Local TASCAM M-512 bargain, is recapping unavoidable?

I

IronWine

Member
Hey fellas
I run a little homy studio, pretty much satisfied with the gear i use (tascam 238, akai mg614 as the heart of it) but i do feel like getting an old Tascam mixing console. and oh boy does this old consoles looks awesome

CzLTzgVVEAEINjD.jpg

(photo's off google)

Theres a wee little studio around my town selling one of this for 250$. they just really don't use it, and the owner wants to get rid of it pretty badly, but i doubt he'd go lower than that.
he reckons it was fully functional and sounded great last time he used it (a year ago or so), and of course i'll test it before buying, but i do take in mind the job i'd have to do if a total recap is nessecery. and that's my question exactly - is it?:confused:

I am aware of the fact that i'm considering here a 30 years old console than many folks woul'd Immediatly disregard , but oh well, i don't have a piece of gear much younger than that :rolleyes:

As far as my electrical knowledge tells me, these electrolytic caps do get tired with time.I mean, i can start off with the PSU first as been suggested around here..but with the time and money that has to be invested in recapping the whole console..it just seems a bit too much.

so,to sum my post:

1. what's really the simptoms of bad caps (i supposed the low frequencies get affected first) ? is there a visual indication on the caps themselve?

2. is it right to assume that if one cap needs a change, then actually all caps needs too?




Cheers people!and thank you
 
Hiss

The main symptom of a tired cap would be excessive hiss.

I mean, really excessive, as all of these boards have some low level of hiss.
 
IronWine said:
1. what's really the simptoms of bad caps (i supposed the low frequencies get affected first) ? is there a visual indication on the caps themselve?

2. is it right to assume that if one cap needs a change, then actually all caps needs too?
Click to expand...


Don't just go by how much "hiss" you hear.
Bad/old caps will be off spec...which means they are not performing their task as intended...so your EQ section will not work as expected...etc.

30 years old...yeah, those caps are long gone from spec...and yes, to make it worthwhile, you would replace ALL the electrolytic capacitors. You can't just look at them and decide...and to properly test them to see which have gone off spec, you would need to remove them from the circuit anyway.

I recapped my Trident last year...28 input channels and 24 monitor channels. It was a lot of caps...but not that hard to do. I think it took me maybe a couple of weeks working some full days and the rest in my spare time.
You do it systematically.
First make a rough paper layout of the channel strip showing where all the caps are and mark down the value of each cap.
That's your safety cheat sheet.
Then you can count the number of channels and figure out how many of each value you will need to order.
After that, remove all the caps from all the channels.
And then start putting in the new ones...go one value at a time, and just stick them through the holes (if that's how they are mounted) and bend the legs back on the other side.
Once you have all the caps in on all the channels....then fire up the soldering iron and bang them out.
Then you flip to to backside, and clip the excess legs off neatly.
If they are surface mount...that's more of a PITA...'cuz you have position them just right before you solder, so not possible to first put them all on and then solder later.

If you do one channel at a time...complete...it will be more tedious...but find your own workflow.

I can tell you one thing for sure...the hardest and most important part is removing the old caps.
I used an actual de-soldering gun that applies both heat and suction to the old solder....but the gun alone is going to set you back about as much as you're paying for that console.
Doing it with just an iron and a manual sucker or a copper wick will take a looooong time, and there is a potential of making a mess or destroying the PCB traces unless you have top-notch skills working like that.
On thing...you can always resell the de-soldering gun after you're done...if you have no further use for it.

The gun made my job almost enjoyable...and it went very fast and clean. I think I hit one spot only where I forced it a bit and pulled up the PCB trace some, but otherwise the gun was worth it, IMO.
 
