BBC Tape machine maintenance / alignment specs - UK Vintage Radio Repair and Restoration Discussion Forum

John_BS · 7th Dec 2022, 6:28 pm

This documant is available on the bbceng.info website, but I've attached a copy here for ease of access.

For recorders with VU meters, align 0VU to correspond to 320nWb/m for most tapes.

Mods; I don't know if this is worth making sticky?

John

jamesperrett · 7th Dec 2022, 11:35 pm

That document makes interesting reading but it also makes a few assumptions which may not necessarily be true outside the BBC. There is no mention of the different equalisation standards commonly encountered - probably because the BBC only used one standard. The reference levels are also higher than normally encountered with domestic machines.

It probably should be read in conjunction with a more step by step guide and also the service manual for the machine that you are working on.

John_BS · 8th Dec 2022, 10:58 am

Quote:

Originally Posted by jamesperrett

It probably should be read in conjunction with a more step by step guide and also the service manual for the machine that you are working on.

Yes, if you have one. Ditto, data on the tape-type you're using.
BBC standard was IEC EQ.

JOhn

Stevie342000 · 8th Dec 2022, 8:51 pm

Quote:

Originally Posted by John_BS

Quote:

Originally Posted by jamesperrett

It probably should be read in conjunction with a more step by step guide and also the service manual for the machine that you are working on.

Yes, if you have one. Ditto, data on the tape-type you're using.
BBC standard was IEC EQ.

JOhn

Is that IEC 1 or IEC 2? I read it as you need to refer to your manual and use it as a guide. The best bit is make sure the tape is running past the heads correctly without that the rest is not of much use as it will be out of kilter.

John_BS · 8th Dec 2022, 9:11 pm

The "original" IEC standard (= DIN/CCIR) is now known as IEC 1, and that's the one which the BBC used, and corresponds to the "IEC" position found on Revox A77's etc.

As I understand it, the old "NAB" standard was absorbed into IEC and became IEC 2.

So, if an A77 was re-issued today, the replay switch would be labelled "IEC 1" and "IEC 2"
John

Plus4db · 24th Dec 2022, 12:51 am

Most 'domestic' machines were Nab and normally the consumer line up of 250nWb/m, except for the Revoxes and some European models. That document is for professional machines, as used by the BBC. It is always best to get the service manual for your particular machine and follow those specific guidelines.

7th Dec 2022, 11:35 pm	#2
jamesperrett Octode Join Date: May 2007 Location: Liss, Hampshire, UK. Posts: 1,771	Re: BBC Tape machine maintenance / alignmet specs That document makes interesting reading but it also makes a few assumptions which may not necessarily be true outside the BBC. There is no mention of the different equalisation standards commonly encountered - probably because the BBC only used one standard. The reference levels are also higher than normally encountered with domestic machines. It probably should be read in conjunction with a more step by step guide and also the service manual for the machine that you are working on.

8th Dec 2022, 9:11 pm	#5
John_BS Octode Join Date: Dec 2008 Location: Wincanton, Somerset, UK. Posts: 1,669	Re: BBC Tape machine maintenance / alignment specs The "original" IEC standard (= DIN/CCIR) is now known as IEC 1, and that's the one which the BBC used, and corresponds to the "IEC" position found on Revox A77's etc. As I understand it, the old "NAB" standard was absorbed into IEC and became IEC 2. So, if an A77 was re-issued today, the replay switch would be labelled "IEC 1" and "IEC 2" John

24th Dec 2022, 12:51 am	#6
Plus4db Triode Join Date: Feb 2021 Location: Stourbridge, West Midlands, UK. Posts: 21	Re: BBC Tape machine maintenance / alignment specs Most 'domestic' machines were Nab and normally the consumer line up of 250nWb/m, except for the Revoxes and some European models. That document is for professional machines, as used by the BBC. It is always best to get the service manual for your particular machine and follow those specific guidelines.