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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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1st Apr 2020, 8:30 pm | #1 |
Octode
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Grundig C480 cassette record din socket
I have a C480 and am struggling to know what the 7 pin din on the side connections are. I’m hoping for line level out. Or is this just for stereo microphone in. Can anyone advise please.
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1st Apr 2020, 9:41 pm | #2 |
Dekatron
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Re: Grundig C480 cassette record din socket
Hello Terry,
German Service manual is attached, only one I can easily find. Second to last page shows the C 480 electrical schematic. Pins 1 and 4 as usual are the 2 stereo inputs. Pins 3 & 5 as usual are the 2 stereo high impedance outputs, with pin 2 as usual being 0V/ground. Unsure about pin 8, sometimes on multi pin DIN for microphones it is the Electret microphone supply voltage. Also not sure about pin 7, maybe Remote Motor Stop/Pause. Shame it has only got internal mono output. David |
2nd Apr 2020, 8:12 am | #3 |
Octode
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Re: Grundig C480 cassette record din socket
Thank you David. That helps.
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2nd Apr 2020, 4:55 pm | #4 |
Dekatron
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Re: Grundig C480 cassette record din socket
Pin 7 is connected, through a contact in the play/record (or wiedergabe / aufnahme ) switch, to the base of an NPN transistor which switches the motor; there is a pull-up resistor so this transistor is normally turned on. Pin 6 is grounded.
It looks as though applying a short from pin 6 to pin 7 while the machine is in record mode would stop the motor without affecting the electronics, so this is probably for a remote switch on the mic. Pin 8 seems to be connected to supply + to power an electret mic.
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4th Apr 2020, 5:10 pm | #5 |
Octode
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Re: Grundig C480 cassette record din socket
Hi, i would echo what others have said about the DIN socket connections however - This looks like a Mono machine from the circuit provided (unless I have missed something) the DIN socket is wired similarly to some ITT/KB models I have encountered.
Pin 2, as always is ground Pin 1 is low level input, for an external microphone or other equipment producing signal levels to DIN standard so around 1mV to 5mV in to 47K Pin 4 is not connected(?) Pins 5 and 3 are line level output to an external amplifier on PLAYBACK only, this signal will be in the order of 500mV to 1.5V into around 100K or more Pins 5 and 3 may also accept line level inputs during record however I haven't looked that closely at the circuit. Pin 6 is also ground and tied to pin 2 (see later) Pin 7 will be some kind of motor stop/start signal; the simplest way of doing this would be to have a switch, in series with the motor supply, which is operated by insertion of the Microphone DIN plug, I don't think that your machine uses this technique though despite having a switched socket shown on the diagram. Pin 8 is most likely for an external DC power supply in conjunction with pin 6 Regards Andrew |
4th Apr 2020, 5:49 pm | #6 |
Octode
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Re: Grundig C480 cassette record din socket
Thanks for the further info both Julie m and Andrew. I am transcribing some interviews I made 40 odd years ago using a basic Phillips cassette recorder. In the absence of a proper dictation player that rewinds a second or 2 on pause I’m putting these on the computer and playing back with VLC. I do have a stereo cassette deck somewhere but this Grundig is a well made unit and is more convenient. I just need line level out to direct connect to the computer as using a microphone connected to the laptop to record the cassette speaker is a little crude.
I agree with a Andrew that although this is emblazoned ‘stereo automatic’ there seems no evidence of how this is stereo. |
4th Apr 2020, 5:58 pm | #7 |
Dekatron
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Re: Grundig C480 cassette record din socket
Looking at the service manual it appears that the C450 and C460 are mono machines but that the C480 does have 2 channels of record/playback amplifiers (alhough only one intenral speaker and power amplfiier) and thus is a stereo machine.
Another thing.... Some time ago I bought a load of 'tape recorder microphones' mainly to get a Philips one I wanted (and also the right one for a little Sanyo portable reel-to-reel machine). Amongst them was one with a remote control switch on the body with a cable ending in a 7 pin DIN plug with a much longer than normal metal casing round the pins. I wonder if that was to operate a switch in a machine such as this one (to allow the remote switch to work) while a normal DIN plug put in the socket wouldn't. so you could use normal audio cables for record/playback. |
4th Apr 2020, 11:07 pm | #8 |
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Re: Grundig C480 cassette record din socket
Yes the C480 is one of those strange machines with stereo inputs/outputs but only a mono output power amp stage, rationale behind this is unknown to me.
I am sure pin 4 is used for right channel low level record input. Agree about pins 3 & 5 can also be high level inputs on record. |
4th Apr 2020, 11:51 pm | #9 |
Dekatron
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Re: Grundig C480 cassette record din socket
I don't know how large the stereo version is, but perhaps it isn't big enough to space two speakers far enough apart to get an adequate stereo effect. I have a Sony radio with a single speaker and a stereo headphone socket, and a Philips stereo cassette deck with line, mic, and headphone sockets, bu no internal speaker.
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5th Apr 2020, 11:58 am | #10 |
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Re: Grundig C480 cassette record din socket
The reel-to-reel Uher 4200/4400 machines were stereo recorders but only had a single speaker for mono playback. For a machine intended primarily as a field recorder, this was less of a limitation; the actual intended playback would be on a stereo machine in a studio, and it's more important just to know you have actually captured something; the two meter needles behaving differently are your clue that it's two distinct channels of sound.
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5th Apr 2020, 2:38 pm | #11 |
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Re: Grundig C480 cassette record din socket
Uher carried that idea on into cassette recorders. My CR210 is a fully stereo machine but with just one internal speaker. It does have 2 power amplifiers though so can drive a pair of speakers or stereo headphones.
And of course some Revox reel-to-reel machines like my G36 have only a single internal power amplifier/speaker. Fully stereo up to that point though. |
5th Apr 2020, 3:43 pm | #12 | |
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Re: Grundig C480 cassette record din socket
Quote:
Also maybe a consideration of achieving good sound without increasing the unit size, i.e. mono sound through a good size speaker may sound better than stereo from 2 smaller speakers. It could also be done for cost considerations and practical consideration of keeping the size compact. I think there are some larger examples such as the older Grundig Reel to Reel TK 55. |
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