Friday, June 23, 2006

Grampian Ribbon Microphone - With Crumblies


The Grampian Ribbon is similar in construction to a Reslo, and has the ribbon frame which can be positioned, a bit, within the confines of the magnet assembly. This is a fairly conventional setup with two horseshoe magnets and tapered pole pieces defining the magnetic gap.

The Grampian looks larger in photographs, and has a sculptural aspect, but is rather smaller than one would expect and therefore not very impressive when seen "in person". The transformer (not shown) is an EI type with a low Z output. The cast potmetal base and frame are well executed and nicely finished, and the recessed blue metallic label has a simple but good look to it.

This picture was shot right after we opened this ebay purchase up. The crumbly bits are a reminder of what happens to most polymers over a long time, which is why we avoid them in our mics. Only certain polymers have the stability needed for a planned 50 year service life, which we learned making medical devices and doing accelerated aging studies. That's why we can predict such long service lives for the Crowley and Tripp mics.

I love the name. Grampian. So English, stodgy, appropriate.

12 comments:

rooster said...

Fascinating to find your picture and comments courtesy Google. I was searching Grampian, in particular GR2. In about 1965, then a tender seventeen year old, I started on what turned out to be a lifelong interest in sound recording by purchasing two GR2's. I even lovingly constructed a leatherette covered box to house them since they came in rather bulky blue cardboard boxes. Recently they showed up in a long forgotten cupboard, still looking like new! I hope to try them out in my studio soon and see if time has got the better of them. I will let you know if the crumblies have struck.

rooster said...

Fascinating to find your picture and comments courtesy Google. I was searching Grampian, in particular GR2. In about 1965, then a tender seventeen year old, I started on what turned out to be a lifelong interest in sound recording by purchasing two GR2's. I even lovingly constructed a leatherette covered box to house them since they came in rather bulky blue cardboard boxes. Recently they showed up in a long forgotten cupboard, still looking like new! I hope to try them out in my studio soon and see if time has got the better of them. I will let you know if the crumblies have struck.
Nick Sykes
Rooster Studios
London

Bob Crowley said...

They have a wonderful shape and are very handsome microphones. I like the gold ones with the one black rear grille. The blue metallic label is a nice one.

Clean out all the foam and if you must have a cushion, replace it with cotton which lasts much longer. The Egyptians figured that out some years ago.

rooster said...

Thanks for the cotton tip, I hadn't thought of that and cut up an old mic shield!. Since my last post I have tried my two GR2's and they do sound great after I removed a large amount of crumblies and resoldered the connecting wires which had broken. VERY low output though, so since you are the guru's of such esoteric high end ribbons, I wondered if you had a favourite pre amp that would give them the ooomph they need to compete with today's horrors. Historical note.
GR2's were made by Grampian Reproducers in Feltham, West London and I think I paid about £17 10 shillings for mine each in 1965. Mine have a red metallic ring to denote low Z 200ohm output.
I have two spare connectors by the way!

Bob Crowley said...

Excellent!

Let's see that red metallic ring. Also thank you for the manufacturer's information - I have hopes of finding an image of Grampian if there was ever such a person.

Your magnets may have weakened over time. Nonetheless, a low noise preamp with clean gain is probably in order. True Systems makes a Solo P, Grace Brothers make a very low noise preamp, and of course Great River has a preamp (with a bit more tone to it) with a healthy dose of gain. You might also consider making a little preamp for your preamp. Avenson Audio has a circuit that is a simple low noise preamp that might be suitable

rooster said...

I have taken some photo's of my GR2's for you, now all I need to do is to work out how to post them! Thanks for the pre-amp information, very handy. In the photo's is the box I built age 17 which is very rough but has done it's job of protecting them ok.
Grampian is a strange name I agree, I don't think there is a Mr Grampian, I suspect the founder of the company might have been Scottish since there is a range of what we British laughingly call mountains in Scotland called the Grampians. There is also an Art deco block of flats near me in Shepherd's Bush, london called The Grampians,perhaps he lived there!

Anonymous said...

I wonder if you got the photo's of the GR2's attached to an email to your company ? Anyhow I am sure you may already have looked at the following links but in case not here are two sites I found treading the same area. http://www.omnipressor.com/Other/www.zebra50.com.
Some very nice pictures and information although I am not sure who the author actually is! The other link is
http://www.historyofpa.co.uk/gallery/APAE/gallery_apae.htm
and is related to the APAE site, a British body of public address engineers and there you will find reference to one A.R. Williams MC. of Grampian Reproducers Ltd., who was their first chairman...so now we know.
I promise no more convoluted development of this blog!

Bob Crowley said...

I saw those websites and the history of the PA site. Great stuff!

I did NOT see any pictures in your email and I do not see an email address from you.

Try again?

rooster said...

Sorry for the pause, I've been away.
My email is roosteraud@aol.com and if you let me know a return address I will certainly try to send those pics again
Regards

Anonymous said...

Hi

I just found my old grampian GR1/L in the loft and I'm wondering if it still works. It worked about 20 years ago and sounded pretty good. Re the the disappearing foam inside when you say replace with cotton do you mean cotton wool or something else?

Bob Crowley said...

Cotton wool should be fine, though cotton gauze may provide fewer loose threads, thereby lessening the chance that something can get into the works.

Cotton last a very long time, is stable, and retains its flexibility. It won't support mold unless it is very damp, and it is suitable for use in microphones. When packed loosely, it works as a rumble filter with little loss of high frequencies.

TheLoneRoger said...

I recently found a pair of 600 Ohm GR1/M's at work and have started to restore them. I found the perfect thing for replacing the disintegrating foam - a panty liner!
I cut off the plastic backing and placed it with the weave facing inside and it was just the right size.
I'd be interested to know where you could get the connectors from. I'm guessing you could bodge something up from an old 2-pin DIN speaker plug, but it would be nice to find the real thing.
Looking forward to testing them soon...