Who Invented the Diode Bridge Compressor?

[ITHertz]

Hi All,

A little history question for an article I'm working on - who invented the Diode Bridge compressor?

I was under the impression that it was Rupert Neve:

https://www.youtube.com/watch?v=yV6OW0fKIcE

However, I came across this page:

https://www.tab-funkenwerk.org/history-of-tfk/the-u73-history/

which says the following:

The U13 was the next generation of audio compressor. Introduced in the 1940's, it was developed based on the same components and technology as the V72's predecessor and was the first diode bridge compressor ever designed and made.

This would pre-date Rupert Neve's design by at least twenty years.

Was the diode-bridge compressor developed by two companies independently? Anyone know any more about this?

Cheers,

Chris

[Matt Houghton]

Funny that you should mention it: Hugh mentions this in his review of the RND5254 that will appear in the May 2021 issue of SOS. At least he does in the extra box supplied for the online version of the article. Yes, the U13 was the first compressor to use this approach.

[ef37a]

Hey! Does that mean there are thing I don't get for my infirm cephalopod when I buy the paper magazine?

On 'valve' compressors I would thing this is entangled with the development of AGC for radios?

Dave.

[Folderol]

Fascinating read. Although obvious in hindsight, I'd never heard of valve diode compressors. The earliest ones I came across were germanium diode ones - well, drawings for them

[ef37a]

Fascinating read. Although obvious in hindsight, I'd never heard of valve diode compressors. The earliest ones I came across were germanium diode ones - well, drawings for them

I once built a diode bridge signal switch but the levels they can handle are very low. Thank heavens for FETs!

Dave.

[Hugh Robjohns]

A little history question for an article I'm working on - who invented the Diode Bridge compressor? I was under the impression that it was Rupert Neve:

The earliest diode-bridge audio compressor I'm aware of was the Telefunken one, the U13, which was developed for German broadcasters. And it used valve rectifiers as the active devices. Clever people, them Germans...

Neve's 2254 from the very late 1960s is obviously the best known implementation of the idea, but Rupert Neve didn't actually design it himself.

It was one of his employees, an ex-BBC engineer called David Rees who borrowed Telefunken's idea -- possibly after coming across it somewhere in his broadcast career -- and redeveloped it using solid-state circuitry.

I don't believe it was designed independently. Telefunken's concept would have been known about. But I imagine Rees did a lot of original R&D to get it to work with solid-state rectifiers. Allegedly, his first prototype was built using nails hammered into wood as a DIY turret board ... which is believable... although standard turret board was readily available at the time and would probably have been a lot easier to use! So I take that with a pinch of salt.

Rees' first working model was actually issued with the module number 2253 -- infamous the 2254 came a bit later and was a more 'developed' version -- although it evolved further still over the years, with the 2254A, and then later the 2254E which had a faster attack time I think.

There have been lots of variations on the theme subsequently. Neve themselves went on to make the much more versatile and lovely-sounding 33609, beloved of BBC TV Sound Supervisors (amongst many others), and the current AMS Neve company still makes versions of the 2254 and 33609.

But many other manufacturers have taken the core design and either copied it more or less as is, or updated it to remove some of the transformers and improve transformers. Some have re-developed the concept using different types of diode to get better performance characteristics too.

I don't know of anyone that has reverted to using valve rectifiers... but I wouldn't be surprised is some American niche manufacturer didn't offer it one day...

[Hugh Robjohns]

Hey! Does that mean there are thing I don't get for my infirm cephalopod when I buy the paper magazine?

Yes.

When space is tight in the paper mag (when isn't it?) elements of articles deemed not 'mission critical' are often carried on line but not in the paper mag. This often includes things like box-outs of related interesting but not essential info, many of my test and measurement plots and that kind of thing.

Take out a print+digital subscription and you get instant access to it all!

[ef37a]

More expenditure? Maybe next year Hugh.

The "nails in the wood" story is probably true. Where we get the phrase " breadboard layout" from. Early crystal sets were built on varnished hardwood later supplanted by Ebonite a very hard form of rubber then of course Mr Baker came up with his phenolics!

Dave.

[Hugh Robjohns]

More expenditure? Maybe next year Hugh.

