Need help to understand power requirements for 4355 and use of external crossovers

[markustubesnow]

Realizing how little I actually know is turning out to be kind of fun. I have many more questions than answers and every time I learn something new the list of questions only seems to get longer.

Here's the background:
I've been driving my 4430s with ~7 watt 300B triodes, and loving the sound. Most of my listening is actually at comparatively low volume. Right now I'm listening to my Quads (2805s) in the near field at about 60dB, driven by a Quad 909 solid state amp. If I switch to the 4430s I'm right about the same volume, so even though it's only 7 watts I seem to have all the control, dynamics and headroom I need. But what do I know?

Now it looks like I'll soon have a pair of 4355s. They require bi-amping and it appears that conventional wisdom is that the bottom end should be driven by an amp with a couple hundred watts. Is this correct? Or is it a function of room size and how loud a person desires to listen? If everything comes together and I become the happy new owner of the 4355s I'll need to buy another stereo amp. That will be a function of what I can afford.

What direction should I go? Should I seek out something like, say, an old Hafler 200 watt amplifier to drive the woofers? I've been planning on driving the top end with the 300B triode amp. Can I drive the bottom end with, say, 50 watts?

Will I need an external crossover? My preamp has the ability to drive three amplifiers. Right now I have one setup for the 300B stereo amp and another output for the Quad 909. When I bi-amp the 4355s will I need an external crossover or will the existing, stock, internal crossover/network suffice so that, in effect, I can drive the amps with a full range signal and the networks will tailor the signal to the drivers?

When I see pictures of 4355s they all seem to have a pair of big, monstrous solid state amps sitting between them. Like Macintosh, Plinius, Rowland or whatever. I don't think I've seen anyone driving them with tubes. Why is that?

Thanks, in advance, for any wisdom anyone can share.

[speakerdave]

I like your collection in that it represents a selection of distinctly different approaches. The 4355's will be very different—at the far other end of the spectrum from Quads. I've never heard them called refined, or that someone liked them for cozying up. Speakers, especially ones with multiple drivers, tend to come into their own at a particular range of sound levels. The 4355's are built to make big sound in big spaces. You can certainly give them a trial with the amps you have, but I think that if you want to explore their capabilities, you will want more power for both the woofers and the higher ranges.

You will need an external line level crossover to divide the frequencies at about 250 to 300Hz. The crossover will feed the power amps and provide a suitable load for your preamp.

[Mr. Widget]

Here's the background:
I've been driving my 4430s with ~7 watt 300B triodes, and loving the sound. Most of my listening is actually at comparatively low volume. Right now I'm listening to my Quads (2805s) in the near field at about 60dB, driven by a Quad 909 solid state amp. If I switch to the 4430s I'm right about the same volume, so even though it's only 7 watts I seem to have all the control, dynamics and headroom I need. But what do I know?

Now it looks like I'll soon have a pair of 4355s. They require bi-amping and it appears that conventional wisdom is that the bottom end should be driven by an amp with a couple hundred watts. Is this correct?

Ok, so you like to listen at extremely low SPLs. That's fine and in the long run will preserve your hearing... but why are you planning on getting a pair of 4355s? This seems to be a big mismatch between user and equipment.

The 4355 was developed to playback rock music to stoned musicians that had been blasting their hearing for hours in the studio... and they do this quite well. Listening to the nuanced sounds of 300B tubes at SPLs below what most acoustic instruments produce is not really their forte.

Will I need an external crossover?

If you get 4355s yes.

When I bi-amp the 4355s will I need an external crossover or will the existing, stock, internal crossover/network suffice so that, in effect, I can drive the amps with a full range signal and the networks will tailor the signal to the drivers?

The internal crossover does not have a built in filter for the crossover between the dual 15" woofers and the 12" mid bass woofer. If you do not use an external active (or passive) crossover your 15" woofers will be fed full range music and will cover up the mid bass and midrange frequencies with their unfiltered output. The 12" mid bass woofer will attempt to produce lower frequencies, but since it will acoustically roll off naturally and since it is a robust device, the speaker will not be harmed and the ill effects will be more subtle than that of the 2235H woofers reproducing 1.5Khz at surprisingly high levels.

