Should this amount of coil rub affect tone?

playloud

Well-Known Member
Joined
Dec 28, 2020
Messages
782
Reaction score
922
After months of patient waiting, I finally found a second Pulsonic T1281 to fill my 2x12 - a '72 'Rola' this time.

It arrived yesterday, after the seller confirmed there was no coil rub and agreed to ship it halfway 'round the world. To be fair to the seller, he didn't claim to be an expert, and he did a bang-up job of the packaging.

Unfortunately, there was some clear coil rub on arrival:



Slightly disheartened, I installed both speakers in the cab and did some playing. The nice thing about the 1936 cab is how easy it is to switch between the individual speakers, so I was pretty quickly able to ascertain that they're both "good", with the standard variation in tone you expect from similar speakers. The '70 is a tad louder, but the '72 (this one) has a softer top end. They complement each other nicely.

Most importantly, I couldn't hear any of the telltale sounds of coil rub. No scratching sounds or painful resonances. I didn't absolutely crank the speakers, but I did eventually run the cab in parallel out of my JTM 45/100 (with a loadbox), so it would have been seeing half the 45/100s power - and it sounded fine (spectacular, even!)

Is this surprising? Should I expect coil rub to rear it's ugly head in future? Are there any further tests I should try?

I did orient the speakers in a way they wouldn't have been previously, with terminals facing the bottom of the cab. I've read that this can resolve coil rub over time, but no idea how effective this really is...

Edit: here's the other, for comparison:
 

pulsonicsound

Well-Known Member
Joined
Apr 6, 2019
Messages
396
Reaction score
614
I'd get your money back if I was you, its not like that is a slight rub.

you can remove the dust cap and clean the gap (thats not guaranteed to solve the problem) with rubbing cones I find that it tends to exhibit itself more at higher volumes,
 

BygoneTones

Well-Known Member
Joined
Aug 27, 2013
Messages
1,583
Reaction score
1,395
Something I've come to realise lately is that playing through the speaker trumps every other manual test you can do. If it sounds good when you play through it, then it's a good speaker. Just make sure you play through it at a good volume. I'm finding if you play some muted power chords it tends to reveal the coil rub, or a nice loud G chord with a bit of gain. Get as much bass out of your guitar as you can. Doesn't have to be deafeningly loud, but fairly loud.

Still do those tests of moving the cone by hand, and check spider support is glued, that can weed out a lof of duff speakers, but ultimately you want to play through the speaker.

btw if you're moving the cones from underneath like that, it's better to have your fingers as close to the center of the cone as possible where it is stronger. You don't want to put your fingers through the cone!
 

playloud

Well-Known Member
Joined
Dec 28, 2020
Messages
782
Reaction score
922
Seller says he tested before sending and there was no rub. Possibly a fanciful question, but is it at all likely the coil rub developed during shipping?

It's going to cost me a bomb to send this back to the US. Return shipping could easily end up costing me ~ US$300. An expensive return indeed!
 

StrummerJoe

Well-Known Member
Joined
May 3, 2021
Messages
4,087
Reaction score
13,294
Seller says he tested before sending and there was no rub. Possibly a fanciful question, but is it at all likely the coil rub developed during shipping?

It's going to cost me a bomb to send this back to the US. Return shipping could easily end up costing me ~ US$300. An expensive return indeed!
I'd say anything was possible from that far abroad. I have no reason to doubt the seller because shipping damage is entirely possible.

I can't exonerate the seller either - they may have known a return would be difficult, but I think it unlikely they planned for such a faraway sale to dick some poor fella.

Very unfortunate.
 

playloud

Well-Known Member
Joined
Dec 28, 2020
Messages
782
Reaction score
922
Honestly, this seller seems like a stand-up guy. I messaged him originally because he had a few details wrong in his product descriptions, and it transpired he was a drummer selling on behalf of a guitarist friend, amended the listings right away and was really grateful for the help.

I sent him a video of how to check for coil rub prior to sending, and he did that and confirmed all was well. It would be weird indeed to try to deceive me in this case, knowing full well that this was the first thing I'd check on receipt.

On playing with it more, it seems the likely outcome here is that I've got a speaker that works fine and sounds great - just isn't worth much anymore. Might be worth taking up with UPS for once. After all, I did pay extra for full insurance!
 

metromutt

Well-Known Member
Joined
Jul 15, 2009
Messages
771
Reaction score
385
Location
England
Feel disappointed for you if those cost a lot. If they sound great for what you need them for and the price was good then enjoy. I hope the seller is willing to refund some cash back as you've honestly done a demo vid, sending the speaker back is clearly not an option at that price... and, if the packaged wasn't damaged in transit then I find hard to believe that it's now got coil rub, especially if it was packed well.

