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I’ve been farting around with “Hi-Fi” for almost 50 years and never ”blew” a speaker before… and it had to be one of my beloved Tannoy 15” HPD Dual Concentrics (Arden c. 1976).
I was “wiggling wires” (inputs) and created a loud horrific blast to the speaker. It now buzzes on certain bass frequencies and the voice coil can be felt to rub when pushed in, gently, by hand. I live in Phoenix and had the speakers re-coned at Field Services to the tune of about $800, about 8 years ago. I still have the original cones w/ voice coils intact. Only the suspension was rotted away. My initial search for their phone/address yielded nothing.
My questions:
1- What kind of repair might I be looking at?
2- Can anything be salvaged from my original cones/coils?
3- Might I also have fried an electronic component in the cross-over?
4- Is “Field Services" still around, or who in Phx. might be recommended for the necessary repair(s).
Thanks to all.
Follow Ups:
Ouch! Events like this can ruin your day, or week or ?I've had several vintage drivers reconed by Field Services, I believe they are still in business, at 24th street & Thomas. Many members of the local audio group have used another recone expert, and with a little research I could get his contact info.
Thanks for the input. I wasn't sure if Field Services was on Indian School, or Thomas. I certainly hope they're still around. I would still welcome your alternative source, if it's not too much trouble.
No luck so far in locating the reconer, this guy used to work at Speakers etc. on Indian School Road. Others believe that Field Services is still in business, just east of 24th st & Thomas, south side.
play but with a slight rub.at this point you have nothing to lose so its worth trying in my opinion.
it involves detaching the surround and inspecting the voicecoil and former for damage.
damage might be slightly deformed former at bottom from being smacked into the back of the motor.
this can be reformed into concentric again --i use a pencil and dont even think of trying to use something magnetic-- like i have done with a dynaco a25 woofer and a conrad-johnson scan-speak woofer among others.
you have to be able to lift the entire vc former out of the motor assembly to inspect it.
if the former is slightly warped and the cone can be pushed from at least 1 place on its surface that doesnt rub then you have a good chance of saving the driver.
dust cap must be removed in order to shim the vc former concentric in the gap.
then the surround is reglued while pushing the cone down onto the basket.
this has always been effective for me in getting the driver to play buzz free.
week before last i saved a nice b&w mid-bass driver that way.
there is a chance that even though it will play without rub at moderate levels it will start to rub at higher levels due to the warped vc former.
i have yet to encounter this but it should be mentioned.
i know what you mean about those sparky wires. :(
good luck.
You're right -- I have nothing to lose at this point. I will certainly give this first consideration, before spending $$$ on other solutions. I just hope that being a dual-concentric doesn't render this too difficult.
Thanks for your suggestion.
If you overheat the voice coil it can either warp or actually break at a weak point and cause a projction of wire which then rubs. Most likely if the speaker still makes sounds the coil/former may have warped.
I had that happen when a transistor amp went to the rail. Now I only use low power tube amps with my Supravoxes and Lowthers.
This is good information. Thank you. I had no idea that the damage might be purely mechanical. My speaker still plays but "buzzes" on certain low frequencies. Truth be known, it was a Mac MC7270 (270 watts per) solid state amp that helped me do the deed.
Thanks again.
I'd reinstall one of the original cones with a new surround (and spider if necessary). Google 'recone' for suppliers/techs.
I agree that that is certainly an option, but what, exactly, did I "blow"? ... and how?
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