Dead Audax ap130 in Mission 78c

[Ian J]

Looks like there was some sort of QC problem with the 'keraform' units ( ap 130mn4 -not aerogel) used in the 78/780 range as I've googled and seen that other people had failures. Both of the units in my friend's 78c centre speaker have gone to ~50k ohms, I'm not optimistic about repair - any ideas for drop in replacements now the ap range is not in production?

[sreten]

Hi,

Falcon Acoustics | The Leading DIY Speaker Parts and Kit Supplier since 1972
sell Audax drivers but they are not cheap.

A complete used replacement would probably be cheaper.

Willys-hifi on e-pray do cheap decent drivers that may not be ideal
but get things going. The 78C claims to be 8 ohms, so it presumably
has 2 : 12 to 16 ohm units in parallel or 2 : 3 to 4 ohm units in series.

These might work in series:
Peerless SKO130 POLY 5" Bass/Mid hifi woofers - 4 ohm! | eBay

These might work in parallel :
Peerless SKO130 5" Bass/Mid KEF B110 alternative | eBay

If the above don't fit because they are too large then in series should fit :
http://www.ebay.co.uk/itm/Peerless-L...#ht_4619wt_808

rgds, sreten.

[5th element]

Have you tried contacting mission for replacement parts?

[Ian J]

Thanks guys - will drop Mission a line first and then investigate the suggested alternatives.
Ian

[sreten]

Originally Posted by 5th element

Have you tried contacting mission for replacement parts?

Hi,

From what I can tell Mission sold there inventory of replacement drivers
online at amazon.co.uk and this particular driver is no longer available.

rgds, sreten,

I really don't know know where willys-hifi get there part numbers from.
8" drivers and above are described as usual by the diameter, but below
that they mix up cutout and diameter specifications.

Ignore the first option, they simply won't fit, 130mm cutout, 160mm dia.
The third option will be too small, 100mm/130mm now I've looked into it.

The second option should fit, 120mm cutout versus Audax 118mm.
Each mounting hole will be less than a mm out, and should not
be a problem with the slotted mounting holes and frame.
You might need to chamfer the cutout edge slightly.

So go for two of these only (in parallel) for a £20 budget fix :
http://www.ebay.co.uk/itm/Peerless-S...#ht_4264wt_808

[5th element]

Originally Posted by sreten

Hi,

From what I can tell Mission sold there inventory of replacement drivers
online at amazon.co.uk and this particular driver is no longer available.

I wish I'd known about that I'd have purchased some if the prices weren't insane.

[sreten]

Originally Posted by 5th element

I wish I'd known about that I'd have purchased some if the prices weren't insane.

Hi,

There is the rub. The drivers were £18 each * (+P&P) and almost certainly
not exclusively bought by those needing replacement drivers, presumably
the opposite. So not a great approach to long term customer service IMO.

rgds, sreten.

* definitely a sell-off price rather than a service replacement price,
but now I can't find where I got that price from, so I may be wrong.
http://www.amazon.co.uk/Mission-spea.../dp/B0013ISVEA

[5th element]

I agree selling them off is particularly poor, mission should have held onto them for occasions like these. £18 each is certainly not a lot of money, although one could also say that the original AP aerogel series from audax cost about the same too so perhaps the price was about right. Who knows maybe the mission custom units had better motors, I doubt it though considering the end cost of the mission loudspeakers.

[sreten]

http://www.audiolabga.com/pdf/SKO130-4.PDF

Hi,

Well the 4 ohm version of the suggested replacements
seems a very good driver, given they are £10 a pop.

Lowish Fs, low Qts, good Xmax and flat response.

rgds, sreten.