Lowther: please read before considering !

[Billy60300]

Hi all
I'd like to let you share what happened to me with this company.
I have bought and received some EX3 drives. Fine.
recently, I tried to push them with a good solid state amp and both blew.
It was the second time it happened.
the first time I sent the blown one in a double packaging, fully insured.
they answered that the parcel had been crushed by the post office and that I had to pay for the repair. I never got evidence of what happened and could not claim anything from the post office.
this time one of the drives which I sent arrived OK. they looked at it and said the following: (please better sit !):
Hi Billy

The EX3 drive unit has now been inspected.

The coil wire is not only blistered, but the speech coil is buckled. This suggests more ampage than voltage is going through the coil.

The problem lies with the amplifier, as you would be unable to listen to the volume needed to cause such damage, it would be unbearable.

Therefore, the amplifier either needs rectifying or you may wish to consider changing the amplifier altogether, otherwise this problem will continue to occur. As previously mentioned, Lowther drive units require only 1-3 watts to fill a normal listening environment. There are various low watt amplifiers on the market which would enhance the sheer musicality of Lowther drive units.

We can fit a new diaphragm to this unit for you, at a cost of GBP90 plus carriage (quote exclusive of VAT as you have a registered VAT number).

If you would like to return the second unit of the pair for repair, this will save on return carriage costs for you.

great technical analysis indeed, the amp gives out too much ampage and not enough voltage !!!
repaired mine alone with no trouble and found an incredible thing: while Lowther advertises and sells a choice between aluminium or silver coils, I found an ordinary PAPER coil inside !

So this is total fraud and either they deliver the propser thing or there will be blood on the sidewalk.

Please read carefully !!!

[SY]

Originally Posted by Billy60300

...while Lowther advertises and sells a choice between aluminium or silver coils, I found an ordinary PAPER coil inside !

I think the metal they refer to is the wire, not the former. Aluminum has lower conductivity than silver, but lower mass. Take your choice.

What sort of amp have you been using?

[Billy60300]

No, it is not the wire which is in aluminium: the wire in thin plain usual copper. More, its insulation appeared pretty weak: disappearing with the heat of a small soldering iron.
they say it is rated to 100 watts power handling, believe me with such a gauged copper wire it is a max of about 30 watts you can expect.

[Billy60300]

... my amp was at the first time a A class 6080 triodes (paralleled, own design, was published by Mr Hiraga some years ago) and now it is a KA9X sstate Kenwood. the triode amp was to harsh with those drives, well known for being very hard to the ear.

[chrisb]

Your service experience would certainly be frustrating, but publicly claiming fraud and threatening bloodshed is not required or prudent.

If you're happier with the sound of your Kenwood amp, it might well be time to consider another brand/type of driver.

Frankly, I think the Lowther repair agent's suggestion that both drivers should be reconditioned is very wise, which you can either choose to follow and then resell the drivers to avoid future damage, or continue to repeat the same actions with the expectation of different results.

[Bob Brines]

Originally Posted by chrisb

....or continue to repeat the same actions with the expectation of different results.

An understatement I might have expected from an Englishman.

I have run Lowther drivers for years off of a 100w/ch Yamaha HT receiver, although they do sound better on my 9w/ch PP tubes. Your drivers should have been complaining long before you fried them. Don't know.

Bob

[UKPD]

I run mine EX 3's with 180W Hypex amps, no problems. Have you per chance tried checking for DC offset on the output of your amps? Lowthers hate DC

Regards,
Peter

[BudP]

What exactly did you repair on your own?

Bud

[kach22i]

A quick Google search on that Kenwood unit:

KA9X
Kenwood KA-9X info anyone? [Archive] - AudioKarma.org Home Audio Stereo Discussion Forums

PS
I recieved a reply from my post in the yahoo Kenwood group:
"i owned this amp (2x120w/8ohms , big powersupply , with a special technology called DLD :
a low power amp together with a high power one only for the signal peaks ) very powerfull
but the sound was not so good i found why you have to take off the little PCB called
"preamp fast cut off" onthe top of the amp and then it's a really good amp"
Anyone know about the preamp pcb?

.................................................. .

Kenwood KA-9X | Owners Manual, Service Manual, Schematics, Free Download | HiFi Engine

Description

The main amplifier in the Kenwood KA-9X / 9XG consists of a 3-stage differential class A voltage amplifier and a 3 stage Darlington class B SEPP.

Power output: 120 watts per channel

Frequency response: 20 to 20,000 Hz

............................................

KENWOOD KA-9X 9XG SM Service Manual free download, schematics, eeprom, repair info for electronics


............................................

Ideas:

1. The amperage/voltage spikes provided for musical peaks from the staged amps are too much for the drivers. Perhaps the power jumps in too fast or something like a turbo boost on a car.

2. There seems to be several different ways of hooking up speakers on the back of the unit, maybe one way is less likely to burn out a low power rated driver.

.................................................. ..........

Kenwood KA-9X info anyone? - Page 2 - AudioKarma.org Home Audio Stereo Discussion Forums

[chrisb]

Originally Posted by Bob Brines

An understatement I might have expected from an Englishman.
Bob

well, some mixed Brit on mom's side and ukapolaranian on dad's -does that explain anything?