Tascam M-216 Question...

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Beck

Guest
Looks like I lost track of this thread and forgot to come back with those resistor values. I'll put this on my list of things to do over the next week. I've done a lot of mods on the 200-series to make them more recording friendly. They were designed by Tascam to do a little of everything, but you can tweak them more with recording in mind rather than live sound. Glad the op-amp swap helped. More to come shortly.
 

famous beagle

Well-known member
Looks like I lost track of this thread and forgot to come back with those resistor values. I'll put this on my list of things to do over the next week. I've done a lot of mods on the 200-series to make them more recording friendly. They were designed by Tascam to do a little of everything, but you can tweak them more with recording in mind rather than live sound. Glad the op-amp swap helped. More to come shortly.

I have a 216 as well, so I'd be interested to see a comprehensive list of your recording-geared mods if you have such a thing.
 

KidProcrass

New member
I know im this thread is rather old but i just wanted to say thanks to everyone who contributed in this thread you guys are awesome. Just scooped up one of these today for 50$ not really knowing what to expect since i had no way of testing it other than powering it up. After some heavy cleaning (this thing looks like it was in a shed for 15 tears cob webs and all) and fixing the scratchy faders (water and q-tips worked wonders btw) everything is fully functional and which i couldnt be more thrilled about (rahter noisy tho). Anyway after reading becks(THE beck?!?) mod suggestions im looking forward to getting my brother to switch the op-amps, recap the PSU and possibly the resistors. Ever get around to checking those resistor values after all?
 

Ignatius-

New member
Nice Find! I still use mine for live purposes, and I love the sound of this era of Tascam boards. I did a lot of recording on that board, and I was never displeased with the results. Best of luck with the upgrades!
 

KidProcrass

New member
Yeah got kinda lucky especially for the price. Only issue with the board is that 2 nobs (the black plastic piece not the cover) are broken. Would you know if its an easy fix? I do mostly instrumental hiphop beats and wont be using more than 8-9 channels at a time so i was thinking of taking them from the 16th channel. Is it just a question of switching the piece or would there be soldering involved? this is my first board and i am not totally clueless but lets just say i am not as well versed in hardware than most of you guys.
 
B

Beck

Guest
Lost track of this thread again LOL

I should probably use the Subscribe feature on these forums sometime, which I never have... not even one time since I became a member. :facepalm:

Best thing for broken pots (knobs) is to order new ones from Tascam Parts or find replacement channel cards for cheap on eBay if you can. You can't switch cards from channels 1-8 with channels 9-16 because the cards are a bit different. Channels 1-8 have RCA tape-in jacks and one extra button on the channel strip. You might be able to find replacement pots from Mouser or Digi-Key, but I've never had broken ones so I'm not sure.
 

KidProcrass

New member
Ok thanks i guess ill contact teac/tascam for the parts. Im pretty new to hardware used to do everything in the box and this is my first board so sorry for the noob questions. Also im at work right now so i cant open it up to check but im guessing the op amps are soldered on or are they just clipped in like some of the more resent electronics? Also any idea how many there are approx in the board?
 

KidProcrass

New member
Thanks for the reply beck. I actually got around to opening this thing up last night and that's exactly what i was planning on doing. Pretty much same amount of work and a lot less headaches down the line.
 

dukeofearl

New member
Sorry to resurrect this old thread but I have a M-208 and I'd like to lower the noise. Would a NE5532 be a drop-in replacement for the current opamps? I also plan to recap the psu. Thanks
 

sweetbeats

Reel deep thoughts...
Hi there.

So, the answer from me is not gonna be a simple "yes" or "no".

First of all, I think the single best thing one can do to try and lower the noise floor in an older analog device is to look at the power supply and identify if there is adequate HF filtration (including looking at the filtration throughout the device), looking at the voltage regulating circuits to identify if there are components that could be replaced/upgraded with lower noise components, and also to consider if it is time to recap (and the answer is "yes" if you see leaky/bulging caps, or "possibly" if the device is 25 years old or more). I took a look at the M-200 Series' schematics. It looks like there is good filtration in the power supply both primary and secondary with specific components to address HF filtration. I also see throughout the console there are additional filters on many of the audio PCBs...not over-the-top...I've seen better, but I've seen a lot more worse...these are not the droids you are looking for. It might be worthwhile to recap the power supply just because of the age, though Teac did a nice job designing good circuits in the era of the M-200 Series that considered stress on components like caps, so the electrolytic caps generally last longer then maybe other company's products. If your only problem is "noise", then recapping the supply is a cheap stab to address that. I don't see any values I would change...If it was me I'd use Nichicon PW caps. It wouldn't hurt to upgrade the primary 1,000uF caps with something like 2,200uF, but this really isn't necessary either.

