Reel-to-Reel Recorder Pops and Clicks

Dust or contaminants on the tape is a possibility. Is the playback clear if you discount the pops and clicks. If not it may be the deterioration of the tape. Try using a soft dry fabric that won't create static and very lightly wipe the tape as it comes off the reel and see if the noise disappears. If it comes back after you remove the clothe, the tape is in need of cleaning. If it makes no difference look for contaminants that may be dried onto the tape by looking for discoloration or watermarks on the tape. This is much harder to remove but is possible but tedious. Cleaning the heads and capstans is done with isopropyl alcohol and cotton swabs. The tape can be done by hand with filtered de-ionized water and a lint free rag.

Thank you for your comments. The playback is clear with the exception of the pops and clicks. Since the pops and clicks are not in the same location in relation to the music from one playback to another it would seem to me that contaminants on the tape would not likely be the cause. Dust seems the most likely culprit yet this tape has been kept for years with all of the other tapes and this is the only tape that has produced clicks and pops. And it did not present this problem during the first times I played it. The problem cropped up seemingly out of nowhere. A few of the tapes had "sticky-shed syndrome" but I baked those tapes in a dehydrator at 120 degrees for hours, allowed them to cool for a day and they played like new. However, I cannot remember if this tape was one of those i had to bake. I am in the process of transferring personal concert and recital performances from analog to digital via my Intel IMac 24 computer using the A/D chips in the computer. All are 1/4" tapes on 7" or 15" reels, most of them in quarter track and a few in half track formations. I have been getting good results, no pops or clicks, and quality sound. Then I had the three heads replaced with new heads which were mounted and aligned by a lab that specializes in such work. The new heads produced a deeper, richer sound and the signal strength is much higher. And, no pops and clicks. I had already made a digital copy of this tape and other tapes with the old heads. I now decided to remake copies with the new heads and all has gone exceedingly well. Until I came to this tape, which, by the way, is on a 15" reel. I did not notice the pops and clicks while monitoring the tape at the recorder but I did hear them when monitoring the result from the computer and after the transfer they are very visible in the power spectrum shown on the screen. Yet in checking the tape for damage at the point of the pop or click in the music there is no sign of any damage. When I checked again I noticed that the pop or click was no longer there but would appear elsewhere.

Hi LWH,

Along with Charsley's good answer, the playback/recording head(s) and surrounding parts may need to be demagnetized. Heads that are magnetized can cause excessive noise and distortion and can even erase the tape over time, beginning with the higher frequencies.

There are many sites that will point you to a demagnetizer as well as show you the demagnetization procedure.

Hope this helps.

Mike

I have ordered a demagnetizer for this machine (Teac A3440) However, the heads are brand and have been used for only about 10 hours of play. When the demagnetizer arrives I will, of course, put it to use. I always thought that magnetized heads would add a his to the sound. Can it also add intermittent sounds such as pops or clicks?

Just out of curiosity, are you using ProTools?

The only other thing I can think of is the tape being wound on the reel incorrectly. Sometimes the tape shifting can cause noise but usually not clicks. If other tapes have recorded well it probably wouldn't be the computer. Is the recording medium different from the other reels? If the problem was crosstalk or magnetic contamination you would most likely be hearing an echo effect.

Let me check and I'll get back to you.

The tape is 1/4 inch Ampex, Audio Mastering 406 on a 15" Aluminum Reel. I have a few other reels like this but most of my tape is 1/4 inch on 7 1/2 reels with no way of knowing the brands of tape; some have a black backing, some do not but none of them are acetate. Most have been recorded in quarter track stereo, a few in half track stereo. Occasionally I will hear some very faint crosstalk from the other quarter track channels.

The first question I have is what signal are you monitoring ? As you record, you must NOT listen to playback ! Why ? Because you can never tell at that point what is actually being recorded. The heads may be operating properly but the output may be distorting (like heavily recorded bass tracks) or the output connections on the machine may be dirty or the actual "cards" or one in particular may be freaking out. Maybe it is the input signal to your converters that is clipping ? Could it be digital distortion / Clipping ?

I have used all sorts of analog tape machines (I still love them) and digital recording systems (Pro Tools, MOTU, you name it) and you must always check the signal coming back from your recording otherwise you can think you are getting a good recording but you won't know if you are always listening to playback.

Did you align the machine ? Did you bias the machine ? Every time you put a new tape up it will be different enough where you must realign the machine.

Is that particular tape a +6 ? +8 ?+9 ? Probably not +9 since it isn't common and most magnetic tape will not take to it like the new BASF 900 does.

