EMI 806 mic amps (REDD style)

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6 days 13 hours
Submitted by Anonymous on Tue, 07/29/2003 - 11:52

a friend of mine brought me in a couple of these funky 60's ex abbey road pre's today for restoration- theyre a bit similar to the redd47 line amp in construction, but the circuit looks different- ill be tracing out the schems for them over the next coupla weeks, will post them when done.... they look well cool- little magic eye level meters, in a red cartridge, same size as the V-series.... one ef86 and an ecf80....

of course, if anyone knows anything about em or has any docs, please share...

rich

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6 days 13 hours

Hollowstateman

Tue, 07/29/2003 - 13:26

Hi,
Is it RS.806? I do know that the REDD.47 was also named the RS.812 (I think that's the right #) but I've never heard of an 806.
Before Abbey Road installed the REDD.51 console, with its REDD.47 amps, I believe there was an attempt to make amplifiers that fit in place of the V72S' in the REDD.37 desks. Maybe that's what you have? It's interesting stuff. Can you post a picture of them?

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6 days 13 hours

ANDY LAWRENCE

Wed, 07/30/2003 - 05:01

Hi
Some time ago I had 14 of these amps eminating from an EMI desk we retrieved from Gateway Studios London,back in the mid 80's
The desk had 14 chanels each one with an 806 and a passive HI LO equiliser(very nice soft eq).The desk had been modified with solid state summing amps etc.The faders were dual chanel contant impedance type made by Elcom.These are works of art those guys new how to use a hot stick !
I sold most of the amps and eq's about a year ago to various people in the London area.
I was not over impressed by their performance but they had nice I/O trafos.I had a circuit diagram that I may be able to find.It is pointless contacting Hayes they have never heard of them !
IMHO the best thing about the 806 is that it's bloody rare!
I have some pics of most of the equipment together with a BTR2a (stereo) and a BTR4.if your interested.

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Shalimar

Wed, 07/30/2003 - 10:13

Sounds funky, synthpunk! I'd luv to see pics of those and the gear you mentioned Andy..

Beam it to of at shalimar dot dk

Btw, any of you folks know anything 'bout BBC trannies? They got a bunch at Canford..

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Morpheous

Wed, 07/30/2003 - 10:25

I have one of those BBC trannies. Canford are selling them for £40 a go. But I got mine from a surplus supplier for £6.5!!! And they've got more if anyone wants one.

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Shalimar

Wed, 07/30/2003 - 10:36

Aha! I'll just go look in my Canford catalogue ('nother case of a useless website!), but I seem to remember them being rather odd looking with odd ratios etc. Perfect!

What model# have you got? And where do I buy them?

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thermionic

Wed, 07/30/2003 - 13:49

A respected designer I know has a stash of the round black BBC trafos and rates them highly. He recently re-designed a linking adaptor for a vari-mu comp for me and used St Ives instead of the BBCs 'cos he said they were too good!

Hey Morpheous, where are you getting them from?
£6.50 ? Very nice!

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6 days 13 hours

Mark Burnley

Wed, 07/30/2003 - 18:01

[[url=http://[/URL]="http://www.distel.co.uk"]This may be the place....[/]="http://www.distel.co.uk"]This may be the place....[/]

(In a voice of mystery...)

;)

BTW, I got a Canford "Summer Sale" brocure today. In the "Bargains" section, it cryptically mentions an AKG 12-pin female (?) connector, list price £70ish, "sale price" is £3

Could be useful to someone :eek:

...I've seen those BBC trannies in Canford. I think I'll e-mail their Tech Support for further details.

Mark

--------------------------
"Oscillators don't, amplifiers do....."
Anon.

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Shalimar

Thu, 07/31/2003 - 02:41

Didn't someone here just ask for that very connector recently?

Special Agent Burnley, report back to HQ!

We _need_ BBC trannies..

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Tommytones

Fri, 08/01/2003 - 10:58

I used LL88 ASC at the front of my SSL comp and they sound great. Very performant. The 76 is a little smaller in size but I would wager to be very similar in performance.

