MS-16 Puzzle

[bdoughty2005]

Those connectors are for the meter bridge. IMHO The meters can be installed in number of different places. I've got a set of them too. Lt lease that Is what it appears like to me.

Thanks! That solves one mystery.

Any chance that you have something prerecorded to listen to?

Unfortunately, no. But if I record myself talking or singing and play a good section back, it plays back perfectly everytime, leaving me to believe the problem is not with playback.

Noise from caps would be hearable regardless of input conditions if it is in the playback path (heads to line out). THis means that you would hear when listening to a tape without regards to what is recorded or not recorded on it.

Noise from caps on the record side would only be hearable for tracks that you laid down on a single or perhaps more than one channel but most likely not all channels. Again this would be without regard to the singal recorded or not recorded.

There is no noise at all when there is no signal. Apply just a slight signal, and the noise is at it's maximum.

OK, just listened to the noise. That "clicking" sounds like bad caps or noisy pots. Which is interesting as that it should be different per channel.

Is the DBX in or out?

Oh, On the clip you post I hear it from the start of the clip. Is this clip just the playback? I thought that youhoping that this is said that half of it was the input source. And that the input was clean.

I have disabled DBX for all tests. The recorded sample I last posted is all repro, not half input like the first sample I posted. The noise is only present if I montor a recorded signal on the repro head. It is not present if I monitor the input directly.

If I short the wires going to the record head directly to the playback head and monitor 'repro' there is also no noise. The noise seems to be occurring in the magnetic process of recording the signal onto the tape.

Cap/pot noise is random and unique per channel - it happens without regard to signal. Thus each channel may have noise but it will not happen at the same time (test - listen to 2 channels stereo and see if the noise unique per channel)

I tried the stereo test, and the noise is definitely different per channel. Also, the noise only happens when there is a signal present at the input.

If the noise is being generated in the record circuit then the pattern of noise should be the same on each playback of the tape and it should be unique per channel. (Test as above in stereo)

I have done this test. The noise is definitely the same on each subsequent playback of a previously recorded segment. It is unique per channel. Again, bypassing the actual heads in the signal chain (by shorting the record wires to the playback head) eliminates the noise, so it wouldn't seem that the problem is with the record amp circuitry, but possibly the bias circuitry.

Moving on to dropouts - looks like tape path issues - dirt, tension etc....

Just some thoughts off the top of my head.
Regards, Ethan

Thanks very much. It's all good stuff. The only thing you mention that I haven't been able to test is the tape tension because I don't have a tentelometer, but my instinct and experience with other tape machines tells me that the tension is within acceptable ranges.

 

[bdoughty2005]

Yes, that is the thing I forgot to add as well. Without a mod the MS16 cannot bias 499 properly. Just not enough bias.

Being that the test tone is near 1kHz I would not expect to hear rocks like this. Perhaps I'll test it out tonight with 499.

In the MS16 there is a master bias osc that supplies bias amps on each channel. If the master bias osc is faulty then all channels will get that fault (too low output for example)

If the bias freq changed then the bias tuning on the channel cards will all be off.

Try 456 for a test and also try turning the bias level all the way up on one card to see what happens to the sound.

Also as Danial said, adjust the bias level by (I use 12 Hz or so) recording a low freq signal and listening to the playback head signal. Adjust bias for the lowest distortion (rocks).

-Ethan

I will work on getting some 456. If you happen to test your 499 at 1Khz, let me know what you find.

Also, if you had any inclination at all, I could send you one of my reels and you could try it on your machine. That would be helpful in either identifying the problem as the tape itself or ruling it out. I could even send you one of my cards...

Perhaps I could try the bias mod on one of the cards and see if it helps. If it's just changing out one capacitor, that shouldn't be hard to do. I may do this as soon as I get the time. I don't think there's much to lose by trying it.

Regarding the bias oscillator, I did not realize that there is a master oscillator for all channels. I've seen the bias waveform on the oscilloscope and it looks very tight and regular. However, given that the oscillator is common to all channels, perhaps it deserves further investigation.

 

[bdoughty2005]

I don't think there is anything wrong with the machine. This sounds like the oxide coating isn't totally uniform on the tape. I may have asked this before but have you recorded any program yet? I'm betting you won't hear any "rocks" with anything other than test tones.

RRuskin, I was hopeful that your theory would hold true, but alas I tried recording a simple vocal passage and the noise revealed itself in the first second of a sustained note, meaning the machine is not usable in its current state.

I'm steering towards a biasing problem or the possibility that I have two bad tapes.

 

[bdoughty2005]

Thanks

Just wanted to say thanks to everyone for taking the time to share your thoughts. Your ideas are both helpful and educational. I hope that this thread will help others along the way as it has already helped me. And I hope to be on the other end of similar threads once I get this beast up and running!

 

[Herm]

Wow my hearing is so bad I cant hear what everyone else is talking about.
I took your sample and compared it to a 22-4 I use and was shooked at the way my meters bounced with a 1k tone.
If some of you guys dont mind would you go take a listen to this and tell me what you hear or see in your computer programs.

