Mystifying Cassette Recorder Issue

[NoiseWiki]

When it's recording to a tape, it will erase the original audio with no difficulty, but only the absolute loudest of sounds through the onboard mic seems to be picked up.

Sounds like a bias problem to me. Was the former user someone who like to tinker? Often bias adjustment amounts to a trimmer on the inside. At this point, it sounds like you have little to lose by tinkering yourself.

Hmm but if this deck only has one head then would it not also have issues playing back if the bias was off?

[crochambeau]

When it's recording to a tape, it will erase the original audio with no difficulty, but only the absolute loudest of sounds through the onboard mic seems to be picked up.

Sounds like a bias problem to me. Was the former user someone who like to tinker? Often bias adjustment amounts to a trimmer on the inside. At this point, it sounds like you have little to lose by tinkering yourself.

Hmm but if this deck only has one head then would it not also have issues playing back if the bias was off?

Playback head is essentially passive, you only want magnetically charged conditions on the *print*.

[The Mysterious Creep]

When it's recording to a tape, it will erase the original audio with no difficulty, but only the absolute loudest of sounds through the onboard mic seems to be picked up.

Sounds like a bias problem to me. Was the former user someone who like to tinker? Often bias adjustment amounts to a trimmer on the inside. At this point, it sounds like you have little to lose by tinkering yourself.

Nope, they barely used it. Listening back what I thought I heard wasn't there. The tape is just silent for the duration of the recording. It was apparently tested extensively before shipping. It seems almost like it has a working erase head but not a working record head. Of course I have no electronics knowledge so I can't identify what the record head looks like or where it is, but I suspect that's the issue. Because both jacks and the built-in mic all failing in transit seems unlikely.

[NoiseWiki]

When it's recording to a tape, it will erase the original audio with no difficulty, but only the absolute loudest of sounds through the onboard mic seems to be picked up.

Sounds like a bias problem to me. Was the former user someone who like to tinker? Often bias adjustment amounts to a trimmer on the inside. At this point, it sounds like you have little to lose by tinkering yourself.

Nope, they barely used it. Listening back what I thought I heard wasn't there. The tape is just silent for the duration of the recording. It was apparently tested extensively before shipping. It seems almost like it has a working erase head but not a working record head. Of course I have no electronics knowledge so I can't identify what the record head looks like or where it is, but I suspect that's the issue. Because both jacks and the built-in mic all failing in transit seems unlikely.

One thing just occurred to me which is that the output jack on the Monotron is a bit weird.. like it doesn't really work right if you plug a mono cable into it.. it has to be a stereo cable because it is a stereo jack. If you plug a mono cable into it the output cancels itself out. The way I deal with it is to use a stereo to rca splitter and then use an rca to whatever I want to plug it into.

But you also mentioned you did receive a separate mic with it? What I would suggest is trying to plug some other sound sources into it and see what happens.

[crochambeau]

It seems almost like it has a working erase head but not a working record head. Of course I have no electronics knowledge so I can't identify what the record head looks like or where it is, but I suspect that's the issue. Because both jacks and the built-in mic all failing in transit seems unlikely.

I'm not familiar with this unit, but given the conversation so far it really does sound like it's a single multipurpose head doing the job of both record and playback, plus an erase head. The erase head is obviously working, so you have a high frequency oscillator intact.

I've always ASSumed that low end (no offense) decks use DC bias, which would be a different circuit - but it's possible they utilize the HF erase signal as well.

Of course, none of this is germane anymore since no recording is hitting the tape.

I would suspect next a common stage (shared by the multiple inputs) to the record process. Either a switch is bad/dirty (the switch is probably actuating electronic switching, not carrying audio itself) or the drive amplifier for the record head.

I guess it still could be bias, but no signal at all hints elsewhere.

[crochambeau]

both jacks and the built-in mic

Another possibility is that the stuff you speak of in this quote are all on a smaller PCB that connects to the rest of things via a ribbon cable, and that cable became unseated in transit.

[NoiseWiki]

Playback head is essentially passive, you only want magnetically charged conditions on the *print*.

I was thinking of azimuth.. I still wanna know if he tried some other sound source besides the Monotron for the reasons I mentioned.

[The Mysterious Creep]

Playback head is essentially passive, you only want magnetically charged conditions on the *print*.

I was thinking of azimuth.. I still wanna know if he tried some other sound source besides the Monotron for the reasons I mentioned.

Plugging the mic into a digitech death metal and using a 1/4 inch converter with an aux cable was my plan to test input volume as a solution, after using the mic and monotron on their own. The cable is stereo, it's the only one I have. Just a standard cord with a 3.5mm plug at either end.

[FAP]

most likely the input is mono. you can get a mono 1/8" cable or even a 1/8" mono male to 1 /4" mono male quite easily and cheaply.

In general, most "pro" audio devices don't use 1/8" stereo as a standard input. It's far more common to see stereo channels separated into two mono channels, usually 1/4" or XLR. This goes for mixers, pedals, digital recorders, etc. Generally trying stereo cables or adaptors with this stuff means it either won't work at all or only produce a signal in the left channel (look up TRS cables). Doesn't matter if it's a stereo cable with mono adapters at either end: you're best bet is to have mono all the way through until you reach your mixer where you can, well, mix in stereo.

may I ask what exactly you're trying to achieve with this tape recorder?

[NoiseWiki]

Plugging the mic into a digitech death metal and using a 1/4 inch converter with an aux cable was my plan to test input volume as a solution, after using the mic and monotron on their own. The cable is stereo, it's the only one I have. Just a standard cord with a 3.5mm plug at either end.

Yea if your cable is stereo and one end is plugged into the stereo output of the monotron and the other is plugged into a mono jack its the same problem I described.

Try plugging just the mic into it.

You can also try plugging the stereo cable only half way into the Monotron.

Also try plugging your computer headphone output into the tape deck using the stereo cable.