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6 days 13 hours

synthpunk

Fri, 08/01/2003 - 11:33

right... my internet access is buggering up (again!), so i might not be about much over the next week, but ill borrow a camera and post some piccies of the two amps when i can.... theyre pretty hammered, but i reckon theyre saveable... any schematics would be a real plus, otherwise ill draw a new one as i go....

rich

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9 years 9 months

Russell

Sat, 07/09/2011 - 17:39

I helped with the design of these mic preamps the 806 and the line amp 805, also its powersupply system and Studio feedback amps. I amade up all of the protype metalwork and electronis for them in 1958 and 1959 at EMI of Hayes in the Studio Sound section with P. D. R. Marks who had come from Marconi to work in the EMI STUDIO SOUND of Research Engineering and Development at Hayes. I still have two sets undrilled prototype cabinets for them that I made up in the laboritory, as the workshop said that the front panel and chassis with the runners was impossible to make, Marks asked me if I would attemt to make up one, so I set to and made ten of them!

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9 years 8 months

BrianK

Wed, 08/10/2011 - 12:16

Although most people assume an EMI name means Abbey Road - that was just one of dozens of EMI studios around the world; Abbey Road became the most famous. EMI built a lot of stuff that went to these studios. In some cases (like the BTR2 tape machine) they sold things to the BBC and other parties.

These were designed NOT for EMI studios but as "for sale" to outside studios. From what we can tell, these "maroon" 806 modules are the ones from Joe Meek's former Lansdowne Studios in London, circa middle 1960s. At the time, they said Joe had ordered a "purple" desk, but if you see the modules, they're really more reddish/maroon. Many people have these now. The EMI "BRED" desk was used at Lansdowne until about 1970.

Don't confuse these with REDD designs (which are much sturdier and generally higher quality). REDD and RS items were built for EMI's own studios and these were from a division called BRED that was make products to be sold to outside firms. Much of this detail is in the [="http://recordingthebeatles.com"]Recording the Beatles[/]="http://recordingthebeatles.com"]Recording the Beatles[/] book, although the Joe Meek info is not, there is a [[url=http://="http://www.amazon.com/dp/1931140081/?tag=recording.org-20"]book[/]="http://www.amazon.com/dp/1931140081/?tag=recording.org-20"]book[/] on his life and gear, too. It's not very detailed, but it's all we have for now.

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9 years 8 months

Brian_G

Thu, 08/11/2011 - 01:48

Hollowstateman, post: 318592 wrote: Hi,
Is it RS.806? I do know that the REDD.47 was also named the RS.812 (I think that's the right #) but I've never heard of an 806.
Before Abbey Road installed the REDD.51 console, with its REDD.47 amps, I believe there was an attempt to make amplifiers that fit in place of the V72S' in the REDD.37 desks. Maybe that's what you have? It's interesting stuff. Can you post a picture of them?

I don't know where your information came from but it's wrong, the REDD47 was never named an RS812.
RS numbers finished at RS175.
There was a proposed design for solid state amplifiers for the REDD 51 but they never happened.
There are also solid state versions of the V72 but they were not used by EMI.

These 806 amplifiers do not come from either REDD or Abbey Road, they were manufactured by the Broadcast Equipment division of EMI (BRED), which was a separate department. Although the mechanical construction is very similar to the REDD47 they are different in their power requirements. The REDD47 needs 6.3V heater supply and 380 volts smoothed DC, the 806's take 325v AC and rectify and smooth it inside the unit. They are not interchangeable with the REDD47, nor were they intended to replace them.
Interestingly, Joe Meek had an EMI desk which used these 806 amps. This was a custom order and has sometimes been described as painted purple. In reality the colour was a sort of dark maroon and some of the amps from it are still around.
Here is one.

 

This is the type of console they were originally used in.

 

Regards,
Brian.