Thanks

 

[bdoughty2005]

Wow my hearing is so bad I cant hear what everyone else is talking about.
I took your sample and compared it to a 22-4 I use and was shooked at the way my meters bounced with a 1k tone.
If some of you guys dont mind would you go take a listen to this and tell me what you hear or see in your computer programs.

Thanks

It sounds similar to my samples. There are faint "bumps" in the tone at seemingly random intervals. Looking at it visually, it seems the bumps in the sound are actually very brief amplitude spikes, as opposed to drops as they are for me.

What is this sample from? And please excuse my ignorance if it's obvious, but what is a 22-4?

 

[jpmorris]

What is this sample from? And please excuse my ignorance if it's obvious, but what is a 22-4?

A 4-track version of the Tascam 22-2, by the looks.

 

[sweetbeats]

And the 22-series is a more "consumer" version of the Tascam 32/34. Basically the same trasnport from what I understand, but the amp electronics may be somewhat different in the 22, and the 22 does not accommodate 10.5" reels. From what I understand though it is a great deck. The "specs" look nice and its got a lot under the hood compared to its humble exterior and current market value.

 

[Herm]

Thanks guys This was a 1k tone recorded staight into the tascam 22-4 on qauntegy 407 tape. at 15 ips. The 22-4 is the low end of the chain for tascam recorders.

My hearing is so bad it has to be pretty messed up for me to hear a problem.
If i get a chance later i may try my 34 or 38 and see what they do.

 

[RRuskin]

And the 22-series is a more "consumer" version of the Tascam 32/34. Basically the same trasnport from what I understand, but the amp electronics may be somewhat different in the 22, and the 22 does not accommodate 10.5" reels. From what I understand though it is a great deck. The "specs" look nice and its got a lot under the hood compared to its humble exterior and current market value.

If anything is different it is probably the transport. Cheaper/smaller motors since the physical demands of the 7" reels are less.

 

[pianodano]

I'm kind of late coming in on this thread but:

Tascam MS-16 is built for 456. It doesn't have the bias current for 499.
Tape curling could be caused by insuficient holdback tension or maybe a need to adjust the tape path because the tape is riding high / low and snapping back. Try turning the rubber roller upside down first and see if that stops it. Or it could be badly slit tape. 499 is also too thick for a MS-16, which could be the problem.

Don't adjust any trimmers until you have the MRL except input levels. You don't need the alignment tape for that. You do need to input into the rca exactly -10 dBv .775 v @ exactly 1 k. (OR 1.23 V+4 dBm if using balanced 1/O's but this can be problematic when calibrating). You need to adjust the R206 trimmer until the output rca for the channel reads exactly .775 (with the channel loaded. Adjust the meters by inputing the same tone at the same level until they read 0dB by adjusting trimmer R209.

Put on the alignment tape and calibrate.
Be sure DBX is disabled when calibrating.

IF you get your sillyscope, check on the azimuth FIRST. Check it YOURSELF. Don't rely on phase canceling wizbang schemes. IF the azimuth is out, the wrap cannot be acheived.

Also, for your consideration: Should take about an hour to do the alignment. Maybe the first time 2 or 3. Make a copy of the card wirh trimmer locations and tape it in a location that is clearly visible when turning trimmers so that you don't turn the wrong one. GO back to square one if you turn the wrong one at the worng time. Use something like a plastic screwdriver.

Last thing to do is record a 1 k frequency and count it at playback to verify the accuracy of speed.

Good luck. The MS16 kicks butt. You'll love it. I think it is just under a JH24 and sure as heck cost a lot less to run.

Danny.

 

[sweetbeats]

Hey Danny! How are ya?

Honor to you on Veteran's Day.

Bill, pianodano has quite a lot of exprience running his MS-16...Runs it slaved to Sonar through a TimeLine MicroLynx...interfaces with Tascam DA-78's and a DM-24 as the controller.

Anyway, he knows how to run it right...has technical knowledge as well as the real-world experience...one of the very first persons to step in and help me with my Tasacam 58 project.

Anyway, FWIW, I give a hearty +1 to his post.

 

[evm1024]

Just a minor correction. -10dBV is 0.316 volts which when input through the RCA jack read 0 VU and output 0.316 volts from the output RCA jack.

0.775 Volts is 0 dBu Tascam specs its RCA at 0 VU =-10dBV where 0 dBV =1 volt

 

[pianodano]

Just a minor correction. -10dBV is 0.316 volts which when input through the RCA jack read 0 VU and output 0.316 volts from the output RCA jack.

0.775 Volts is 0 dBu Tascam specs its RCA at 0 VU =-10dBV where 0 dBV =1 volt

Ah man, that's a major screw up. sheesh. Thank you for catching my error. You are absolutely correct. .316v= -10 dBv= 0 on the MS-16 meter. And I still hope he doesn't use the balanced connectors for the alignment. This stuff is getting too hard for an old guy like myself.

