Retro Instruments Powerstrip Recording Channel

http://www.retroinstruments.com/powerstrip.html

* Classic British variable-mu tube compression. ?????

you mean the altec wasn't made in the UK?    :

Looks very nicely built but for 3K I'd want a comp in/out switch and separate preamp gain control.

"At the end of World War II, with Europe flattened and the rest of the world's industry scattered to the wind, the world's leaders set up trade agreements which lasted well into the '60s. Different countries worked in different areas of expertise. The Indians would make the rubber, the Americans made the tyres. Meanwhile, Australians produced whatever they could (usually wool and wheat). But in one very interesting electronic trade agreement between America and Australia, amalgamated wireless A.WA and R.C.A America figured a good use of resources was that America would make one kind of vacuum tube and Australia would make another. Both countries would label the tubes as if RCA made them all. RCA made most of the world's vacuum tube amplifiers (ie the gain stage) and AWA made more complex power and radio types. Some bright spark in AWA Sydney Australia invented a radio tube whose output could be varied depending on a sidechain circuit within it and created the vari-mu tube. This is interesting because when applied to RCA gain circuits (and with a bit of trickery), hey presto you have the makings of the best compressors/limiters ever heard. If you've ever heard a Fairchild limiter or a RCA BA6 that's the sound of an Australian vari-mu tube pumping away..." Rick O'Neill, Audio Technology

Think Vari-mu is a hybrid aust/usa thing... not english afaik.

M

Wow, that's totally wrong; pure misinformation from Rick O'Neill.  Was that in the April edition, by chance?   Vari-mu predates WWII entirely, with the necessary tube types coming long before.  

Agreed on the Retro; British?  What the F are they talking about?    

Thats interesting, so what is the history of the vari-mu?

Not sure which edition...
http://www.turtlerockmastering.com/at_i18.html

I don't know the details but variable mu tubes were invented so that AGC could be applied to RF and IF circuits. Audio apps came later.

Cheers

Ian

I knew THEY were cheating on us.
The big post-WW2 tube conspiracy.
At last someone has dared unveiling the FACTS...

. . . .erm . . . . EF8, EF11, EF13 anyone . . . .european and pre-war for sure. There must have been earlier vari-mu tubes than . . .

Aren't they simply implying they based this particular moo on something british, say something emi?

Did EMI have vari-mu comps?
Abbey Road's first documented compressor was a modified Altec 436, dubbed RS124.
It could be that Retro have use the RS124 as a template for their channel strip's comp.
Calling it a classic British comp takes some creative imagination...

Don't forget we're in pro audio la la land. Of course they'd call the rs124 british.
There's the rs114 which I would assume is a vari-mu. But that one's huge, so the only one you could fit in a channel strip is the rs124 I suppose.

The RCA (2)34 "Super Control" tube appears to be 1930.  RCA 96A vari-mu limiter using 6K7 issued commercially in the fall of '37, and RCA/NBC in-house units in use for several years before 1937.  All documented in trade literature of the time.  The 6K7 is a rebasing of the 1933 78 tube. 

abbey road d enfer said:

Did EMI have vari-mu comps?
Abbey Road's first documented compressor was a modified Altec 436, dubbed RS124.

Click to expand...

Abbey Road had Fairchild 660's before the Altec's. It has been claimed that the timing
modifications to the Altec were to mimic the 660, although I'm not sure how accurate
that is. The RS124 is a beast of a limiter all on it's own.

Mark

My source is "Recording the Beatles", and, just because the RS124 appears before the Fairchild, I assumed it was there before, but you are right, the Fairchild was used before the 436/RS124.
But in fact, it appears EMI had designed an RS114 limiter, which was apparently the first dynamics box at AR. So maybe this is what Retro considers the "classic British". Not much more preposterous than Oram claim at being the "father of the British EQ".

6BC8 and 12AU7 would imply something 436-ish perhaps.

So I sent em a mail(gasp) and they say it's a modified 436, which makes the term 'british' even weirder.

Dear lord...

Me: Seeing that you were using the 6BC8 the 436 was my guess, but why then call it british?
Retro: Because it makes your recording sound classic British.

There we go!

abbey road d enfer said:

My source is "Recording the Beatles", and, just because the RS124 appears before the Fairchild, I assumed it was there before, but you are right, the Fairchild was used before the 436/RS124.
But in fact, it appears EMI had designed an RS114 limiter, which was apparently the first dynamics box at AR. So maybe this is what Retro considers the "classic British". Not much more preposterous than Oram claim at being the "father of the British EQ".

Click to expand...

I think it is important to remember that both pre and post WWII the UK pro equipment market was quite different to that in the USA. In the States there was a huge local radio industry that wanted to get the maximum coverage within their licence limits so lots of compressor/limiters were developed. At the same time in the UK there was no local radio or TV network and the only broadcaster was the BBC. Big UK studios like EMI, Pye, Decca etc were all part of large electronics companies and so made much of their gear in house and did not sell it outside.

So it is possible that there were several British vari mu designs but few if any escaped into the wild.

Cheers

Ian

I think I read somewhere that John Oram invented the Vari Mu, around the same time that he invented compression. 

Emperor Tomato Ketchup said:

I think I read somewhere that John Oram invented the Vari Mu, around the same time that he invented compression. 

Click to expand...

That cannot be possible. He was born in 1949 - he's only a few months older than me.

Cheers

Ian