Need a Replacement 6.5" Woofer (for a Superone)
Hi,
I have a bad 6.5" woofer in one of my Superones, and am looking for a replacement. Or, I would also consider buying another complete speaker, if you have a single that you are not using. Please contact me at tomlarwa@gmail.com if you have either.
Thanks,
Tom
Hi,
I have a bad 6.5" woofer in one of my Superones, and am looking for a replacement. Or, I would also consider buying another complete speaker, if you have a single that you are not using. Please contact me at tomlarwa@gmail.com if you have either.
Thanks,
Tom
Tom,
I don't have any replacement drivers for Super Ones. NHT had a replacement driver made for the speaker that was excellent. We purchased one order of them about 1 year ago. I don't know if there are any left or not. Call NHT's main number and ask for Janne. He can tell you if there are any left.
I don't have any replacement drivers for Super Ones. NHT had a replacement driver made for the speaker that was excellent. We purchased one order of them about 1 year ago. I don't know if there are any left or not. Call NHT's main number and ask for Janne. He can tell you if there are any left.
AC2 6.5 midrange
Does the AC2 center use the same 6.5" Foster NPT-11-025-1 midrange as the 3.3 and 2.9?
Does the AC2 center use the same 6.5" Foster NPT-11-025-1 midrange as the 3.3 and 2.9?
No. The AC2 uses an NPT-11-077-1. If you unhide row 10 in the spreadsheet on the sale site, you can see the specs for it. This driver was built for that application only.
Hi Jack!
I was wondering if I could get the part number for the tweeter portion of a VT-3. I'm in need of one and could use the help. Thanks!
Mike
I was wondering if I could get the part number for the tweeter portion of a VT-3. I'm in need of one and could use the help. Thanks!
Mike
2.9 Foster midrange for 2.5i and 1.5i
Can the Foster 6.5" npt-11-025-1 be used in the 2.5i and 1.5i speaker? If it can, do I need to make any modifications.
Can the Foster 6.5" npt-11-025-1 be used in the 2.5i and 1.5i speaker? If it can, do I need to make any modifications.
The Foster npt-11-025-1 can't be made to fit in either the M2.5i or the M1.5 (we never made an i model). Unfortunately there is no suitable replacement driver available.
Jack,
Two questions:
Basic question, Re the 077 woofer used in the AC2. The rather high Zmax and Qms look like artifacts. Along with the other paramters what if anything do those tall number (Zmax 122 with an fs in the low 30s, Qms around 8) tell about the intended voice/effect of this speaker? Everyone who has listened to this one, and me, has commented on the clarity of voices, clear percussion sounds in the *upper* midrange. My nephew and his roomates are using his pair for a small subwoofer. I'm not clear on what this speaker was "about" (besides the fact that it makes up a great center channel).
From the Klippel reports, any guidance out there for working the Power Series Expansion numbers, f0, L0, etc, how the basic formula works, what the forumla looks like? I don't see this on the Klippel website. I am not clear on setting the intersect and then what to use to push the coefficients. Maybe his computer executes these in some special way so don't worry about making sense of it on my own?
Thanks for any help.
Two questions:
Basic question, Re the 077 woofer used in the AC2. The rather high Zmax and Qms look like artifacts. Along with the other paramters what if anything do those tall number (Zmax 122 with an fs in the low 30s, Qms around 8) tell about the intended voice/effect of this speaker? Everyone who has listened to this one, and me, has commented on the clarity of voices, clear percussion sounds in the *upper* midrange. My nephew and his roomates are using his pair for a small subwoofer. I'm not clear on what this speaker was "about" (besides the fact that it makes up a great center channel).
From the Klippel reports, any guidance out there for working the Power Series Expansion numbers, f0, L0, etc, how the basic formula works, what the forumla looks like? I don't see this on the Klippel website. I am not clear on setting the intersect and then what to use to push the coefficients. Maybe his computer executes these in some special way so don't worry about making sense of it on my own?
