Sound Belle reel-to-reel heads
I have an old Sounds Belle tape recorder - a very neat design from the late 50s - but it unfortunately doesn't produce any sound. There is a button labelled P.A. (I guess for Public Address) which connects the microphone input straight through to the amplifier section and to the loudspeaker, and this works fine.
But nothing at all from the tape, so I suspect the play/record head may not be working. I don't have a signal injector but I managed to wire up an old ceramic record player cartridge to the wires to the tape head (as I believe the signal levels are similar) and miraculously this worked. The tape player is only mono, of course, but the tape head has 4 connectors. Two of these are soldered together and the other two carry the signal. I'm wondering if the other two connectors are for a second channel and if I use those 2 connectors and short out the ones that are currently used, maybe this might work? Any suggestions? Or any ideas where I might find a replacement head at a price that would make this worth repairing? |
Re: Sounds Belle reel-to-reel heads
Tape heads have two coils which are normally connected in series. Sometimes this connection is external, as appears to be the case here.
A crystal cartridge gives several times the output level of a tape head so your replay amplifier may be low gain, equally the head may be faulty. If you have a multimeter check it for DC resistance, assuming there is a reading (out of circuit) the head is probably O.K. Ideally you should demagnetise the head after passing DC through it but at this stage don`t worry. I assume you don`t have a tape with a known recording on it to try. |
Re: Sounds Belle reel-to-reel heads
There is scant information about this recorder as the tape-deck manufacturer may need some researching. To help your searches, your machine is a SOUND "Belle" (not Sounds) made by Tape Recorders (Electronics ) Limited. I have the original 1959 sales brochure for this rare model - but not readily accessible at this time.
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Re: Sounds Belle reel-to-reel heads
The service info is up top:
At any rate for serial 35000 up. Apparently earlier version had ECC83 instead of EF86 front end. https://www.service-data.com/section.php/7622/1/a15935 It's actually a Sound Belle according to the service sheet. |
Re: Sound Belle reel-to-reel heads
I have found a circuit diagram: https://www.service-data.com/section.php/7622/1/a15935. It's a bit hard to follow but seems accurate. I do have a tape but I don't know if there is anything on it. I tried recording on it from the microphone and playing it back, but nothing. Whether it is not recording or just not playing back - or maybe both - I don't know. I was wondering about making a coil with the lead from a jack plug and bringing it close to the head. Would this work? Would it work the other way around to check the recording?
I can't find any replacement heads on ebay unfortunately. |
Re: Sound Belle reel-to-reel heads
I was reading that the Sound Belle does not use capstan drive, that is fairly unusual, I guess it uses a form of rim drive ?
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Re: Sound Belle reel-to-reel heads
Have you checked the heads for continuity readings as advised above ?
If you had access to another recorder (working) you could check if the tape you have has any existing recordings on it and if the new recording attempts are actually being recorded to the tape. |
Re: Sound Belle reel-to-reel heads
I think this is a badged Incis (Italian), as were many budget machines of the 1960s.
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Re: Sound Belle reel-to-reel heads
Yes, it has a rim drive and although the motor is really quiet the drive to the spool via the rim is very noisy so I will have to dismantle that.
Unfortunately I don't jave another tape recorder so need to fimd other ways of testing. |
Re: Sound Belle reel-to-reel heads
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Paul |
Re: Sound Belle reel-to-reel heads
Presumably without a capstan the tape speed will vary as the diameter of tape on the right hand spool changes. This would make it impossible to play a tape from another machine that did use a capstan for constant tape speed. An unusual design!
Checking the signal at the record/playback head, when set to record it looks fine with the bias at about 47kHz. Similarly the erase head shows the right signal. So it seems that the tape recorder is certainly working as far as the r/p head. The tape head does show a reasonable resistance of about 230 ohms so I think I now have to find a way of sending a magnetic signal through the head to see if that gets through or finding a bit of tape that I'm sure has something on. My model also has Daly and ERO capacitors so it sounds like the same model and probably UK made. Surprisingly, the capacitors test out as still withing spec but I will be replacing them once I can sort out the R/P head. Apologies if I seem a bit clueless but this is the first time I've worked on a tape recorder. Record players and amplifiers have been more my thing up to now but this seemed like a challenge. |
Re: Sound Belle reel-to-reel heads
Are you measuring the Record Bias/Erase signals using an oscilloscope ? If you have a scope then you could monitor the record signal and make sure it is getting through to the head.
At the head itself the record audio signal is modulated onto the much larger record bias signal so can be difficult to see. Similarly when replaying a tape (that has a recording on) you can monitor the playback signal. David |
Re: Sound Belle reel-to-reel heads
Yes. On the scope I can see the bias signal and with the microphone connected I can see the overlayed voice frequency. So all seems to be fine recording and previously I injected a signal there from a ceramic cartridge and that played fine. So from the R/P head back through the recorder it all seems to work fine but when I try to record onto the tape and then play it back I get nothing at all.
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Re: Sound Belle reel-to-reel heads
It sounds like it has got a very dirty head.
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Re: Sound Belle reel-to-reel heads
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Re: Sound Belle reel-to-reel heads
Thanks for the interesting information, Paul. Do you happen to know why 2 of the connections on the head are just connected together?
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Re: Sound Belle reel-to-reel heads
Ensure that the tape has not been wound on back to front.
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Re: Sound Belle reel-to-reel heads
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Re: Sound Belle reel-to-reel heads
The tape needs to be in intimate contact with the head face. Is the felt pad in good condition to make this happen?
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