Who is interested in vintage PA equipment (Public Address)

[Lucien Nunes]

PA is arguably the least admired side of vintage audio. It's true for modern equipment but perhaps even more so for vintage. Domestic reproducers are cosy, HiFi is shiny, stage / music amps are glamorous but PA is just tinny.

The equipment is endangered for multiple reasons. None is to be found tucked away in granny's loft. It lurks in larger and public buildings that tend to be upgraded by contractors working to specs, who skip the redundant column speakers and perhaps flog the amps. When those come onto the open market they tend to be snapped up by hackers and modders and converted into guitar amps, regardless of the history or significance of the original PA amp. I have seen horn speakers re-purposed as lampshades. Does even one large (>250W) site-wide valve system survive complete in the UK? (Think Butlins camp install)

Some might know of the collection put together by the late Ken Yaxley of Norwich. Thankfully that survives and will be part of MEET, and very nice it is too. But it is not yet my any means comprehensive and needs TLC and development going forward, so I am testing the water in this thread to see who might be interested in that. To shake the most obvious trees, I wrote a news article for the ISCVE (Institute of Sound, Communications and Visual Engineers, successor to the Association of Public Address Engineers) but it has not so far produced any fruit.

As far as making noise in another way is concerned, I am planning a stunt to cover as large an outdoor site as possible with original purpose-made valve and valve-era PA... but more on that later.

[trobbins]

Wishing you the best in your endeavours Lucien.

Australia typically manufactured its own PA systems. The largest known PA system is described in the attached brochure, which alas was parted out many decades ago. Apart from that assembly, single PA amps typically surfacing nowadays are limited to 100W from a few manufacturers, although the range under 100W was quite extensive, including down to 8W portable shop combos and a wee 5W unit.

[Diabolical Artificer]

I had a load of Tannoy horn's in the Eighties from an old outdoor swimming pool, I remember as a youth furtling round several factories and ex public places around the Nottingham area and seeing old PA horns and amplifiers,most of which had been smashed up already. If any gear did survive valves were looked down on in the Eighties and further, I remember buying several Sound City PA amps in the nineties for peanuts and offering them to local music shops who told me in a sniffy way " the valves would all need to be changed, it ain't worth nothing" Marshall valve amps could be bought cheaply too. Inna nutshell vintage valve gear and PA in particular was looked down on as rubbish.

I tried to buy a massive Tannoy PA amp/radio a few years back but this never came to anything. It stood about 5 foot high ish and needed a pallet to shift it. It may still be in a shed somewhere but I've lost all correspondence and have no idea how to get back in touch with the seller.

Andy.

[wd40addict]

Doing my bit here: I have a pair of Sound City PA amps. One is the ST-50 with 2*EL34, the other is a PA120 with 6*EL34. However I have redesigned both to take full advantage of the quality of the Partridge transformers. Despite its name the PA120 will give a full 150W output so Sound City were underselling themselves here!

I bought the ST for £20 before there was much interest in this stuff. The PA came later and had been mugged of its EL34s.

[Station X]

I restored this MagnetaTime PA Amp a few year ago:-

https://www.vintage-radio.net/forum/...d.php?t=126359

[woodchips]

Must be any number of the Vortexion Wimbledons around, and what is the difference between that an a guitar amp?

[Lucien Nunes]

There might well be, and thanks to the large production numbers a few might survive unmodified well into the future. But that's the easy bit.

Take these installations for example: http://www.butlinsredcoats.com/radio.html - anything extant?

How about those little vertical-throat 360° dispersion horns, once hung from so many ceilings train platforms. How many are in people's vintage audio collections?

Does any of this matter?

[Hartley118]

I grew up about 2 miles from Doncaster Racecourse, and was impressed as a youngster that I could hear the announcements and commentary when the wind was blowing in the right direction. The clarity and range of those 1940s horn speakers always intrigued me. In particular, the audio colorations of those 4-foot straight horns are completely different from those of cone speakers and are ideal for projecting the male voice to a considerable distance, probably because they produce more of a plane wavefront than a spherical one.