Attached files

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Brian_G

Thu, 08/11/2011 - 02:24

Russell, post: 373820 wrote: I helped with the design of these mic preamps the 806 and the line amp 805, also its powersupply system and Studio feedback amps. I amade up all of the protype metalwork and electronis for them in 1958 and 1959 at EMI of Hayes in the Studio Sound section with P. D. R. Marks who had come from Marconi to work in the EMI STUDIO SOUND of Research Engineering and Development at Hayes. I still have two sets undrilled prototype cabinets for them that I made up in the laboritory, as the workshop said that the front panel and chassis with the runners was impossible to make, Marks asked me if I would attemt to make up one, so I set to and made ten of them!

Very interesting.
In the course of my research I have always been confused by the number of different departments at EMI that were building mixing desks and recording equipment. Your post makes things even more confusing, since I had never heard of a "Studio Sound" department as a separate division, despite the fact that the 806 amplifiers are marked "EMI Studio Sound".
I've also never come across a "Research Engineering and Development" department.
REDD was Record Engineering Development Department and EMI Research Laboratories was a separate department who worked in various areas, not just recording equipment. REDD was closed in about 1964/65 and EMI Research took over further mixer development, resulting in the TG12345 in 1967, although there are some TG numbered circuits in the REDD51, which were modifications to the original design.
Neither REDD nor EMI Research manufactured equipment for sale outside of EMI, it was all for the company's own studios.
BRED (Broadcast Equipment Division) was a commercial department, who manufactured equipment for sale to people like the BBC and IBA.

I find it very strange that "the workshop said that the front panel and chassis with the runners was impossible to make" since the mechanical construction of these is virtually identical to that of a REDD47, which were produced in quite large numbers.
I had often wondered, because of the mechanical similarities, if there was an exchange of information between REDD and BRED.
I wonder if you know which came first, the 806 or the REDD47?
I have always presumed that the REDD47 was designed by Len Page of REDD. As far as I know, the first REDD47 were produced in 1958.
Are you saying that P.D.R. Marks designed the metalwork for the 806, or did the design come from elsewhere?
How does this fit with the dates you have for the 806 production and do you have any idea how many were produced?

Regards,
Brian.

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9 years 9 months

Russell

Thu, 08/11/2011 - 23:45


Dear Brian

Thanks for reading my entry in "RECORDING ORG" on the 806 mic preamp

During 1953 to 1959 I was employed at EMI under their training scheme at EMIED, EMI Engineering Development. We trainees worked in different laboratories for 4 month sessions, or if we were required to do so this was sometimes extended by a further 4 months.

I did know Dr Dutton
I did a lot of of early stereo experimental work during my 8 months in Dr Geoffrey F Dutton's Tape laboratory in the Research Building.
I designed and manufactured a special switching unit (including the wafer switch) which enabled Geoffrey to demonstrate at his lectures on Stereo the different complex sounds that were available from the two channel source from a stereo recording, with just a simple rotory switch giving following
Stereo to both channels
Sum (Left plus Right = mono) both channels
Difference (Left minus Right = stereo information) both channels
Left only
Right only

The above selected onto either
Both channels
Left only
Right only

We also made up all of the special motor/generator equipment to operate the recording machines from car batteries to record trains on Hayes station for the EMI stereo Demonstration disc.
Peter Dix (who came from Goodmans Loudspeakers) also worked in this lab, where we made up the monitor loudspeakers for the studios at Abbey Road. These were powered by Leak TL10 amplifiers that had special feedback applied to enable the cabinets to be individually equalised for a flat response.

Philip B Vanderlyn also was in this section, where work was being carried out to attempt the job of sending out stereo information on FM radio without using the GE multiplex patent. Peter was trying to steer a mono signal using the difference channel information, but the results were not really that impressive.

Henry A M Clarke was in the EMI International Division, I was there for 8 months.