NOW...questions: you want to reduce the "noise"...where are you hearing the noise (what outputs)? What does the noise sound like? Most importantly how much noise is there? All analog audio devices produce noise, so you're never going to get rid of it. And I'm asking you these questions because if its hum you hear, that may have other causes than a PSU recap or some opamps is even going to touch. If its sounds like white noise then okay. But then there are the all-important questions how much noise is there, and through what outputs do you hear it? If its only some outputs then your problem might be more localized. If it is all outputs then the PSU recap is a nice place to start -IF- the noise is abnormally loud. I'm going to go out on a limb and guess you haven't measured the noise level, otherwise you might have shared that already. I'm hoping to spur a little conversation here just to flesh out whether or not there is anything abnormal with your console's noise level, or if it is normal noise. I know one time I was working with a console and I thought "Man this thing is noisy...!", only I wasn't actually putting any program signal through the console. Once I started feeding program signal through the console I realized if I'd left the levels where I'd had them when it seemed "noisy", I'd have potentially damaged the loudspeakers. Once the level controls were adjusted to a realistic setting, the noise was negligible when the program was silent. My apologies for responding in a complex way, but I've had too many experiences where I've sent people chasing waterfalls because they didn't provide the whole picture, and I didn't ask.

As to opamps, the M-200 Series use the 4560 opamp throughout the console for all audio pathways...like...that's it. Its not a bad opamp, but there's room for improvement I suppose. Whether or not an "upgrade" gets you lower noise I don't know. There are several things to weigh when you're considering this kind of thing. First of all the 4560 is a BJT type rather than JFET...so is the 5532. So that's good. The 5532 would be my preference over the 4560, but the 4560 offers better drive (higher output drive potential) than the 5532. The 5532 is pretty close, probably close enough, but just keep that in mind. The 5532 also draws more current to operate than the 4560...almost double typically, and potentially about triple under maximum operating conditions. So whether or not the stock power supply is happy with that I don't know. To find out for sure you'd need to load-test the main transformer in the console and then compare what it can do current-wise with a total of all the opamps in the console and their maximum operating current, and then add a factor of 1.5-2x or so. Just consider that swapping opamps isn't like putting in a brighter incandescent light bulb for a dimmer one. Its more like swapping incandescent turn signal lamps for LEDs, and now they don't blink because the car thinks the lamp is dead because there's relatively low load with the LED...and the car keeps yelling at you about it. And you now have to get load resistors or change out the relay, and the guy at the auto parts store just tells you to use the universal one but the wiring diagram doesn't tell you exactly how to interface it with your car, so you end up with some wiring spaghetti and gaffers tape...probably a zip-tie or two. As with an opamp swap it'll still usually work...like, you can drive the car with the turn signals n/f, right? But its not right. And eventually you might get pulled over. With the turn signal lamp analogy its easy to see its not working...the blinker doesn't flash. But with an opamp? You often can't tell its not right unless you measure before and after the swap, like with an oscilloscope and a distortion analyzer and such, and in the meantime its oscillating or your DC offset is out of whack or its actually noisier and more distorted than the stock opamp...or maybe it sounds fine at low levels but you can't see how it is breaking up and puking out at high levels. I'm pretty convinced there are a lot more people "driving around" their analog devices with, figuratively speaking, malfunctioning turn signals and they don't know it, but it sounds "better" because the piece of paper told them the new chips were "faster".

Okay...nerd vomit over...just think through a little to verify you actually have a noise "problem" and be mindful if it is global or isolated, and what kind of noise it is. Recapping the supply is cheap and relatively easy, good insurance and *usually* at this point in your console's age a good idea that usually has *some* benefit beyond preventative maintenance...lastly, a 5532 swap looks to be a pretty safe one for the 4560, but you may lose some output drive and you may overwhelm the power supply at high levels...and a 5532 probably won't oscillate, but it is good practice when "upgrading" to a "faster" opamp to bypass the power rails at each opamp (i.e. solder in something like a 0.01uF XR7 ceramic cap between pin 4 to ground and pin 8 to ground of a DIP8 opamp).
 

dukeofearl

New member
Hi there.

after reading your reply and doing more research, i've decided not to mess with the opamps and leave it as is. the noise was hiss. didn't sound like anything was broken, but just kind of a noisy board when you turn it up.

unfortunately i've caused another problem that's my fault. now there's a constant loud noise that makes the board unusable. sounds like a ground hum. i disassembled the board with the intention of recapping the psu. also cleaned pots etc. but then decided to skip the recap and just put in back together. and now it's a real problem. ugh
 

sweetbeats

Reel deep thoughts...
Well that’s a bummer for sure.
There must be more to the story...any possibility any of the caps or rectifiers on the power supply PCB were handled with any force and now you have a cold solder joint? What about any connectors too-from the power supply board? Does the console function but it’s just there’s a loud hum?

Do you have or know anybody that has an oscilloscope and know how to use it?
 
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