Analog gear is tricky, every part of the signal path is subject to degradation, and assuming you have properly aligned the machine, you must check to see if any of the tracks are particularly overloading their channel.

Sometimes it is just old tape degradation, but make sure that you are properly aligned from one tape to another. All recordings should have tones on the reel so you can align and bias the machine each time.

As an accredited engineer who started on analog gear, and yes, we had 1/2" and 2" machines that were taken extremely good care of by the techs although it was always a good engineer who could tell something was wrong and alerted them. Sometimes it was a subtle difference, and it helps to notice any degradation sooner than late.

People are still amazed that at the multi million dollar facilities even in this day and age, we still use tape machines ! My favorite is the Studer 800's ! Unbelievable stuff ! I also have used the 820's, 827's, and a bunch of 1/2" two track machines for final mixes.

Good hunting, I respect analog tape technology, and still use it although not as often. I am also curious as to what converters you use. Remember that just because you have Pro Tools, doesn't mean that you have the best A/D converters, which is the benchmark of your conversion.

First, I am not recording, I am playing back tape recordings that were made of voice recitals that I performed in 1979 through 1984 at West Texas State University. The tapes were made on 1/4 or 1/2 track professional tape recorders (Ampex) and I am attempting to transfer them to digital so I can present them to my family as CDs. These are all quarter track or half track tapes and none of them have separate tracks for bass or drums or whatever. In other words these tapes have nothing whatever to do with country, rock, pop, or any other kind of music. They are recordings of Classical music by Classical composers such as Bach, Handel, Schubert, Schumann, Benjamin Britten, Finzi, etc with voice, piano or small chamber ensembles in live performances in a 450 seat recital hall. Through a series of test takes I have set the recording level so the signals stay within the limits of the recording medium according to the power spectrum displayed on the computer screen. I have no idea how to "align the machine" or set its bias. I had new heads installed and they were aligned by the company that did the install work. All of my other tapes play fine without any 'noise' sounds. None of the tapes have align or bias tones on the reel. I have two converter available. One is a Video converter made by Canopus (ADVC-300) using only the audio converters, and the other is the Intel IMac 24 Express using the A/C converters built into the computer. I am not using Pro Tools, MOTU, etc because I am not using sonic material that I wish to alter or 'manage' in any way.

Yes, these are "stereo" tracks on 1/4" and 1/2" tape. No separate "multitracking" for bass, guitar, vocal, etc. But they are analog tapes you wish to digitize.

My point was that you ARE recording, when you are digitizing your analog audio files. When you transfer them to any digital format, you are processing the analog signal and converting it to a digital signal. I do that for a living. I "record" vinyl records, (stereo track), vocals, drums, all sorts of analog signals. It doesn't matter what it actually is. You are capturing a signal post conversion, and usually by hitting some type of record button.

I suggest you "record" the music using 24 bit and then "burn" a CD in 16 bit to increase the quality of your recording. That is why there is better gear than others, and if you record the initial music at a higher bit rate or sampling rate, you grab much more from the original analog source. You can always export it later to a CD using 16 bit which is the definitive format of a CD (16 bit 44.1k).

And if you have no tones on any reel, then you can have a tape that drastically differs from another tape, and although you have replaced the heads on your machine, without alignment and biasing, potentially every different tape you can put on it can differ drastically. You are lucky it is only one. But that tape could have been recorded to a different bias.

Is your "power spectrum" a Db meter ? Or a spectrometer ?

Your quote:

"In other words these tapes have nothing whatever to do with country, rock, pop, or any other kind of music."

But they do however have to do with:

.....Classical music by Classical composers such as Bach, Handel, Schubert, Schumann, Benjamin Britten, Finzi, etc

"am not using Pro Tools, MOTU, etc because I am not using sonic material that I wish to alter or 'manage' in any way."

Well you are "altering it" by digitizing the analog signal regardless. And if you used MOTU or other professional gear, you will get a better recording for sure as they have better analog to digital converters. (A/D)

You don't "alter" anything using Pro gear unless you use extra processing. The reference was for converter identification only. I didn't think you were going to mess with the original sound, but it actually may be a possibility to utilize some equalization or dynamic processing and it may even need it.

Good luck

Make sure all the various tape decks, amps & computers have a common shield [ground]

Andy's comment's are probably accurate, there may be a broken, corroded or missing ground or the deck itself.

if there are felt pads for tape guides soak them in deionized water for this tape...

