First, I want to apologize if this is the wrong section. I've got a technical question about crosstalk, and the cassette deck section seemed to me the less wrong to post, for the reasons you are going to see... So, is there among you a wise person who knows a lot about (how to avoid) crosstalk? In short, I've made some recordings with my Pioneer CT-656 II cassette deck. Among the cassettes I used, there's this TDK called "Fe - Ferric" where, in two cases out of two, I got an insane amount of crosstalk. The right channel is picking the opposite track at -30 db! The cassettes, per se, look like very good type 1, with screwed on clamshell and a nice dark tape. No other cassette has given me such an amount of crosstalk, not even half of it. What am I doing wrong? Should I record using a quieter level? Should I reduce the bias, killing as much low frequencies as possible? Are theese TDK Fe cassettes cursed? I found a video on the tube where they are featured, and they emerge as good type I
Yes, I am. At the moment it's the only deck I've got. Also, this deck has got automatic HX pro noise reduction, in both recording and play.
The reason I asked is that most alignment problems like crosstalk happen when a tape is played in a different deck. Any deck should have the least problems when playing back tapes recorded (recently) in the same deck.
I noticed the crosstalk WHILE I was recording. I flipped the cassette to record side B, and there it was the last song of side A played backward! I'm sure I did something wrong, but I don't know what...
You need to do a simple test: does this happen with pre-recorded tapes or tapes recorded in a different deck/recorder ? I read that this is your only deck, but this is the simplest test you can do, so buy a cheap pre-recorded tape if you have none. Checking with a tape recorded on a different recorder will also rule out a potential head height misadjustment (if it has an adjustment) or azimuth misadjustment. Given the fact it's happening only on the right channel, you're probably doing nothing wrong, but it's something wrong with the deck itself or cassette. Some kind of crosstalk between side A and side B will always exist (it's the reason why calibration tapes are recorded only on side A), but it should be very minimal like barely audible with volume turned at max.
Yes, in fact I always have some kind of crosstalk with other cassettes, but it's usually very faint. Even pushing my amplifier or mixer volume very high, it's barely audble over the obvious tape background hiss. However, I do have a pre-recorded commercial cassette, and I just tested it: no crosstalk that I can hear. I'm using also some TDK D I just recorded with the very same deck, and, yes, there's a little crosstalk, but unnoticeable at normal volume, and even when I crank the volume up, it's barely intelligible among the background noise.
I have not read you first post carefully. Now I understand it's a problem you only get with this specific tape. So a problem with the deck can pretty much be ruled out. This is the cassette you are talking about: https://www.retrostylemedia.co.uk/product/tdk-fe90-ferric-blank-audio-cassette-tapes ? You say that in 2 cases out of 2 it does the problem: you only have 2 blanks and both are manifesting the issue ? I have encountered BASF Sound I tapes that degraded over time, although stored properly. To me it clearly seems the tape itself is the problem. Try to record a 315Hz -10dB signal on it and also a 10kHz -10dB signal. What output do you get in each case on left/right channels ?
I will try your suggestion in the weekend, Valentin. Yes, the cassettes are exactly the one you linked. I've got three other blanks of them, as I actually bought a 5-pack on ebay.
The -10 db, 315 Hz signal gets recorded at - 15 db on both channels. If I flip the cassette, I can hear crosstalk at normal volume, but the vu meter doesn't move (it it would, the led next to - infinity would be - 30 db, but the leds stays at - ininity, the - 30 db level isn't reached). The crosstalk is at typical crosstalk volume, so to say, like a far sound in the background, but I have no need to rise my listening volume to tell that it's there. The 10 kHz signal gets recorded at - 10 db on the right, and - 15 db on the left, but if I reach for the minimum bias available both are at - 10 db. If I flip the cassette, I can hear very faint crosstalk at normal volume, but barely noticeable in the background hiss; I have to crank the amplifier to be sure that it's there. Meter leds at - infinity.
Sounds to me like the internal bias adjustment should be done, as bias is not equal on both left and right channel. However, a full calibration is recommended, because most parameters are influenced by each other. For example, the playback level is the first that should be done as this will influence all others. Then the record level, bias and the bias trap (if it is adjustable). You can do just the bias yourself (I can guide you into doing it) or send the unit to me for a full calibration. By the way, how does the head look ? Is there any visible wear ? Some pictures would be interesting to see.
The head looks clean, but I agree that this deck probably needs a calibration. I'd like to try a calibration myself, and your help would be very appreciated, and also necessary, as I've never done it before. Unfortunately, I don't own those AGFA cassettes with calibration tones and advanced instruments like oscilloscope and such... I've just a multimeter lying somewhere...
What multimeter do you have ? You need a multimeter capable of measuring AC voltages at 10kHz. A TrueRMS one is to be preffered as well. If meter is not suitable, adjust so that both channels give the same level on VU-meter as the input at 10kHz. For example, if you feed 10kHz -10dB, you should get -10dB out, not -15dB. If you feed -15dB, you should get -15 on both. Adjust only the one that is off, not both. NOTE: The external bias potentiometer should be on zero when performing this adjustment.
