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Saw these when I was poking around, and they seem like they might be interesting. Not mine, and I will not be buying them. There were a couple of postings on audio boards that touted the product and chided the builder.
Wonder how these would sound against my 604 drivers. I would appreciate hearing your thoughts.
regards -- Roger
Really depends on a number of variables, but one big + with field coils is you can dial in the optimum Qt over whatever range it's designed for and another big + is it won't 'lay down'/harmonically distort due to VC heat rise.
Interesting, on the few examples i looked at, the skiver surrounds appear to have gaps between the sections of skiver.
On the original early speakers i've owned with skiver surrounds, the sections were always overlapped slightly, and glued such that the surround remains essentially airtight.
Thanks for the observations.
I am wondering what performance was left on the table, when cost cutting and convenience (technology) are applied to commercialize a product. I understand that the windings are complex to do and another power supply is required with the field coil. Was the permanent magnet solution actually better or merely more commercially viable.
It looks like this guy has worked to optimize the field coil, rather than eliminate the inconvenient bits. Even the old Telefunken / Klangfilm variants might convey the special flavor. I would really like to hear one, just to get a sense of whether there is something special there.
This has happened to me a couple of times looking for great sound. One time was reading about the Altec 604, which is what brought me here. I enjoy my 604 speakers no end, and I am certainly glad I went there. Another time was when I read about the Ultra Analog DAC chip, and got a DAC with 2 of them and a tube output stage. 'Antiquated technology', but so far surpasses other DACs I have heard that the other DACs are not listenable any more.
I certainly don't need another project, but this may be another going backwards to go forward opportunity (that I likely won't take).
Right, max acoustic efficiency was the overriding pioneer's goal.
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Let me put it this way....until the advent of Samarium-Cobalt magnets, nothing was as powerful as a field coil.Quote:
Was the permanent magnet solution actually better or merely more commercially viable.
The field coil approach looks great, but the real solution looks like a 604 type field coil. The single driver 'full range' are not close to full range, as admitted by their advocates. Small full range drivers give very limited bass, and larger full range drivers can't cover the upper frequency range well. Then you start to move into multiple drivers, and the coherency of a point source is lost.
Likely one of the objectives of the music pioneers was 'max acoustic efficiency", but I think it extends well beyond that into musicality - probably the most important aspect for someone that listens to music. With the application of technology, the emphasis was shifted from musicality to resolution. The technology could achieve cold resolution, but there is a huge difference between resolution and musicality. Nice to have both, but resolution alone is hard for me to listen to.
Has any manufacturer or artisan ever put together a field coil implementation for the 604, or is it even possible?? Could be something particularly stunning and special. One step further for something already stunning and special !!!
When coupled to a matching impedance system (smiley face EQ) the 604 is historically nominally flat from Fs - > 20 kHz measured in free space, though in room with all its variables can be even wider, though of course not nearly as flat.
You can get a 'taste' of this with any wide/full range driver/speaker system by inserting a suitably sized/spec'd pot in series with it and find the widest/flattest response in-room; which I used a cheap one to dial in stereo systems, sometimes to the point of tuning the cab's vent(s) individually.
The original 601 Duplex was field coil...Quote:
Originally Posted by rogerh113
https://www.lansingheritage.org/imag...943/page04.jpg
Thanks for telling me about the 601 - very little out there about the 601 (well pre web), and according to this write up, only 100 made. The article does have some nice pictures of a 601 in impressive condition.
Holy grail driver
Yeah, 'scarce as Hen's teeth' as I've only known of one owned by a 'crusty' old EE by way of his daughter and used for PA loaded in this cab at my various high school class's outdoor (sports) 'bashes', fundraisers, etc., which not surprisingly added 'fuel' to my already 'burning' desire to own (huge) Altec systems, which I was fortunate to do for a very brief period.
I'd hoped to do it again where I live now, but my neighbors voted to add the area to the adjoining historical city of Chamblee with its very strict noise abatement, so can't even crank up what I have indoors without adding some more damping to the house. :mad::(
What a great experience, which led to a very satisfying hobby / career. Imagine if you had gone to a Lincoln Log convention ...: )))
No career, just passionate hobby.........my career was designing electrical power & control systems that was as boring as it sounds, but the places it took me, the satisfaction of the projects I was involved in from a wide range of (in retrospect decided even this info might still be classified :() related, all of which I'll apparently have to carry to the grave based on an 'incident' a few years ago where I mentioned a seemingly thoroughly innocuous, obsolete, 'something' in passing to a racing/vintage cars pen pal in the employ of England's Gov't. as a teacher of some sort.
If cost is not among the first few priorities, it seems like a pair of Shindos pop up for sale about once a year.
For the remainder of us mortals... there was a gentleman(Wolf Von Langa) in Germany several years back who was building field coil converted 604's and 515's. My memory isn't what it used to be, but IIRC, he may have even sold the field windings as a kit for a short time.
They have even been sold on ebay occasionally.
I'm not sure if Joe Roberts looks in on this site anymore. But, if he does, maybe he will post as i think he knows Wolf personally.
The wayback machine might offer more info.
VinylSavor: Cool Links: www.kilimanjaro-series.com
https://www.hostboard.com/forums/hbm.../2024/08/1.png
Yes I seen them Altec Field Coils from Wolf years ago. IIRC they were quite expensive back then, but man they are sweet.. Roger thanks for posting the Holy Grail Driver by Steve Schell. I just learned of his passing last year. I was upset to hear this news as Steve was always a kind fellow always willing to share his knowledge.
Years ago I had a long conversation with Steve about this 601 driver and I just recently learned of his passing. Very Sad as he was such a nice fellow. He posted photos of that Holy Grail Driver. Which I downloaded for posterity. Thought I would post them for other folks to see.. Courtesy of Steve Schell RIP.Quote:
Originally Posted by rogerh113
[img]https://live.staticflickr.com/65535/...46ef9ea3_b.jpg601-7 by Altec Best, on Flickr[/img]
[img]https://live.staticflickr.com/65535/...b93773b3_b.jpg601-2 by Altec Best, on Flickr[/img]
[img]https://live.staticflickr.com/65535/...7d4f70c2_b.jpg601-6 by Altec Best, on Flickr[/img]
[img]https://live.staticflickr.com/65535/...1d7bf2a9_b.jpg601-5 by Altec Best, on Flickr[/img]
The look of the 601 is down to business, as is the 604. The von Langa and Rullit offerings look much more like jewelry. Not a bad thing I guess, and likely a requirement selling into today's market at that price point.
Too bad they made so few 601s - the likelihood of hearing one is vanishing small. I also gather that starting the music without energizing the field coil can destroy the voice coil. The wife is less inclined toward process than I am (safest way to put it), and a small error could result in the demise of the drivers. Still would likely give it a shot if they were affordable (more plentiful).
Roger they would be for the man cave. No wives aloud ! No risk of injury ! Just tell her she could get electrocuted guaranteed not to touch them ... :biggrin2: :cool2:Quote:
Originally Posted by rogerh113
Steve said his had a serial that you can actually see is #150 So I would surmise that there were at least 150 but I don't think there were much more than that. As the permanent magnet 604's came out soon after.
The wife is pretty rough. The SET amp in the living room has 900VDC on the anode caps - doesn't bother her a bit....
Fortunately I think only the coaxial 601s would work for me. It would be hard to move from the point source to multiple speakers. Instead of just moving forward, there are tradeoffs. I think I will just be enjoying the 604 8g for a long time.