Racal Store 4 - UK Vintage Radio Repair and Restoration Discussion Forum

mark_in_manc · 28th Sep 2019, 5:26 pm

hi folks

My employers (a university) are again planning on knocking our building down and building a smaller, flashier one with less facilities (last happened in '05)...so people are starting to clear out their cupboards in anticipation of the move. Amongst the latest batch is a Store 4 in really nice condition with books, new tapes etc etc. It came in a kind of portable shoulder-bag (!), and weighs about 25kg all in - it's a really well-made lump of metal.

So far I plugged it into a lamp limiter which stayed bright as can be, while the thing made unhappy high-pitched buzzing noises. I might go a bit further with it before selling it on, especially if anyone on here is interested in the journey or has some familiarity with them. (I do know it's an FM system which goes down to DC and up to a rather high frequency on a fast tape speed, which was its whole purpose once, long long ago, in the site-recording and lab-analysis of blast noise).

cheers
Mark

ricard · 29th Sep 2019, 5:55 am

Found a youtube video of this machine:

https://www.youtube.com/watch?v=EN5K_5XBNbs

Impressive range of speeds, from 15/16 ips to 30 ips.

Looks like it has an omega wrap capstan with no pinch roller for the drive, a weak point down the line, highly dependent on the rubber quality of the capstan coating one would assume?

TIMTAPE · 29th Sep 2019, 7:41 am

The Nagra TRVR is interesting in having no pinch roller and no rubber parts in the tape path.

mark_in_manc · 29th Sep 2019, 9:28 am

Quote:

Originally Posted by ricard

Found a youtube video of this machine

Yes, that's the one. Thanks for looking that up - it quite inspires me to get involved. First stop, find the power supply, I guess. Actually this one has a 12v DC input (it was used as a site instrument), I'll have to give it a go on that next. Where did I put my big bench PSU?

TIMTAPE · 29th Sep 2019, 12:04 pm

Interesting watching the Racal play tapes. It looks as if like the TRVR, it has no facility for lifting the tape off the heads when merely fast winding tapes. That can chew out the heads quickly. I think the first mod I made on my TRVR was to construct a simple tape lifter mechanism. Not pretty but it saves the valuable heads.

The TRVR has the same four lower tape speeds as the Racal but also speed multiplier functions of x4 and x16, which means that while lacking EQ corrections, it can play tapes at 15, 30 or 60ips like the Racal.

brenellic2000 · 29th Sep 2019, 3:09 pm

There was a basic 4-channel 1/4", 7-channel 1/2" and a 14-channel job (bigger shoulder bag - honest). They are exceptionally well built and much used in military, medical and field research work. So gentle was the tape transport that they were the favourite around the world for air accident investigation to replay the fragile Black Box data tape.

It was originally developed as the Racal-Thermionic T9000 to replace the Truvox 4-speed 200 base T3000. (See my history, 'A Truvox Product').

Problems with high-speed traction was resolved by sandblasting the capstan which broke up the trapped air. Brilliant machine. I had a mint, unissued NHS 7-channel and ex-Davy 14-channel.

donutty · 30th Sep 2019, 2:58 pm

I have one of these that I got for pennies from a military surplus auction. I just don't know what to do with it... keep it or strip it for parts. Maybe I could mod it to a 4 track audio recorder. It is very well made.

And yes.. 'shoulder bag' it aint! (even that bag is nice and padded. Would make a good winter coat!)

mark_in_manc · 30th Sep 2019, 8:24 pm

Donutty

As far as I can work out, the erase head on mine only fires up when all channels are being recorded - and when it does, it deletes all tracks. The inability to delete one track at a time seems to defeat it for music recording multitrack purposes, which is a shame. And mine is FM, so I can only play tapes recorded on this device itself! But what a thing...

brenellic2000 · 1st Oct 2019, 9:03 am

These were not of course designed for inter-channel mixing, but designed for one pass multi-channel recording/playback.

I have/had in the back of my mind a vague recollection/reference to EMI Abbey Road trialling these... can't find my notes so I've probably got it muddled up with something else.

