I've been told that it's not uncommon for Altec drivers stored in hot locations to have the goop applied to the accordion surround to melt and move to different locations. This is an understatement!
Here are some pics of my left woofer from a pair of 1970's 8G's. Did Altec just get sloppy with it's later production units?
It's interesting that the right channel doesn't look like this. This cone actually has a 515 or 416B part number making me think it was reconed at some point and not gooped as heavily.
Per Hasling's website claims the pooling can affect the free air resonance and increase how low the woofer will play. Do you think it would be worth the effort to clean and re-dope this surround? Or is the 604 motor powerful enough that this isn't a problem?
Here are some pics of my left woofer from a pair of 1970's 8G's. Did Altec just get sloppy with it's later production units?
It's interesting that the right channel doesn't look like this. This cone actually has a 515 or 416B part number making me think it was reconed at some point and not gooped as heavily.
Per Hasling's website claims the pooling can affect the free air resonance and increase how low the woofer will play. Do you think it would be worth the effort to clean and re-dope this surround? Or is the 604 motor powerful enough that this isn't a problem?
Attachments
My [4] mid '50s 515Bs look like picture #2 and the early '70s pair like the other two if I don't rotate them mid-Summer, though no one's been able to tell me why the inconsistency other than at some point EPA forced the supplier to switch to a latex base, which is thinner, but that was late '70s AFAIK.
Yes, if extreme and it hardens much the compliance [Vas] spec decreases, raising Fs and at high power can cause the VC to drag in the gap.
No need to re-dope, just heat it up and use a cheap throwaway glue brush to either redistribute it or save it in case you find a pinhole at a later date.
GM
Yes, if extreme and it hardens much the compliance [Vas] spec decreases, raising Fs and at high power can cause the VC to drag in the gap.
No need to re-dope, just heat it up and use a cheap throwaway glue brush to either redistribute it or save it in case you find a pinhole at a later date.
GM
how about a hairdryer? My Audio Nirvana 8 stiffened so much that fs raised a half octave (pulling Qt up too) - turpentine is supposed to help with the Nirvana stiffness.
Rotating them is a great idea! Actually, all three pictures are the same driver. The heavy drips are at the bottom, the other one is higher up on the surround.I'll collect the stuff that pooled on the speaker cover and save it for repairs. The right channel looks okay. It's just the wrong part number, haha!
I'll try your suggestion after rotating the driver.
Freddi, using a hairdryer just might work, great idea!
Thanks again!
Attachments
Understood, my point was that the '50s drivers just barely puddle [and suck back up when cooled, which I just now noticed!] whereas the '70s do big time and don't shrink back, just hardens up a bit.
My Conair Infinity Pro softens it up like right now.
GM
My Conair Infinity Pro softens it up like right now.
GM
I can imagine.......you know you have a good one when you can rebuild a motorcycle in the family room and clean parts in the sink and tub over the Winter to get it ready for Daytona Bike Week. 😀
GM
GM
Here is what Per Hasling wrote about the matter.
The solvent however was not disclosed.
Sorry he can not be asked any more.
The solvent however was not disclosed.
Sorry he can not be asked any more.
Here is anothe thread where two or three solvents are discussed :
Who has done this ?........ ( Older ALTEC Woofers )
Who has done this ?........ ( Older ALTEC Woofers )
We communicated some way back when WRT Altec stuff such as my recommending a much lower A7 tuning, using wings in HIFI apps, cleaning, softening surrounds, etc..
GM
I don't know what he used, but acetone is the original dope's thinner and 91% alcohol for the latex IIRC.
GM