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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 25th Apr 2017, 8:02 am   #21
Stevie342000
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Default Re: Brenell STB-1 Restoration & Help Needed

Thanks Ted & Barry, especially like the "more advanced we become" comment, with the millenials especially, anything born post 1980 has no living concept of what industry is or was in this country. Funny that was talking about that a day or two back, as I am old enough to have caught the tail end of the industrial revolution as its tail was cut off.

Yes I agree on the heads no problem winding the coils but it the head gaps that are the issue especially uniformity of gap width.

The coil winding other than the fineness of the copper wire is not an issue, although women were often employed in this part of the industry.

Would you care to explain Barry? (Lest we should get a feminist backlash.)

It is the setting the two halves together and setting that head gap that is the issue.

Any ideas where I could get laminations(that would be the right shape not really wishing to cut those into shape, as well) in small quantities from?

I do not think I have seen a Brenell Mk510M come up for sale at auction, I would imagine they are fairly rare? Was that series 3 only, Barry? That must have been the ultimate mono half track machine?

Pity Ted you did not still have that staggered head Brenell - if it had Brenell heads then they must have made the stacked stereo heads( I seem to recall price lists or sales brochures that mention this too) for a brief period before they moved to Bogen. Is that right Barry? If they didn't, why didn't Brenell make their own stacked stereo tape heads?

Yes I thought that would be an issue with the Stacked tape amplifiers in the Daphne Oram machines, I wonder if she fixed it herself or was not aware that the bias oscillators were not syncronised? I seem to recall comments or mentions of hers doing the same.

The other option is not to use 2 bias oscillators but a booster amp if needed in the second record/replay amplifer and link them, so it then becomes a master oscillator. Brenell may have been aware of the issue and that is why they moved to developing a proper stereo machine.

I like the blue-gray hammertone finish that those machines came in or the option that you mention you rarely see one of those colour machines come up for auction.

The Black of the control knobs complements it as well which reminds me what is the current source for those knobs? I am specifically interest in the little round star head knob (but all of them really)?
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Old 25th Apr 2017, 10:26 am   #22
Ted Kendall
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Default Re: Brenell STB-1 Restoration & Help Needed

The heads on the machine were two Bogen 2/2 heads with Brenell R/P labels. There were two 1/2 erase heads in bigger, circular cans with Brenell E labels.

Given the connections of the previous owner, this may have been an Audio Fair special - a Truvox contraption came from the same source, and this was a Series 80 deck with two Type M amplifiers and 1/2 erase and 2/2 R/P heads, the whole in a steel frame, finished in a fetching shade of cream.

In days of yore, women were frequently employed in electronic assembly because their dexterity, compared to men brought up to manual labour, was highly prized.

If making a full track head is difficult, making an acceptable 2/2 head is at least four times more difficult. Better to source something ready made, whether by buying second hand or supporting one of the few concerns still engaged on this work - I'd suggest Summertone as a first stop, or of course JRF for Nortronics stock. Nortronics made replacement heads for the Revox 36, so they didn't lack ambition, although I've no direct experience of these.
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Old 25th Apr 2017, 10:47 am   #23
brenellic2000
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Default Re: Brenell STB-1 Restoration & Help Needed

The 10-1/2" was available with the last 'gold' Mk.5.

Brenell never made stacked 'stereo' heads, only ever half-track mono (not sure if they even offered a full track of their own. They were not head-makers per se.

As a former Industrial Engineer, the reason why women were employed is that they have the canny ability to tolerate monotony by 'switching-off' (which men don't) as a result of maternal instinct; thus reducing the risk of strikes. It has nothing to do with politics or 'feminism' (whatever that means). It's a simple fact of life!

Daphne was not interested in stereo - the staggered stereo separation allowed her to experiment to the full; her archives survive... but when I was researching themI was only looking for her Oramics work... and Brenell were not 'officially' involved.

I am sure mica and suitable thin metal laminations/shimming are still readily available from specialist engineers' factors. All you need is a fly-press; a well hardened and engineered set of dies; a large vice and Evostik and some drawn head-block blanks.... but most went over to the vacuum deposition method... and tin of Elbow Grease! It all depends on your interpretation of hi-fi.
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Old 28th Apr 2017, 9:21 am   #24
Stevie342000
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Default Re: Brenell STB-1 Restoration & Help Needed

Have contacted Summertone am awaiting a reply, will contact JRf shortly. The staggered stereo head gives better stereo separation but the problem was with editing the tape which is part of the reason why in line stereo stacked heads became defacto standard.

From my memory the Brenell heads are not potted? It's a long time since, if ever that I have seen inside one.

Brenell re-badged Bogen heads is that correct with the Brenell label?
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Old 28th Apr 2017, 12:32 pm   #25
brenellic2000
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Default Re: Brenell STB-1 Restoration & Help Needed

They didn't 're-badge' them to pass off as their own but merely to show what the function was! They happily advertised that they used Bogen heads.

Stacked stereo really came to the fore thanks to the immense popularity of 1/4 track mono, while 3-channel 'stereo' was still available in some USA studios to 'muddle' true binaural separation to give a more natural effect; indeed I believe the BBC preferred poor cross-talk to that end.
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