EMI BTR-1 info and help required

[Hcrelec]

Hi,

Would anybody have any manuals / service info / schematics or anything at all relating to a BTR-1 Tape Machine?

About to give a full service and restoration, so anything would be greatly appreciated. I’m in Australia so thinking Someone in the UK might have something hidden away.

Thanks

[Robert Gribnau]

Some info (but no schematic) can be found here:

https://www.bbc.co.uk/rd/publications/rdreport_1948_30

[barrymagrec]

I have a copy of a sales sheet somewhere, I`ll try and find it.

One thing I do know is that early versions run at 77 cm/s (the old continental standard) whereas the later models ran at 30 ips (CCIR standard speed).

These old posts have some information :-

https://www.tapatalk.com/groups/vint...peed-t766.html

[Ted Kendall]

TS used BTR-1s for a long time, but the new A80s arrived before I did. These, if I remember the folklore aright, were 30/15 but later converted to 7.5/15. The design was a pretty straight crib of the Magnetophon HTS, including the 77cm/s tape speed, adopted when AC bias arrived. The base-mounted motor was intended to keep the hum level down, an important point with the low output available from contemporary tapes.

A quirk of the line-up is that you start by setting the record level at 10kHz and then tweak the equalisers to get the 1kHz level right.

There is an interesting video on YouTube in which Simon Gibson describes the remastering of the 1948 Furtwangler sessions from Vienna. I think the speed discrepancy is mentioned there.

[barrymagrec]

I think some of the later models had at least the capstan motor mounted up on the deck as per BTR2 -running long thinish 1500rpm shafts is not without it`s own problems in my experience.

[TIMTAPE]

Originally Posted by Ted Kendall

...There is an interesting video on YouTube in which Simon Gibson describes the remastering of the 1948 Furtwangler sessions from Vienna. I think the speed discrepancy is mentioned there.

Thanks for the YT reference. I think Simon only referred to " power supply" fluctuations as a cause of occasional fluctuations in tape speed on the session tapes. He did mention their settling on I think A443 as the standard pitch they worked to in compiling these recordings for release.

[Ted Kendall]

Originally Posted by barrymagrec

I think some of the later models had at least the capstan motor mounted up on the deck as per BTR2 -running long thinish 1500rpm shafts is not without it`s own problems in my experience.

Mr Whippy! TS were never enamoured of the flutter performance of their BTR1s, but this was put down to less than perfect regrinding of the capstan shaft. The TR50, when provoked, could flutter for England, by the way...

[Ted Kendall]

Originally Posted by TIMTAPE

Thanks for the YT reference. I think Simon only referred to " power supply" fluctuations as a cause of occasional fluctuations in tape speed on the session tapes. He did mention their settling on I think A443 as the standard pitch they worked to in compiling these recordings for release.

Funny, that. Vienna tended, and still tends, towards high pitch - when I asked them a few years ago, the answer they gave for that period was A446.

[barrymagrec]

Originally Posted by Ted Kendall

Mr Whippy! TS were never enamoured of the flutter performance of their BTR1s, but this was put down to less than perfect regrinding of the capstan shaft. The TR50, when provoked, could flutter for England, by the way...

You had TR50s? I learnt a lot of my tape machining aged around 14 on a TR50 - no frame, perched on paint cans..... It ended up converted to three motors and running half inch tape on an 8 track head. Still in the loft somewhere.

[Ted Kendall]

Originally Posted by Ted Kendall

Funny, that. Vienna tended, and still tends, towards high pitch - when I asked them a few years ago, the answer they gave for that period was A446.

...and A446 recorded at 77cm/s and replayed at 76.2cm/s is close enough to A443...

[Ted Kendall]

Originally Posted by barrymagrec

You had TR50s? I learnt a lot of my tape machining aged around 14 on a TR50 - no frame, perched on paint cans..... It ended up converted to three motors and running half inch tape on an 8 track head. Still in the loft somewhere.

Not a whole TR50, but the same deck in some sort of Frankenstein console I've never got around to sorting properly. A studio engineer of my acquaintance tells me that the TR51 was referred to in period as the "TR fifty-waaaaahn", pronounced with a sort of onomatopoeic ovine wobble, and my example isn't brilliant in this respect. It may of course be faulty after all this time.

[barrymagrec]

Originally Posted by Ted Kendall

Not a whole TR50, but the same deck in some sort of Frankenstein console I've never got around to sorting properly. A studio engineer of my acquaintance tells me that the TR51 was referred to in period as the "TR fifty-waaaaahn", pronounced with a sort of onomatopoeic ovine wobble, and my example isn't brilliant in this respect. It may of course be faulty after all this time.

It could easily be a dodgy bellows coupling to the capstan or stifness in the jackshaft after all this time.

I have a feir number of spares for the TR50, though no usable ruubber parts, if you need anything.

[barrymagrec]

Brochure mentioned above:-

https://www.vintage-radio.net/forum/...797=1693296897

[Ted Kendall]

Interesting, this - the speeds are given as 30/15 - on a neat little alteration label. I wonder what was there originally.

Where exactly the rationalisation of tape speeds started is a moot point. Mullin's original recordings for Crosby were made on a captured Magnetophon deck, so at 77cm/s. The Ampex 200 was originally laid out as an oxide-out machine in the Magnetophon style, but was probably 30ips from day one, as the 201 upgrade kit issued a couple of years after production began included a new headblock and amplifiers, but no replacement capstan. An Ampex 200/201 was in use at The Mastering Lab in the 1970s. The first BTR-1s were 77cm/s as far as I know, but it seems likely that these were confined to EMI, and possibly Decca, who had a machine early on, even if it was relegated to the corridor outside the canteen because Arthur Haddy wasn't having "that ****** thing" in his control room.

Incidentally, EMI's first stereo recordings were made on modified BTR-1s with staggered heads, and these machines lasted until the BTR-3s came into service. These used a BTR-2 deck, stacked heads and miniature valves in order to fit stereo amplifiers in the space originally occupied by the mono electronics.

[barrymagrec]

In the blurb on page 2 it still states 77cm/s. I think there were a lot of changes during the production life of the machine, 5 years was a long time in those early days of tape machine development.

REDD produced a later miniature valve version of the BTR2 replay amplifier, presumably to overcome the poor headroom of the original when used with later types of tape.

[Ted Kendall]

Originally Posted by barrymagrec

In the blurb on page 2 it still states 77cm/s.

Missed that! So I wasn't imagining it after all

[Hcrelec]

Originally Posted by barrymagrec

I have a copy of a sales sheet somewhere, I`ll try and find it.

One thing I do know is that early versions run at 77 cm/s (the old continental standard) whereas the later models ran at 30 ips (CCIR standard speed).

These old posts have some information :-

https://www.tapatalk.com/groups/vint...peed-t766.html

Mine is 15IPS or 30IPS selectable

[Hcrelec]

Originally Posted by barrymagrec

Brochure mentioned above:-

https://www.vintage-radio.net/forum/...797=1693296897

Thanks I hadn't seen this before