Vintage hi-fi bulb question - UK Vintage Radio Repair and Restoration Discussion Forum

river9999uk · 9th Apr 2020, 9:34 pm

Hi All

What type of bulb is this please? Its a bayonet push and turn type. Only has '18v 0.1A' written on it. Sure these are standard but being new to this I am still not sure what type I should order as a modern replacement LED etc etc.

Pictures attached of bulb in question.

Thanks in advance

G6Tanuki · 9th Apr 2020, 9:41 pm

The metal connector with 2 side-pins and a centre contact looks like what is generally known as a "BA9s" bayonet type.

RS, Farnell, CPC etc. have them in all sorts of voltages - including LED replacements.

Or: https://seaforthmarine.co.uk/indicat...-79-06-04.html

river9999uk · 9th Apr 2020, 9:44 pm

Thanks!

Radio Wrangler · 9th Apr 2020, 9:47 pm

It looks like you can have 6v 12n 24v 60v and 240v from the usual suppliers, so 18v MBC might be difficult to find.

An LED replacement might be possible, but they usually shine straight down the axis and not to the sides, and they usually take less than 100mA.

Which way do you need the light to come out, and is it in a 100mA series valve heater chain?

David

river9999uk · 9th Apr 2020, 10:14 pm

No its just for the light on an 8-track player showing which track is being played. 18V AC is coming direct off a tap on the transformer I think.

Radio Wrangler · 9th Apr 2020, 11:02 pm

There are car/lorry LED alternatives available which cover 12-28v and because the polarity could be either way, I think most have a bridge rectifier already in them.

I used some festoon shape LED replacement lamps in a Revox tuner I was sorting out. They work great in the meters, though the LCD is not so good, I think I need an opal diffuser to scramble to polarisation.

Anyway the LED festoons were so good, I replaced the ones in the car... they were frequently blowing.

David

Uncle Bulgaria · 10th Apr 2020, 11:06 am

If you want to use an LED and after installation find the light has to be less directional, roughening up the surface of the bulb will help with diffusion and make the light more even. I used this method for a tape counter as not enough light was shining on the digits themselves.

AC/HL · 10th Apr 2020, 12:52 pm

For this use an ordinary 24V MBC one may well be bright enough.

river9999uk · 11th Apr 2020, 5:36 pm

Thanks I'll try some LED ones and see how I go. Will report back.

broadgage · 11th Apr 2020, 8:38 pm

The correct replacements are available from CP lighting.

http://www.cp-lighting.co.uk/18V-1-8W-100mA-Ba9s

9th Apr 2020, 9:34 pm	#1
river9999uk Tetrode Join Date: Feb 2020 Location: Exeter, Devon, UK. Posts: 86	Vintage hi-fi bulb question Hi All What type of bulb is this please? Its a bayonet push and turn type. Only has '18v 0.1A' written on it. Sure these are standard but being new to this I am still not sure what type I should order as a modern replacement LED etc etc. Pictures attached of bulb in question. Thanks in advance Attached Thumbnails

9th Apr 2020, 9:41 pm	#2
G6Tanuki Dekatron Join Date: Apr 2012 Location: Wiltshire, UK. Posts: 13,998	Re: Vintage hi-fi bulb question The metal connector with 2 side-pins and a centre contact looks like what is generally known as a "BA9s" bayonet type. RS, Farnell, CPC etc. have them in all sorts of voltages - including LED replacements. Or: https://seaforthmarine.co.uk/indicat...-79-06-04.html

9th Apr 2020, 9:44 pm	#3
river9999uk Tetrode Join Date: Feb 2020 Location: Exeter, Devon, UK. Posts: 86	Re: Vintage hi-fi bulb question Thanks!

9th Apr 2020, 9:47 pm	#4
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,868	Re: Vintage hi-fi bulb question It looks like you can have 6v 12n 24v 60v and 240v from the usual suppliers, so 18v MBC might be difficult to find. An LED replacement might be possible, but they usually shine straight down the axis and not to the sides, and they usually take less than 100mA. Which way do you need the light to come out, and is it in a 100mA series valve heater chain? David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

9th Apr 2020, 10:14 pm	#5
river9999uk Tetrode Join Date: Feb 2020 Location: Exeter, Devon, UK. Posts: 86	Re: Vintage hi-fi bulb question No its just for the light on an 8-track player showing which track is being played. 18V AC is coming direct off a tap on the transformer I think.

9th Apr 2020, 11:02 pm	#6
Radio Wrangler Moderator Join Date: Mar 2012 Location: Fife, Scotland, UK. Posts: 22,868	Re: Vintage hi-fi bulb question There are car/lorry LED alternatives available which cover 12-28v and because the polarity could be either way, I think most have a bridge rectifier already in them. I used some festoon shape LED replacement lamps in a Revox tuner I was sorting out. They work great in the meters, though the LCD is not so good, I think I need an opal diffuser to scramble to polarisation. Anyway the LED festoons were so good, I replaced the ones in the car... they were frequently blowing. David __________________ Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done

10th Apr 2020, 11:06 am	#7
Uncle Bulgaria Nonode Join Date: May 2016 Location: Cornwall, UK. Posts: 2,333	Re: Vintage hi-fi bulb question If you want to use an LED and after installation find the light has to be less directional, roughening up the surface of the bulb will help with diffusion and make the light more even. I used this method for a tape counter as not enough light was shining on the digits themselves.

10th Apr 2020, 12:52 pm	#8
AC/HL Dekatron Join Date: Nov 2003 Location: Heckmondwike, West Yorkshire, UK. Posts: 9,642	Re: Vintage hi-fi bulb question For this use an ordinary 24V MBC one may well be bright enough.

11th Apr 2020, 5:36 pm	#9
river9999uk Tetrode Join Date: Feb 2020 Location: Exeter, Devon, UK. Posts: 86	Re: Vintage hi-fi bulb question Thanks I'll try some LED ones and see how I go. Will report back.

11th Apr 2020, 8:38 pm	#10
broadgage Nonode Join Date: Jan 2010 Location: North Somerset, UK. Posts: 2,129	Re: Vintage hi-fi bulb question The correct replacements are available from CP lighting. http://www.cp-lighting.co.uk/18V-1-8W-100mA-Ba9s