Interference from cassette player
in [UK Mac]
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From: T i m on 18 May 2010 11:09 On Tue, 18 May 2010 15:48:37 +0100, Martin S Taylor <mst(a)hRyEpMnOoVtEiTsHm.cIo.uSk> wrote: >> Out of interest is it recording on just one channel ... do you have >> any control over that. > >Left to itself, it records on one channel, but I can fix that using Amadeus. > Ah, right, well I think I'd like the idea of it recording on both on it's own (and hence my question), not so much about being able to fix that within the software as such. There is no reason (that I can think of) why you (especially for this exercise) wouldn't have mono coming from the cassette playing feeding both the L and R inputs on the Mac. I'm thinking that even if you 'suppressed' one input (as you would with a mono jack in a stereo socket) it (the Mac) might ramp the gain up and therefore be picking up more 'noise'. Given a signal it might AGC back to a more normal sensitivity <shrug> Good luck anyway though. ;-) T i m
From: Woody on 18 May 2010 11:45 T i m <news(a)spaced.me.uk> wrote: > On Tue, 18 May 2010 15:48:37 +0100, Martin S Taylor > <mst(a)hRyEpMnOoVtEiTsHm.cIo.uSk> wrote: > > > >> Out of interest is it recording on just one channel ... do you have > >> any control over that. > > > >Left to itself, it records on one channel, but I can fix that using Amadeus. > > > Ah, right, well I think I'd like the idea of it recording on both on > it's own (and hence my question), not so much about being able to fix > that within the software as such. > > There is no reason (that I can think of) why you (especially for this > exercise) wouldn't have mono coming from the cassette playing feeding > both the L and R inputs on the Mac. That would be the ideal. Well, idealy it would be stereo! > I'm thinking that even if you 'suppressed' one input (as you would > with a mono jack in a stereo socket) it (the Mac) might ramp the gain > up and therefore be picking up more 'noise'. Given a signal it might > AGC back to a more normal sensitivity <shrug> There isn't any AGC on the input of the mac, it is nominally line level, although adjustable. -- Woody
From: zoara on 18 May 2010 12:58 T i m <news(a)spaced.me.uk> wrote: > On Mon, 17 May 2010 11:49:46 +0100, Martin S Taylor > <mst(a)hRyEpMnOoVtEiTsHm.cIo.uSk> wrote: > > >I've been trying to transfer some old cassette tapes onto the iMac by > > > >plugging a cassette player into the audio input and using Amadeus to > > record > >the output. > > > >You know that "Bzzzzz-bzt-bzt-bzzzzz-bzt-bzt" noise you get from time > > to time > >when a mobile phone is too near the Mac's external speakers? Well I'm > > getting > >that on all the recordings I make. I've taken the iPhone out of the > > room, but > >it seems to be the tape recorder itself which is causing the > > interference, as > >the sound only happens when the motor is running. > > > >At first I thought it was just affecting the speakers, but the sound > > is on > >the recording, too. Moving the cassette player further from the > > computer > >helps, but not enough. > > > >Any thoughts? > > > Yes, what is the construction of the cable you are using for the audio > from the player to the Mac? I'm presuming it's a 3.5mm stereo jack at > the cassette player end and possibly the same at the Mac end. However, > there are screened and unscreened types and they might look the same > from the outside. > > You might be able to tell if it's screened if either plug can be > opened (ie, not moulded) or, if you can feel a screen / braid under > the outer sheath (as opposed to just 3 wires). Anyone know where I can get one of those tape adapters (with a 3.5mm stereo jack at the other end) which is screened? -z- -- email: nettid1 at fastmail dot fm
From: Duncan Kennedy on 18 May 2010 13:33 Peter Ceresole <peter(a)cara.demon.co.uk> wrote: > Woody <usenet(a)alienrat.co.uk> wrote: > > > Earth loop, yes. I can't remember if the iMac actually uses the earth > > though. I guess I should have looked when I had mine apart. > > I know the macbooks don't. > > I don't think it does. > > When I had bad hum problems, with a TiBook , I made an earth lead that > went from the earth terminal of the 3mm jack to a nearby radiatpr. That > sorted it nicely. FWIW when I was getting a buzz from my new MBP somebody here kindly pointed out that the plug that goes directly onto the power supply isn't earthed (you can see that when you know!). The one using the loger lead does seem to be earthed as there is no buzz when that is used. -- duncank
From: Chris Ridd on 18 May 2010 13:58
On 2010-05-18 18:33:11 +0100, Duncan Kennedy said: > Peter Ceresole <peter(a)cara.demon.co.uk> wrote: > >> Woody <usenet(a)alienrat.co.uk> wrote: >> >>> Earth loop, yes. I can't remember if the iMac actually uses the earth >>> though. I guess I should have looked when I had mine apart. >>> I know the macbooks don't. >> >> I don't think it does. >> >> When I had bad hum problems, with a TiBook , I made an earth lead that >> went from the earth terminal of the 3mm jack to a nearby radiatpr. That >> sorted it nicely. > > FWIW when I was getting a buzz from my new MBP somebody here kindly > pointed out that the plug that goes directly onto the power supply isn't > earthed (you can see that when you know!). The one using the loger lead > does seem to be earthed as there is no buzz when that is used. I don't think the TiBook power adapters had a metal earth pin. -- Chris |