Studer A80 meter bulbs

[Dr Funk]

I need to get a handful of replacement VU meter bulbs for my A80 16 track. Does anyone know the power requirements/specs of the bulbs? I've checked the meter schematic in the A80 service manual and I've searched online but I can't get the info anywhere.

Cheers
Frank

[Radardoug]

I know I've looked at this, and the manual is not clear, but if you take a card out it becomes clear. They are strapped across the +/- 12 volts, but I can't remember whether they are 12v or 24. When you pull the module it is obvious, and I guess you are going to have to take one out anyway. The meter module comes out from the front, undo the 4 chrome screws, note they are two different lengths!

[Dr Funk]

Thanks for the info! I've already taken the modules out, but I think the bulbs have been 'customised' at some point, because they are wire lead types, and they're soldered on to the mounts for the original bulbs.

I'll keep hunting for the specs. I reckon they probably are 12V, but I have no idea how much current they should draw...

Cheers
Frank

[Radardoug]

Ah its all coming back to me now. I think they are that bulb which has two little bumps either side that was used by Studer, used in Revoxes in the meters. maybe the wired bulb is not so silly. Look for something about 50 mA, try and get a 14 volt one, it'll last longer.

[Dr Funk]

Thanks! I'll do that. Here's a pic of what I've got at the moment:

Studer A80 meter bulb

What you said about bulbs with two little bumps sounds about right by the looks of it.

Cheers
Frank

[Studerfreak]

I think you need this type...
A Ba7S which is a bajonet type.
It will fit into the socket as it is supposed to do instead of the soldering work that has been done now.
Indeed this type of lamp also was used in Revox tape recorders.

In the Netherlands these lamps are still available in several voltage types.
Just measure the voltage now. I would assume is would be 24v or 12v.

You are in Ireland? Try looking for Ba7S at Farnell.com

[Dr Funk]

Excellent, thanks!! They look like the correct bulbs alright. I've just had a look at a meter module and the schematic, and the bulb terminals are on the +12 and -12 rails, so it looks like they're 24V bulbs.

Just as well I didn't order a bunch of 12V bulbs and watch them all blow up...

Cheers
Frank

[Studerfreak]

They do not look like the correct lamps, they ARE the correct lamps......
Here we can get these in 50mA and 100mA types.
I think 50mA will do.

[Radardoug]

See if you can get them in 28V, then they'll last a bit longer!

[Dr Funk]

I had a look, and Farnell have either a 3W/125mA, or 1W/40mA available. I think the 1W/40mA is the way to go - hopefully it'll be bright enough. I'm guessing 3W would be far too bright, and 16x3W=48W, which is a lot of power just for meter bulbs!

Thanks for your help - it's very much appreciated!

Frank

[Dr Funk]

Originally Posted by Radardoug

See if you can get them in 28V, then they'll last a bit longer!

No 28V unfortunately - 24V is the highest voltage they have.

Frank

[Studerfreak]

Here we can get 28v/60mA and even 30v/50mA...
How many, including some spares...., would you need ?

[analogtodd]

Hey, anybody have a US part ### mouser or newark or bulbtronics for the 50ma/30v ones??? I'd love to pick up about 50 of those!!!!

[Dr Funk]

Originally Posted by Studerfreak

Here we can get 28v/60mA and even 30v/50mA...
How many, including some spares...., would you need ?

I'd need about 20 including spares.

Frank

[Dr Funk]

Actually, best make it 24 - then I'll have 8 spares, which should last for a long time, especially if the bulbs aren't available here in Ireland. Where can you get these? Do they ship to Ireland?

Cheers
Frank

[analogtodd]

I just looked at mine tonight and they are 35 or 36v (can't quite tell) at 50ma

[Studerfreak]

Probably 36v/1.8w = 50 mA.

I think these are still available here and will check.

[Mixermend]

The modified 'wire end type' lamp in your Flickr photo looks like a LED to me - but if so - must have a dropper resistor somewhere surely?

If it has been modified to use LED's - it would seem that the previous user had got fed up with changing lamps?

[analogtodd]

I've considered the LED route... recently did that to my MCI power supplies and it was fun. I don't know if I'd want to do 24 meters though, but you never know.

I found a couple options from bulbtronics.com

TA 7123-00-024-050 | TAUNUSLICHT | Incandescent

Thats a 6000h bulb and you can order in multiples of 10

BT B22.024.050 | BULBTRONICS | Incandescent++++

Or that one, its cheaper @ 78cents, but its in multiples of 100 and its only a 2000h bulb

[Studerfreak]

Are 24Volts, not 36Volts.....

[Dr Funk]

Any update on ordering these bulbs? I have to place an order with Farnell here, and I've been holding off until I know whether or not to include the 24V 40mA bulbs they stock. It would seem that 36V 50mA would be ideal but I can't get them here.

Cheers
Frank

[analogtodd]

Originally Posted by Studerfreak

Are 24Volts, not 36Volts.....

Yup. But guess what the original rating is? 24v I assume someone stuck 36v lamps in because thats what they had.

According to the actual Studer documentation:
Bulb 24V 40 mA / BA 7S

[Dr Funk]

Originally Posted by monkeyt

Yup. But guess what the original rating is? 24v I assume someone stuck 36v lamps in because thats what they had.

According to the actual Studer documentation:
Bulb 24V 40 mA / BA 7S

Ha - good find! thumbsup I searched the A80 manual again for 'bulb' and sure enough it's there (section 5, p104) - "VU meter bulb 24V/40mA".

Thanks for finding it! I'll get them from Farnell tomorrow.

Cheers
Frank

[Dr Funk]

The Farnell bulbs arrived today, and I started by replacing the failed bulbs only. I was expecting to have to replace all 16 for consistency of light level, but the illumination from the new bulbs is identical to the existing wire lead bulbs, so I'm happy now, I have a full complement of illuminated meters, and I'll just replace the rest as they fail...

Thanks for the help!
Frank