Ohm F drivers for sale?
Merry Christmas, y'all. Haven't visited this thread in a long time and not surprised it is still going!
Sold my main pair of Ohm Fs to fund a horn-based system. Anyway, I still have a backup pair of Ohm F (drivers only) in decent condition. I know that this group prides themselves on their DIY engineering prowess to continue and improve on the concept, but does anyone have an acquaintance that may be interested in purchasing these?
Now back to your regularly scheduled program.
Merry Christmas, y'all. Haven't visited this thread in a long time and not surprised it is still going!
Sold my main pair of Ohm Fs to fund a horn-based system. Anyway, I still have a backup pair of Ohm F (drivers only) in decent condition. I know that this group prides themselves on their DIY engineering prowess to continue and improve on the concept, but does anyone have an acquaintance that may be interested in purchasing these?
Now back to your regularly scheduled program.
Wow, a rare opportunity...you go, Glo. *G*
Post some pics, please, if available. It's always educational to see some close-up views of the entire cone and it's interior for reference's sake. Since the odds of an F showing up at the local Habitat is next to nil and they're not usual 'naked', I'd appreciate that...
And it's one for the files in this forum. When we get visitors that wonder wtf we're talking about when mentioning the F's, it'll be part of the forum's thread.
Just asking. *S*
Post some pics, please, if available. It's always educational to see some close-up views of the entire cone and it's interior for reference's sake. Since the odds of an F showing up at the local Habitat is next to nil and they're not usual 'naked', I'd appreciate that...
And it's one for the files in this forum. When we get visitors that wonder wtf we're talking about when mentioning the F's, it'll be part of the forum's thread.
Just asking. *S*
No reply yet on the Ohm "f". Had hoped for photos, and would like to know where Philajoe is located. Long distance shipping could be a breaker.
Finally was able to find a partial schematic of the Infinity Servo sub. As I expected, they used current feedback with a couple of integrators (damping) in the feedback loop. One of the integrators appears to boost the low end, ala the Bagg End subs, the other tailors the overall feedback.
Current feedback is derived from a small high wattage resistor between the low side of the driver and ground. There is nothing special about the LF driver- just an 18" EV (according to service manual) driver. Very surprised to find such a low wattage amp in this application- maybe 100W tops. The EV driver is very efficient, but in a small sealed box, not so much.
Finally was able to find a partial schematic of the Infinity Servo sub. As I expected, they used current feedback with a couple of integrators (damping) in the feedback loop. One of the integrators appears to boost the low end, ala the Bagg End subs, the other tailors the overall feedback.
Current feedback is derived from a small high wattage resistor between the low side of the driver and ground. There is nothing special about the LF driver- just an 18" EV (according to service manual) driver. Very surprised to find such a low wattage amp in this application- maybe 100W tops. The EV driver is very efficient, but in a small sealed box, not so much.
Thanks for the pic, phil...that's certainly the genesis of this forum in it's multiple material flesh. And since there's a potential transaction in progress, I'll refrain from anything other than that verification. Nobody likes a 'buttinsky', and it's not an auction. *S*
An 18" EV, really? Interesting....I looked again at the EV I have, and it's actually a 15". Heavy bugger, likely of the same ilk. I've toyed with putting it into 'a small sealed box' but the 'not so much' observation gives me pause. I remember that era of driver used to put into reflex boxes that tended huge by today's standards. I've been considering a circular 'coffee table' enclosure +/- 2' dia. x 18" d. that perhaps should get vented. My EV doesn't have the compliance of modern subs of it's size, so a vented box didn't seem the best option. Don't want to 'accidentally' send it off to the infirmary workbench due to 'overindulgence'....
The low wattage...hmm...well, considering the era of the Infinity Servo, 100w. back them seemed massive, and with an efficient driver would probably strike most as plenty of power. I recall that impression at the time; then the 'race for power' began. Higher wattage amps became smaller, more efficient, better specs, all that.
Funny, it coincided with the 'Cold War' in retrospect. *L* I guess my age is showing.
How complex is/was the circuitry? I'd bet that it'd be considered obsolete by modern standard and practice. What took a breadbox then is a thimble now...
An 18" EV, really? Interesting....I looked again at the EV I have, and it's actually a 15". Heavy bugger, likely of the same ilk. I've toyed with putting it into 'a small sealed box' but the 'not so much' observation gives me pause. I remember that era of driver used to put into reflex boxes that tended huge by today's standards. I've been considering a circular 'coffee table' enclosure +/- 2' dia. x 18" d. that perhaps should get vented. My EV doesn't have the compliance of modern subs of it's size, so a vented box didn't seem the best option. Don't want to 'accidentally' send it off to the infirmary workbench due to 'overindulgence'....
