplifiers out there. Good Luck, -Tom Quote Link to comment Share on other sites More sharing options...
edwinr Posted February 9, 2009 Share Posted February 9, 2009 Greg, the high sensitivity of the Jubilee should have compensated for the lower impedance. What is the sensitivity of the Jub's? It'd have to be at least 103 db... While the few watts of output some low powered SET amps produce is IMHO, only enough for smaller rooms and undemanding music, it should be enough to drive highly sensitive speakers to reasonable listening levels - regardless of the relatively low impedance. The poor bass reproduction is definitely the warning sign that your amp has run out of juice. There has to be more going on here than just the low impedance. Maybe there's a problem with your amplifier. Although if it drives the Klipschorns okay... Curious. [*-)] Quote Link to comment Share on other sites More sharing options...
edwinr Posted February 9, 2009 Share Posted February 9, 2009 Check this link, Greg. I don't know whether the Fi X 2A3 amplifier's design bears any resemblance to yours, but the reviewer does make the comment that their 2A3 amplifier is best suited to higher impedance loads - this amplifier showing an intolerance for low impedance... http://www.tnt-audio.com/ampli/fi-x_e.html Still, we're talking about 103 db plus... Quote Link to comment Share on other sites More sharing options...
Coytee Posted February 9, 2009 Share Posted February 9, 2009 Just last night, I finally inserted a Viva 300B amp, although I do not know if it's a SET, PP. I also do not have it in a passive so it's not the same comparison on several fronts. Only listened to a tv show since the wife was there but given that task, it was working and sounding just fine. I hope to crank things up a bit either tonight or tomorrow and see how this 300B does on HF duty only. Oh, and I forgot the nice looks of tubes when they are glowing blue...(fluorescence?) Quote Link to comment Share on other sites More sharing options...
Coytee Posted February 9, 2009 Share Posted February 9, 2009 What is the sensitivity of the Jub's? It'd have to be at least 103 db... I'm personally a bit confused. I recall having been told as high as 108/109 depending on passive/active (active passives taking a small hit because of insertion loss) yet the website on the KPT 535 says 105db. Do i believe what I read or what I'm told...what I read or what I'm told... If I believe what I read, then the bass bins also have a tag on them saying 1,200 watts max and I've been told that's a typo. They're not rated for that. So now, what do I do, believe what I read or what I'm told... I think I'll just go crank em up & listen... [8] Quote Link to comment Share on other sites More sharing options...
greg928gts Posted February 9, 2009 Author Share Posted February 9, 2009 1200 watts! LOL. Might want to have a fire extinguisher available. The Jubs are a bit more efficient than the Khorns. It's noticeable to me, so I would guess 2db? Which would make them 106db. But as Tom said, there's not enough current. I don't understand it, but I can tell you that efficiency rating isn't the only factor in determining how much sound you get out with a given wattage in. There is a clear differernce between the Khorns and the Jubs with my SET amps. Greg Quote Link to comment Share on other sites More sharing options...
Coytee Posted February 9, 2009 Share Posted February 9, 2009 But as Tom said, there's not enough current. I don't understand it, Greg, I don't pretend to understand it either... I long long ago, asked Roy something like "why do they sound a bit more snappy when I turn the volume up" and he muttered something technical about voltage and the like... I think he then heard the crickets chirping in my brain and said (paraphrasing) "Richard, don't forget there are TWO woofers in there that need to get moving and to move them you need to add some volts" I'm sure I butchered his comment so please don't take this as a quote but something from the dust bins of my brain as a simple note that since there are two drivers in there, they take a bit more juice to get dancing. Quote Link to comment Share on other sites More sharing options...
greg928gts Posted February 9, 2009 Author Share Posted February 9, 2009 But as Tom said, there's not enough current. I don't understand it, Greg, I don't pretend to understand it either... I long long ago, asked Roy something like "why do they sound a bit more snappy when I turn the volume up" and he muttered something technical about voltage and the like... I think he then heard the crickets chirping in my brain and said (paraphrasing) "Richard, don't forget there are TWO woofers in there that need to get moving and to move them you need to add some volts" I'm sure I butchered his comment so please don't take this as a quote but something from the dust bins of my brain as a simple note that since there are two drivers in there, they take a bit more juice to get dancing. Yes, and once you get em dancing to a little juice, things get very interesting. Don't forget all those evil electronics I keep talking about, there's got to be some loss there too. More than just voltage I suspect, but we won't go there. Jubs are back at the shop now in storage. The Khorns made it back into the living room and the wife is a little happier with me right now. Greg Quote Link to comment Share on other sites More sharing options...
DrWho Posted February 9, 2009 Share Posted February 9, 2009 yet the website on the KPT 535 says 105db. That's measured in half space. Everytime you cut the space in half, you get another 3dB (in the ideal world)....so 1/8 space would theroetically be 111dB. I believe it was Trey who mentioned that you normally see closer to +4dB, which would correlate to the 109dB mark. Quote Link to comment Share on other sites More sharing options...
edwinr Posted February 10, 2009 Share Posted February 10, 2009 Maybe the passive crossovers are soaking up the power somehow. From my understanding, many SET amplifiers are happier driving simple horn speakers with even more simple crossovers, like the now defunct Loth-X designs using drivers similar to the popular Lowther transducers... Quote Link to comment Share on other sites More sharing options...
Marvel Posted February 10, 2009 Share Posted February 10, 2009 I am using the low order crossover from John Albright, the DHA2, which is also a constant impedance type. My 2A3s work well with them. The more complex, I think the more power loss in the crossover you will have. All that being said, did anyone hear Rigma's all out passives that Roy worked out for him? I am wondering what he uses to drive them, as he does have some 300B amps (I think). Greg, keeping the wife happy is an important part of the mix, too. Bruce Quote Link to comment Share on other sites More sharing options...
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