When I see pictures of 4355s they all seem to have a pair of big, monstrous solid state amps sitting between them. Like Macintosh, Plinius, Rowland or whatever. I don't think I've seen anyone driving them with tubes. Why is that?

I'm sure that many have been powered by tube amps, but see above. The purpose of these speakers is to reproduce a Marshall stack at 120dB or a rock drum kit with its dynamics and SPL intact... to do this requires massive amounts of power.

Also, these speakers require that you sit back at least 8-10 ft for the drivers to properly blend and they are not small so you end up needing a fairly sizable room which again calls for more power.


Widget

[markd51]

Quite an interesting dilemma you have. Wish I had such problems to sort through!

But I have to question in this particular instance, why would you want such a speaker which to me is at the total other opposite end of the spectrum, unless you can acquire these speakers for a give away price?

This is almost like asking "Which Ferrari should I buy for day to day grocery shopping and running errands to the hardware store?"

You mention the ownership of the 4430 which I own. Sure, with their efficiency, I imagine a small Amp-Receiver could power these, I could probably hook a good ole Sansui Seven to them, and at what, 40-45wpc and get very enjoyable sound at some pretty decent SPL sound levels to boot in an average sized room, but one could find 100's of other Amps to better power, and deliver gobs of much better sonics also.

As you have many questions, and if I was in your shoes, I might likely ask as my very first questions, what would the fine folks here then recommend for a very good quality external Crossover to mate with this Speaker?

Then go from there. I'd imagine amplifier pairing could be infinite. All Tube, or Solid State for the Bass Drivers, Tube for the rest, or a plethora of SS, Class A, Class AB, Class D Amps.

One could probably run 2 tiny Bel Canto Amps to power the whole smear, which both would take up the equivalent space of an everyday thrift shop find 1986 Samsung-JVC Wally World VCR. And although small, might throw enough SPLs that in a year or so, you'll be looking to buy hearing aids. LOL

I never heard this particular speaker, but I'd have a good hankering of what directions I'd be going with Amplification, and as Roland Martin the Champion Bass Fisherman might say, "Son, we're talking Big Watts!" LOL

I'd be throwing my two Bryston 7BSST2 600w Mono amps for the Bottom, and another smaller Bryston Stereo Amp for up top as one example. IMO, that's how such a speaker should be "properly driven".

But what the hell do I know?

[BMWCCA]

If everything comes together and I become the happy new owner of the 4355s I'll need to buy another stereo amp. That will be a function of what I can afford.

Time to talk about budget now that you know you'll need new amps and a crossover. The crossover alone could bust your budget. Or you could do as I did with my 4345 and go with a used Ashly XR1001 for $125. My Crown PS400 and PS200 amps cost around $400. I would recommend something like that if your amp and crossover budget was less than, say, $2,000. If your amp and crossover budget is over $10k, then I'm not qualified to offer suggestions!

[Ian Mackenzie]

Hi Mark,

I had an email like this a while ago.


Your post suggests your about sound quality.

I would use your Quad 909 on the woofers and the 300B for a period to evaluate your requirements.

Avoid a SH Hafler.

Have a look around for a SH First Watt B4 discrete Jfet crossover.
Once you have that sorted have a good listen

From here you have a number of things to evolve and refine the sound quality.

1. A charge coupled crossover
2. Diaphragm or compression driver upgrade
3. A horn upgrade like the Joseph Crowe horns (CN).
4. A Quick Silver valve power amp rated at 50+50 watts
6. A big Rotel SS power amp (no fans) on the woofers.
7. Check out Troels diy loudspeaker website on the A1 loudspeaker design.
8. Check out this kit

https://www.xkitz.com/collections/ac...i-amplifiers-1

I would suggest you can get close to electrostatic accuracy with dynamics. if you are patient and prepared to put some work into it

What you have is a wide bandwidth clinically accurate multi way loudspeaker waiting to be reborn.
Some magazine reviewers use similar vintage systems like Altec for their dynamic life like qualities.

Have fun and enjoy the journey.

