Confused re Marconiphone.

[oliverbrown]

Hi all!

A while ago I picked up a Marconiphone reel-to-reel tape recorder (pic attached) cheaply. As far as I can tell, it works pretty much perfectly if I only want to record/play/erase one track on a tape, which is fine for me. I'm a composer, so it's more about getting cool sounds out of it than high fidelity recordings.

My question is about the mic input (pic attached) - I've tried soldering 5-pin DIN inputs, and they don't fit. It doesn't fit any conventional 3-pin XLR. I can't for the life of me work out what input/adaptor to use, and google has been no help. Furthermore, I'm now wondering if my regular Shure SM-58 will even work with it if I do find a connector that fits. Do I have to use a Marconi mic?

I'm sure there's a simple answer to all this, but I'm totally confused and was hoping you might be able to help!

Thanks in advance,
Oliver

[dazzlevision]

The microphone socket is a special 4 pin DIN type and the front two of the four contacts are used to break an internal circuit when the microphone plug is inserted.

The original microphone also had a switch in it, to operate the "pause" function (activated by a solenoid in the recorder).

Note that the microphone supplied with the recorders was a high impedance crystal type, not a dynamic/moving coil type.

[paulsherwin]

These machines were certainly not intended to be used with a professional mic of any sort. You would be better off making up a lead for the line level input (standard DIN connector I think) and recording through that. No doubt you have existing interfaces or preamps for mics.

[dazzlevision]

Originally Posted by paulsherwin

These machines were certainly not intended to be used with a professional mic of any sort. You would be better off making up a lead for the line level input (standard DIN connector I think).

Yes, in the rear compartment: Radio; PU1 and PU2. All 180 degree, 5 pin DIN plugs.

[dazzlevision]

Here are the specifications for the rear sockets.

[Heatercathodeshort]

here is a picture of the original mic with it's odd Din plug. I purchased one of these recorders when I was 19 in 1967! It still works 100%. One of a series of the best domestic recorders. Regards, John.

PS. Must give that plug a clean!

[jamesperrett]

Looks like you could plug a microphone into the radio input - XLR pin 2 to pin 1 on the DIN connector and XLR pin 3 to pin 2 on the DIN connector. The impedance is a bit high but the sensitivity looks about right. If you really want to use the right impedance you could use a matching transformer like the one at

https://cpc.farnell.com/unbranded/ma...mer/dp/MP33028

but you would need to replace the jack plug with a 3 pin DIN plug.

[ricard]

Originally Posted by Heatercathodeshort

here is a picture of the original mic with it's odd Din plug.

Is that basically the same layout as the 5 pin "domino" DIN configuration, but without the centre pin (and with the extra flat plastic pin)?

[barrymagrec]

No, it`s a symetrical 4 pins, the plastic pin operates a switch in the socket, I think it`s a McMurdo special, not part of the standard DIN range.

[TonyDuell]

I seem to remember that the 4 pin are in the same positions as pins 1,2,4,5 of the 5 pin 240 degree (type B) plug. But if you want the switch to open when you insert the plug you must put a plastic pin in the right place, it just goes between the 2 contacts so a metal pin would keep the circuit completed.

[DMcMahon]

The picture of the female socket in Post 1 looks strange, what I thought would be the 2 right hand (as looking at the image) socket pins, when you enlarge the image looks like maybe 1 contact ? if so then the 4 pin DIN in Post 6 may not fit ??

[ms660]

Originally Posted by DMcMahon

The picture of the female socket in Post 1 looks strange, what I thought would be the 2 right hand (as looking at the image) socket pins, when you enlarge the image looks like maybe 1 contact ? if so then the 4 pin DIN in Post 6 may not fit ??

So far as I can make out, the two outer faces of the switch contacts form two of the sockets pin contacts.

Lawrence.

[ricard]

I knew I'd seen a similar connector somewhere ... the Tandberg model 5 has two similar sockets, for special purposes, but apparently without cutouts in the plastic for the two pins on each side of the plastic stud. So this particular one is two pin only, but still with the stud.

[DMcMahon]

I found one of the 4 pin DINs, compared to 5 pin Domino in attached photo, very similar, maybe very slight differences in pin spacing, difficult to be sure.

[ms660]

So far as I can make out pins 2 and 4 are the switched contacts which make when the Mic. plug isn't inserted, in which case the PU2 and Radio inputs are routed to the amplifier input via the Rec/Playback switch when in record.

Pin 1 is the Pause control line, it operates the Pause solenoid when shorted to ground via a switch on the microphone.

Pin 2 is the input from the Radio and PU2 sockets.

Pin 4 is the output to the amplifier via the Rec/Playback switch when in record.

Pin 5 is Mic. ground.

The sockets ground connection is connected to the main ground (HT-ve)

Inserting the Mic. plug breaks the switch contacts and connects the signal from the Mic. to Pin 4 and the ground from the Mic to Pin 5, and enables the pause control switch on the Mic. if one is fitted.

If that's any help.

Lawrence.

[DMcMahon]

Looking at one Marconiphone (model 4216) I think now I am beginning to understand how the 4 pin DIN works.

The 2 lower pins (pins 2 & 4) where there is no DIN body on the inside of the pins are normally closed (N/C).

If no 4 pin DIN plugged in then the closed contacts of pins 2 and 4 feed either a Radio signal from the Radio phono or PU (Pick Up) signal from the PU phono into the Record amplifier. If a 4 pin DIN microphone is plugged in then the plastic pin/peg on the DIN plug breaks open pins 2 and 4 and the microphone signal is inputted into the Record amplifier from pins 4 and 5.

I assume similar applies when the Radio and PU are inputted via 5 pin DIN but do not know Oliver's model number to double check.

Update - Clashed with Lawrence's inputs.