Sorry, I misunderstood you. When you said I was recording I thought you meant I was recording onto my tapes. I have been recording the files as AIFF at 96,0 Khz/32 bit, the highest level available with "WireTap Studio" the software I am using. I am sending the stereo signal directly from the tape recorder into the Intel IMac 24 and, thereby, using the A/D chips that are built into the compute. I have one other alternative which is a video converter made by Canopus, the ADVD-300 and this will feed the digitized sound into the IMac via a firewire cable. It is my impression that the A/D chips in the IMac do just as good a job of converting the files as do the chips in the ADVD-300. I burn the CD's from ITunes which automatically converts them to 16 bit 44.1K.

I have never heard of audio tapes having adjustment tones on them. That is new to me. The new heads on R to R machine, a Teac A3440, have been mounted,tested and aligned by JRF Magnetic Sciences in NJ. It was my understanding that it is best to not change their alignment unless something is wrong. I know of now way to change the bias on this machine. Can you suggest something?

The power spectrum I believe is a Db meter. I can send this through software to read it as spectrometer file.

I know of Pro Tools and MOTU but it is my understanding that these are used more by musicians who are recording live into multi track digital software. I would very much like to have an excellent A/D setup with better chips but since i do not record live anymore (I am 75 and a classical singer) the expense of having to buy more equipment than I need is not too appealing.

"the expense of having to buy more equipment than I need is not too appealing."

Boy do I understand that ! Well sir, I love your choice of computing, it is a wonderful machine. So i understand your situation a little better now as well with regards to your converters. Video driven converters are usually low quality, they are compacting video and audio compression and or conversion into one small package, and quality does not correlate to affordability. I am unfamiliar with this unit but it may work well for your purposes regardless.

I would tend to just use the Apple codec, (not sure of what converters are in there) but I would suggest do both and listen back to hear which one is better. Your musical knowledge and perception will kick in and you will most likely notice the difference in quality. Treat it like you would treat a musical performance. Listen acutely at different volumes and the differences will become clear.

As for the expense of buying better converters, I am not accustomed to having anyone purchase something they do not need. However, there are units on the market such as the maudio firewire solo and the like that give quite a bang for the buck although do not stand up to gear such as MOTU or Pro Tools.

But get this... The MOTU HD units (any MOTU unit) has the same converters as the Pro Tools units. So as I say, why pay three times more for the same thing ? Hardware is hardware, and A/D converters are the single most important part of any piece of A/D gear.

My professional opinion is to continue doing what you have been, using the Imac (I guess 1/8" input ?) and use the 96/32 configuration as you mentioned earlier. The only other option you may have is to use other software, which Apple provided ( garage band ) or you can use open source software like Audacity ( http://audacity.sourceforge.net/ ) which has had very good reviews. Just make sure that any open source software you use is stable on your system.

And remember, a Db meter is a meter based on a reference level of 0db. And not all db meters tell you the same thing. Check the range on the side of the meter to see if you are watching a full meter (infinity to 0db+) or a peak meter (say-50db +). Lower the output of the tape machine if you start to get digital clipping, which is entirely different than analog distortion, it will also click and pop also randomly. But if you lower the input into the computer and it still clicks and pops, you will most likely have a problem on the machine end.

Also. every reel SHOULD have tones on them, three sets in fact, 1k, 10k, and 100 hz. These tones are how you are able to align a tape machine. There usually is a small section separate from the tones where you would record new tones from an oscillator at those specific frequencies thus aligning the rec head. They are recorded at a level of +4db I believe.

The place you had the heads done had to align and bias the machine. Too bad you couldn't get a test reel from them. A possibility is also that and unaligned and unbiased tape may be outputting excessively from your machine making for the disparity among the others. That would also lead me to ask if it was even recorded by the same person on the same day. Why ? Because initially, during the recording, it all depends on the engineer, what his mix is doing, how it is "mixed down" to a stereo track (through some type of console) and then bounced to a tape machine to be recorded on what type of magnetic tape (ampex, basf, etc.) that was aligned and biased to what exactly who knows. If there is any writing on the reels or their boxes, it should state at least bias, and match them up to the others. If one says +8 and the other says +6, there exists a problem.

Just in case you may be curious, here is a link to a great little pdf file on magnetic tape. http://www.aes.org/aeshc/docs/3mtape/soundtalk/soundtalkv1n2.pdf

I will check with the repair firm that replaced the heads on my machine to see if I can get a test reel from them.

I also must correct my description of what I called a power spectrum. The WireTap Studio application provides only a Waveform Envelope and it is this display that I use to set my playback volume on the tape recorder to avoid clipping of the signal by the computer and/or software.

Bias, even if wrong, would not cause the problems you are having.

Bias is for recording not playback.

The general quality of the recording might be impacted if bias was wrong as you recorded the tape.

You are only playing back.........

