Grundig TK 18 microphone 5 pin DIN socket

[James D]

Hello and thanks in advance for any advice given.
I’ve bought a nice old Grundig TK 18 Reel-to-reel which has a microphone socket with a 5 pin DIN connector.
I’d like to get a vintage Grundig microphone for the TK 18 but most on sale seem to have 3 pin DIN connections.
My knowledge is less than basic - I used my elder brothers R2R in the sixties and knew which buttons to press.
My question is CAN 3 PIN CONNECTORS BE USED WITH 5 PIN DIN SOCKETS.
I imagine the answer is no but cannot find any vintage Grundig microphones with 5 pin DIN connectors.
Thank you again.

[julie_m]

Yes, 3-pin DIN plugs absolutely will fit 5-pin sockets (at least, the 180-degree type); and the connections are arranged with the left channel on the outermost pins and the right on the next pins in towards the common earth return in the middle.

Grundig mics were typically dynamic with a built-in impedance matching transformer, or sometimes condenser mics; but in any case, a cut above the crystal types usually supplied with most reel-to-reel tape recorders.

If using a non-Grundig mic with a Grundig recorder, you might need to do some rewiring, is all.

[TonyDuell]

The service manual for the TK18 shows a 3 pin microphone socket. It's entirely possible that the other 2 holes actually have no contacts fitted, as Julie said, the 3 pin plug will go into 3 of the holes of the 5 pin socket.

BUT.... Many older Grundig microphones are 'condenser' types (model numbers are GCM<digit> -- GCM seems to mean Grundig Condenser Microphone or the equivalent in German). Such microphones need a high-ish voltage (100V or more) at a very low current.

Some older Grundig tape recorders supply this voltage. The TK18 doesn't seem to. You therefore can't use a GCM microphone with that machine.

I believe the correct microphone will be a dynamic (moving coil) one in the GDM series

[James D]

What can I say other than a very big thank you to both replies, knowledgeable and helpful.
Following the advice I’ve ordered myself a Grundig GDM 313 Dynamic Microphone.
All the best!

[Uncle Bulgaria]

The point of DIN connectors is that the pin numbering remains the same. Thus a 5-pin connector will have pins 1, 2 & 3 in the same positions as a 3-pin connector (9, 12, 3 o'clock) with four and five in between. A three pin connector can thus be used with, say, an eight pin socket and have the same pins mating. The use of certain pins for inputs and outputs was commonly standardised. If you do a search I recently posted a document containing common DIN pinouts for different audio applications.

There is a caveat to this as there are two 8-pin connector layouts, so not all 8-pin plugs fit all 8-pin sockets.

[emeritus]

The TK18 seems to be a mono recorder, so it is possible that contacts in positions 1 and 4 might present and connected together, likewise for contact positions 3 and 5. That is the arrangement with the 5 pin DIN socket of my mono Philips yEL3585, and allows recording/playback from/to both channels of stereo equipment using a 5 pin DIN stereo cable.

[TonyDuell]

Originally Posted by Uncle Bulgaria

The point of DIN connectors is that the pin numbering remains the same. Thus a 5-pin connector will have pins 1, 2 & 3 in the same positions as a 3-pin connector (9, 12, 3 o'clock) with four and five in between. A three pin connector can thus be used with, say, an eight pin socket and have the same pins mating. The use of certain pins for inputs and outputs was commonly standardised. If you do a search I recently posted a document containing common DIN pinouts for different audio applications.

There is a caveat to this as there are two 8-pin connector layouts, so not all 8-pin plugs fit all 8-pin sockets.

One of the best (non-audio) cases of that is the Epson HX20 RS232 port, which uses an 8 pin DIN connector, the type with the outer pins in a circular arc so a normal 7 pin plug will fit.

The pinout is :
1 : Ground
2 : TxD (Transmit data)
3 : RxD (Receive data)
4 : RTS (Request To Send)
5 : CTS (Clear to Send)
6 : DSR (Data Set Ready)
7 : DTR (Data Terminal Ready)
8 : DCD (Data Carrier Detect)

Not only are the signals on much the same pins as those on the DB25 RS232 connector, but :
A 3 pin plug will give you the 2 data signals and ground]
A 5 pin plug adds the RTS/CTS handshake lines
A 7 pin plug further adds DSR and DTR
And finally to get DCD you do need the 8 pin plug.
But all the subsets from fewer-pin plugs are useful.

Getting back to the TK18, the circuit diagram I have shows only 2 pins of the microphone socket wired : pin 1 is signal and pin 2 is ground. Yes, it's a simple mono machine, 2 track (flip the spools over for the second track) and single speed (3+3/4 ips). It does have automatic recording level control (and no manual override). I am not sure what the original microphone was, but the DCM313 will almost certainly work

[DMcMahon]

The original Grundig microphone supplied with the TK 18 as referenced in the User Manual (Guide to the TK 18) was the GDM 18. As already stated the GDM 313 will be a good alternative, although I have read that some refurbished GDM 313s may be supplied with XLR connector fitted.

Also as already stated pins 4 & 5 of the microphone DIN on the machine are not fitted with contact pins and only pins 1 and 2 are actually wired.

David