Technics RS-B355. Slight imbalance in recorded output

[Skylark UK]

I've just bought a second hand Technics RS-B355 cassette player.

The primary purpose for my buying it is to record tapes to play while driving my 1980s Ford Escort.

The deck looks to be in good condition and everything seems to work fine, with one minor exception.

If I record with the balance knob central in its notch, while recording the two peak level bar graphs look nicely balanced. However, on playback, the left side peak level is not as strong as the right.

If I adjust the balance knob to slightly overdrive the left channel, on playback the levels look good. I'd prefer to leave the balance knob in the centre and have balanced outputs on the peak level display.

Any ideas as to why the left channel recording isn't as strong as the right? Is there a simply fix for an amateur?

Many thanks

[cmjones01]

I also have an RS-B355 deck and it still works well even though it's 35 years old. In the case of channel imbalance like this, I'd check the cleanliness of the heads and the rest of the tape path first, then inspect the head to see if it's worn. The heads in these decks are permalloy, not sendust, so they do wear. Mine's quite worn but still works OK, though a worn head does tend to accumulate dirt at the edge of the tape path.

To go further than this really needs a proper calibration tape and the associated equipment, first to make sure that playback levels are correct on both channels, and then to check the recording levels.

The other thing I note is that on my RS-B355 the head height isn't quite right. It plays back its own recordings fine, but the tracks on the tape are slightly misaligned when compared with various other decks. There's no adjustment for this - it's just the way the deck is made. It's a budget machine so this is to be expected to some extent. So I'd also suggest trying a different cassette, especially as it's the left channel that's low - the left channel is nearest the edge of the tape, so is most likely to be affected by head height. Another cassette might have slightly wider tape and not be affected so much.

Chris

[Skylark UK]

Originally Posted by cmjones01

I also have an RS-B355 deck and it still works well even though it's 35 years old. In the case of channel imbalance like this, I'd check the cleanliness of the heads and the rest of the tape path first, then inspect the head to see if it's worn. The heads in these decks are permalloy, not sendust, so they do wear. Mine's quite worn but still works OK, though a worn head does tend to accumulate dirt at the edge of the tape path.

To go further than this really needs a proper calibration tape and the associated equipment, first to make sure that playback levels are correct on both channels, and then to check the recording levels.

The other thing I note is that on my RS-B355 the head height isn't quite right. It plays back its own recordings fine, but the tracks on the tape are slightly misaligned when compared with various other decks. There's no adjustment for this - it's just the way the deck is made. It's a budget machine so this is to be expected to some extent. So I'd also suggest trying a different cassette, especially as it's the left channel that's low - the left channel is nearest the edge of the tape, so is most likely to be affected by head height. Another cassette might have slightly wider tape and not be affected so much.

Chris

Many thanks, Chris.
I carefully cleaned as much as I could using a cotton bud with IPA. It didn’t seem to make a difference. According to the peak level meters, output from a recording shows a lower left channel.

Unfortunately, the situation has now worsened. By the time I got to the end of a 45 minute tape, the left channel was virtually dead. During record, there was a mechanical noise too, sounding like in need of lubrication.

Appreciate your further thoughts. Thank you.

[cmjones01]

At the end of the tape was the left channel low on playback or on record? It's not unknown for tapes, especially older ones, to shed some oxide and partially clog up the heads. This happened to me recently when recording on an old TDK SA cassette which I didn't notice had some crinkled damage near the start. I found that the first few seconds of the recording were OK, but the left channel faded out almost completely after that. The recording deck's head had got clogged with bits of oxide which had fallen off the damaged tape.

Technics decks of this era do apparently suffer from crumbling of the plastic gears in the mechanism. Mine still works but makes some awful noises during fast forward and rewind, so something's probably on the way out. Yours may have similar issues but that shouldn't stop it recording and playing back properly, at least until it gives up altogether.

To find out what's going on, it's really useful to have a another known good deck and some good recordings, to see whether the problem is about dirty heads or some electronic problem. Does the Technics play back a known good cassette properly? Do the Technics's recordings play back worse or better on another deck?

Chris

[Skylark UK]

Thanks again @cmjones01

I think that you hit the nail on the head by suspecting the tape. It was an old but unused Philips tape and it left a residue on the head. Cleaned it off again and the deck is playing pre-recorded tapes well. Tried recording with an old but unused TDK tape and it’s all working well.

Really appreciate your input, thank you.

[cmjones01]

I'm glad to hear you've found the answer. Enjoy your cassette recordings!