Differences between 604-8k's....And Thanx for the A5 advice!

[Old Guy]

There were quality control issues- the Pink Floyd debacle was due to an entire shipment of defective woofers that had to be replaced with Gauss to finish the tour.

But mostly it's things like glue work.

The OKC 604's sounding different from Californies is just plain wrong. They did not redesign the units.

This stuff gets started on the net and amplified by repetition. Just trying to stop the repetition.

If by chance a pre or post OKC 604 was defective, treat it like any other defective unit and recone it. Not rocket science.

Re Urei- JBL did have Altec replacements in the pipeline, and of course JBL owned Urei...

[GM]

You're welcome!

Me too.

You're right, and why I probably spend about as much time de-bunking 'conventional wisdom' as I do helping folks with their designs.

[Old Guy]

Great Plains claims NOT to use the original motor. John Hilliard was involved in their changes supposedly.

Iconic is made by GPA. So as one goes obviously..

I'm aware of that magnet change- But that came Way after the move to OKC and only affects a small portion of the K models. Yes I didn't think of that.

EV certainly didn't mandate a magnet change years prior to associating with Altec.

So the OKC models as a lot being different is just plain silly.

K models after about 87 maybe- but not from the previous 5 years. The original statement said that OKC models as a lot were different. I know that not to be true from personal experience.

I had forgotten about the magnet change, I've never owned any of those, there are not that many out there.

[Old Guy]

Jim Dickinsom sez:
The improvement to the LF came out of the research and prototyping, by Jerry and I, of our 164-8A woofer. During measurements of the late 604Ks, Jerry found they were over-damped in the LF. We then applied the entire 164 low frequency section into the 704 which now has more linearity than any previous model including the alnico units. GPA is simply using the same LF motor structure of the 704. JIM

Any way is seems as with most Internet legends there is some truth.

But it not OKC 604's that are the actual problem, if it is that, came much later.

[Don McR]

Originally posted by Old Guy:

All the K models sound about the same. The OKC models use the exact same parts as the California ones. NO DIFFERENCE!

Did I mention no difference?

<font size="2" face="Verdana, Helvetica, sans-serif">That's not true. It has been posted a number of times on this forum (verified by Todd) that, under EVI ownership, management directed a redesign of the 604K bass motor structure to use the same standardized magnet of EV's 15" bass drivers. This resulted in an improved mid bass efficiency, but loss of LF extension. That is why Great Plains and Iconic reverted to the original 604K design when they reintroduced their versions.