Is it ok to trim away part of the speaker frame?

[DaveG]

I just picked up a Cannabis Rex speaker for my BF Princeton Reverb clone; the amp was built from a Weber kit, and already has a 12" speaker installed (Blue Dog). The problem is that one of the parts (I think it's a transformer) hits the speaker before the chassis is fully seated in the cabinet. The frame on the CR is pretty heavy... would it hurt the speaker to trim a small amount away on one of the frame "legs," just enough to clear the transformer? Thanks!

[Trout]

I just picked up a Cannabis Rex speaker for my BF Princeton Reverb clone; the amp was built from a Weber kit, and already has a 12" speaker installed (Blue Dog). The problem is that one of the parts (I think it's a transformer) hits the speaker before the chassis is fully seated in the cabinet. The frame on the CR is pretty heavy... would it hurt the speaker to trim a small amount away on one of the frame "legs," just enough to clear the transformer? Thanks!


If it were me, I would rotate and re-mount the speaker so the transformer lines up in the opening on the frame. It is not likely you will get enough cone travel to be an issue.

Trout

[DaveG]

I've spun the speaker 360 degrees (a couple of times!), and if I rotate it so that the transformer has clearance, then the cap can is hitting and the speaker would need even more trimming. My other option would be to make a whole new baffle, and move the speaker cutout over, but that's a ton of work...

[Trout]

I've spun the speaker 360 degrees (a couple of times!), and if I rotate it so that the transformer has clearance, then the cap can is hitting and the speaker would need even more trimming. My other option would be to make a whole new baffle, and move the speaker cutout over, but that's a ton of work...

Oh Man I hate when that happens.

I guess I am not an advocate of gringing on the speaker frame, I always fear it will eventually distort/warp and start getting coil rub. But I do know making a baffle takes a bit of effort. Not so much getting the board to fit, but getting all the stuff like grill cloth, paint, hardware and of course putting it together.

Not especially fun.

Trout

[donnyjaguar]

Grinding a bit of the basket away probably won't cause a problem. That said, I'm not keen on bastardizing components. Can you relocate the transformer just enough to let the chassis slide in?

[mbratch]

I've spun the speaker 360 degrees (a couple of times!), and if I rotate it so that the transformer has clearance, then the cap can is hitting and the speaker would need even more trimming. My other option would be to make a whole new baffle, and move the speaker cutout over, but that's a ton of work...Some of the after-market Princeton baffles (http://www.mojomusicalsupply.com/item.asp?pid=81428&pg=45614&id=1006142) I've seen have the 12-inch speaker hole offset from center to avoid the problem. If it were me, I would not want to cut the speaker frame for fear of adversely affecting the frame and ending up having to buy a new speaker. It would certainly hugely cut the resale value of the speaker if you wanted to sell it and put a different one in. Having a usable spare 12-inch baffle, though, gives you some options.

[DaveG]

Thanks, guys!

I've been messing with this thing, off & on, all morning. I noticed the speaker hole was offset some towards the transformer, so I flipped the baffle 180 degrees, and put it back together. It pretty much puts the speaker as far over (away from the transformer) and down (without hitting the reverb tank) as it can go. Unfortunately, the top corner of the transformer still hits the speaker frame... but it's on the bottom vertical rib of the frame, and a much smaller area to trim. It looks like there's just no way to squeeze this speaker in without "clearancing" it a little bit.

As far as moving the transformer goes, that would be a huge undertaking for me, and given my lack of electrical expertise, almost certainly disastrous. :o I'm going to examine it further, though, to see if a new baffle will gain me any more room; if it won't, it looks like I'm going to trim the speaker frame.

[Popoon]

Try loosening the transformer bolts and jiggling it a little.

[fullerplast]

As far as moving the transformer goes, that would be a huge undertaking for me, and given my lack of electrical expertise, almost certainly disastrous. :o I'm going to examine it further, though, to see if a new baffle will gain me any more room; if it won't, it looks like I'm going to trim the speaker frame.

Moving the transformer is by far your easiest solution. It's undoing a pair of mounting screws and drilling one or two new holes. Piece of cake. You've already done way more work than that.

[DaveG]

Moving the transformer is by far your easiest solution. It's undoing a pair of mounting screws and drilling one or two new holes. Piece of cake. You've already done way more work than that.

It's pretty hard to tell, but I don't think there's enough slack in the wires to move the transformer; plus, I'd be leery of drilling new mounting holes, as the chassis is packed pretty full. The mounting screws are just under the end of the fiberboard... Here's a pic:

http://i19.ebayimg.com/07/i/000/b0/14/9b27_12.JPG

[fullerplast]

It's pretty hard to tell, but I don't think there's enough slack in the wires to move the transformer; plus, I'd be leery of drilling new mounting holes, as the chassis is packed pretty full. The mounting screws are just under the end of the fiberboard...

Well, only you know how much it needs to move but it sounds like just a little bit. Can't tell much from your photo other than they didn't leave much slack....but then you don't have a photo of the clearance needed. If it just has to swing over a bit, just one new hole may work.

[DaveG]

Good point, Fullerplast. I'll take one side loose & see how much the transformer will move. Thanks!

[DaveG]

The end of the saga:

I tried taking one side of the transformer loose to see if it would swing to one side, but it wouldn't budge. The wires come in from both sides & two different holes, so no matter which way I moved it, the wires would tighten. Oh well, it was worth a try.

In the end, I just trimmed the speaker frame. It didn't need a lot, and I don't think it affected the stiffness of the frame at all. I put everything back together & it works well... and no left over parts! :AOK The Cannabis Rex is noticeably smoother than the Blue Dog that I took out, and the highs are definitely rolled off a little more; I like it so far, but I won't make a final decision on it until I spend some more time with it.

Thanks again, guys, for all the advice!

[mbratch]

Maybe to bring it to closure for everyone, you could post a pic of the trimmed speaker. I'm curious. :)

[trdlasvegas]

I've done this before with no adverse effect. Here's a frame notched for a large Mercury Magnetics transformer:

- Tony


http://www.thermalrelief.com/super/Super_transformer_cutout.JPG

[DaveG]

Maybe to bring it to closure for everyone, you could post a pic of the trimmed speaker. I'm curious. :)

Sorry about that, I wasn't thinking... I should've snapped a pic before I put everything back together! I'll see if I can get one without tearing it all back apart.

The notch I made was about the size of the one in Tony's pic, but while his is at the top of the frame, mine was at the bottom of one of the openings (on the vertical lip, just above the mounting flange). It turned out well and sounds good, but if I had it to do over, I think I would put a Jensen Neo in it & save the aggravation. :o