Vintage Diamond?

[norm]

Six or seven years ago I puchased a Scully Lathe off Paul Mcleod "A very close and personal friend of Rick"'s, I understand he was allways trying to get behind him to advance his career." Anyway back to the story:- Two days ago whilst moving into the new shed I decided to open the boxes they arrived in.

Box one turned out to be the electronics and they are valve/tube driven. Out trundles this wood grain box full of blue panels, black knobs and big dials. Ok looking but not exciting so I trundle it over to the space I had earmarked for it, flipped it around and to my suprise there was a dirty great tube limiter and power supply. I could feel the blood pooling and the excitement rising. Having handled a small semi of tube limiters this one stopped me in my tracks, what the f### was it? There were no names and no faceplate. She used 13 Tubes and a load of tin can things. Going back to the packing in the box I found a blue face plate with the following engraved upon it. 2GB Type 5, Peak Limiting Amplifier, Serial # 1. No information anywhere to be had so far and a new job comming up for Rob.

[Sammas]

Norm! You sure know how to dangle a carrot in front of a rabbit.

We need photos!

I thought you were going to mention 6... 7.... 0... for a moment there. Wouldn't that be a nice surprise!

[rick]

well what can i tell you norm
anything that creep sold you cost too much and is worth too little

but he is a smart waste of humanity so it was probably quality ,

i cut my first record on that lathe..
i have no recollection of a limiter attached to it ,

i had to worry more about my young personal safety at that point in time

you see i opened up on this thread thinking i was getting a chance to admit i have neil diamonds greatest hits in my car at the moment and i love it ..

thread titles norm
thread titles

[wez]

Is this the same Paul Mcleod that was selling Leslie cabinets by the dozen on ebay a few years ago?

[rick]

The same

[norm]

Ah Leslie cabinets, I ended up with three from him. That is another thing I will be sorting out soon, I will have 3 or 4 to get rid of and before you all start pming me there will not be any spare tube models but some tall boys and some others.

[wez]

Ahh ok, that explains one or two things.

[Chris H]

Nice one Norm.
Some photos and more info would be cool.
So is the brand of this limiter "Scully" or is it "2GB"?

.I think the 2 GB might refer to the radio station in Sydney.........?......

.......come on you gear detectives!!

[rick]

Norm doesnt mind letting us just imagine His stash ,
my mental picture of it ( and i have never seen it ) just kept score
Is riduculous

We were talking rolls royces the other day - who else am i going to be doing
That with in this game ?
It seems he has a silver shadow in the shed as a spare parts
Car if the other one he never drives has a problem one day !

When i eventually get my 1969 park ward coupe and my unicorn
I cannot concieve of the ridulous stereo i am going to put in it
But a few of those spare leslie cabinets mightnt go astray norm !

Give the kids a photo uncle norm
Stick it next to your two fairchild 670 limters just for giggles !

[Alastair Reynolds]

OK , detective hat on here.

yes it is likely that the limiter is a custom built unit by 2GB engineers, they built a lot of their own equipment and had a full fabrication workshop at their transmitter site at Wentworth Point, though it is now in a sad state of decay.
A "type 5 " limiter suggests the design is early 60s, perhaps an Australian made copy of the GE-BA7 limiter from the US. The Type 4 limiter (like the AWA G58) was pretty close to a RCA BA-6B limiter. I have a type 4 MkII made by Transmission Products (model 216) circa 1961 which is like the GE-BA7, using a modulated Audio signal at 455KHz using DSBSC (Double Side Band Suppressed Carrier) to apply the limiting to then demodulating back down to base band audio. This technique was used to reduce "thump" .

Now as I've been typing this I've been talking to one of the Engineers from 2GB from the early 60s who used to use those Scully Lathes at 2GB to cut discs when there were a pair of them in the Phillip St Studios.

The Scully Lathes had Westrex Mono heads with feedback coils going back to the amps. 2CH at the time had Neumann Lathes with Stereo Heads. The limiters (as Norm has) were RF style ones made by 2GB and Olive green from memory (he said).
2GB used to cut the mono masters for RCA at the time, both the red seal classics and the 45s, so when a new Elvis 45 came in, usually 3 copies arrived from US , these were dubbed on the Scullys using Ortofon cartridges over to Ampex 350s then a new laquer cut and sent out to RCA's plant for pressing. Albums were done at 2CH the same way but in that "new fangled Stereo".

The Scully lathes were sold by 2GB to someone in St Peters when they were no longer in regular use .

Hope that shed's a little light.
Norm I have a schematic (Coutesy of Rob Squire) for the Type 4 MKII limiter which is probably very similar to the one you have. Send me a return email address and I'll send over a PDF of it.

How is Bunbury looking these days Norm ?
I was born there just about 47 years ago and lived at Capel for 4 years, til the family moved back east.
It's 20 years since I was last down there , but I'll get back again one day.

[Manning]

Wow.

All hail the Master of the Dark Arts.

[Chris H]

Alastair Reynolds
Chief Engineer 2UE - Fairfax Radio Network

Master of the Dark Arts (Broadcast).......
Shirlock Holmes of oz broadcast gear !

[rob]

see, just as I told you Norm on the phone the other day, Alastair would have the inside skinny on that limiter! The circle also seems complete as I may have the schematic of something very close to it! Although the tube line up is a bit different and there seems to be too many in yours, however there could be some design similarities.

[rick]

the scully lathe lived in crystal street petersham in the early eighties run by said creep

[Alastair Reynolds]

No Magic here, just lucky enough to have met and talked to a few of the great broadcast engineers from the golden age of radio when it was more exciting and less corporate BS and all about the bottom line.
like many of the early studios, stuff had to be built locally when it was too hard to bring in from o/s.
Australia had a great broadcast manufacturing industry as anyone with an AWA device or RME, Optro, PKE ,Trimax etc can attest. much of the equipment designed and built here were world leaders (well before the fabulous Fairlight stunned the music world).
There are many old engineers from the old radio and recording days still around, some in their 80's and 90's who can tell some fabulous stories and give brilliant insight into circuits and techniques of yesteryear.
I was lucky enough 12 years ago to have 1/2 an hour to talk to Murray Stevenson when he was 95. He was ,along with his father Cecil Stevenson, the founders and first engineers of 2UE. He recalled building their first 500W AM transmitter and going to Air on 26th Jan 1925 (legally) as a B class (Commercial) station, although they were previously part of the co-op that started 2SB Sydney Broadcasters (now ABC 702)in 1923 and built their 1st transmitter as well. The wealth of knowledge in our "elders" is astonishing. Do youself a favour if you get the chance to have a beer or a cup of tea with one of them and take the time to listen. You'll get more out of that than you'll ever get from just surfing the net.