Fostex B-16D issues

M

Muckelroy

Member
Ok, maybe I got what I paid for this time. :(

It's a Fostex B-16D, 16 track 1/2" tape machine. For those of you curious bout its features, here's the jist:

One speed - 15 ips
Dolby C NR (whether you like it or not, can't be turned off)
2 head design (making calibration of rec levels and bias nearly impossible)

I really don't care about the above limitations. What's bugging the crap outta me is that the electronics are noisy. When listening to the tape-outs on my mixer, at modest, unity levels, and turning the tape machine on, an incriminating hiss protrudes through my monitors. It's not my mixer. I'm 150% positive that the tape out circuits are all noisy. It's not bad, but multiply it by 16, it's pretty annoying.
Also, my tracks sound like raw tape (maybe worse). Is Dolby C Noise Reduction supposed to WORK, or not? On top of the noisy electronics, there's TONS of tape hiss. Maybe it's the heads. THey're evenly worn, but it's a bit flat. THey have shape, but, you know. a bit of wear.......... I'm very tempted to sell it for a 38, or maybe a 48 or a 58. I'd much rather have 8 good tracks than 16 noisy tracks. :confused:
Is there anything that I, the pissed off user that's handy with tools, can do besides sell it, or pay an arm and a leg for 16 tracks worth of gates? I don't want to have to transfer the tracks to a digital domain just to clean them up.

-callie-
 
The B-16 was Fostex' first foray into the 16 on 1/2". It's not the best of the line, but I wouldn't think it should be that bad. Dolby C is quite effective and preferred by many over dbx.

Someone may have fiddled with it that didn't know what they were doing and set the playback amps too high. Dolby doesn't work right if input and output levels are out of whack.

What kind of tape are you using? Do you have a manual with setup info in it?
 
I'm using quantegy 456.

There's no manual. But I took it apart and figured out where the cal tweakers are. Just need a cal tape. That's a possibility. I'm the 3rd or 4th owner, and who knows what the 1st or 2nd owners did w/ calibration.

-callie-
 
Should I set the operating levels to +6? +5? +4? +3?

I know that with DBX, 456 tape needed to operate at +3dB.

What kinda headroom is needed with Dolby C on 456?
 
456 is the right stuff for that machine. Another possibility is that someone reset the unit for a lower output tape, so 0 vu is not as hot as it should be.

Or the heads are so badly worn everything is tweaked to the max.

Here's a link with calibration portions of the B-16 manual. It's a little annoying being in jpg rather than pdf... but hey, it's free.

http://synthetizer-sche.chez.tiscali.fr/listtape.html
 
Except that I need a test tone generator, and an oscilloscope. I'll have no problem obtaining an oscilloscope, but I don't even know where to start looking for a test tone generator. Looked on ebay, and they were all cheapo telephone repairman things :confused:

What's the technical name for an audio test tone generator, and where can I find one? WHo make them?
 
Muckelroy said:
Except that I need a test tone generator, and an oscilloscope. I'll have no problem obtaining an oscilloscope, but I don't even know where to start looking for a test tone generator. Looked on ebay, and they were all cheapo telephone repairman things :confused:

What's the technical name for an audio test tone generator, and where can I find one? WHo make them?
Click to expand...

Look for the TEAC TO-122A, or the Fostex TT-15 test tone oscillators. I use the Fostex and it works great. I don't have an oscilloscope, just a frequency counter on a good multi-meter -- works like a charm.

Here's a tt-15 currently on ebay.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7310667558
 
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Kool. One more question - the instructions in that link up there -- what operating level would that set the machine to? (+3dB, +5dB, +6dB?) The only dB level that I could find thorugh the entire instructions was +1dB, not sure.....

Also, it frequently mentions the use of an external level meter. I have a mixer w/ analog meters. Could I hook it into my mixer's Ext in, and set the meter to monitor the Ext in, and get an accurate level reading?

Thank you so much for your help. I really appreciate it.

-callie-
 
and........What fluxitivity of calibration tape should I use? +3dB, or Those calibration instructions don't say so. It says to play back the calibration tape, and adjust until the meter reads 0dB.

Depending on if the calibration tape is a +3dB tape, or a +6dB tape, uh, that could be the difference between life and death.

