JBL 4648A with SET's? [message #39329] |
Wed, 04 December 2002 06:07 |
jlharden
Messages: 94 Registered: May 2009
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You guys have me thinking again. The 2226J woofer is reported to be working well in a number of SET based systems. Has anyone tried the 4648A cabs off the the little amps? We'd gain our 3db(or is it 6?...depends on who you ask.) Would having the woofers paralleled also double the impedence at resonance? Seems it might...Can't win at this game!!! Some days I think I should just build a push pull EL34 amp!
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Re: JBL 4648A with SET's? [message #39332 is a reply to message #39330] |
Wed, 04 December 2002 08:56 |
jlharden
Messages: 94 Registered: May 2009
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Hi Till, I know the 4648 is a bass cabinet. I would be crossing over to the hf horn at 800 HZ. My point is that the dual woofer cabinet nets a good gain in system sensitivity which is a major plus when we're dealing with 3.5 watts. My concern is that that's a whole lot of speaker motor for a little triode to control. I know there's many of these 4648A enclosures around and wondered if anyone had tried running a pair of the 2226J's per channel rather than a single. Building up a dual 15" Pro Pi 4 in the Pialigned 3.9 cu. ft. enclosure would be one bad looking "little" cabinet, wouldn't it? That's where my system was at 1 year ago when I put all these 2226J woofers aside due to a gut feeling that they weren't going to sing with the set. Recent posts have indicated otherwise, at least in a single woofer cabinet. Who's got a 4648 with 16 ohm woofers and a Paramour? I think for some preliminary testing that might work. Perhaps one could tell pretty quickly if the amp "works" or if it rolls off everything and is "dynamically challenged". Hoping for some good feedback. Take care! Jerrod
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Re: JBL 4648A with SET's? [message #39339 is a reply to message #39332] |
Wed, 04 December 2002 13:46 |
mikebake
Messages: 243 Registered: May 2009
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Grand Master |
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Hmmm, well, I'm in favor of trying funky stuff to see if it works. My first reaction here was a)don't do it b)it's crazy c)you need more power d)wrong application of the 4648A e)too high of a x-over point f)JBL would laugh g)then again, maybe not h)WHY do this?So anyway, if I was faced with all this it probably pretty well guarantees that I would try it..........just for the hell of it..and if it worked and sounded good, it would be all the more amusing!
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Re: JBL 4648A with SET's? [message #39345 is a reply to message #39336] |
Wed, 04 December 2002 18:42 |
jlharden
Messages: 94 Registered: May 2009
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Hi Wayne! If I recall the Zmax of the 2226H was around 55 ohms, assuming two 2226J's are electrically very similar, the impedance at resonance shouldn't be an issue. The increased sensitivity is always a plus. I don't understand how two drivers offer greater extension than one though. I thought the actual response would be the same but a bit more efficient accross the bandwidth. J
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Re: JBL 4648A with SET's? [message #39346 is a reply to message #39339] |
Wed, 04 December 2002 18:48 |
jlharden
Messages: 94 Registered: May 2009
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HA! Thanks Mike! I hadn't actually thought it that outrageous until reading your post. Problem is I have this extra set of woofers and need to do something with them. Have any Altec 811B's and 902's sitting around you want to trade for a pair of 2226J woofers? I'll have to see what develops, I can either run a single 2226 in a corner cabinet or run a pair in a reflex cabinet. Sensitivity is the same either way.
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Tube friendly JBL's [message #39347 is a reply to message #39345] |
Wed, 04 December 2002 22:28 |
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Wayne Parham
Messages: 18783 Registered: January 2001
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Illuminati (33rd Degree) |
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I know that you've been through the archives for information on the subject, and have participated on many of the threads therein. But in order to make it easy for others interested in this issue, I suggest that the collection of posts about "tube friendly" speakers on this forum yields a lot of useful information. As an aside, you'll notice that I used to consider the Professional Series offerings to be "tube friendly" until experience showed that their performance on SET amps was marginal in some cases. So maybe the 2226's work well for some people but not for others, as one might expect from its moderately high Zmax. It isn't terribly high, but isn't low either. It probably works well on some amplifier configurations and not on others. Also, some very interesting articles on the technical issues surrounding interfaces between electrodynamic speakers and triodes have been written by Steve Bench and by Norman Koren. I suggest not only the articles directed by these links, but also the others at each authors' sites. About how two drivers will interact, at low frequencies, they will combine and even act as acoustic mirrors to one another. It's like having them up against a room boundary in the way they reinforce one another. But as frequency rises, there comes a point where the two begin to form nulls in the room. The pattern looks like dual slit diffraction experiments, with hot spots and dead spots.
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