Cerwin Vega Model 26 Woofer Issue
- Thread starter cimchazz1
- Start date
Does anyone "out there" know if the risers/pedestals can be easily removed (with screws) from the bottoms of the CV D7 cabinets? I might have a line on a pair and I need to get the height down to 32" without permanently altering the cabinet. If it isn't possible, I will look for something else (like D5)
fisherphile
New Member
you can just knock them off with a hammer they are tacked on.
fisherphile
New Member
I've got 3 pair that I am repairing. Hopefully you got your sorted out. Alan's health has taken a turn for the worse. I've been doing repairs out of my garage for a few years and we all know each other. These heppners are correct. this same basket can also be found in other CV models like the 12T but with different motor dimensions. What happened here is your hepper was rebuilt using a Genuine CV L121-4 recone kit which is a woofer used in the D5. The woofer mounting is different FYI but I think you found that out. The Heppner cone is deeper and the spider is a deeper cup dimension. in order to make a lateral move into a L121-4 kit you have to use a spider spacer so the spider doesn't crash into the frame. The alternative is to leave a gap between the spider and the cone which will leave some of the voice coil visible but will allow everything to rest in a neutral position. Part of the trouble is without having a proper build to start with it's a bit of guess work to determine exactly where the voice coil should sit. Fortunately I have an original un molested pair of R26 heppners.
Last edited:
fisherphile
New Member
Per usual I am thinking more and I want to add more to what I said. The starting point is getting the correct cone in the Heppner basket and as you can imagine that might be tough especially considering CV couldn't even do it in 1980 for you. The Heppner cone is deeper and therefore has more surface area. The different shape and surface area equates to different sound. Also a very important detail you must know: The Heppners are 4 ohm (3 on the meter) Alan should have known this. There are (2) 121 models: L121-4 which is 8 ohm (what you ended up with in your recone) and W121-4 which is 4 ohm. If you are going to do a woofer swap you need the W121-4 woofer or at least convert an L into a W. but this still doesn't solve the cone dimension issue. CV was good for making changes along the way. In searching you'll find that the later 121 R26 models look differnet and likely have different crossover values. Just a note: I am currently trying to source a properly dimensioned cone for the Heppner. But if it cannot be done the alternative is to convert the GEN1 R26 into a GEN2.
Would you be able to provide the dimensions of the original cone(s)? The depth of the original would be very helpful in finding replacement cones. That would be from the basket where the surround rests, to the top of the magnet pole. What I do many times in a "retrofit" is find the center of travel for the voice coil. I measure the depth of the gap (bottom of the magnet) to the top of the pole piece, find the center of travel, then adjust slightly upwards to prevent bottoming out. Then shim the coil so it doesn't move in it's "neutral" position, and find what spider dimensions to use that leave room for the cone to rest on. Then measure from the basket lip down to find what depth of cone is needed. Then go looking for a cone that is "close enough" to trim if need be. Knowing the original dimensions allows for as close a replacement as possible. And the "type" (smooth, ribbed, etc) plus thickness (weight) of the cone material to try and maintain as close to the acoustical properties as possible. It's next to impossible to get it "perfect", but you can get it "close enough" to be satisfactory.
Just curious, where do you buy cones? I've bought plenty of surrounds but never a cone.
I would think the thickness/stiffness and total mass of the cone would have an effect on sound as well. So many parameters to match. Not to sound discouraging, it's the only way with an unobtanium woofer.
I would think the thickness/stiffness and total mass of the cone would have an effect on sound as well. So many parameters to match. Not to sound discouraging, it's the only way with an unobtanium woofer.
There is a place called "The Speaker Exchange".
Oh my they do have a lot of cones don't they.
575 is Heppner Sound.
Cerwin Vega bought Heppner sound, some time in the late 1970s- Heppner had produced many of the older CV drivers, and CV basically took them in-house later.
Depending on the voice coil diameter and magnet configuration- it may be possible to recone those Heppner frames to perform like the 121-4s. It would take a custom recone to do that- making sure that the voice coil has the right winding dimensions, and that the coil is properly vertically positioned in the magnet gap at rest (so that it has proper linear travel without the coil winding moving out of the gap in one direction before the other, as it goes in and out), and using the proper stiffness spider and proper cone.
I have seen many of the classic cast-frame CV drivers, that also had stamped-frame Heppner equivalents. It used to be pretty common in guitar amps- less so, but not unheard-of, for home speaker cabinets as well...
Regards,
Gordon.
Cerwin Vega bought Heppner sound, some time in the late 1970s- Heppner had produced many of the older CV drivers, and CV basically took them in-house later.
Depending on the voice coil diameter and magnet configuration- it may be possible to recone those Heppner frames to perform like the 121-4s. It would take a custom recone to do that- making sure that the voice coil has the right winding dimensions, and that the coil is properly vertically positioned in the magnet gap at rest (so that it has proper linear travel without the coil winding moving out of the gap in one direction before the other, as it goes in and out), and using the proper stiffness spider and proper cone.
I have seen many of the classic cast-frame CV drivers, that also had stamped-frame Heppner equivalents. It used to be pretty common in guitar amps- less so, but not unheard-of, for home speaker cabinets as well...
Regards,
Gordon.
Just came across a possible pair of Heppner/CV 12" woofers while moving my gear around. These were installed in another set of speakers I purchased years ago as replacement driver's and I knew they were incorrect when purchased. Original model of speakers they came in is unknown so I began searching and ended up here. Maybe another member will be able to identify them as to the CV Model they came from. Below the CV sticker are the numbers 7206-9983 419 and 7206-9983 406, both cones have XK2010 on the back. The DC resistance is 5.6 ohms, and if you subtract the lead resistance that would be about 5 ohms. There is no 575 code to indicate Heppner though? Not trying to thread crap and I have sent a message to @cimchazz1 just in case these are the driver's he has been looking for.
Attachments
Last edited:
teal'c
Nuclear Cardiac Parent
Spiders too.
I just wanted to add a few more pictures and more Information. The voice coils appear to be 1 1/2" as measured above the spider. The outside diameter of the basket is 12". These were re-foamed prior to me owning them, so I'm not sure if the red CV surrounds are correct. Odd thing is that the "575" Heppner code is missing?
Attachments
I was going to say the magnet structure looks like the L121-4 magnets with the 1.5" voice coils. These are more than likely from just before they switched to the cast aluminum frames. They probably sound about the same as the ones @cimchazz1 was looking for. BUT the steel frame are slightly smaller outside diameter which also is slightly different for the mounting screw circle. But a slight spin gets you "fresh meat" for screwing them fast.
Just curious if these are from 24 or 26 models in your opinion?
I honestly couldn't tell you. The one set of 26 model I had at one time used the aluminum frame woofers. But that doesn't necessarily mean all 26's had them. In-production changes happen a lot without being documented.
Newer ones (well newer relatively) yes. They were all steel baskets at one time. I have some aluminum ones that still have the "old style" magnets that were on the steel ones, during the transition to aluminum. I have no idea what models they were from though. 122W2 woofers came in both versions plus the "transition" version.