-callie-
 
Muckelroy said:
Kool. One more question - the instructions in that link up there -- what operating level would that set the machine to? (+3dB, +5dB, +6dB?) The only dB level that I could find thorugh the entire instructions was +1dB, not sure.....

Also, it frequently mentions the use of an external level meter. I have a mixer w/ analog meters. Could I hook it into my mixer's Ext in, and set the meter to monitor the Ext in, and get an accurate level reading?

Thank you so much for your help. I really appreciate it.

-callie-
Click to expand...

What you want is a meter that measures an absolute value in AC millivolts (mV). I use a Radio Shack multimeter, catalog number 22-811 for $29.99. That meter is right on when measuring the output of my Fostex TT-15 tone oscillator.

Technically you could use a vu meter on a mixer for "close enough" but you would have to be confident that it is calibrated correctly (not usually). Also, depending on the brand of mixer the meter they use could be good quality or not so good. Calibrating a mixer to a tape machine is a separate operation to be completed after the tape deck is set to spec.

The + 1dB in the B-16 link is referring to the acceptable range of deviation (plus or minus 1 dB). It's not referring to tape operating level. An output of 1 kHz @ -10 dBv will read about 316 mV on a multimeter and should show 0 dB on the B-16 bar graph meter.

I'm not sure what the flux level is on the B-16. The E-16 was 320 nWb/m or +5. The A-8 was 250 nWb/m or +3, but I can't say for sure about the B-16. 456 will work either way.

-Tim
 
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I e-mailed Fostex, and they said that the B-16D requires a test tape of a 320 nWb/m (+5dB) fluxitivity.

That being said, MRL's standard tapes only come in +3 and +6, so I'm just gonna get a +6 one, and adjust accordingly.

-callie-
 
I Feel Like An Idiot

Turns out the NR switch on the back was set to EXT. I flipped it to INT, and viola. Virtually noiseless recordings. Though I feel like kicking myself in the ass 50 times, i'm still RELIEVED!!!

I'm still gonna calibrate it, though. I've already ordered a multimeter and a cal tape.
 
ack!!! I had thought of that, but didn't want to say anything. :D

Amazing how quiet they are, isn't it! These guys here are always knocking them, but I think they are great!

BTW, I also own a 2inch Otari, and an MS16. So I'm not biased. I just think in the 1/2" format, Fostex got it right.
 
Muckelroy said:
Turns out the NR switch on the back was set to EXT. I flipped it to INT, and viola. Virtually noiseless recordings. Though I feel like kicking myself in the ass 50 times, i'm still RELIEVED!!!

I'm still gonna calibrate it, though. I've already ordered a multimeter and a cal tape.
Click to expand...

Good deal! Yeah, 50 times seems about right for self-inflicted ass kicking on this one. Sometimes I will even go 75 for a simple switch setting. :D
 
OK, so after a long hiatus of SCHOOL, I finally started to calibrate this thing.

Turns out there's several calibration tweakers right behind the meters, but the manual mentions even more tweakers, and voltage test points, at which point i was like, what the crap? where are they?

So, I started slicing and dicing the thing, and FINALLY found them. They're in the most inconvenient spot -- ON THE BOTTOM. SO, for those of you who own one of these suckers, here's how to start calibrating them --

Remove the front meter bridge cover, and the control panel with an allen wrench. THey'll dangle, but it's ok. This'll unveil about half of the tweakers.

Then, turn the machine on it's side (or upside down, i guess either way will work), and be sure to align the front face of it on the edge of a desk, CAREFULLY, so that you can still play a tape on the front of it, without the flanges rubbing against anything.

NOW, remove the bottom 4 rubber bumpers, and take off the bottom cover. VIOLA. there they are. Each track card is right there, you've got a few more tweakers, and all of those test points the manual talks about.

That's as far as I've gotten so far. Now I've gotta get some alligator clips for my multimeter, cuz these probes won't cut it.

-callie-
 
did you make any progress with that?

I have an E-16 that I half assed calibrated.

I also noticed that with 456 hiss is horrible...with GP9 you dont even need the dobly. I am still trying to figure out which is better.
 
thanks for this thread guys. i'm going to be borrowing one of these machines for a few months to work on my lo-fi 'masterpiece'. everything slamming to the tape and work it out in the mix. kind of like the high water marks sound.

i hope there's enough saturation to achieve this.
 
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