I seem to recall that, thanks to horn speaker efficiency, the entire racecourse was covered with a single 90-watt amplifier.

To cut a long story short, this interest, plus something of a past reputation for providing PA for local events, I've accumulated a collection of horn PA speakers. Because of sheer size, most of the horn metalwork has to live outdoors (horticultural features). The pressure unit drivers live safely indoors in the dry workshop.

The first picture below shows part of my collection, which includes Grampian and Vitavox horns. In the centre are a couple of Grampian 'Maplins Holiday Camp' directional baffle speakers which use conventional cone speakers as drivers and give a more extended low frequency response at some sacrifice of efficiency.

Just in case audiophiles are inclined to dismiss the sound quality of these horns, I couldn't resist the second picture of a high end 'Excalibur' stereo system which clearly includes some rather similar speakers.

Martin

[Lucien Nunes]

Aha, one collector, good start.

Most of my horns are re-entrant but the three straight horns I take apart, stack the flares so that they take only the space of one, and then the throats add little to that.

I am quite keen to increase the stock of straight horns, but for the very reason you mention most that come onto the market are devoid of drivers as they have a following from the HiFi brigade and are all getting re-purposed, as usual to the disadvantage of the PA enthusiast.

Now about this loud noise experiment. Thanks to forum member @Cre8anet we have recently added to the PA collection, two Marconi valve amplfiers of some 300W or more each. They need overhaul and new output valves but that is not totally impossible, as it might have been with an earlier generation of power triodes. I have an idea to mount a full circle of ten Grampian horns, fitted with identical 50W drivers, on our 20' tower and park it in the middle of our Bedford site. I am not sure what announcement I would make but it would be interesting to station people at various distances and discover the total area covered audibly.

[Radio Wrangler]

The Butlins announcement schedule linked to above would be traditional... if you fancied becoming public enemy number one.

I can't imagine what you could put over it and still remain at liberty. But in the US there are people collecting civil defence sirens, even petrol V8 powered ones.

David

[Lucien Nunes]

"Your attention please. An escaped rhinoceros may be loose in the MK44 postcode area. If you see it, remain calm, do not approach it. Furthermore, we are currently offering for sale four pairs of tested NOS Marconi-Osram DA42s, used once for demo purposes only. Please contact ...."

[Techman]

Old PA amplifiers are certainly unloved. I've got three now, but all of them are of the solid state type. I actually bought one last Saturday at an auction and I was the only bidder at £1. I bought another one at the same auction a couple or three years ago, also for £1. In between these two I got given another one that had apparently originally come out of an old factory.

I've got a couple of Sound City valve amplifiers, but neither of them are of the PA variety. I've had them for years and one of them the chap I got it from told me that he found it at the tip. I swapped him a radiogram for it. I still know the chap and talking to him about it more recently he says it didn't originally come from the tip, although he can't remember where he did get it from, so one of us has forgotten the original story. The radiogram I swapped for it was rather unusual in that it was fitted with a spring line reverb tank in the bottom of the cabinet with controls on the front radio dial. I've still got the Sound City amplifier, but sadly he scrapped the radiogram years ago.

[Hartley118]

The announcement least likely to provoke complaint would probably be something along the lines of the boring "1, 2, 3, Testing". It would simply leave the 'audience' waiting for a festival or sporting event that never actually happens.

Your idea of erecting a 'ring' of speakers on a tower can certainly work well. I've experienced a similar successful configuration at a sizeable country fair in the Lake District. I think that one used just 4 or 5 re-entrant horns, but gave clear speech intelligibility over the whole fair. Such an arrangement has the advantage that the sound all comes from one point, avoiding echo delay problems.

The one 'killer' problem with outdoor PA projected over some distance is of course wind, which can cause all sorts of of interruptions and phasing effects due to velocity gradients sending the sound in all sorts of unintended directions. I've experienced on occasion some complex and costly concert and festival speaker installations where the performance has been ruined by a windy day.

So the experiment planning needs to include the weather forecast.

Martin

[lesmw0sec]

Now THAT is a PA system!