Vicboduk · 1st Oct 2019, 12:58 pm

I used to see a lot of these in the mid to late 80’s. The input channels were configured by the use of different plug-in cards, in my case they were FM modulators so that DC to a few KHz signal could be recorded. They were used to record sub Hz physiological events. The most recurrent problem I had was within the tape tension arm assembly.
It consists of a (incandescent) light source, four CdS cells in a bridge circuit and mechanical paddles that interrupted the light.
Typically, a CdS cell would fail sending the machine transport haywire. I seem to remember that replacing a cell and resetting the paddles was quite critical.

barretter · 1st Oct 2019, 3:36 pm

You used to be able to buy these quite cheaply on eBay (I have several) but I see that currently someone in Moscow is trying to get over $1000 for one - bonkers! You can download the technical manual free if you google "Racal Store 4 manual". The major downside is that they are instrumentation devices and don't use either NAB or CCIR equalization ; and the Store 4 is not quite big enough for the use of 10.5" reels.

ricard · 2nd Oct 2019, 12:09 pm

Quote:

Originally Posted by brenellic2000

These were not of course designed for inter-channel mixing, but designed for one pass multi-channel recording/playback..

So is the erase head full width then? (Rather than individual tracks).

mark_in_manc · 2nd Oct 2019, 4:39 pm

yes, That's what the manual tells me.

ricard · 3rd Oct 2019, 4:59 am

Certainly makes sense for the intended usage.

I was once given a 7-track data recorder, taking 7 inch reels, intended for taking backups of data, which had the same arrangement.

Come to think of it, most cassette recorders have the same philosphy, i.e. a mono erase head even if the recorder is stereo because there's no need to erase the tracks separately. I guess it's just the traditional 4 track reel-to-reel mindset where the tracks in the same direction on the tape are not adjacent to each other which always warrants a 'stereo' erase head even in a mono recorder.

brenellic2000 · 3rd Oct 2019, 8:46 am

Don't forget Ricard that 1/4" 1/4-track has better crosstalk than a twinned pair on cassette, yet the worse stereo separation can give a more natural 'stereo' sound on cassette!

28th Sep 2019, 5:26 pm	#1
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,874	Racal Store 4 hi folks My employers (a university) are again planning on knocking our building down and building a smaller, flashier one with less facilities (last happened in '05)...so people are starting to clear out their cupboards in anticipation of the move. Amongst the latest batch is a Store 4 in really nice condition with books, new tapes etc etc. It came in a kind of portable shoulder-bag (!), and weighs about 25kg all in - it's a really well-made lump of metal. So far I plugged it into a lamp limiter which stayed bright as can be, while the thing made unhappy high-pitched buzzing noises. I might go a bit further with it before selling it on, especially if anyone on here is interested in the journey or has some familiarity with them. (I do know it's an FM system which goes down to DC and up to a rather high frequency on a fast tape speed, which was its whole purpose once, long long ago, in the site-recording and lab-analysis of blast noise). cheers Mark

29th Sep 2019, 5:55 am	#2
ricard Octode Join Date: Mar 2006 Location: Lund, Sweden Posts: 1,632	Re: Racal Store 4 Found a youtube video of this machine: https://www.youtube.com/watch?v=EN5K_5XBNbs Impressive range of speeds, from 15/16 ips to 30 ips. Looks like it has an omega wrap capstan with no pinch roller for the drive, a weak point down the line, highly dependent on the rubber quality of the capstan coating one would assume?

29th Sep 2019, 7:41 am	#3
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,969	Re: Racal Store 4 The Nagra TRVR is interesting in having no pinch roller and no rubber parts in the tape path.

29th Sep 2019, 12:04 pm	#5
TIMTAPE Octode Join Date: Jul 2006 Location: Perth, Western Australia Posts: 1,969	Re: Racal Store 4 Interesting watching the Racal play tapes. It looks as if like the TRVR, it has no facility for lifting the tape off the heads when merely fast winding tapes. That can chew out the heads quickly. I think the first mod I made on my TRVR was to construct a simple tape lifter mechanism. Not pretty but it saves the valuable heads. The TRVR has the same four lower tape speeds as the Racal but also speed multiplier functions of x4 and x16, which means that while lacking EQ corrections, it can play tapes at 15, 30 or 60ips like the Racal.

