Imperial College Operatic Society: Even More Tapes


Grand Duchess tapes

The Grand Duchess

Deborah Miles-Johnson, ICOS alumna and Musical Director of IMVC, contacted me to say she'd found two large reels of tapes from the College production of Offenbach's The Grand Duchess of Gerolstein, recorded in 1979. I volunteered my services to transcribe them, thinking this would be as simple as the Mikado tape done previously. [Click the pictures for a larger view, ESC to return]

Tape with track list

I picked up the tapes in January 2022 from Deborah's house and was pleased to find comprehensive notes on the contents with running order and track length. The two tapes were for the Friday performance and the last night, Saturday. They had been recorded at only 3¾ inches per second - not the best quality recording, but maybe adequate. The claim was that the recordings were ½ track stereo, but see later how they turned out.

Spooling off

Next came the problem of spooling the tape off onto 7 inch reels that were playable on my tape recorder. I had forgotten how tricky it was to get the height between the gramophone turntable and the tape deck right. Experiments with a brick and piles of books found the right combination. I started with the Saturday tape, for no reason other than it was on top. I spooled off what I guessed was Act 1 ready for transcription.


Spooling off
Brenell tape recorder Replay amplifier

Tape recorder

The next problem was my elderly Brenell tape recorder (left). I bought it as a separate tape drive and Hi-Fi tape link in the 1960s. My late father made the oak case to hold the two parts. The Tape Link was originally a valve device, but in the early 1970s I rebuilt it with integrated circuits from a kit design in Wireless World magazine.

By 2022 the tape deck still worked fine but the electronics were showing their age. The replay circuit board (right) was faulty. The usual action with old electronics is to start by replacing all the capacitors - notorious for dying when old. Once the caps were replaced it started working but only on one channel.

Track layout

I persevered using my Uher Report as playback device with a vintage Tandberg to hold the 7 inch spools. This is where an earlier problem raised it's head. The Mikado tape I transcribed previously suggested that the so-called ½-track recording didn't line up as it should with my ¼-track tape heads. This meant that the right-hand channel was very much quieter than the left-hand channel. I had solved the problem before by playing back on a Fostex 8-track recorder and choosing tracks that gave the best signal. Unfortunately the Fostex has been sprited away by son, Tim, to show his students what tape recording was like in the ancient analogue days. However, I was determined to get some sort of transcription and made a transfer of most of Act 1 in mono using the Tandberg as the playback device playing back only the upper track.

Oxide shedding

Moving on to spool off Acts 2 and 3 the most serious problem arose. As spooling progressed masses of oxide flew off the tape in the phenomenon known as oxide shedding. This appears to have been prevalent on tapes made in the 1970. I know this because our wedding tape from 1977 disintegrated in a similar fashion, though not before a cassette copy had been made. The coating of metal oxide which holds the recording loses its adhesion to the supporting plastic tape and falls away, taking part of the recording with it. The loss is not necessarily total, but the sound level will fluctuate. In addition, playing the tape will cause further oxide to come off coating the playback head, reducing the sound even further.

Oxide shedding

Oxide shedding [click for larger image]

I managed to get some sort of copy of the remainder of the Saturday performance by playing back a track at a time and cleaning the tape head between. The result is mono - better than no result at all.

Print-through

Yet another problem turned up during the process. In a number of places a loud conclusion to an item was followed by quiet dialogue. The dialogue was partly covered by an echo of the previous crescendo. This is known as print-through, where the magnetic recording from one layer of tape transfers itself to the adjacent layer causing either a pre-echo or a post-echo some seconds earlier or later. It's never happened to any of my own recordings, but is well-known and happened here in a number of places.

It was now time to re-spool the Saturday tape and spool off the Friday tape. From the recording notes I gathered that the original recordings had evidently been made on separate 7 inch reels and had later been spliced together and wound onto the 10½ inch NAB spool. I wonder why.

Akai 4000

New Recorder

I realised that diagnosing and repairing the old Brenell was going to take more time than I cared to devote to it. So I bit the bullet and bought a second-hand Akai 4000 recorder from eBay. This turned out to be an excellent choice.

Playing backwards

In spooling off the Friday tape I could see that it was less damaged than the Saturday one, although there was still some loss of oxide. The end of Act 1 announced itself as I wound the tape by the splice parting company. The splice at the end of Act 2 was harder to find, but nonetheless it was there.

Whilst I was thinking about how to avoid the large difference in sound level between the left and right channels, I had a thought. If I turn the tape over and play the recording it will come out backwards, but the tracks will be slightly differently placed across the tape - possibly to the good. I experimented with the overture and found indeed that the difference between channels was now only about 6dB, which is not too much to correct in editing. The recording software has a single click option to reverse the recording. It then only remains to swap the channels and equalise the levels.

I was able to play all 3 Acts backwards in convenient 10 to 15 minute bursts with pauses to clean the tape head. The later parts of Act 2 and Act 3 suffered from drop-out where oxide was missing but the overall result was better than the Saturday tape. Because I was able to recover both audio channels it now became plain what I had noticed on the Saturday tape that there was no obvious stereo separation, so the result is sadly monophonic. I was also disappointed in the overall sound quality compared with other recordings made by Dramsoc or me.

The Grand Duchess of Gerolstein Recordings

Play the complete acts by clicking the play button or download the MP3 file by right click and choose 'Save Audio as'. The ZIP files contain separate individual tracks together with a playlist file (m3u format).

Press illustration from 1867

Saturday Act I    Zip File

Saturday Act II    Zip File

Saturday Act III    Zip File


Friday Act I    Zip File

Friday Act II    Zip File

Friday Act III    Zip File


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