The low wattage...hmm...well, considering the era of the Infinity Servo, 100w. back them seemed massive, and with an efficient driver would probably strike most as plenty of power. I recall that impression at the time; then the 'race for power' began. Higher wattage amps became smaller, more efficient, better specs, all that.
Funny, it coincided with the 'Cold War' in retrospect. *L* I guess my age is showing.
How complex is/was the circuitry? I'd bet that it'd be considered obsolete by modern standard and practice. What took a breadbox then is a thimble now...
The schematic is titled "Servo Woofer" and was found as a search result for Servo-Statik sub woofer. Dated 1991, but I'm sure it is a much older design due to the lack of feed back coils you mention. At one point during the search, the EV name came up, so I made the assumption.
If I can figure out how to upload the drawing, I will post it. Sorry for going off topic again.
If I can figure out how to upload the drawing, I will post it. Sorry for going off topic again.
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*G* Y'all ARE off-topic, but that's kinda par for around here...consider how often I wander off jabbering inanely... *L*
The Servo Statik was what came to my mind, BTB...well, what's left of it, anyhow....
Merry Christmas, guys.
My gift to self, tacitly approved by spouse, are the drivers for the V.4's. Let's see if I can make some 'new junk' sing better in the new year. *S*
The Servo Statik was what came to my mind, BTB...well, what's left of it, anyhow....
Merry Christmas, guys.
My gift to self, tacitly approved by spouse, are the drivers for the V.4's. Let's see if I can make some 'new junk' sing better in the new year. *S*
Hi Guys,
Merry Christmas and HNY. Hope everyone is doing well and having a great day.
Hey, Glo maybe you should give me a call. Did you forget I own H & H Research, one of the oldest and still running Laser companies in the USA? IO have built and designed more lasers than China has rice. Well maybe not, but quite a few.
I am actually building some 7 foot long Helium-Cadmium lasers right now. Still hooked. I love the ways these things look. Damn Diodes are more like glorified Flashlights. They have their good points, but will never have the beam qualities of good old Gas Lasers.
I am sure I can help you out with your need for Photons. Hehehe.
Nice rendering on the speakers Jerryrigged. But, I am still puzzled as to why you insist on splitting the driver up into sections. Resembles more of an MBL design than a Walsh. Remember, keep it simple. Only get nuts when you have to. Think Occam's Razor...
BTW, the pic of the old "F" is a series 1 driver, circa '74-75.
Best to all
Dale Harder
Merry Christmas and HNY. Hope everyone is doing well and having a great day.
Hey, Glo maybe you should give me a call. Did you forget I own H & H Research, one of the oldest and still running Laser companies in the USA? IO have built and designed more lasers than China has rice. Well maybe not, but quite a few.
I am actually building some 7 foot long Helium-Cadmium lasers right now. Still hooked. I love the ways these things look. Damn Diodes are more like glorified Flashlights. They have their good points, but will never have the beam qualities of good old Gas Lasers.
I am sure I can help you out with your need for Photons. Hehehe.
Nice rendering on the speakers Jerryrigged. But, I am still puzzled as to why you insist on splitting the driver up into sections. Resembles more of an MBL design than a Walsh. Remember, keep it simple. Only get nuts when you have to. Think Occam's Razor...
BTW, the pic of the old "F" is a series 1 driver, circa '74-75.
Best to all
Dale Harder
Dale-
Back atcha re: holiday wishes. I am very aware of your laser prowess, and you're right- I will give you a call after the holidays.
7' HeCad's eh? been a while since I've seen one of those- are you doing blue/violet only or RGB? How much output?
For years, I've wanted to do a HeSe, but the selenium vapor is hard on quartz bores. Nasty stuff when the tube breaks.
Way off topic here, but I am re-furbishing an old LaserMedia Imagen and an LMS beam table. Been quite a ride getting parts, but I'm about 95% complete. Amen to the beam quality, and the color spread of diodes sux- especially the DPSS green. Using diodes now, but hope to get a mixed gas ion under the hood in the future.
So we are wondering (getting back on topic), have you played with interferometry to visualize "cone" break-up modes? Seems like it would be enlightening (no pun).
Good to hear from you
J
Back atcha re: holiday wishes. I am very aware of your laser prowess, and you're right- I will give you a call after the holidays.
7' HeCad's eh? been a while since I've seen one of those- are you doing blue/violet only or RGB? How much output?
For years, I've wanted to do a HeSe, but the selenium vapor is hard on quartz bores. Nasty stuff when the tube breaks.
Way off topic here, but I am re-furbishing an old LaserMedia Imagen and an LMS beam table. Been quite a ride getting parts, but I'm about 95% complete. Amen to the beam quality, and the color spread of diodes sux- especially the DPSS green. Using diodes now, but hope to get a mixed gas ion under the hood in the future.