[Robh3606]

Don't skimp on the low end. You have 2 2235's in parallel so the impendence can drop to 4 ohms of lower. Just keep that in mind.

Rob

[Mr. Widget]

What you have is a wide bandwidth clinically accurate multi way loudspeaker waiting to be reborn.

The JBL M2 is a wide bandwidth clinically accurate multi-way loudspeaker. I think calling the 4355 that is a stretch.

Have fun and enjoy the journey.

Well, then there is that. There is much that can be done with these speakers in the analog or digital realms that will provide a wonderfully rewarding journey.

I don’t see these speakers ever matching a pair of good electrostats in sub 100dB SPL playback... except perhaps in the lowest octaves. But there is no denying that one can spend years tweaking and modding them to great effect.


Widget

[markd51]

I know very little about JBL Electronics, but might guess that back in the day and in their Pro Catalogs, they had such as Crossovers to work with these very speakers, am I correct?

I might also guess acquiring such components might be quite hard, that such might be as rare as Hen's Teeth?

I see one reasonable priced unit mentioned here.That would be a start of the search for such, or other similar components with similar features.

Again, I would assume this would be termed "Pro Gear, and as such, wouldn't such components be a common sundry item at places like Guitar Center, Musician's Friend, and others like these businesses I mention?

I love such topics as this, because of the share of information, and learning more about such speakers and what they would require for proper operation.

[Robh3606]

I know very little about JBL Electronics, but might guess that back in the day and in their Pro Catalogs, they had such as Crossovers to work with these very speakers, am I correct?

I might also guess acquiring such components might be quite hard, that such might be as rare as Hen's Teeth?

I see one reasonable priced unit mentioned here.That would be a start of the search for such, or other similar components with similar features.

Again, I would assume this would be termed "Pro Gear, and as such, wouldn't such components be a common sundry item at places like Guitar Center, Musician's Friend, and others like these businesses I mention?

I love such topics as this, because of the share of information, and learning more about such speakers and what they would require for proper operation.

Look up 5234/5235 they used plug in cards both 12 and 18dB. Also had specialized cards for the monitors 433X 434X's and some cinema systems. Then you had the Digital and Analog for the DMS-1. The last were the M552/553 I think which were in Guitar Center. There are others as well. Just go digging through the library.

Rob

http://www.lansingheritage.org/image...pro/page23.jpg

http://www.lansingheritage.org/image...pro/page51.jpg

http://www.lansingheritage.org/image...pro/page50.jpg

[markustubesnow]

Gentlemen - I feel like the ideas I've written below are scattered and unfocused. Please accept my apologies in advance. I don't mean to be frustrating and will try to be more systematic in my future replies.

Thanks for everyone's comments, questions and advice. They are all appreciated very much. As I mentioned, the more I "learn" (not sure I'm learning yet, but I do appreciate the ideas and topics which I'll have to research and from that research and the ongoing advice of this august form, surely I will absorb and get something through my thick skull, right?) So please forgive any questions I ask to which your natural response would be "why are you considering this option when you've already been advised of a better way to do this?"

By way of explanation let me say I'm wary of how far to increase the scope of this project. For instance, looking at the internal, stock wiring, I'm struck by how thin it is. Surely, nowadays anyone refurbishing these speakers would be sure to replace the thin, stock wiring with something newer, thicker and better, right? Well, probably. Like I said, my inclination is not to try to perfect it to state of the art, but to get them together so they work. Improvements can come later. But, just like it makes sense to do some things "while I've got the car up on the rack" your collective advise will help me get more comfortable with more ambitious and advanced tweaks and upgrades.

As to the question "why" am I doing this? I thought Mr. Widget and MarkD51 framed this question very well. It's simply a matter that this project fell right into my lap. I've had to do some fancy explaining to convince my wife that it's a good idea (I'm still not sure she's convinced) but I've always lusted after 43XX series JBL monitors, though I've had limited exposure to them. I'm thinking of these as an experiment. At the price I don't think I'll lose money if it turns out I need to move them along.

