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Vintage Tape (Audio), Cassette, Wire and Magnetic Disc Recorders and Players Open-reel tape recorders, cassette recorders, 8-track players etc.

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Old 9th Oct 2021, 8:49 pm   #1
kellymarie
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Default Cassette help

I have a large collection of cassettes mostly c60 and c90 some date back to the early 1980s and one in particular has got a problem in that the played back audio sounds very muffled and is missing a lot of the higher frequencys my question is is there a way to revive old cassettes like this? Or is it a lost cause?
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Old 9th Oct 2021, 8:50 pm   #2
Nickthedentist
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Default Re: Cassette help

Check the pressure pad hasn't dropped off!
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Old 9th Oct 2021, 11:24 pm   #3
kellymarie
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Pressure pad? Where do I find that pkease?
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Old 9th Oct 2021, 11:32 pm   #4
Cobaltblue
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Default Re: Cassette help

The pressure pad is arrowed.

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Old 9th Oct 2021, 11:36 pm   #5
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Default Re: Cassette help

The pressure pad is shown in this picture.
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Old 9th Oct 2021, 11:36 pm   #6
Ted Kendall
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Default Re: Cassette help

The hole in the centre of the front edge of the cassette accomodates the record/playback head. Across this there is usually a little bronze spring with a felt pad at its centre, although some pre-recorded cassettes just have a foam block with a plastic facing. If the pad is absent, the tape does not make intimate enough contact with the head and muffled sound is the result.
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Old 10th Oct 2021, 1:03 pm   #7
kellymarie
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Default Re: Cassette help

Great thanks guys I will carefully check that with any luck il get it to play properly again although I've noticed now I've exercised the tape a few times it does seem to be slowly getting better but I will definatley check the little pad is there hasn't come off or whatever thanks again for the help and advice
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Old 10th Oct 2021, 2:37 pm   #8
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Default Re: Cassette help

The pressure pad may be the problem. Muffled sound can also occur if the recording was made on an azimuth misaligned machine. Both problems can normally be addressed.
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Old 13th Oct 2021, 1:58 am   #9
kellymarie
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I had a close look at the cassette in question the pressure pad was deffinatley still where it should be I fast forward and rewound the tape a couple of times and played it on my best tape deck it sounded OK after a couple more plays the sound is getting better my next move will be to copy it onto a new tape so I've got it preserved whilst it's performing well or at least as good as it going to get
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Old 13th Oct 2021, 4:20 am   #10
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If the recording is important to you it's probably not a good idea to repeatedly fast wind or play it. It will probably do more harm than good. Is it possible it was always a muffled recording?
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Old 13th Oct 2021, 7:53 am   #11
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Default Re: Cassette help

I would save the audio as a file to my computer and enhance the upper frequencies using WavePad, (a freeware programme), then put it on a CD.
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Old 13th Oct 2021, 10:37 am   #12
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Default Re: Cassette help

A lot of cassettes, especially prerecorded ones, have pressure pads made of just a thick lump of foam with no spring behind it. The foam goes soft and crumbly with age so no longer presses the tape against the head properly, leading to muffled playback. I've got lots of old computer cassettes which suffer from this.

So it may appear that the pressure pad is there but it may not be doing its job. Better cassettes have a thinner pressure pad mounted on a spring, which doesn't suffer from aging in the same way.

For cassettes afflicted with this problem there are various solutions:
- take the cassette apart and replace the pressure pad with a new one (a small piece carefully cut from a dishwashing sponge with a scalpel will do the job)
- take the reels out of the cassette and put them in a different housing with a better pressure pad
- play back the cassette on a high-end cassette deck with a dual capstan transport. This keeps the tape in contact with the head without using the pressure pad at all.

Trying to boost the high frequencies in an audio editor on a poor cassette playback will only lead to disappointment with a lot of background hiss. The old adage, garbage in, garbage out, applies. Get the best playback possible by correcting the pressure pad problem and adjusting the playback head azimuth to suit the tape, and only then try editing the audio.

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Old 13th Oct 2021, 10:45 am   #13
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Default Re: Cassette help

If the recording is valuable, I would digitise it too, but I wouldnt throw away the cassette either. The cassette may well outlast the CD-R to which it is copied.

Much of the value of digital is in allowing quick, high quality and easy access. Access and long term preservation arent quite the same thing.

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Old 13th Oct 2021, 12:00 pm   #14
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Tape paths can also have multiple issues that strip high frequencies with every pass. I'm not suggesting that your current machine is doing this, but is there possibility that the tape could've been played in a machine that did? A common fault is a high-frequency tone, say 12 or 15K, loses amplitude with every pass when measured with an RMS meter. This can be due to erase head problems, as well as tape path wearing the top oxide layer off.

On top of the above, there is also the issue of 'shed'. After many years, the oxide layer can lose its integrity and start to deposit itself on the heads. You will see that some tapes can deposit a load of junk onto the heads just in a few minutes of play. This definitely won't improve HF response!

If the recording is valuable to you, then I can only second what's been recommended so far. Transcribe the tape via a machine that's in known good fettle and use some kind of EQ to restore HF clarity. If the tape is precious, find a cassette nerd with a Nak or Revox to do it for you. EQ will also bring up hiss.

I find that chrome or metal tapes in mint condition give similar HF response on either my Technics or Sony machines. However, tapes that are most likely shedding, i.e. have diminished HF, sound a lot brighter on the Sony.
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Old 13th Oct 2021, 1:48 pm   #15
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Default Re: Cassette help

NB - a couple of other points to note:

Nakamichi decks have a system that lifts the pressure pad, so the tape's tensioned by the capstans - taking the pad out of the equation. If the tape's precious, then see if someone can copy it with a Nak

To back up point I made in previous post: if you buy commercially-made tapes secondhand (not always a great idea, sound-wise!), you'll note that the most popular tracks often have the least top end due to being played more often than the others.
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