Stellaphone 454

[JonathanRMB]

If anyone has the manual for this model, could they send it to me. Also, if anyone knows of any blog or resource concerning these type of 4 track machines (the 1-4, 2-3). Essentially, the 1/4” tape was divided into eight channels ? I know these machines were mono, but given that they used two tracks to record - would it have been possible to record stereo ( in theory) ? Lastly, what are the correct connectors for the inputs and outputs that aren’t the obvious DIN sockets ? I presume they are bananas, but I’m a novice at this - and I haven’t found an account of this sort of connector.

[ms660]

So far as I know the service data for the Philips EL3541 will do:

https://www.service-data.com/section.php/6073/1/el3541

Mono 4 track on record & playback.

Stereo 2 track on playback with an external amplifier.

There's a review from the Tape Recording magazine here:

https://worldradiohistory.com/hd2/ID...-Page-0029.pdf

Lawrence.

[Sideband]

Not sure what you mean by dividing 1/4" tape into eight channels?. No they were a four track mono machine so the tape was divided into four mono tracks. Tracks were arranged as 1,4 on the outer edge and tracks 2,3 in the middle...1
3
2
4
It was usually possible to PLAY a stereo tape in mono by using the PAR (parallel) switch but there was no way to record in stereo since it only had a mono amplifier anyway.

I think some machines had a different order for the four tracks.

[Simon Gittins]

There is some information about the connectors (it isn't clear what they are called though) in this thread:
https://vintage-radio.net/forum/showthread.php?t=124489

[ricard]

Many mono 4 track machines, I think including the EL3541, had a 'stereo' connector (on the EL3541 I think it is one the side of the top plastic cover) which was connected to the half of the head that was not being played back by the machine itself. An external amplifier with proper amplification and equalization could then be used to play back the other channel. On many machines, this only worked when the machine itself was playing the would-be left channel (track 1 or 4).

Another use for this 'stereo' connector would be for a slide projector synchronizer, where some form of sync signal (a 'bleep' of some sort) would be recorded on track 3, while the ordinary audio was recorded on track 1.

Having access to "the other half" of the head meant that one could fathomably record in stereo, with the proper external equipment (amplifier with proper equalization and bias generation); indeed, the slide synchronizer would have had a simple recording circuit for getting the 'bleeps' onto the tape in the first place. I don't think anyone used it this way; even stereo playback was probably rarely used on machines like this.

Another issue would have been that the machine could only erase one track at a time, thus, for re-recording stereo over existing material, one would have had to run the tape through the machine one extra time, to erase the right hand channel.

So, theoretically yes, one could record in stereo, but in practice, most likely not.

Regarding the four tracks, this will be familiar to most readers of this forum, but for the purpose of this thread: most manufacturers numbered the tracks 1-2-3-4 from above, with the heads having two sections which accessed tracks 1 and 3 when playing in one direction, and 4 and 2 when the tape was flipped over. Hence the markings '1-4' and '2-3' on the track selector.

Grundig however, and possibly other German manufacturers, however numbered the tracks 1-4-3-2 from above, the logic being that the legend on the track selector would then be a more logical (from a user's point of view who had no idea of the actual arrangement of the tracks on the tape) '1-2' and '3-4'.

For stereo, tracks 1 and 3 would be used for the left and right channels of side A, and tracks 4 and 2 for the left and right channels of side B, respectively. (or 1 and 2 vs 3 and 4 in Grundig parlance).

[DMcMahon]

Originally Posted by Simon Gittins

There is some information about the connectors (it isn't clear what they are called though) in this thread:
https://vintage-radio.net/forum/showthread.php?t=124489

Looking at the various Philips documentation there are at least 3 slightly different variants in regards to the input connectors, one with 3 DINs, one with 2 DINs + 5 pin in-line connector (referred to as Pick Up IEC connector in the older linked Thread) and one with 1 DIN (Microphone) + 2 round pin round connector (for Phono/gramophone/radio).

The 2 round pin connector is also used for the 2 output connectors, namely headphones and loudspeaker.

It is not clear from the documentation if these 2 pin connectors are actually integral 2 pin connectors or just separate 1 pin connectors. Either way 2 suitable diameter banana/wander plug connectors etc could be used (on the external cable connections) per input/output connector.

The documentation images show a 2 pin plug going into the connectors in question, the plug looks similar to a continental 2 pin mains plug but I am not familiar with similar plugs used as audio connectors.

David

[TonyDuell]

As others have said, Stella was a brand used by Philips, and Stellaphone tape recorders are normally closely related to Philips models of a similar date.

I find a Focal Press book entitled 'The Philips Tape Recorder Book' to be very useful. The last section is 'working instructions in a nutshell' and gives descriptions of the controls and connectors for most of the models. The rest of the book is more general information on tape recording which will explain the '1-4' amd '3-2' switch for example. This book went through several editions, you want to make sure the machine you have is in the book you get.

As for that 2 pin connector, it is a 2 pin plug with a dummy pin in the centre. The book I mentioned says that that pin is to prevent you plugging the plug into a European wall socket. I think some plugs had a flat pin, others a round pin in the centre, there was a convention that one type was used for inputs, the other for outputs, but I forget which was which. But a pair of 4mm plugs fits fine.

[DMcMahon]

Interesting that Tony about the third (dummy) pin. The Dutch documentation I looked at appears to show 2 pin plugs/sockets.

The UK manual did appear to show a middle pin in addition to the 2 normal pins, it show the 3 pins on mechanical layout drawing.

Looking at an EL3541 on eBay (UK sale) for the input connectors the middle pin looks circular but with a rectangular cut-out section, the output pins have a circular middle pin.

Do you think it was proprietary to Philips ?

Because the middle pin is a dummy pin (when fitted) there is nothing to reflect the dummy pin on the schematic.

David

[TonyDuell]

Philips were certainly one of the main manufacturers to use such connectors but I don't think it was only them.

A couple of points :

I have a Revox tape recorder where the instructions say that the mains plug was inserted in the extension speaker socket for shipping (so the pin spacing was the same) and I am pretty sure there was a hole between the sockets for the dummy pin on such a plug.

I've seen Philips radios with similar sockets for the extension speaker, pickup input, etc. I can't think of other makes that used them though.

The plugs were sold under the 'Tape Recorder Spares' brand at one point and were not described as being 'for Philips' or anything like that.

[DMcMahon]

Thought I might have found an example of 2 pin mains cable being fitted in a 2 pin audio connector for shipping in this Grundig TK 6, but reading up on it, it is a stowage position for the mains cable when using the internal batteries and when removed the battery circuit is isolated (presumably there is a switch in the female socket that is actuated).

David

[DMcMahon]

Originally Posted by TonyDuell

I find a Focal Press book entitled 'The Philips Tape Recorder Book' to be very useful. The last section is 'working instructions in a nutshell' and gives descriptions of the controls and connectors for most of the models. The rest of the book is more general information on tape recording which will explain the '1-4' amd '3-2' switch for example. This book went through several editions, you want to make sure the machine you have is in the book you get.

Philips book sound good so have just brought one.