Is recapping unavoidable? Well...yes...eventually. Will you probably be able to use the console as-is without recapping anything? Probably so. You’re asking for an absolute answer to a condition that’s not absolute. Caps age s different rates depending on the circuit design and parts installed, the number of hours of use, and environmental circumstances. The absolute is that eventually any electrolytic cap will dry out and need replaced. When that is, well, that’s the variable. So you use the console and repair what needs repaired. I like to do a wholesale recap of a unit just because I’d rather avoid having to pull it apart piece-meal as stuff needs replaced. Get it done. But with rare exceptions I don’t think any of the 80s Tascam stuff I’ve touched has been inoperable because of a bad cap. There are a couple main things electrolytic caps do in an audio device like a mixing console: block DC voltage in the audio path (coupling cap...audio signal is AC voltage), and shunt unwanted noise to ground (filter cap). Symptoms of dried up or out-of-spec coupling caps would be DC artifacts such as increased pops and clicks when engaging switches, increased “skritchies” when sweeping pots...howling, yelping or squealing feedback-like artifacts when sweeping the gain of an EQ band especially when the center frequency is swept to extremes (in the case of an EQ band with an adjustable “sweepable” center frequency), and in extreme cases loss of signal, except with strong dynamic peaks and then the audio will come through all crunchy just during the peak...note: a blown amp stage can sound like this too in my experience. Symptoms of dried up or out-of-spec filter caps include an increase in the noise floor.
 
Yeah...for sure plug it in and try it out first before you dive into recapping...but if you want it back to spec, then the recap would be the right way to go.
 
Just for your information about whether it's worthwhile, I've been through a fair amount of desks and bought a Tascam M-3500 a couple of years ago. If you search my posts you'll find something about it. I re-capped the supply as well as various bits in the master section. In the end I stopped and sold it on as I couldn't face re-capping very bit of it. The mixer did work although I couldn't tell how much out of spec it was. I decided in the end though, that if I was working with tape, then by having a sub-standard mixer in the signal path, if there was a problem with the tape itself or the tape machine, it would be harder to diagnose if I was also working with a sub-standard mixer.
I decided to pickup an Allen & Heath ML3000, which although is designed as a PA mixer, works equally well as a 24-track summing mixer. As I use outboard pre-amps the whole bussing /routing of a studio mixer wasn't essential. The mixer has hardly been used, probably a dozen shows in its lifetime. Since it's a mixer from around 2004-8, it's not suffering from old caps and sounds amazing. It also comes with 8 DCAs which in a mixing situation are very handy. I have a MACKIE Ultramix module that I am going to install to give me fader automation. Mixing consoles these days are cheap as chips....I personally wouldn't rule out a class PA mixer. FWIW, I paid around £600 for a £8-10000 mixer complete with flightcase with dogbox.
 
Just check it out and see how it works.

I have a same time era M520 (the big brother to yours)

It still has all the original caps. While I'm sure they're not in spec from the day it came off the line, it works just fine.

It's quiet and sounds good. That's good enough for me :D

What's that old saying? Don't fix it if it ain't broken?
:D
 
Well, it ended up taking some time untill me and the seller found out a good timing for inspecting this console, but there she is(!!:D) :

my tascam m512.png

I was a bit skeptic about the purchase, but at the first look i was pretty sure it's going back home with me. it's just a really fine example of a well-maintained console. no parts missing, all lights work, all the inserts jumpers are present. All the main features we've went thru worked flawlessly. the knobs and faders are super smooth, the kind i woul'd expect from a recently serviced console.
it did spent the last year at his storeroom, therefor i've declared a cleaning-day ahead!
channels sounded fine to us. i woul'd take the time to get familier with this console before i dive into recap.

i didn't even bargained with him, as 250$ felt super fair for me.
gonna hook it up with the Tascam 238 to make a fierce 8-track setup..!


THANK you guys for your awesome inputs, appriciate that.
 
Last edited:
That sounds perfect, and sounds like a very reasonable purchase price. Congrats and keep us posted!

:D
 
There is a very simple way to tell if your audio coupling caps are faulty. Apply a sine wave generator at 1 kHz to the input of the module. Using a suitable meter, measure the output level of the module. Switch the oscillator to the lowest frequency you can, from 100 Hz down, lower the better. If the meter reading has dropped significantly, then caps in the chain are faulty. I wouldn't worry about 1 dB.
To zoom in on individual caps, use a scope. Put the scope on the input side of the cap, with a very low frequency applied. 10 Hz is good. Then put the scope on the output side. A drop in level of 1/2 is 6 dB of loss. If your cap does this, change it.
The other method is to use one of the cheap component testers available these days. Pull a few caps and measure them. If they are all close to their rated values, then you dont need to do a wholesale change. In my experience, even very old caps are often fine. People tend to get very carried away with un-necessary cap changes.
 
