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"fingers" on edge connectors

Posted: Sun Feb 12, 2017 9:50 pm
by brianroth
OK...lol...giving a hint on a new project here! <g> 500 cough cough.

15 contacts at 0.156" spacing.

(/sidebar) WHERE DID 0.156" COME FROM???? 5/32" equals 0.15625". I would think that over many fingers the spacing would drift...(/sidebar).

ANYWAY...

What would be suggested for plating on a circuit board? yes...I've read this and that re. "hard" nickel and gold.

What should I specify for Olde School circuit edge connectors that will last for many insertions? What vendor can do that without a huge quantity order?

Thanks!

Bri

Re: "fingers" on edge connectors

Posted: Mon Feb 13, 2017 10:28 am
by JR.
I would avoid these unless there was some compelling reason.

There are more robust modern connector systems.

Of course the customer is always right.

Gold plated fingers (over nickel) on PCB are not cheap.

JR

Re: "fingers" on edge connectors

Posted: Mon Feb 13, 2017 10:52 am
by brianroth
The standard connector for 500 series modules and the "lunchboxes" is that infernal edge connector which API began using decades ago.

Bri

Re: "fingers" on edge connectors

Posted: Tue Feb 14, 2017 8:54 am
by JR.
I used them in very early consoles (decades ago),,, absolutely horrible... poor mechanical indexing for self alignment, etc. Probably less of an issue for small modules.

Contacts exposed to environment so easily corrupted, gold is necessary, but I've seen fingers come off PCB due to poor adhesion (and perhaps heating).

Good luck.

JR

Re: "fingers" on edge connectors

Posted: Tue Feb 14, 2017 6:55 pm
by brianroth
I regularly encounter edge connectors on the older desks that I service/restore. SSL, MCI, Trident, and API just to name a few. I would NOT use that style connector on a new design except for the fact that the 15 pin format is standard for the highly popular 500-series "lunchbox" gizmos...and there are dozens (hundreds?) of preamps, EQ's, compressors, etc. manufactured by dozens of companies in that form-factor. For instance:

https://www.sweetwater.com/insync/500-s ... ing-guide/

I discovered that Sullins offers a "male blade" connector which looks like an attractive alternative. Example which has a fairly decent photo:

https://www.digikey.com/product-detail/ ... ND/1922847

Alas, the correct form factor I would require seems to be a special order item, so I'm back to finding a PC board fabricator which can apply the appropriate plating(s) on the fingers.

BTW....what connectors did you use for the AMR modules?

Bri

Re: "fingers" on edge connectors

Posted: Wed Feb 15, 2017 8:02 am
by JR.
brianroth wrote: BTW....what connectors did you use for the AMR modules?

Bri
Ribbon cable and multi-pin (molex?) headers/connectors.

Back at Loft (70s) we/they used edge connectors, mechanical alignment in big modules was another PIA.

JR

Re: "fingers" on edge connectors

Posted: Sun Feb 19, 2017 7:56 am
by mediatechnology
Part will become a non-stocking item when stock is depleted
Looks like that Sullins part is discontinued at Digi-Key.

MicMix used a male right angle similar to the Sullins in some of their very early Studio C Reverbs.
John Saul, one of the co-owners, had been an aerospace engineer and refused to use PC edge fingers.

With the 500-series format you're just stuck using them and finding a PC board house that will do it in gold may be difficult.

Re: "fingers" on edge connectors

Posted: Sun Feb 19, 2017 10:23 am
by emrr
That Sullins part looks like a miniaturized Amphenol blue ribbon connector, which also seems unloved.