Less, actually Dave. The [UK] issue cover price paid in a newsagent is currently £5.99, so £71.88 per year if you buy all 12 issues.

The Print+Digital sub is currently £59, or £56 for renewals. So you'd save over £12 a year... and you'd get more content via the online articles, and SOS would get more income because every stage in the news trade wouldn't be slicing off their own profit margins, and it would flop through your letter box a day or two before it appears in the shops... (usually!)

A sub is better for you, and definitely better for us...

https://www.soundonsound.com/shop/subscriptions

The "nails in the wood" story is probably true.

I remember watching my dad build prototypes this way too, so I don't doubt it was a 'thing'... but it just seems odd to do in a professional factory environment in the mid-late 60s... But I wasn't there...

[Drew Stephenson]

Hey! Does that mean there are thing I don't get for my infirm cephalopod when I buy the paper magazine?

Yes.

When space is tight in the paper mag (when isn't it?) elements of articles deemed not 'mission critical' are often carried on line but not in the paper mag. This often includes things like box-outs of related interesting but not essential info, many of my test and measurement plots and that kind of thing.

Take out a print+digital subscription and you get instant access to it all!

Having a Print+Digital subscription I'm more than happy with this approach, but it would be nice if these articles said when there was more content online. My default is to read the paper and only go to the online version for sound files.

[Matt Houghton]

it would be nice if these articles said when there was more content online. My default is to read the paper and only go to the online version for sound files.

Sometimes they do. Sometimes we don't realise there is extra material until after we've laid everything out and are in a rush to hit print deadlines. Sometimes the very reason things go online only is because we've edited down every last syllable to make the content fit the available print space and there's just nowhere to mention it.

As a rule, a certain Technical Editor who shall remain nameless (but who someone really needs to nominate for a gong, for services to audio education!), often supplies far more material than is commissioned for the print mag — AP plots, internal photos of review gear, the occasional history box, and so forth. Rather than let it go to waste, we'll put it in the App (sometimes) and online (almost always), where it eventually becomes free to read and will sit there in perpetuity to enlighten the World.

Plenty of other authors supply more pictures than we could hope to accommodate in print and these will often also be included in the App and Web editions. But rest assured nothing that's essential to a review or other article is omitted from the print version, other than perhaps audio examples, which should be mentioned along with a short URL.

[Drew Stephenson]

I can understand that, I have briefly worked on print magazine production.
I just hate the feeling that I might be missing something!

[ef37a]

Ok Hugh I get that, maybe later as I say. I still like to patronize the stores though!

Everything is going online and shops are shutting all over the place. My town centre is getting very drab!

I don't suppose I could get the online version for a paltry sum and still keep the newsagents in business?

The 'bread board' might have gone but we still lashed up simple circuits on a bench top. Tack soldering them and holding things down with paper masking tape!

Dave.

[Forum Admin]

I can understand that, I have briefly worked on print magazine production.
I just hate the feeling that I might be missing something!

Drew, you have a Digital sub as part of your P+D bundle so you might as well get into the habit of coming and glancing at the web versions of the articles each month on the MAGAZINE page (click on the Magazine menu button at the top of any SOS page) -- then you won't miss anything.

[Folderol]

The 'bread board' might have gone but we still lashed up simple circuits on a bench top. Tack soldering them and holding things down with paper masking tape!

Dave.

I still do
Mind you, I've got a bunch of 14 and 16 pin chipholders on veroboard with pins for soldering bits to.

[Drew Stephenson]

I can understand that, I have briefly worked on print magazine production.
I just hate the feeling that I might be missing something!

Drew, you have a Digital sub as part of your P+D bundle so you might as well get into the habit of coming and glancing at the web versions of the articles each month on the MAGAZINE page (click on the Magazine menu button at the top of any SOS page) -- then you won't miss anything.

Yeah, but, you know, habits...
And it's not like i visit this site often.

[Hugh Robjohns]

I still like to patronize the stores though!

Yes, me too... but on the other hand, the more income to SOS the longer they can keep me doing their bidding!

I don't suppose I could get the online version for a paltry sum and still keep the newsagents in business?

The standard digital-only sub includes the tablet edition and costs £33 I think... so it would cost you significantly more rather than less.