Thanks for any help.
I was looking for the schematics of the 250w amps and powersupplies...
No luck on your site.
Do you still have them? I am hoping I have time to get to them this spring....
-tINY
Tiny,
The 250W amplifier modules and power supplies are long gone. We sold 1 pair in 2 months, so they were scrapped.
The 250W amplifier modules and power supplies are long gone. We sold 1 pair in 2 months, so they were scrapped.
Patch,
The 077 woofer wasn't designed by me, so I can only give you some insight into how it works, but not why certain things were choosen.
The high Qms and Zmax are because there is very little mechanical damping in the driver. Mechanical damping/losses can come from a couple of places. The spider and surround have internal loses from the internal friction in the materials. Ferrofluid adds a lot of mechanical damping the viscous friction. Using electrically conductive voice coil formers (aluminum in most cases) causes mechanical damping. As the coil moves through the magnetic fields, there are eddy currents that flow in the voice coil former. Since the voice coil former material has some finite resistance, this impedance is reflected back to the mechanical domain where it tries to act as a brake to keep the coil from moving.
As an experiment, take a woofer and tap on the cone and see how much it moves. Now short across the voice coil terminals and then tap on the cone. The resistance of the voice coil is acting as an electromagnetic brake.
Almost all other NHT drivers in the spreadsheet have aluminum voice coil formers. This adds mechanical damping and lowers there Zmax and Qms qalues. I'm not sure why the 077 uses Kapton. Aluminum has much higher power handling than Kapton. We would never use Kapton unless we had to. In some cases we have used it when we needed to raise the Qts of the driver to get adequate bass response. That may be the case in the 077.
Another effect of using Kapton is that distortion due to eddy currents flowing in the former will be removed. However, this is a very small effect since distortion due to eddy currents flowing in the steel parts of the motor will be 50 times higher.
The nonlinear coefficients are used with a standard polynomial. For example:
ax^2 + bx + c = 0
In Klippels terms, this would be:
BL2x^2 + BL1x + BL0 = 0
In all three cases, the 0 term is setting the y intercept. I'm only showing the last three coefficients here.
Without software that does nonlinear analysis, the nonlinear coefficients are not that useful for the hobbyist. If you have a DSP controller, you could use them to program it for feedforward distortion correction, but you'd have to know what you were doing.
The 077 woofer wasn't designed by me, so I can only give you some insight into how it works, but not why certain things were choosen.
The high Qms and Zmax are because there is very little mechanical damping in the driver. Mechanical damping/losses can come from a couple of places. The spider and surround have internal loses from the internal friction in the materials. Ferrofluid adds a lot of mechanical damping the viscous friction. Using electrically conductive voice coil formers (aluminum in most cases) causes mechanical damping. As the coil moves through the magnetic fields, there are eddy currents that flow in the voice coil former. Since the voice coil former material has some finite resistance, this impedance is reflected back to the mechanical domain where it tries to act as a brake to keep the coil from moving.
As an experiment, take a woofer and tap on the cone and see how much it moves. Now short across the voice coil terminals and then tap on the cone. The resistance of the voice coil is acting as an electromagnetic brake.
Almost all other NHT drivers in the spreadsheet have aluminum voice coil formers. This adds mechanical damping and lowers there Zmax and Qms qalues. I'm not sure why the 077 uses Kapton. Aluminum has much higher power handling than Kapton. We would never use Kapton unless we had to. In some cases we have used it when we needed to raise the Qts of the driver to get adequate bass response. That may be the case in the 077.
Another effect of using Kapton is that distortion due to eddy currents flowing in the former will be removed. However, this is a very small effect since distortion due to eddy currents flowing in the steel parts of the motor will be 50 times higher.
