Anyone know how to get inside one of these old mic connectors?

[GrannyGremlin]

So I got this cool Aiwa omni dynamic HiZ mic at a pawnshop during a road trip. Sounds cool but the cable is super short (4ft) and annoyingly stiff. I wanna make a longer nicer cable but I can't figure out how to get inside the mic-end connector to the solder connections. The set screw seems to only release the strain relief spring. I tried pushing out the brown phenolic disk from the rear.




Looks like a Switchcraft 2501F, which are still available. I'd just buy another one but the price at Digikey is almost $40 (CAD). I've seen as low as USD15 but thats still stupid and I'd get dinged for shipping and brokerage fees crossing the boarder making it not much better. The part is AKA Amphenol 8075MC1F or Heathkit 432-1 (both disco'ed) and was popular for unbalanced mic connections on NAmerican PA amps (schools etc vs music venues), like my old Bogen (switched them out for 1/4" and modded for guitar). The one thing that would be good about buying a new one is that I assume it will be more obvious how to get in there to solde rthe wires on - perhaps this is the stock AIWA cable and it wasn't meant to be messed with (like a molded 1/4" today).

Anyway this is the mic:

 

[GeorgeToledo]

If you screw that grub screw on the side of the connector into the connector shell so that it is fully inside the exterior, the shell may then slip off downwards.

 

[Walrus]

Now thr spring is pulled back, is the cable loose? It may 'screw' into the connector so the cable braid makes contact with the shell.

In the Shure mics using the MC1F, the centre contact is soldered, is this one soldered?
If so, then desolder it and try unscrewing the cable.

To make up the Shure version, we pushed the cable through the spring strain relief, stripped back the cable insulation and screening braid,
then folded back the braid all around the outside spring, then carefully soldered the braid to the spring.
The centre conductor is stripped back as neccessary so that the insulation just touches the back (inside) of the connector hole when the spring is fully pushed back in,
then solder the wire leaving a slightly raised 'blob' of solder.
Once soldered, tighten the screw to fix the spring in place.

 

[GrannyGremlin]

If you screw that grub screw on the side of the connector into the connector shell so that it is fully inside the exterior, the shell may then slip off downwards.

Negatory - I even tried completely removing the grub screw

Now thr spring is pulled back, is the cable loose? It may 'screw' into the connector so the cable braid makes contact with the shell.

In the Shure mics using the MC1F, the centre contact is soldered, is this one soldered?
If so, then desolder it and try unscrewing the cable.

To make up the Shure version, we pushed the cable through the spring strain relief, stripped back the cable insulation and screening braid,
then folded back the braid all around the outside spring, then carefully soldered the braid to the spring.
The centre conductor is stripped back as neccessary so that the insulation just touches the back (inside) of the connector hole when the spring is fully pushed back in,
then solder the wire leaving a slightly raised 'blob' of solder.
Once soldered, tighten the screw to fix the spring in place.

I can't get in there to desolder (I assume it is soldered, but can't really see in there).

Braid is not soldered to the spring (I assume to the shell).


....wait a minute, the connector's center conductor on a new 2501F is hollow, and mine is not - did they solder it in from the front.... looks like it might be... [firing up the iron to check] ... OMG that was totally it. Cable dropped right out when I melted the blob (the shield braid was folded back and would ostensibly make contact with the shell but not actually attached in any way. I will solder it to the spring when I put the new wire in.

Ah, on re-read I see that's what you meant by implication but I didn't pick up on that (or maybe just sub-consciously ;P ) - soldered from the outside not the inside.

Thanks y'all,

 

[C.B. - Boudio]

Since it's a high-Z mic, you probably don't want another cable, because the capacitance of the cable (the longer, the less high end, for example) greatly affects the high-end response in these cases.

 

[Walrus]

Shure high impedance mics were supplied with a 15 foot cable.
Just check that the cable you use is low capacitance.

 

[GrannyGremlin]

Yeah I know about all that - not me first HiZ mic. The original cable was only 4 feet (and very stiff). Since it's omni, it feeds back hard if it's that close to an amp or speaker. I made the new one just 8 ft; enough to put some distance though, again since it is omni, I will be more likely to use it thru a transformer/DI into a proper mic pre as a character mic/room mic when recording.

When I re-cabled my HiZ only Shure Unidyne I put a longer cable on it because that I do use for plugging into HiZ inputs on the regular. No noise/RF issues yet.

I use Gotham wire for unbalanced Hi Z applications - double shield braid and < 146 nF/km (=146pf/m). I am close to the end of the spool though and considering switching to Canare next time (bigger conductor - 18AWG vs 24 but 160pf/m - probably worth thr trade off there for lower R and added robustness).

 

[Ike Zimbel]

"I'd just buy another one but the price at Digikey is almost $40 (CAD). I've seen as low as USD15 but thats still stupid and I'd get dinged for shipping and brokerage fees crossing the border making it not much better."
Just FYI, all Digi-Key shipments to Canada are "DDP" (Duty paid) so the $8.00 shipping fee (for orders under $100) gets it to your door without any interaction with brokers, CBSA etc. And often, you get it the next day. That's been my experience over the last 25 years, YMMV.

 

[Khron]

Just FYI, all Digi-Key shipments to Canada are "DDP" (Duty paid) so the $8.00 shipping fee (for orders under $100) gets it to your door without any interaction with brokers, CBSA etc.

It depends on the shipping method you choose, but they have a DDP option "even" for Europe (or at least the EU), which is very welcome indeed. Sure, takes around a week or so to get this far, but with no hassles.

 

[Ike Zimbel]

It depends on the shipping method you choose, but they have a DDP option "even" for Europe (or at least the EU), which is very welcome indeed. Sure, takes around a week or so to get this far, but with no hassles.

The cool thing about Digi-Key shipping to Canada is there are no other options. It's FedEx Air, for $8.00, and that's it. On several occasions I have been on a job in the US, gone to order some parts for the next day, and discovered that there are many options for shipping, and that next-day air is stupid expensive.

 

[GrannyGremlin]

"I'd just buy another one but the price at Digikey is almost $40 (CAD). I've seen as low as USD15 but thats still stupid and I'd get dinged for shipping and brokerage fees crossing the border making it not much better."
Just FYI, all Digi-Key shipments to Canada are "DDP" (Duty paid) so the $8.00 shipping fee (for orders under $100) gets it to your door without any interaction with brokers, CBSA etc. And often, you get it the next day. That's been my experience over the last 25 years, YMMV.

Yes, but their price for the part is $40 which I am not paying for a shitty obsolete connector. I use Digikey all the time, cuz yeah the shipping is great (even compared to Mouser). The comment ab shipping was for other US shops where the part was cheaper, but they don't have the economy of scale on shipping to CA (as well as, I suspect, a biz strategy to edge out Mouser for the CA market, which is totally working) so it would be almost the same total in the end.

Anyway, it's sorted and I don't need a spare hanging around as this isn't a critical go to mic and for all it's imperfections the connector is pretty bulletproof.