[Bill]

Several PA amps here. About 1970, I managed to get a couple of horn units from a local railway station, this involved turning up at midnight when the demolition contractors could start work on the station buildings, the horns being fixed to the platform canopy. We had to get a ladder and some spanners to remove them. I swapped the horns for a 15" Fane speaker, that better suited needs at the time.
PA amps range from an ancient,much modified, Grampian that came with EL34s , that works well with 6V6s and is 6v battery or mains powered: a small Philips 20w with EL81s
a bigger cast alloy chassis Philips EL6420, that thrashes the EL34s with 800v HT, a Burman(made in Newcastle )100w PA with PPP EL34s;a Rediffusion 90w 807 amp,made by Clarke & Smith and a couple of modern (1980s )2N3055 based amps. Haven't really got a use for any of them! Mentioned before on here I once had a Kilowatt Star amp , that had 3000v HT @700mA , too scared to switch it on!

[trobbins]

In oz the primary schools typically had a standalone PA system cabinet containing tuner, record player, mic, monitor speaker, and an amp up to 100W - and used for all the classrooms and parade and play grounds etc.. One special addition was a plug-in 'bell module' based on a NE2 oscillator with rate, decay, and vol trim-pots. Perhaps some recall their childhood school sounds - which continue on to today as I can certainly hear my nearest primary school announcements and bell when the wind is right.

[Lucien Nunes]

Now THAT is a PA system!

So it is. And anything with five pairs of what look like V1505s qualifies for some capital letters. Where is it located?

[Valvepower]

Interesting thread.

Yeah, the PA equipment gets largely forgotten about.

I’ve had to pass up on few ‘group’ PA amps over the years as there is limit to just how much you can collect, even with that I did end up with too much stuff and ended up in a bit of pickle to say the least about 6 years ago. I did have a Vortexion, which went to a chap on the Forum when I moved house and had the clear out.

I’ve taken pity on a few of the odd ball ‘bargain’ basement amps like the Northcourt, Liner and RSC which got used for PA use.

Sadly, it’s solid state, but I have what I believe is one of the Phase Linear 700B amplifiers as used in the Pink Floyd Brit Row system, mind you that dates back some 42+ years looking at the date code on the parts in the amp! This keeps a Crown DC300 company in the workshop.

Many, many years ago when I was working at Roost there was a collection of Partridge transformer in the workshop, which I was told came from the Sound City factory in the early 70’s. Amongst this lot there were two set of transformers for what I was told was a 400Watt amplifier using triodes like the DA100, mind you, I suppose I could have been multiple KT88’s..?. This lot was sold as scrap metal in the late 1970’s

I remember a Ackuset PA system, once owned by the band Love Affair coming into to the Roost workshop for a service. I have an Ackuset mixer somewhere as I kept that when I had the great clear out.

There was a crossover between hi-fi and PA as the Leak TL50 was used as a PA amp.

Sorry, I'm just rambling on now...

Terry

[GrimJosef]

I seem to recall reading somewhere that voice announcements are perceived to be 'clearer' when any bass components have been filtered out. This had a knock-on effect on the design of amps intended only for speech and, perhaps, light background music. It allowed the manufacturers to save significantly on the physical size of the output transformer, since this is largely driven by the need, or otherwise, to deliver deep bass at high power. This, in turn, saved cost.

Hi-Fi amps such as the TL/50, or the Quad II for that matter (which I believe was sometimes used for railway station announcement systems), do make perfectly good PA amps. But some amps built specifically for speech PA, rather than band use, may turn out to be light in the bass.

Cheers,

GJ

[Lucien Nunes]

There is also little point in equipping the amp to handle full power all the way down, if it is only going to be driving small speakers in terrible acoustics.

used in the Pink Floyd Brit Row system

I was a young child when I first encountered some of those racks in the 1980s. American organist Carlo Curley toured the world with his vast Allen electronic; I saw him a few times at Alexandra Palace, with quadraphonic PA by Brit Row.

Sorry, I'm just rambling on now...

Ramble away, it's all interesting and relevant.