Custom built for Abbey Rd by EMI using late-1960’s technology. Features mainly silicon transistors in class-A configurations + transformers here & there.

And then there’s those iconic EMI resistor-ladder faders that follow an arc in operation.

Did it really have a magical sound? Maybe, as it avoids the pitfalls of later tech: Low slew Op-Amps with electrolytic output coupling caps running unbiased.

https://www.rollingstone.com/music/music-news/dark-side-of-the-moon-recording-console-sells-for-1-8-million-126105/

And still maintainable today.

It would need a lot of new electro's, and no doubt the audiophiles will complain:
"it doesn't sound the same" because replacement caps are "not the original brand"

There is a discussion about some Russian "oil filled" caps on the American Forum (http://antiqueradios.com/forums/viewtopic.php?f=19&t=349925) And yes I did add petrol by wondering if the signal would go through them faster (and they were not filled with snake oil)

The point is that there is comment on what difference these would make in the sound? Consensus was a wave form etc. analysis was the only way to prove differences.

Some have a habit over there as calling these people "Audiophools", as some will pay big money for some really dubious hyped up stuff.

Marc

I'm always amused when I see ads on eBay for 50 or 60 year old "bumble bee" capacitors pulled out of equipment.

Yeh! That's how transformer's get like the one I posted, in the discussion forum. Actually saw a brilliant effort by a stick welder today, at the Mens Shed. Secondary went to ground & used the earth wire in the cable as a fuse........ Smelly

I've always been of the opinion that if one wants a good sound they should spend their money on better speakers rather than a better amplifier. Quality speakers can make a hell of a difference but any half decent audio amplifier will create sound in the normal human hearing range of 20Hz to 20kHz.

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A valve a day keeps the transistor away...

That I would agree with. I have a home made speaker box, made decades ago, with four speakers 8" woofer, tweeter crossover etc. The difference in sound quality from a rough old Astor JJ chassis wired to it is phenomenal: So really the JJ's audio capability is far far, superior to its original reproducer.

Those (especially guitarists) who pay stupid money for old capacitors, etc, are seeking a recreation the 'tone' of an era long gone. They are not interested in hi-fi as such.

Console replaced valve EMI-'REDD' used for early Beatles recordings:

"..a significant improvement over the 8 microphone inputs and 4 tape outputs of their previous vacuum tube based REDD .51 mixing console. This enabled the studio to replace its 4-track Studer J37 multitrack tape recorder with the 8-track 3M M23. Unlike its predecessors, it had a compressor as well as EQ built into each channel.."(wiki)

However, the musicians/producers didn't like the 'sound' of these solid state compressors and stuck with outboard 1950's-tech Fairchild [not the same as the semiconductor company] compressor/limiters.

This console was said to sound better than the 1950's-tech EMI-'REDD' mixing desk:

"The solid-state TG12345 had a much smoother and brighter sound than the valve REDD.51 it replaced." (MusicTech)

There were still a few 3M multitrack recorders around in the 80's, I worked on a few around here [16-track by then] they had patented 'Isoloop' tape transport. They were more difficult mechanically to work on than the popular MCI multitracks but, luckily for Abbey Rd, probably sounded better as 1970's MCI were criticised for "poor sound due to using many (low slew rate) 741 ICs", in fact MCI issued a Tech Bulletin attempting to refute criticism of the "audible inferiority" of 741 ICs, it made for interesting reading.

1970's MCI were criticised for "poor sound due to using many (low slew rate) 741 ICs", in fact MCI issued a Tech Bulletin attempting to refute criticism of the "audible inferiority" of 741 ICs, it made for interesting reading.

I haven't come across the 741, but the Fairchild uA739C was used in the Playmaster 127 preamp (EA Nov 1969) and that was a very noisy preamp. A mate of mine had it coupled to the Playmaster 128 power amp. The hiss at high volume was unacceptable. Blame was laid on the 739 chip. Some said it wasn't designed for such use. It would be interesting to read that MCI tech bulletin.

QUOTE: guitarists) who pay stupid money for old capacitors, etc, are seeking a recreation the 'tone' of an era long gone.

Thing is, they will not get that 'tone' today, because the old capacitor has gone bad. Maybe there are paper caps inside metal and glass hermetically sealed cans (that keep moisture from the air out) that may give the guitarist the tone they want to replicate?

Motown Records used to use older recording mixers in their studios, probably tube based. They decided to spend the money on artist development, marketing and such, as the boards were "good enough".

" It would be interesting to read that MCI tech bulletin."

The bulletin in question tried earnestly to counter emerging talk about sonic problems [perceived by musicians & audiophiles] with early chips; it was about 4 pages with graphs & references.

-- At the time (late 1970's) IC Op-Amps & capacitors were copping flak from the audiophiles --

"Later the model JH-24 [tape machine] appeared which had inferior sounding electronics and was introduced when Sony bought MCI [in 1982]. It was transformerless and used more ICs than discreet[sic] components." (wiki)

And

"The [MCI] JH-600 series [mixing console] was a totally new transformerless design, including many of the JH-500 features in a more compact frame with automation. They were relatively low priced and many people did not realise just how good this desk was sonically. However many engineers agree that this was the cleanest sounding console of all." (wiki)

I have a JH-600 service manual. Looking at its circuits, I see many IC's using non-polar electros for signal coupling - except at the transformerless Mic input where positive side of polar caps face the XLR connector (fair enough when phantom power is present I suppose.)

Also have a folder of service bulletins for their various 1970's products. One bulletin advises doubling value of many coupling NP electro caps for "improved sound".

Another interesting bulletin (quoted below) advises replacing early type 741 & 748 Op-Amp chips with TL081 & TL080 IC's:

"Product: 500 Series Desk
Bulletin No. 544-A
Date: May 6, 1977 ...
Reason for change: IC type change for improved performance" ...

This would appear to somewhat contradict their paper defending the 741.

Just took a look at MCI/Sony campus (1400 W Commercial Blvd, Ft Lauderdale) on Google. Naturally they are gone from there. Let's hope Sony sold it in the midst or aftermath of the severe 2006-2009 recession when Florida real estate collapsed - looks like they did, as the sprawling property is now held by the County! It's good to see Japan's greed and vaulting ambition rewarded with hard-learned lessons (again and again!)

QUOTE: I'm always amused when I see ads on eBay for 50 or 60 year old "bumble bee" capacitors pulled out of equipment.

Thanks for mentioning this - was not aware that these are desirable to the fanatics - as am about to sell two McIntosh C-8 units (1955) which I see are loaded with those striped black caps - would have thought they'd be a liability - but will now tout them and show pictures on ebay listing!