BED under Felix Trott
When I joined the Broadcast Equipment Division (which covered Television and Audio) in 1958 to help with mic preamp design under Philip P D R Marks in the Studio Sound section, we were not only were designing the pre-amp to replace the Seimans Halske V72 and the new desk , together with the Studio Talk Back Amplifiers, but we were fitting out a complete mobile van for the Australian Broadcast Company. I believe the mixing desk that used the 806 series went into the van first, and then when being specially painted for Joe Meek at Landsdown Studios (to record I believe Acker Bilk initially) in Red, instead of the normal EMI green. The studios naturally had them to try out initially.
The 806 mic amp went out as EMI Studio Sound whilst I was there.

When Marks asked me to move this huge outside broadcast vehicle, I stated it should have some windows in the sides of left and right foot wells, to enable safer manoeuvring. So Marks asked me to cut out the sides out and make up some curved formed Perspex clear windows. This was possibly the first vehicle to have these side observation windows.

As regards to Philip P D R Marks, he designed the 806 completely from scratch as well as the drawings for the cabinet. I did all of the prototype metal work, which was before the REDD. In fact, when we wound the special input and output transformers, we did not want our competitors to cut through them to see our special windings layout, so Marks had then potted not only in Araldite, but with very fine sand added to the mix

In actual fact, it was quite a task trying to improve on the V72 specification initially, but we managed it and produced a very low noise pre-amp for that time, with good bandwidth and transient response.

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Brian_G

Sat, 08/13/2011 - 03:19

Hi again Russell,

This is such an interesting subject to me.

I too was an EMI Apprentice, although from a slightly later era.
I joined Hayes in 1962 as a "Student Engineer" and we did a day release course (ONC then HNC) at Southall Technical College. I too, went through the 4 months rotation through various departments, although my chief interests were sound recording and reproduction. I'd been building amplifiers and tape recorders when I was at school, mainly from designs published in "Practical Wireless" magazine. After I finished my Apprenticeship I managed to secure a job in the tech department at Abbey Road, where I worked for over 30 years.
Since leaving Abbey Road I have continued to work as a frelance tech, specialising (for obvious reasons) in old EMI equipment.
I met the other Brian posting here (BrianK) during the course of he and his partners research for their book entitled "Recording the Beatles" and I have continued my interest in the subject of EMI's audio history. In 2004/5 I landed the job of restoring the EMI REDD51 mixing console that was originally in EMI's studio in Milan.
One of my other customers has a rack of the 806 Mic amps which started this discussion thread, although unfortunately they are in storage and I do not have access to them at the moment.
You mentioned a number of names from Hayes, some of whom I also knew.
Dr Dutton's department that I knew was actually EMI Research Laboratories, who developed the TG12345 transistorised mixer (1967), that replaced the REDD consoles.
The designer of the TG desk was Mike Batchelor and some of the other people I knew from that project were Mike Terry, who was in overall charge of the TG development, Gerry Kelly, Don Paine, Katie Phillips and Dave Browning. Other members of Research included Peter Dix, whom I knew very well although he was involved with speakers and microphones. He used the large anechoic chamber located next to the Research building. Another name from Research was Reg Willard. EMI International was run by Wally Rand.
I wonder if you recall any of these people?

REDD was formed under the auspices of Len Page in 1955/56 for the purpose of developing stereo recording equipment for use within EMI's studio network. One of the first REDD products was the REDD17 (1956) which was developed in conjunction with EMI/Electrola in Germany, and used the Siemens-Halske V72 amplifiers.
I was interested by your statement that the 806 was developed to replace the V72. Was this for a specific console or just as a general purpose amplifier?
The V72 is not specifically a Mic amplifier like the 806, and is really a fixed gain modular "building block" that can be used in a number of ways.
I'm not really surprised you could not match the V72 since they are a masterpiece of miniaturisation, particularly integrating the power supply in such a small package.
The REDD47 was the REDD replacement for the V72, but it was not as reliable, although the performance is really good. Keeping up with replacing the EF86 first stage valves can be a bit of a chore since they go noisy with boring regularity.

I was going to send you a personal email to discuss these things further if that's OK with you.

Regards,
Brian.