I've bought a lot of greenback speakers over the years and I would say 75%ish would have an issue of rub when manually tested (not tickled!) but more than 60% would sound well at low volume. I just wish people would think twice about spending big bucks on these old speakers... unless the seller is clearly willing to test them and except a return if there are issues.
 
Last edited:

StingRay85

Well-Known Member
Joined
Aug 18, 2019
Messages
2,116
Reaction score
1,847
It sound to me like you have a corroded pole piece and possibly the entire part which is covered by the spider. It could be that shipment broke free a few particles, and this is now in between the gap. Also the glew of the spider can break lose and get distributed in between the voice coil gap. But in any case, this is not a speaker worth much anymore. Cleaning just by removing the dust cap will not solve everything, because the other part of the gap is inaccessible.
 

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,208
Reaction score
20,733
Honestly, this seller seems like a stand-up guy. I messaged him originally because he had a few details wrong in his product descriptions, and it transpired he was a drummer selling on behalf of a guitarist friend, amended the listings right away and was really grateful for the help.

I sent him a video of how to check for coil rub prior to sending, and he did that and confirmed all was well. It would be weird indeed to try to deceive me in this case, knowing full well that this was the first thing I'd check on receipt.

On playing with it more, it seems the likely outcome here is that I've got a speaker that works fine and sounds great - just isn't worth much anymore. Might be worth taking up with UPS for once. After all, I did pay extra for full insurance!
If its not worth much and it sounds good just play it until it doesnt sound good and get it reconed. See if you can get some money back from UPS. :yesway:
 

BygoneTones

Well-Known Member
Joined
Aug 27, 2013
Messages
1,583
Reaction score
1,395
A knock can uncouple the glue at the spider support, and maybe other corrorded debris into the coil gap, as Stingray85 says. But if they were packed well with cushioning materials around them, that shouldn't happen. In my experience most people selling speakers online just don't check them properly.
 

Seanxk

Well-Known Member
Joined
May 14, 2018
Messages
974
Reaction score
907
As Brian mentioned earlier, coming from the back with fingers isn't a real test. You will also put a bias on the cone which can tilt or deform the coil slightly, effectively you need many fingers to even out the contact and get a true idea.
Coming from the face also isn't great but at least you can try to get an even spread to push, does it still do it then?

Edit, try from the back and be as gentle as possible without gloves, with a good finger spread push up and try to move it without making the coil rub, if you can do this then I think you're fine. I gig Bass with a pulsonic 4x12 G12M 55 cab, I record with it too and my favorite miked speaker has coil rub, but it never comes through on recordings and I'm sure never at gigs ( although I can't be sure), I put it down to just me badly biasing a push on it one day and being paranoid from then on.

Edit 2, lol, should read '' G12H 55'', actually I don't think I've ever seen an M 55 pulsonic.
 
Last edited:

KraftyBob

Well-Known Member
Joined
Sep 5, 2017
Messages
2,152
Reaction score
2,992
Location
Chicago Suburbs - USA
I recently bought a '93 Fender Blues DeVille 410 that the seller said was good. Playing it a low to moderate volume it sounded fine. When cranked I kept hearing a vibration and though it was loose screws in the cab, speaker, etc. Turns out one of the speakers had voice coil rub and it only showed at high volumes. I wasn't upset with the seller as, like you, I don't believe he was being purposely misleading. I was able to find the correct era replacement and all is good in the DeVille world.

If you decide to keep and play it, one thing to consider is if the speaker completely goes how will that affect the impedance the amp sees and could it cause harm?
 

playloud

Well-Known Member
Joined
Dec 28, 2020
Messages
782
Reaction score
922
As Brian mentioned earlier, coming from the back with fingers isn't a real test. You will also put a bias on the cone which can tilt or deform the coil slightly, effectively you need many fingers to even out the contact and get a true idea.
Coming from the face also isn't great but at least you can try to get an even spread to push, does it still do it then?

Edit, try from the back and be as gentle as possible without gloves, with a good finger spread push up and try to move it without making the coil rub, if you can do this then I think you're fine. I gig Bass with a pulsonic 4x12 G12M 55 cab, I record with it too and my favorite miked speaker has coil rub, but it never comes through on recordings and I'm sure never at gigs ( although I can't be sure), I put it down to just me badly biasing a push on it one day and being paranoid from then on.