The nonlinear coefficients are used with a standard polynomial. For example:
ax^2 + bx + c = 0
In Klippels terms, this would be:
BL2x^2 + BL1x + BL0 = 0
In all three cases, the 0 term is setting the y intercept. I'm only showing the last three coefficients here.
Without software that does nonlinear analysis, the nonlinear coefficients are not that useful for the hobbyist. If you have a DSP controller, you could use them to program it for feedforward distortion correction, but you'd have to know what you were doing.
I have several pairs and power supplies in my garage...
I need schematics (tracing them seems unplesant).
-tINY
Amplifier schematic here:
http://home.comcast.net/~jhidley/250W_amplifier_module.pdf
Power supply schematic here:
http://home.comcast.net/~jhidley/250W_amplifier_power_supply.pdf
http://home.comcast.net/~jhidley/250W_amplifier_module.pdf
Power supply schematic here:
http://home.comcast.net/~jhidley/250W_amplifier_power_supply.pdf
Just a note to say that the 8-inch Peerless woofers Jack has can put out a good bit of loud low sound. I'm giving a hand installing lights for a community stage; the hall will hold 850. I do not have a sound meter or know much about acoustics, but at 120 Hz just one of those was quite loud at the back center stage wall about 80-90ft back. I estimate the rest of the hall at 120ft W X 30-40ft H - right now no furniture. Hard painted walls, no coverings anywhere, bare concrete floor, open rafter hard ceiling, est 60ftW X 25ftH stage, no curtains yet. From a 2cubic ft box on the center stage, and then below on the ground (and old Genesis cabinet) with dual 4" vents cut into the front. For a by-the-numbers small sub, that Peerless was darn good...for the recorded music we were playing. Maybe someone knows what math applies to get the decibels, but the sound level and depth around the hall surprized everyone in there.
Given how low the price is, I wanted to do a mythbuster and see if I could destroy it with the P1500 amp I had in there, so we put on a subharmonic filter for 95/48/24 and we could not get it to die. We cut the exectution period short after a few minutes because the paint crew in the lobby threatened to strangle us. It coundn't match the throw of an 8-inch woofer alone in one of the JBL cabinets that a misinformed benefactor donated for stage monitors, but it played the low octaves louder.
Given how low the price is, I wanted to do a mythbuster and see if I could destroy it with the P1500 amp I had in there, so we put on a subharmonic filter for 95/48/24 and we could not get it to die. We cut the exectution period short after a few minutes because the paint crew in the lobby threatened to strangle us. It coundn't match the throw of an 8-inch woofer alone in one of the JBL cabinets that a misinformed benefactor donated for stage monitors, but it played the low octaves louder.
Just a follow up on my prior post. We were not able to expire the 8 inch peerless/nht sub with the output of a middle-aged P3000. It still works fine.
Also talked too hastily about a benefactor's choice of sound going into a new 850 seat hall. He knows how to pick a contractor. His guy put up a number of little 8-inch JBL cabinets into arrays, fronts, monitors...then hoisted up to about 15 feet two JBL srx728s cabinets (I wrote it down), dual 18-inch 12 cubic foot boxes. Then an Imax looking rack of new Crest amplifiers rolled in. A stack of Parasounds would have been very neat for this venue -- but everyone knows that the volunteer who suggests such a thing is the one most likely to end up paying for it, so... Still it sounds darn good in there, the little boxes working together like a choir. And the subs rattling my scaffold without playing all that deep -- it actually made me appreciate what one peerless 8-incher was able to do. It should get even better in there when somebody figures out how to trim back that 3-second decay.
Also talked too hastily about a benefactor's choice of sound going into a new 850 seat hall. He knows how to pick a contractor. His guy put up a number of little 8-inch JBL cabinets into arrays, fronts, monitors...then hoisted up to about 15 feet two JBL srx728s cabinets (I wrote it down), dual 18-inch 12 cubic foot boxes. Then an Imax looking rack of new Crest amplifiers rolled in. A stack of Parasounds would have been very neat for this venue -- but everyone knows that the volunteer who suggests such a thing is the one most likely to end up paying for it, so... Still it sounds darn good in there, the little boxes working together like a choir. And the subs rattling my scaffold without playing all that deep -- it actually made me appreciate what one peerless 8-incher was able to do. It should get even better in there when somebody figures out how to trim back that 3-second decay.
