Tiny earphone socket - UK Vintage Radio Repair and Restoration Discussion Forum

Avid_Nerdlinger · 19th Sep 2020, 7:35 pm

Just got an Ingersoll XK-791 (£10) MW/LW tinny tranny ca 1981. It was originally supplied with an earphone but I didn't get one with this old used item off ebay.

My earphones won't fit the tiny socket.

I have found references to 2.5mm jacks being used on cellphones and 2-way radios but have read that these weren't used for music sources which required the better quality audio handling of 3.5mm jacks... I suppose AM radio qualifies.

I've just ordered a 2.5mm earpiece (99p), is this likely to fit or could it be something even weirder? A sticker on the back says "exclusively for Ingersoll in British Hong Kong".

stevehertz · 19th Sep 2020, 7:43 pm

You'll have to wait and see when it arrives, but I'd say there's a good chance it will be the correct one. I can't see there being another size. Difficult as it is to do so, try to measure the hole diameter in the socket, if it's 2.5mm as near as you can measure, then it's probably the one.

Herald1360 · 19th Sep 2020, 7:56 pm

Try poking a 2.5mm drill bit in for size or (a bit loose) 3/32" if you're old style.

paulsherwin · 19th Sep 2020, 8:49 pm

2.5mm earphone sockets were quite common at one time.

Avid_Nerdlinger · 19th Sep 2020, 9:10 pm

A 2.5mm drill bit is a close fit. Thanks for the responses, looks like it will be all standard sized then, apart from my new LW radio which is very small indeed - 135x75x32mm.

emeritus · 19th Sep 2020, 11:59 pm

The cheap AM/FM Hong Kong trannies of the early 1970's often had 2.5mm mono earpiece jacks. The same size was used for my 1990's Philips pocket dictating machine. CPC sent me a paper catalogue last week, and I see it lists a comprehensive range of 2.5mm connectors and adaptors in mono, stereo , and 4 pole versions.

dalgwcobl · 20th Sep 2020, 9:10 pm

The 2.5mm plug/socket was referred to as a sub-mini jack, whereas the 3.5mm was the mini jack.

Avid_Nerdlinger · 24th Sep 2020, 5:25 pm

Got the earphone today. It turned out to have a mic so I had to mod it a bit but it fits and works well. I might see if I can get a better sub-mini (thanks) earphone from somewhere though.

19th Sep 2020, 7:35 pm	#1
Avid_Nerdlinger Pentode Join Date: Apr 2019 Location: Durness, Sutherland, UK. Posts: 108	Tiny earphone socket Just got an Ingersoll XK-791 (£10) MW/LW tinny tranny ca 1981. It was originally supplied with an earphone but I didn't get one with this old used item off ebay. My earphones won't fit the tiny socket. I have found references to 2.5mm jacks being used on cellphones and 2-way radios but have read that these weren't used for music sources which required the better quality audio handling of 3.5mm jacks... I suppose AM radio qualifies. I've just ordered a 2.5mm earpiece (99p), is this likely to fit or could it be something even weirder? A sticker on the back says "exclusively for Ingersoll in British Hong Kong". Attached Thumbnails

19th Sep 2020, 7:43 pm	#2
stevehertz Dekatron Join Date: Sep 2011 Location: Rugeley, Staffordshire, UK. Posts: 8,834	Re: Tiny earphone socket You'll have to wait and see when it arrives, but I'd say there's a good chance it will be the correct one. I can't see there being another size. Difficult as it is to do so, try to measure the hole diameter in the socket, if it's 2.5mm as near as you can measure, then it's probably the one. __________________ A digital radio is the latest thing, but a vintage wireless is forever..

19th Sep 2020, 7:56 pm	#3
Herald1360 Dekatron Join Date: Feb 2007 Location: Leominster, Herefordshire, UK. Posts: 16,536	Re: Tiny earphone socket Try poking a 2.5mm drill bit in for size or (a bit loose) 3/32" if you're old style. __________________ ....__________ ....\|____\|\|__\|__\_____ .=.\| _---\__\|__\|_---_\|. .........O..Chris....O

19th Sep 2020, 8:49 pm	#4
paulsherwin Moderator Join Date: Jun 2003 Location: Oxford, UK Posts: 27,970	Re: Tiny earphone socket 2.5mm earphone sockets were quite common at one time.

19th Sep 2020, 9:10 pm	#5
Avid_Nerdlinger Pentode Join Date: Apr 2019 Location: Durness, Sutherland, UK. Posts: 108	Re: Tiny earphone socket A 2.5mm drill bit is a close fit. Thanks for the responses, looks like it will be all standard sized then, apart from my new LW radio which is very small indeed - 135x75x32mm.

19th Sep 2020, 11:59 pm	#6
emeritus Dekatron Join Date: Jan 2012 Location: Brentwood, Essex, UK. Posts: 5,349	Re: Tiny earphone socket The cheap AM/FM Hong Kong trannies of the early 1970's often had 2.5mm mono earpiece jacks. The same size was used for my 1990's Philips pocket dictating machine. CPC sent me a paper catalogue last week, and I see it lists a comprehensive range of 2.5mm connectors and adaptors in mono, stereo , and 4 pole versions.

20th Sep 2020, 9:10 pm	#7
dalgwcobl Pentode Join Date: Dec 2008 Location: Royston, Hertfordshire, UK. Posts: 131	Re: Tiny earphone socket The 2.5mm plug/socket was referred to as a sub-mini jack, whereas the 3.5mm was the mini jack.

24th Sep 2020, 5:25 pm	#8
Avid_Nerdlinger Pentode Join Date: Apr 2019 Location: Durness, Sutherland, UK. Posts: 108	Re: Tiny earphone socket Got the earphone today. It turned out to have a mic so I had to mod it a bit but it fits and works well. I might see if I can get a better sub-mini (thanks) earphone from somewhere though. Attached Thumbnails