These speakers are coming with the 3155 network. Does that help? I'm still fuzzy one why I'll need an external crossover, but I'm not resistant to the idea. Just still scratching my head about it a little bit.

Yes, budget will be a factor in selecting whatever amps and crossover I go with. For some reason when I have tried to use my Quad 909 with my 4430s it's "motor boated" - that is, I've heard a loud, deep hum. Took the 909 into the shop and spent $100 to find out there's nothing wrong with it. It works perfectly with my 2805 electrostatics. I plan to look around on Craigslist and pick up an external crossover and a couple of amps, like the Crowns mentioned on this thread, to get these up and running. I'd love to put higher-pedigree amps on these things but need to be a little conservative about the $$.

I'll be researching the charge coupled crossover. I'm guessing if it's a good idea for the 4355s then it might be a good choice for the 4430s, right?

Should I plan on having the 3155 network refurbished to replace aging components? I don't think the crossover in my 4430 has ever been serviced and it seems to function ok. There's a local guy who advertises repair and construction of crossovers, so there's a potential resource. Any advice about what to pay attention to before I go shopping for the crossover will be appreciated. I'm crossing my fingers that whatever I buy will be adjustable, for where to set the crossover point and slope rate.

Any advice about the kind of wire I should use if I upgrade the internal wiring?

[markd51]

Gentlemen - I feel like the ideas I've written below are scattered and unfocused. Please accept my apologies in advance. I don't mean to be frustrating and will try to be more systematic in my future replies.

Thanks for everyone's comments, questions and advice. They are all appreciated very much. As I mentioned, the more I "learn" (not sure I'm learning yet, but I do appreciate the ideas and topics which I'll have to research and from that research and the ongoing advice of this august form, surely I will absorb and get something through my thick skull, right?) So please forgive any questions I ask to which your natural response would be "why are you considering this option when you've already been advised of a better way to do this?"

By way of explanation let me say I'm wary of how far to increase the scope of this project. For instance, looking at the internal, stock wiring, I'm struck by how thin it is. Surely, nowadays anyone refurbishing these speakers would be sure to replace the thin, stock wiring with something newer, thicker and better, right? Well, probably. Like I said, my inclination is not to try to perfect it to state of the art, but to get them together so they work. Improvements can come later. But, just like it makes sense to do some things "while I've got the car up on the rack" your collective advise will help me get more comfortable with more ambitious and advanced tweaks and upgrades.

As to the question "why" am I doing this? I thought Mr. Widget and MarkD51 framed this question very well. It's simply a matter that this project fell right into my lap. I've had to do some fancy explaining to convince my wife that it's a good idea (I'm still not sure she's convinced) but I've always lusted after 43XX series JBL monitors, though I've had limited exposure to them. I'm thinking of these as an experiment. At the price I don't think I'll lose money if it turns out I need to move them along.

These speakers are coming with the 3155 network. Does that help? I'm still fuzzy one why I'll need an external crossover, but I'm not resistant to the idea. Just still scratching my head about it a little bit.

Yes, budget will be a factor in selecting whatever amps and crossover I go with. For some reason when I have tried to use my Quad 909 with my 4430s it's "motor boated" - that is, I've heard a loud, deep hum. Took the 909 into the shop and spent $100 to find out there's nothing wrong with it. It works perfectly with my 2805 electrostatics. I plan to look around on Craigslist and pick up an external crossover and a couple of amps, like the Crowns mentioned on this thread, to get these up and running. I'd love to put higher-pedigree amps on these things but need to be a little conservative about the $$.

I'll be researching the charge coupled crossover. I'm guessing if it's a good idea for the 4355s then it might be a good choice for the 4430s, right?

Should I plan on having the 3155 network refurbished to replace aging components? I don't think the crossover in my 4430 has ever been serviced and it seems to function ok. There's a local guy who advertises repair and construction of crossovers, so there's a potential resource. Any advice about what to pay attention to before I go shopping for the crossover will be appreciated. I'm crossing my fingers that whatever I buy will be adjustable, for where to set the crossover point and slope rate.

Any advice about the kind of wire I should use if I upgrade the internal wiring?