29th Sep 2019, 3:09 pm	#6
brenellic2000 Octode Join Date: Aug 2006 Location: Rye, East Sussex, UK. Posts: 1,647	Re: Racal Store 4 There was a basic 4-channel 1/4", 7-channel 1/2" and a 14-channel job (bigger shoulder bag - honest). They are exceptionally well built and much used in military, medical and field research work. So gentle was the tape transport that they were the favourite around the world for air accident investigation to replay the fragile Black Box data tape. It was originally developed as the Racal-Thermionic T9000 to replace the Truvox 4-speed 200 base T3000. (See my history, 'A Truvox Product'). Problems with high-speed traction was resolved by sandblasting the capstan which broke up the trapped air. Brilliant machine. I had a mint, unissued NHS 7-channel and ex-Davy 14-channel.

30th Sep 2019, 2:58 pm	#7
donutty Pentode Join Date: Aug 2010 Location: Sheffield, South Yorkshire, UK. Posts: 163	Re: Racal Store 4 I have one of these that I got for pennies from a military surplus auction. I just don't know what to do with it... keep it or strip it for parts. Maybe I could mod it to a 4 track audio recorder. It is very well made. And yes.. 'shoulder bag' it aint! (even that bag is nice and padded. Would make a good winter coat!)

30th Sep 2019, 8:24 pm	#8
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,874	Re: Racal Store 4 Donutty As far as I can work out, the erase head on mine only fires up when all channels are being recorded - and when it does, it deletes all tracks. The inability to delete one track at a time seems to defeat it for music recording multitrack purposes, which is a shame. And mine is FM, so I can only play tapes recorded on this device itself! But what a thing...

1st Oct 2019, 9:03 am	#9
brenellic2000 Octode Join Date: Aug 2006 Location: Rye, East Sussex, UK. Posts: 1,647	Re: Racal Store 4 These were not of course designed for inter-channel mixing, but designed for one pass multi-channel recording/playback. I have/had in the back of my mind a vague recollection/reference to EMI Abbey Road trialling these... can't find my notes so I've probably got it muddled up with something else.

1st Oct 2019, 12:58 pm	#10
Vicboduk Hexode Join Date: Aug 2007 Location: S.W. London, UK. Posts: 416	Re: Racal Store 4 I used to see a lot of these in the mid to late 80’s. The input channels were configured by the use of different plug-in cards, in my case they were FM modulators so that DC to a few KHz signal could be recorded. They were used to record sub Hz physiological events. The most recurrent problem I had was within the tape tension arm assembly. It consists of a (incandescent) light source, four CdS cells in a bridge circuit and mechanical paddles that interrupted the light. Typically, a CdS cell would fail sending the machine transport haywire. I seem to remember that replacing a cell and resetting the paddles was quite critical. Last edited by Vicboduk; 1st Oct 2019 at 1:05 pm.

1st Oct 2019, 3:36 pm	#11
barretter Heptode Join Date: Jan 2006 Location: Todmorden, West Yorkshire, UK. Posts: 870	Re: Racal Store 4 You used to be able to buy these quite cheaply on eBay (I have several) but I see that currently someone in Moscow is trying to get over $1000 for one - bonkers! You can download the technical manual free if you google "Racal Store 4 manual". The major downside is that they are instrumentation devices and don't use either NAB or CCIR equalization ; and the Store 4 is not quite big enough for the use of 10.5" reels.

2nd Oct 2019, 4:39 pm	#13
mark_in_manc Octode Join Date: Nov 2011 Location: Manchester, UK. Posts: 1,874	Re: Racal Store 4 yes, That's what the manual tells me.

3rd Oct 2019, 4:59 am	#14
ricard Octode Join Date: Mar 2006 Location: Lund, Sweden Posts: 1,632	Re: Racal Store 4 Certainly makes sense for the intended usage. I was once given a 7-track data recorder, taking 7 inch reels, intended for taking backups of data, which had the same arrangement. Come to think of it, most cassette recorders have the same philosphy, i.e. a mono erase head even if the recorder is stereo because there's no need to erase the tracks separately. I guess it's just the traditional 4 track reel-to-reel mindset where the tracks in the same direction on the tape are not adjacent to each other which always warrants a 'stereo' erase head even in a mono recorder.

3rd Oct 2019, 8:46 am	#15
brenellic2000 Octode Join Date: Aug 2006 Location: Rye, East Sussex, UK. Posts: 1,647	Re: Racal Store 4 Don't forget Ricard that 1/4" 1/4-track has better crosstalk than a twinned pair on cassette, yet the worse stereo separation can give a more natural 'stereo' sound on cassette!