Thanks Cory. How you doing ? I hope all is well.

Danny

 

[bdoughty2005]

l

Thanks, Danny + Ethan.

Is that RMS voltage for a 1KHz sine?

Anyone have an old 1" test tape laying around going begging? Or some old 1" 456?


Bill

 

[evm1024]

Hi Bill,

Yes, that is RMS. You should also take care that the meter is accurate at the frequencies that you need to measure (up to 10 kHz or so for HF EQ).

-Ethan

Thanks, Danny + Ethan.

Is that RMS voltage for a 1KHz sine?

Anyone have an old 1" test tape laying around going begging? Or some old 1" 456?


Bill

 

[RRuskin]

Thanks, Danny + Ethan.

Is that RMS voltage for a 1KHz sine?

Anyone have an old 1" test tape laying around going begging? Or some old 1" 456?


Bill

Get a new test tape. You are going to need to use it on a regular basis because analog gear needs to be maintained. Don't look for used 456 or anything else for that matter. Buy some new tape that is bias-compatible to 456 and be more assured that the media is not the problem.

 

[pianodano]

Thanks, Danny + Ethan.

Is that RMS voltage for a 1KHz sine?

Anyone have an old 1" test tape laying around going begging? Or some old 1" 456?


Bill

Hi Bill,

I only have 5 or 6 new reels that I will use for whatever recording time I have left. I do have some old masters from the 80's but they have already been baked and are essentially worthless. You could also be on the lookout for some old Scotch tape. It does not exibit sticky shed quite as bad as Ampex and it sounded wonderful on the MS-16 for certain material. Kind of a softer sound but huge in my opinion. But try to get new modern era Ampex if you can. Musician's may still have some left. My current alignment tape is only a couple years old, it's full length and I would really be afraid to ship it. Whatever you do - get a full length or you'll be sorry.

Because you have limited eq's to work with on the channel cards, you will be mighty lucky if you can get the response to the + or - 2 db Tascam calls for. I would expect your reproduce response to come in like mine does at maybe + 3 or - 3 or so on higher and lower frequencies. Try not to be overly concerned about that. You've got eq on the console anyway and don't forget, it's a part of how the tape magic happens. Listen to anything recorded by the Doobies, Bee Gees or anyone that recorded on MCI's during the Muscle Shoals or Miami golden era and try to set your machine up to sound as close as possible to that "sound". You really can get the bass and drums to sound ALMOST that good on a MS-16 and that . . . will be as good as it gets or for that matter anyone could possibly hope for. My brother owns a perfectly maintained MCI and a Sony built MCI APR24 so I have no problem at all making the comparison.

Danny

 

[RRuskin]

Hi Bill,



Because you have limited eq's to work with on the channel cards, you will be mighty lucky if you can get the response to the + or - 2 db Tascam calls for. I would expect your reproduce response to come in like mine does at maybe + 3 or - 3 or so on higher and lower frequencies. Try not to be overly concerned about that. You've got eq on the console anyway and don't forget, it's a part of how the tape magic happens. Listen to anything recorded by the Doobies, Bee Gees or anyone that recorded on MCI's during the Muscle Shoals or Miami golden era and try to set your machine up to sound as close as possible to that "sound". You really can get the bass and drums to sound ALMOST that good on a MS-16 and that . . . will be as good as it gets or for that matter anyone could possibly hope for. My brother owns a perfectly maintained MCI and a Sony built MCI ATR24 so I have no problem at all making the comparison.

Danny

He's just had the heads done, yes? If so, there is no reason why the machine can't be lined up to spot-on spec. Once the repro and sync are properly tweaked, set each record eq pot to its mid point before doing anything else. That will assure that you won't be using the bias to over come too much record eq and allow for a reasonable amount of +/- adjustment when it comes time for that.

As I recall, TASCAM machines never allowed for a lot of +/- range when it came to adjusting the eq trimmers.

The idea of making up for a machine's deficiencies at the board is not a very good one, imho.

 

[pianodano]

He's just had the heads done, yes? If so, there is no reason why the machine can't be lined up to spot-on spec. Once the repro and sync are properly tweaked, set each record eq pot to its mid point before doing anything else. That will assure that you won't be using the bias to over come too much record eq and allow for a reasonable amount of +/- adjustment when it comes time for that.

As I recall, TASCAM machines never allowed for a lot of +/- range when it came to adjusting the eq trimmers.

The idea of making up for a machine's deficiencies at the board is not a very good one, imho.

Yes, he said he had the heads done. But I don't think that will overcome the age of the electronics. You can bet 1K will be 0 error. 2 will be close to zero. 500 will be almost zero. 100 will start the head bump smiley face. 16 K will look like the unsmiley face. The machine could be nearly 23 or more years old. +or- 2 was the original brand new spec. + or -3 is still pretty darn good, I think. But, to each his own.

http://www.endino.com/graphs/

Danny