IMF ALS30

**Macca** · 08-09-2018, 22:18

Originally Posted by walpurgis

I've never had an amp blow speakers, but I have had a couple of amps blow.

Yep likewise. Not worth worrying about. I always switch off before swapping stuff around though. That's a good way to blow a speaker, changing leads and that with it all powered up.

**Edward** · 09-09-2018, 11:23

The seller has refunded in full for the blown speakers. Seems that in Jan he had an amp go bad on him which probably blew the bass drivers. The speakers were fine immediately afterwards so he sold them as in good condition. Maybe the coils took a while to go open? The seller even offered to arrange a refuse collection or suggested, if I wish, I can just keep the speakers and try sell the drivers.

Good to deal with someone who is this straightforward.

I may hang onto them and try to find a broken ALS30 I can cannibalise. Anyone got one?

But I may just remove all the drivers, measure them and flog them. I said to the seller I would give him half of any proceeds if I go down this route. Fairs fair. Based on his email I do think he sold the speakers in good faith.

**walpurgis** · 09-09-2018, 11:35

Modify the lower opening by converting it into a port (of the right size). Replace the upper drivers with some highish flux units of the right size and you have an eighth wavelength transmission line speaker. You could even use full range units and do away with the tweeter.

**Edward** · 09-09-2018, 21:33

Originally Posted by walpurgis

Modify the lower opening by converting it into a port (of the right size). Replace the upper drivers with some highish flux units of the right size and you have an eighth wavelength transmission line speaker. You could even use full range units and do away with the tweeter.

Thanks Geoff

Sounds interesting - but way over my head.

If I try squeeze my coral bass drivers in will that work?

Alternatively would you like to have them so you can play with them? No charge.

**walpurgis** · 09-09-2018, 21:48

Originally Posted by Edwardlon

Alternatively would you like to have them so you can play with them? No charge.

Thanks for the offer Edward, but I'm not in a position to take on projects at the moment, much as I'd like to.

**Edward** · 09-09-2018, 22:05

No problem Geoff. If you change your mind give me a yell.

This question probably reveals my naivety but is there a way of measuring the working bass drivers such that I go and find equivalents?

**walpurgis** · 09-09-2018, 22:17

Originally Posted by Edwardlon

This question probably reveals my naivety but is there a way of measuring the working bass drivers such that I go and find equivalents?

Unfortunately, it's the ones that are not working that you'd need that info for. They are different to the working set of drivers. I'm assuming it's the lower pair that are duds.

**Edward** · 09-09-2018, 22:32

Originally Posted by walpurgis

Unfortunately, it's the ones that are not working that you'd need that info for. They are different to the working set of drivers. I'm assuming it's the lower pair that are duds.

No the blown ones are on the right hand speaker. The bass drivers on the lhs are the same and are working just fine. So I just need to replicate the lhs ones.

§

**walpurgis** · 09-09-2018, 22:35

Keep an eye out for a tired set of ALS 30 speakers that have (some) usable drive units then. Could be worth it, they are reputed to be a fun speaker. The bigger ALS40 certainly was. For their size the bass was ridiculous.

**struth** · 10-09-2018, 10:11

I had a bit of dc going out to a speaker once on a valve amp. it was a leaky cap. enough to give a hum but not enough to cause damage. replaced it and all was well..

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