Replacement Driver for a Model II
Jack,
I own a pair of Model II's that I purchased back in 1991 which I love. Both of midranges have rotted foam surrounds that need to be replaced (something that I used to do professionally a while back).
I was wondering if the NPT-11-025-1 could be used as a replacement for the midrange driver in a Model I/II system? (Yeah, I realize that 025's do not have the bucking magnet or shielding cup)
Both of my drivers have no manufacturing data stamped on them and the NHT website does not even mention the Model II's or I's in its Vintage Producs section so I am assuming there are no replacements available.
Is it worth the risk? Are they even the same 167mm size? Should I just refoam?
Thanks for your help,
Eric
Jack,
I own a pair of Model II's that I purchased back in 1991 which I love. Both of midranges have rotted foam surrounds that need to be replaced (something that I used to do professionally a while back).
I was wondering if the NPT-11-025-1 could be used as a replacement for the midrange driver in a Model I/II system? (Yeah, I realize that 025's do not have the bucking magnet or shielding cup)
Both of my drivers have no manufacturing data stamped on them and the NHT website does not even mention the Model II's or I's in its Vintage Producs section so I am assuming there are no replacements available.
Is it worth the risk? Are they even the same 167mm size? Should I just refoam?
Thanks for your help,
Eric
Eric,
The NHT MII, M1, M1a, M1.8, M2.1 all use the exact same 6.5" upper woofer/midrange (11-004-1 old part number, NPT-11-016-1 new part number). About a year and a half ago, we designed a replacement driver and had a number of them built. Currently NHT is out of stock of these. It is my understanding that they will be ordering more of them. I don't know when they will arrive.
Aside from the fact that the 025 woofer has the wrong high frequency response, Qts and sensitivity, it won't fit in the cabinet. The motor is too large. The angled baffle on your speaker causes the driver motor to interfere with the inside of the cabinet wall. A number of NHT speakers have large recesses routed in the inner wall of the cabinet for this. If you pull one of the subwoofer's out of your speaker, I think you will see them. The M3.3 definitely has them for the 025 driver.
The NHT MII, M1, M1a, M1.8, M2.1 all use the exact same 6.5" upper woofer/midrange (11-004-1 old part number, NPT-11-016-1 new part number). About a year and a half ago, we designed a replacement driver and had a number of them built. Currently NHT is out of stock of these. It is my understanding that they will be ordering more of them. I don't know when they will arrive.
Aside from the fact that the 025 woofer has the wrong high frequency response, Qts and sensitivity, it won't fit in the cabinet. The motor is too large. The angled baffle on your speaker causes the driver motor to interfere with the inside of the cabinet wall. A number of NHT speakers have large recesses routed in the inner wall of the cabinet for this. If you pull one of the subwoofer's out of your speaker, I think you will see them. The M3.3 definitely has them for the 025 driver.
Replacement Driver for a Model II
Thanks for the info Jack, I was affraid that was the case. I guess I will have to refoam for now. The downside is the foam is never *really* an exact fit no matter how close you get and you get to refoam again at some period down the road.
Do you have the specs for the NPT-11-016-1? Also, do you have any of the VT-3 Sub Amps left?
Thanks again,
Eric
Thanks for the info Jack, I was affraid that was the case. I guess I will have to refoam for now. The downside is the foam is never *really* an exact fit no matter how close you get and you get to refoam again at some period down the road.
Do you have the specs for the NPT-11-016-1? Also, do you have any of the VT-3 Sub Amps left?
Thanks again,
Eric