As for Internal Wiring, I would say running to the 2235H Drivers, use good quality 12ga Copper Hook up wire, which would be specific for such a task, and 16ga should be fine everywhere else.

Do it piecemeal, to hopefully insure you don't mix up polarity to any of the drivers.

I know nothing about the 3155 Network, but perhaps this would negate the need for an external Crossover I'm thinking? At least short term.

As for the 4430 Speakers, that's another can of worms. I've heard some discuss that the Switch on back for internal-external Crossover is a weak point-link, and to bypass such. I've not done such to mine, and think for the foreseeable future will leave such alone unless I start having issues with that Switch.

As I age, I've become more and more of being in the camp of, "if it isn't broke, don't fix it". LOL

[markd51]

Just as I thought, the 3155 "is" a dividing network. This has opened my eyes, and as well no doubt some others, that your worries might be over.

To say that this particular dividing network is in fine shape, needs work or refurb or not I cannot say?
But there might be those here that have been down this very same path with these components, and can help in whatever way they can.

Whether they need checking-testing, perhaps can provide or point you to white sheets and manuals? And if in the event of needing work, who or where could perform such?

If all is well, then much of your worries might be over.

I'd be the last here to call myself a "JBL Authority", but I doubt anyone here would contest what I'm about to say, and that is, that these are truly one heck of a very special speaker system, "The baddest of the bad"!, that some would probably donate a Kidney to possess.

Again, and from some things you note, wimpy internal wiring, and we don't know whatever shortcomings they might have, Veneer, baffle paint, or other cosmetics, drivers in need of repair or re-foaming-etc, but I'd say they'd be worth every penny to properly restore to their former brand new glory.

As to whatever design and manufacture shortcomings the very best technical minds here might have to say about this particular Speaker System, you would probably be shocked and your jaw would hit the floor to find out what such a system today would cost to build by JBL.

And that many would say what you have here is one very rare and highly desirable speaker, and one which will give a degree of sonic nirvana that cannot be accomplished by virtually any other speaker made, both yesterday, and today.

Again, and perhaps unlike the Japanese, who would set such a speaker up in a 12'x12' room because that's often the way things are in Japan, these speakers deserve some square footage space to "breathe", and good quality Amplification will most definitely bring out the best that these speakers can offer.

"Small Watts" will of course let these speakers play. But more serious Amplification will provide headroom, and distortion free power to them. And again if it were me, I'd want some good power going to those Bass Drivers, I might be inclined to say 300wpc. And up top, probably an honest 100wpc minimum should work fine.

I'd likely be inclined to stick with similar brand and model type Amps so they might integrate and play well together, but that's just me. I'd be the type that would try to give these speakers what they deserve to have.
And since I'm not top crazy about Tube Amplification, rolling tubes, and all the other headaches that might be associated with Tube Gear, my choices would be Solid State Amplification.

Tubes, sure a nice Tube PreAmp could be used to go along with.

Just some brain farts, but hope others will further help you here.

[grumpy]

Replies #2 and #3 were sufficient... helpful as the rest was intended.
There are two sets of speaker inputs for each speaker.

One pair of terminals goes to the woofers directly (IIRC). The other goes to the internal, passive crossover (drives -only- the 12", the horn and the tweeter). They are electrically separate.

That is why you will need an electronic crossover and a 2nd amp. One amp to power the woofers and one amp to power the crossover and the remaining speakers. The electronic crossover accepts your preamp signal, and then it sends LF to the woofer amp and everything else (above 290-300Hz) to the amp for the MF/HF/UHF network and drivers.

I (sort of) humbly suggest you stay out of rewiring, crossover updating, or other value reducing endeavors, until you understand how it all works and you get some satisfactory sound out of them. They worked just fine in state of the art recording studios at the time... weenie cables and all. Might have to check connections at or inside drivers if some element isn't playing (and L-pads if not working properly).

4355_manual.pdf

If you subsequently wanted to go bonkers with the passive crossover portion :

http://www.audioheritage.org/vbullet...l=1#post415320

[speakerdave]

Replies #2 and #3 were sufficient... helpful as the rest was intended.

Yes, the signal to noise ratio is sagging.