Cassette recording issue: bright/loud to muddy/quiet and back

[lo.fi.love]

Hello,

I've got a problem when recording to cassette, and it happens every so often. It happened at my friend's band's show the other day and I'm really upset since almost the entire set's recording has to be scrapped because of this.

Apparently there were issues with the tape when I was recording. When I play it back, the signal goes from being loud and clear to being quiet and muddy, in an almost consistent pattern (equal intervals between low and high).

I've had this problem before. I thought it was the tape, but I was able to rewind the tape and record again without this problem occurring on the same stretch of tape.

I'm using a Marantz PMD-430 stereo cassette field recorder with two dynamic mics, if this provides any insightful information. Also, the first two bands' sets came out OK on the A-side of the tape. I flipped over the tape and rewound it before recording the third band, which is the recording that I have this problem with.

Is it a matter of adjusting some settings on the recorder? Or, is it about the tension of the tape in the cassette (the reels held the tape too tightly)?

If anybody can help I will be really thankful. I'd like for this to not happen again.

Thank you!

[analogkid]

I am about 90% certain that what you have is a flat spot on the pinch roller. Basically if the heads were left enagged with the tape with the power off thsi could happen - I'm not familiar with that model of recorder, but assuming you've done all the cleaning/demagging etc and it's NOT the tape (and sounds like not because it isn;t in the same spot each time) then you need a new pinch roller.


Anyone else think of another possible cause?


AK

[lo.fi.love]

Here is an uneducated guess: Could it have anything with the noise reduction screwing up? My recorder has two N.R. setting (aside from "off"): Dolby B and dbx. It was set to dbx when I recorded all three of the bands' sets, so it might have nothing to do with this.

[analogkid]

If it was DBX encoded and failed to decode correctly you could get some odd sounds..... but I would expect it to be the same each play. You could test the recorder with noise reduction off and see if the problem repeats. Didi you try to play it back with each different setting of the noise reduction?



AK

[lo.fi.love]

Originally Posted by analogkid

If it was DBX encoded and failed to decode correctly you could get some odd sounds..... but I would expect it to be the same each play. You could test the recorder with noise reduction off and see if the problem repeats. Didi you try to play it back with each different setting of the noise reduction?



AK

I played it back with the same noise reduction settings. I haven't played it back with the NR off or in the Dolby B position.

I'll also try playing the tape in another Type IV-capable deck and see if I get similar results. But if I remember correctly, the playback was the same on every deck I tried playing through when I last encountered this problem.

Is there any possibility that the tape was rolled up too tight? It's a 100-minute TDK MA-X cassette, and I was wondering if it could be wound up so tight on a full rewind that the mechanism pulling the tape through the machine might have problems pulling it through at a consistent speed. Does this make sense? Am I describing my thought clearly? Is this an actual issue or am I just making an unfounded speculation?

[cjacek]

First make absolutely certain that if you recorded with dbx, you need to play it back with dbx. What you're describing sounds as if you're either playing back a dbx encoded signal with the dbx off [or vice versa] or the dbx system doesn't work. Check carefully.

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[Herm]

I would guess its the tape. All I ever had was bad luck with long tapes.
Also did you use batteries with this recorder?

[jjones1700]

I know this may be a rudimentary question, but did you clean your tape path recently? I had a similar problem with my 424 and dbx. The pinch roller and capstan were dirty so (I can only assume) that the tape wasn't tracking properly. With dbx, misalignment is a big headache. I gave the whole transport a thorough cleaning and haven't had a single problem since. Just a suggestion.

[RRuskin]

With cassettes, anything longer than C-60 is asking for trouble. The thinner tape stock just doesnt behave consistantly on a good day. Analog tape units need to be cleaned after each use. Waiting for a problem is usually too little too late.

[lo.fi.love]

Originally Posted by Herm

I would guess its the tape. All I ever had was bad luck with long tapes.
Also did you use batteries with this recorder?

Yes, it runs on three D-cells. I put fresh batteries in the recorder that evening, though.

[lo.fi.love]

Originally Posted by jjones1700

I know this may be a rudimentary question, but did you clean your tape path recently?

I'm still developing my rudimentary knowledge No, I haven't cleaned the tape path. I really should do this.

I had a similar problem with my 424 and dbx. The pinch roller and capstan were dirty so (I can only assume) that the tape wasn't tracking properly. With dbx, misalignment is a big headache. I gave the whole transport a thorough cleaning and haven't had a single problem since. Just a suggestion.

I'll give this a try. I don't have the correct material/fluid to clean the pinch roller but I will do whatever else that I can with alcohol. I'll refer to the guides that I've found on the Web on how to do this. I'm going out again tonight so hopefully I'll be able to get it working well enough.

I'll also be using a C90 Type II tape. I don't see much of a point in using the Type IV right now since I'm using cheap mics until my new mics arrive.

[lo.fi.love]

I cleaned the heads and capstan before I went out on Tuesday to do another recording. The capstan left a reddish-brown stain on the swab. It's totally clean now, which I hope will help.

I managed to get a recording without this issue, using a C90. I need to have my recorder serviced, anyway (dirty recording-level pots) so I'll see about getting the pinch roller cleaned while I'm there.

[RRuskin]

Originally Posted by lo.fi.love

I cleaned the heads and capstan before I went out on Tuesday to do another recording. The capstan left a reddish-brown stain on the swab. It's totally clean now, which I hope will help.

I managed to get a recording without this issue, using a C90. I need to have my recorder serviced, anyway (dirty recording-level pots) so I'll see about getting the pinch roller cleaned while I'm there.

Be smart and have a new one installed and then maintain it properly.

[lo.fi.love]

Originally Posted by RRuskin

Be smart and have a new one installed and then maintain it properly.

Brilliant idea. Thanks for the tip!