EL84 and Subwoofer

It seems that if you want to use that amp that you would want a rather large (read efficient) subwoofer that doesn't require a lot of damping. Maybe a horn sub. I know they are big and complex to build but I think that a horn would provide the best possible load for that amp.

Qualifier... I am no expert so I could be entirely soaking wet on this. :}

mike

P.S. You might also want to post a link to this thread over on the tube forum as those guys have a lot of experience with the amps that you are wanting to use and can probably give some good insight.

mike

scherffi said:

I will wait what other then have to say...

FrankieS

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Could you maybe give some more background into what "turns your crank" in audio? What I mean is, your suggestion sort of baffles me, because, if a person was such a tube purist as to want a tube subwoofer amp, why would you stick a Behringer in your signal path That being said, if that is what you want, mashaffer is right, your application screams "Horn!", or at least a highly efficient PA sub driver.

I would run the ESL full range with no crossover and only use a crossover on the sub where the ESL starts to cut out. Electrostatic bass is great, but usually there is just not that much of it. Cutting out the crossover from the signal chain will reduce any coloration those components would empart on the ESL. If you were using a more powerful amp and listening at high SPL, then you may want to limit bass to keep the panel excursion down- but 12w does not warrant this.

In terms of subwoofers- IMHO I don't think most horns will mate well with your panels. Integrating subs with the speed and accuracy of ESL's is very tricky. I also think that going with a modern design of amplifier will provide you with better results, as this will allow you to use a subwoofer that will has good extension and low distortion without having to worry about sensitivity rating or huge cabinets. For design ideas, I would take a look at the Martin Logan Descent- they make subs to mate with ESLs for a living and this unit is highly rated. I am also a fan of any sub that has a balanced driver configuration (with the drivers on opposite sides of the cabinet, pushing in and out of the cabinet at the same time, counteracting the force the opposing driver is imparting on the cabinet). I find that they transmit much less vibration to the floor/walls and usually sound very "tight."

Maybe the Augie 15s From Hawthorne (scroll down the page) might integrate well with your current system if you can afford the space to put them on a moderate sized OB out away from the wall a little bit.

I don't know how hard it would be to get the Dayton High Output series where you are but the12" one Should be very nice in a ported box of about 40-45 liters. A pair of those each fed 12 Watts or so should do OK at moderate levels.

One question though is how good (or rather how well designed for bass) is the iron in your amps. If the OTs are not of pretty high inductance (physically big generally speaking) they may not do too well at the really low frequencies.

I wish you luck with this. I also would love to design a tube subwoofer system just for the fun of doing it all tube.

mike

Sub

Hi,

I`d recommend a semi-amp-driven closed box or dipole sub.
Both can be built quite small, but need more wattage than a small EL84 amp can deliver. To cross over You could go several ways.

I: just cross over the subwoofer and have the ESL running full range

II: cross over the sub with the active crossover of its amp-module and cross the ESL with a passive filter (a high quality capacitor) at the Input of the EL84-amp

III: use the crossover of the sub-amp-module for sub and satellites


I: easiest posibility, could give probs with sub and ESL running parallel in the transition band, relatively low dynamic (SPL max)

II: easy to handle, You can use simple sub-amps that have just filters for the sub but not the ESL. ESL and EL-amp are much less stressed with high energy bass which in most cases leads to better sound and much higher dynamics

III: If the sub-amp features active(!) filters for the satellite channels You can use those since theyre filter slope is steeper. Sound can depend on filter quality. Even more headroom for the ESL than version II


Since Your demand for ´loudness´is moderate, I´d suggest solution II for You. To change the low frequency end of the amp simply change the Input cap to a lower value by directly changing the cap or by series connecting a smaller cap (might be done within the cable connector). As a Sub You can use some 8" drivers in Closed box or dipole and a simple and cheap 50-80W amp-module

jauu
Calvin

lne937s said:

In terms of subwoofers- IMHO I don't think most horns will mate well with your panels. Integrating subs with the speed and accuracy of ESL's is very tricky.

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Dunno about that comment about horns, I'd beg to differ, but to each his own.


That apart, I don't think tubes are the most practical choice for a subwoofer amp (though I have once driven a pro horn sub with a 10watt 6v6 amp and shaken the walls). I think a plate amp will do just fine for sub duties.

maybe a bit late to reply, but I find this a very interesting thread!
I've experimented with several subs, built a couple myself too, but I have to agree on Ine that dymanic sub's are not easy to mate with the electrostats.

My situation is a bit different because (for space reasons) I use only the mid-high range unit from the esl-57 combined with MOREL bass-midranges(17cm)placed in transmissionlines(shaped like B&W "nautilus", but then open at the end..). I use 2 subs placed right next to the esl panels, I love stereo bass!

Connected the lot to an AUDIODIGIT "mc4x100" 4 channel "class T" amp from http://www.autocostruire.it (this one can drive 1ohm loads when connected to 12 volts), but http://www.41hz.com may also provide you with a good DIY 2 channel or mono amp(for active sub..) That is if you want to use other amping for the sub(s) afterall..(and they're very very good for the price!)
I made passive line level crossovers(only 2 components per channel(!), "always loved simplicity, mostly my ears too..."), they have a little insertion loss side effect, but either at 6db/octave or using a powerfull amp you can overcome the loss.
Look at:

http://www.t-linespeakers.org/tech/filters/passiveHLxo.html

Created two "ladder attenuators" out of ELNA switches with metalfilm resistors, built the filters in there on a switch(to shut the filter off).
Folded my own aluminum casing...

This setup sounds pretty much the way I like it, very natural and "open" sound, but not to much "sparkles". It just sounds incredibly realistic and with very good staging as well. Find myself getting out of my chair many times to listen whether a sound(from an unfamiliar soundtrack offcourse heheh) is coming from the speakers or out of my open windows!

But, as with all esls, placing is very critical, and I had to flip the phase(+ and -) on the subs to get the timing better and it is still a bit of a compromise, but isn't it always?

At least the bass has very good dynamics now, goes very deep and is fast enough to let it melt together with the esls very well (love to listen to bach's "dorische toccata&fuge passacaglia" played by "the magician" Karl Richter (Archiv production) on a pipe organ (this cd made me discover how impressive "pipes" can sound, man what a rush!) If I close my eyes my small room changes into a BIG church!
Do keep in mind that all this has been pretty inexpensive, can probably still be improved, but hope I've still been of some help here, always open for suggestions
on my setup, or questions on your setup...
Must have built hundreds of speakers for friends in the past, trying to take it a step further everytime, just follow the'ol' ears, they never tend to let me down(only my wallet heheheh)...

oh, and don't try any subs above 8"(cone) unless you're a real bass boom fanatic, they've always let my quads down in terms of speed to my experience the're all to sluggish.

just found this...http://www.soundstage.com/maxdb/maxdb061999.htm
may be helpfull

oh yes and look at http://www.bandor.com

I have a hunch the 15cm bass is quite suitable to match with an esl..