I think that this particular tape makes a static problem, probably somewhere in your machine a ground is missing, either a cable or one of those carbon grounds on a piece of springy metal that rubs against a moving part.

The tape may be from a different manufacturer or a different batch from the same manufacturer and has a higher insulation factor that the others.....this means that it will take a higher static charge and the pops are happening when a component eventually discharges to ground......

A humidifier nearby may reduce the frequency.....get your humidity to 70% or higher, this will either reduce the "loudness" and/or the frequency....it may even be a temporary fix....assuming that your humidity is 45% or more, if less, fix the humidity first!!!

If you watch the machine at night with the lights off, you may see a spark somewhere....this might help in locating the area to search and fix.

Trouble is, the problem might be inside the case......then you need to open up, run that tape and look inside without touching the mains anywhere....!!!!

It will be somewhere where the tape is moving, even the spools themselves can be a cause.....

The only other way is to record it with the pops and use PC software to erase just the pops, Audacity for example will do just that for you.....

You may be correct about the lack of ground. Late yesterday the pops and clicks appeared in three places in the conversion of a different tape from analog to digital. Prior to this it occurred only with the one single tape which prompted my initial request for help.

When I removed the tape stack to have new heads installed and aligned it was necessary for me to unplug four separate wire harnesses from circuit boards within the computer. The Teac A3440 is a four track machine. The tape stack with the 4, four wire harnesses which were soldered to the tape heads was sent to the company doing the work . Of course the repair work included the need to solder the new heads to the 16 wire harness.

Although I was extremely careful in removing the harness plugs from the circuit boards and equally careful in all of my maneuvering around inside the recorder (which, by the way is a wonderful maze of hand assembled wiring) I suppose it is possible that I might have disconnected something.

I live in my home in northern Arizona. The relative humidity here is usually in the 15% range. The chance of raising it to 70% does not exist.

I will try playing a tape in the dark as you suggest to see If I can discover any sparking etc.

I don't have experience of this problem, but whilst the alignment and demagnetisation of your machine is critical for good quality reproduction, it has absolutely nothing to do with your present problem. As Andy has suggested static is the most likely culprit. It is possible that an old and dry tape is being charged by friction with non-conductive tape guides, pressure pads, rollers etc. It is so long since I used the Teac A3440 that I can't remember the details of the tape path now.

The problem is almost certainly static charge build up on the tape. How do I know? I have the same problem and literally saw the discharge!

Also the problem disappeared when I left the tape overnight! And it gets worse each time I play it.

Unfortunately, I was hoping to find a solution. Things I have tried/thought of trying are:-

1. Raising the room humidity (but after I sat the tape on a damp towel I suddenly thought that too high a humidity on one side might just buckle the tape!)

2. Leaving the tape for a day or two (not the best option if your recording equipment covers the dining room table!)

3. Anti-static brushes (or carbon brushes). These are often found on the output paper path in old printers - if only I hadn't thrown them all away. From a technical point of view this is difficult. If the brushes are too conductive, you will get the small lightning strike anyway. If they are not conductive enough, the charge will remain on the tape only to jump ship the first time it comes near any roller tied to ground.

Worst of all, it is possible the brush could scratch the coating, or even the rubbing could GENERATE static!!!

4. Anti-static tape cleaning solution (I seem to recall such cleaners were once available but no idea where to look now). I suppose these could be added to the pressure pads and/or applied using cotton wool.

Remember a few things, all parts of the (of a good!) recorder, except the head itself and the erase head, should only touch the non coated side of the tape.

The tape itself (not the coating) gets charged up.

Properly earthing the various rollers rollers should get rid of the charge completely. heads need also to be earthed usually, especially if metal.....

Old tape formulations can have this problem quite badly, modern formulations are far less affected.

Keep a 55% or better (but not more than 65%) humidity in the room.

Using the tape in a machine where the earthing is bad will cause more charge build up on the tape.....check the carbon contacts, clean if required.

Good luck.

What tape machine are you using?

I note the reference to pressure pads so I assume it is a domestic machine as professional machines don't use them. I suspect the pads could be responsible for charging up the tape or at least worsening the effect as there will be friction between two insulators. (Professional tape often had a conductive backing but most consumer and semi-pro tape did not.) Antistatic solution on the pads might help so long as the pads are on mounts that have a conductive path to chassis.

tapes from this period, the magnetic dust separates from the surface of the tape collecting on the pinch rollers, tension arm, pb rec heads...

make sure you clean the tape path with head cleaner,..

when i transfered my reels to disc (,144 reels ) i made sure i was ready on the 1st attempt, the practice of preview, que , record was changed to cue , record..

hope this helps..

gl

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