This is an excellent suggestion. Will try later today.

Played through it pretty loud last night and still no issues, just great tone. I guess I now live in two parallel worlds: one in which the speaker is everything I had hoped for, another in which it is worth significantly less than I paid. There are worse predicaments...

If you decide to keep and play it, one thing to consider is if the speaker completely goes how will that affect the impedance the amp sees and could it cause harm?

Good point in general, but I'm using this with 100W heads, so I'm either running it in parallel with another cab/attenuator (so one speaker failing results in an impedance drop of 1/3, which should hardly be fatal), or after the SS poweramp of my TAE, where impedance doesn't matter. Although now I'm tempted to build something closer to 50W for a more compact setup...
 
Last edited:

Tatzmann

Well-Known Member
Joined
Nov 8, 2021
Messages
1,077
Reaction score
1,540
I once bought a 1960ax from the 90s.
I did listening test before buying. There
was no speakerrub.

At home i opened it and physically tested
the speakers for rub. Nothing. Sounded
good.

Couple months later 3 G12M in this
cab had the rub, i didnt even played it
very loud.

Its old stuff that breaks down, but can be repaired.
 

neikeel

Well-Known Member
Joined
Feb 12, 2014
Messages
7,187
Reaction score
6,724
To Playloud
That is very loud rub
I presume you have checked that the spider is not coming away from the speaker frame?
If it is you can repair it by removing the dust cover, shimming all round the air gap and then regluing the spider
- bit of a faff but saves a pulsonic coned speaker. Don't forget to vacuum it too to get dust out of the air gap.
 

playloud

Well-Known Member
Joined
Dec 28, 2020
Messages
782
Reaction score
922
As Brian mentioned earlier, coming from the back with fingers isn't a real test. You will also put a bias on the cone which can tilt or deform the coil slightly, effectively you need many fingers to even out the contact and get a true idea.
Coming from the face also isn't great but at least you can try to get an even spread to push, does it still do it then?

Edit, try from the back and be as gentle as possible without gloves, with a good finger spread push up and try to move it without making the coil rub, if you can do this then I think you're fine. I gig Bass with a pulsonic 4x12 G12M 55 cab, I record with it too and my favorite miked speaker has coil rub, but it never comes through on recordings and I'm sure never at gigs ( although I can't be sure), I put it down to just me badly biasing a push on it one day and being paranoid from then on.

Edit 2, lol, should read '' G12H 55'', actually I don't think I've ever seen an M 55 pulsonic.

I tried using all four fingers on each hand, distributed approximately evenly around the cone, and was able to reduce the rub significantly. Could be a good sign? Either that, or I too am now a member of the "it rubs, but it sounds great" club!

To Playloud
That is very loud rub
I presume you have checked that the spider is not coming away from the speaker frame?
If it is you can repair it by removing the dust cover, shimming all round the air gap and then regluing the spider
- bit of a faff but saves a pulsonic coned speaker. Don't forget to vacuum it too to get dust out of the air gap.

Good point. I hadn't checked the spider too closely, but just did and appears to be tight and even.

Honestly, my experience making IRs with these speakers yesterday has improved my confidence somewhat. I put a fair amount of volume (not to mention bass frequencies) through them and didn't detect anything sonically untoward.

Given where I am in the world, I don't have a huge amount of recourse in this situation - even if I chose to be difficult with the seller - so I think I'm just going to have to accept it, and enjoy the great tone while it lasts. I would say I'll treat every note as if it were the speaker's last, but that would simply result in silence!

And that's the... err... rub.
 

StingRay85

Well-Known Member
Joined
Aug 18, 2019
Messages
2,116
Reaction score
1,847
I think I have close to 10 of those G12H pulsonic 55 hz cone rubbers on the shelf. Not worth my time at this moment
 

Seanxk

Well-Known Member
Joined
May 14, 2018
Messages
974
Reaction score
907
I tried using all four fingers on each hand, distributed approximately evenly around the cone, and was able to reduce the rub significantly. Could be a good sign? Either that, or I too am now a member of the "it rubs, but it sounds great" club!
That sounds better, I notice in your video that you were deforming the cone as you pushed, so not a fair test for the speaker really.
I have an original SVT 810, each a sealed 2 x 10 ( I totally air sealed them ), when you push one speaker in the other moves out, that's a fair test with no bias.
 

Latest posts



Top