Fender Hot Rod Deluxe 4 x 10 Speaker Replacement

[nickb]

Has The Destructor dialed down his need for excessive volume? I hope so, or he's going to find himself in the same pickle again, soon enough. Tougher speakers would be the answer, but which fit into the space allotted?

True indeed. The evil Destructor now unleashes his wrath on other, unsuspecting victims, so I hear.

[nickb]

Well, the Jensen came in. Comparing heights of the magnet and frame to the original looked good about 1-2mm to spare. Trial fitted and still had an issue with the power transformer fouling the frame. There are raised sections on the spokes and this is where the problem lay. So I pulled the chassis again, unbolted the PT and moved it as close the edge of the chassis as I could, about 5mm and drilled new holes. I only needed to drill two as there were two others already drilled in the right place. Now it all fits.

I can't be the first person have to do this. The Jensens really are tiny and I'd have a hard job to find anything smaller. At least if anyone else has to face this issue they'll know it can be made to work with the Jensens.

How did it sound? Well actually pretty good with nice tones for slightly crunchy blues and clean jazz. I felt it a bit lacking on the high end and need to used the bright switch more than usual.

Many thanks to all

[SoulFetish]

Trial fitted and still had an issue with the power transformer fouling the frame. There are raised sections on the spokes and this is where the problem lay. So I pulled the chassis again, unbolted the PT and moved it as close the edge of the chassis as I could, about 5mm and drilled new holes. I only needed to drill two as there were two others already drilled in the right place. Now it all fits.

Still though, that’s a pain in the bum. It’s bad enough having to do that for a Transformer replacement.
But this is helpful info. Now I know that if we are confronted with this going forward, if they have a surviving speaker of the 4, it’s going in that spot. You situation was a little unique in that they managed to destroy the full quad. If that happens, it is getting reconed. We have a guy who is quick, good, and does pickup and drop offs.

[Chuck H]

Well, the Jensen came in. Comparing heights of the magnet and frame to the original looked good about 1-2mm to spare. Trial fitted and still had an issue with the power transformer fouling the frame. There are raised sections on the spokes and this is where the problem lay.

So it wasn't possible to rotate the speaker and achieve a different geometry where the spoke rib didn't meet the transformer? Hell, I've rotated speakers so that can caps that would otherwise keep a speaker from fitting were actually IN the open portion of the frame (just a little).

[J M Fahey]

Chiming in to say the same but chuck H already suggested it : you are not forced to use original speaker mounting holes by any means, just rotate it enough (and itīs just *one* speaker) so transformer corner fits in the middle of a frame window.


Probably your amp uses those pesky dangerous double thread pointy screws, some use an even cheaper version which is hammered-on, redrill and remount screws twisted, say, 10 to 15 degrees, doubt you need more than that.
You may even convert that one only to use T Nuts and matching bolts.

[olddawg]

I just skimmed this and excuse me if I missed it being suggested earlier... But why isn’t re-coning an option? It’s USUALLY less expensive than replacement. Especially if you a have a local speaker savant. Doesn’t seem to be done as much as it used to be.

[nickb]

@g1 & JMF,

I did consider the rotation. To do it required four holes and four t-nuts. The PT move required two holes. It was pretty much of a wash time wise.

[nickb]

I just skimmed this and excuse me if I missed it being suggested earlier... But why isn’t re-coning an option? It’s USUALLY less expensive than replacement. Especially if you a have a local speaker savant. Doesn’t seem to be done as much as it used to be.

I used to do reconing when I lived in the US as it was easy to get supplies. Here in the UK I can't find anything useful. There's a place in Germany but when you factor in shipping it gets expensive. And frankly I was never happy with the process. If I took into account the cone tonal differences and time taken it was never worth it on the low end speakers. I know of just one company here that offers a reconing service. It would cost me about the same in shipping alone than just buying a new speaker.

[TimmyP1955]

One of the ways a voice coil dissipates heat is by radiating it into the top plate; the metal edge of the cap actually conducts heat away from the coil better than air. With square waves, the coil spends more of each cycle partially outside the gap, reducing cooling compared to a sine wave, so square waves do cook voice coils to destructive temps.

A square wave is comprised of a number of sine waves. The speaker acts no differently. It's all about the amount of power fed to the speaker, not the waveform.

[The Dude]

Oh, here we go again!

[Leo_Gnardo]

A square wave is comprised of a number of sine waves. The speaker acts no differently. It's all about the amount of power fed to the speaker, not the waveform.

Rich Koerner at Time Electronics would give you a helluva argument on that. Word is he has passed away and his website that had his thoughts on the subject, well I can't find it. Those who have better luck than me on the wayback machine might give it a try. Helluva lot of hard-gotten knowledge lost if that website went into the great digital beyond with him.

Suffice it to say: square waves KILL speakers. Granted, less of a problem with tube amps compared to solid state.

[drewl]

Got a couple of these from the same guy, all speakers loose and most missing the screws?

Talk about punishment!

[nosaj]

Rich Koenig at Time Electronics would give you a helluva argument on that. Word is he has passed away and his website that had his thoughts on the subject, well I can't find it. Those who have better luck than me on the wayback machine might give it a try. Helluva lot of hard-gotten knowledge lost if that website went into the great digital beyond with him.

Suffice it to say: square waves KILL speakers. Granted, less of a problem with tube amps compared to solid state.

Here ya go
https://web.archive.org/web/20180403...timeelect.com/
nosaj

[Leo_Gnardo]

Here ya go
https://web.archive.org/web/20180403...timeelect.com/
nosaj

Thanks nosaj! I got his name wrong too, it's Koerner - I corrected it in my entry above.

Somewhere in there I hope there's still Richard's article on hard clipping, square waves, and how to wreck perfectly good speakers.

[J M Fahey]

Just a small side comment: when you apply a square wave to a speaker, cone/voice coil do NOT stay "fixed in space" by any means (what most anybody seems to believe) .

While itīs within the square wave "flat top" area, it is continuously receiving a fixed voltage, same constant value as squarewave peak voltage , and voice coil, which is a (linear) electric motor continues to push and move forward/backwards, same as any DC motor will keep turning while it receives steady DC voltage.

To see it another way: to keep constant sound pressure (the flat top of a square wave) in front of a speaker which is radiating into open space , cone must keep moving.

It is NOT the case of a piston compressing air inside a closed and relatively small cavity, in which case it will keep still holding said pressure.

Now drill a hole in that cavity so air can escape, and piston will have to move to keep pressure constant.

Counterintuitive at first (I mean expected speaker behaviour) until it "clicks".