So we are wondering (getting back on topic), have you played with interferometry to visualize "cone" break-up modes? Seems like it would be enlightening (no pun).
Good to hear from you
J
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Back at you, Dale. *S* Hope the NY is prosperous and fulfilling for your two endeavours in light and sound.
Big-*** 'flashlights, there'. Certainly not in the category of the flashlight pop-up e-ads that seem to be everywhere of late. Not your typical photons, either... Must be interesting to be around the Harder household on Xmas for the light display...
"DO NOT stare into the lasers. Not responsible for decapitations."
Thanks for appreciating the drawing; I still own and use a drafting machine periodically for client renderings. People still respond to that 'old fashioned' touch. (That, and rendering a playset in SketchUp just takes longer...and it just looks like everything else out there.....*G*)
Yeah, I've cut myself with that razor a lot over the years. It does resemble an MBL only for the 'stacked' structure, for sure. I'm 'spoofing' the GP DDD driver on the bottom, as I've noted. The upper driver is an experiment in trying to extend the high end, a little more 'brilliance' in the response. A 'spoof' of the (infamous?) Infinity 'ice cream cone', but 'flipped' as it should have been in the first place, IM not so HO. *G*
...and anyone that knows me knows that 'nutz' is SOP. The most complicated part of the sketch is the cone structure, which I want to try because of my experience with the V.3's. The rest is pretty much as close to the KISS principle as I can manage and keep it on target. The target being 'better', of course. *S*
A series one, huh? Wow...that would be about when I first heard an Ohm. *L* Not too bad for a 40 yr. old 'anything', at least from the pic. I would suppose you've seen others that haven't weathered that span quite as well. Of course, it's what you can't see that's the big issue, ultimately....
Time and tide wait for no man...nor for the things we create, or cherish...*sigh*
Big-*** 'flashlights, there'. Certainly not in the category of the flashlight pop-up e-ads that seem to be everywhere of late. Not your typical photons, either... Must be interesting to be around the Harder household on Xmas for the light display...
"DO NOT stare into the lasers. Not responsible for decapitations."
Thanks for appreciating the drawing; I still own and use a drafting machine periodically for client renderings. People still respond to that 'old fashioned' touch. (That, and rendering a playset in SketchUp just takes longer...and it just looks like everything else out there.....*G*)
Yeah, I've cut myself with that razor a lot over the years.
It does resemble an MBL only for the 'stacked' structure, for sure. I'm 'spoofing' the GP DDD driver on the bottom, as I've noted. The upper driver is an experiment in trying to extend the high end, a little more 'brilliance' in the response. A 'spoof' of the (infamous?) Infinity 'ice cream cone', but 'flipped' as it should have been in the first place, IM not so HO. *G*...and anyone that knows me knows that 'nutz' is SOP. The most complicated part of the sketch is the cone structure, which I want to try because of my experience with the V.3's. The rest is pretty much as close to the KISS principle as I can manage and keep it on target. The target being 'better', of course. *S*
A series one, huh? Wow...that would be about when I first heard an Ohm. *L* Not too bad for a 40 yr. old 'anything', at least from the pic. I would suppose you've seen others that haven't weathered that span quite as well. Of course, it's what you can't see that's the big issue, ultimately....
Time and tide wait for no man...nor for the things we create, or cherish...*sigh*
Hi Glo,
I'll keep my answers short to prevent too much wander from the baseline of this forum.
The 7 foot lasers are based on the SP 185 footprint. Though I am building my own tubes with several improvements. These will be 442nm. I just love the color. I expect up to 250mw output.
Building some HeSe too! Maybe 1 4ft and 1 7ft. I am not using Quartz. Yea, Cd or Se are both toxic. But, the colors are intoxicating.
I agree, finding parts for old products can be a real challenge. But, still rewarding.
Regarding the Laser Interferometer, I have to be honest, I have used them in the past for some projects, but I have not done any modeling for the Walsh drivers. A good system can really set you back and I have not made that leap for our shop.
Must run
Dale
I'll keep my answers short to prevent too much wander from the baseline of this forum.
The 7 foot lasers are based on the SP 185 footprint. Though I am building my own tubes with several improvements. These will be 442nm. I just love the color. I expect up to 250mw output.
Building some HeSe too! Maybe 1 4ft and 1 7ft. I am not using Quartz. Yea, Cd or Se are both toxic. But, the colors are intoxicating.
I agree, finding parts for old products can be a real challenge. But, still rewarding.
Regarding the Laser Interferometer, I have to be honest, I have used them in the past for some projects, but I have not done any modeling for the Walsh drivers. A good system can really set you back and I have not made that leap for our shop.
Must run
Dale