This ^ ^ ^ (quote from just above)!
"People tend to get very carried away with un-necessary cap changes."

I do realize that this is an older post (which I also realize that many may whine profusely about "resurrecting"), but since it just popped up today as I searched in regard to a similar, good 'ol TASCAM board that I've recently got here (M-512) . . . AND may just pertain to ANY "older, vintage" mixer or console, it may very well help someone else.
Anecdotal perspective;
I've been working on electronics & tech since designing & building ham radio gear as a kid in the '60's, and then graduated on to avionics, RADAR and computer controlled & operated silicon wafer writing systems (VERY precise stuff), etc.
All the while, my love for music and pro audio has been around, as well as my tinkering of almost anything electronic. Guitars, guitar amps, effects & recording gear have always been on and off of my workbench.
Audio signal is often FAR more forgiving than we my consider in reality (although suppliers LOVE to sell components).

The popular in-vogue "advice" that SO many people tend to proliferate and toss about (many who have had NO direct experience as an actual audio tech) by just repeating "something" that they read or heard, is;
"Oh, you're going to have to replace ALL the caps in that _ _ _ _ _ _ _ _ ", simply due to the age of the device.
Which, as has been stated, is utter nonsense to make such a general statement.
Can modern caps tighten the specs of a given system? Sure. Of course.
Necessary? As a blanket statement for any gear over _ _ years of age? LOL
And, we are talking audio here, which all things considered is a tiny, TINY band of the frequency spectrum and is NOT Rocket Surgery by a long shot. Designers have been building FINE audio gear for far more then half a century.
Many STILL oooh and ahh over and search high and low for certain gear from the '50's, '60's, '70's, etc.
And guess what? LOTS of that gear will still function perfectly fine AS IS (caveat; for a given application).

In our current world of digital, where we are nearly splitting atoms with our obsession over higher and higher bitrates (really?!?!) that are WAY over the threshold of human hearing discernment, it may seem "obvious" that we also want our analog components to be as nit-picky (technical term).
Do remember; MOST listeners are now using earbuds (or phone speakers?) that cost maybe $.75 cents to produce!
Regardless, do let your ears be the guide and do NOT discount older gear offhand as "requiring all new caps", etc.

Just some perspective when someone pooh-poohs your purchase of that cool, old, vintage mixer.
 

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AshokanKid said:
This ^ ^ ^ (quote from just above)!
"People tend to get very carried away with un-necessary cap changes."

I do realize that this is an older post (which I also realize that many may whine profusely about "resurrecting"), but since it just popped up today as I searched in regard to a similar, good 'ol TASCAM board that I've recently got here (M-512) . . . AND may just pertain to ANY "older, vintage" mixer or console, it may very well help someone else.
Anecdotal perspective;
I've been working on electronics & tech since designing & building ham radio gear as a kid in the '60's, and then graduated on to avionics, RADAR and computer controlled & operated silicon wafer writing systems (VERY precise stuff), etc.
All the while, my love for music and pro audio has been around, as well as my tinkering of almost anything electronic. Guitars, guitar amps, effects & recording gear have always been on and off of my workbench.
Audio signal is often FAR more forgiving than we my consider in reality (although suppliers LOVE to sell components).

The popular in-vogue "advice" that SO many people tend to proliferate and toss about (many who have had NO direct experience as an actual audio tech) by just repeating "something" that they read or heard, is;
"Oh, you're going to have to replace ALL the caps in that _ _ _ _ _ _ _ _ ", simply due to the age of the device.
Which, as has been stated, is utter nonsense to make such a general statement.
Can modern caps tighten the specs of a given system? Sure. Of course.
Necessary? As a blanket statement for any gear over _ _ years of age? LOL
And, we are talking audio here, which all things considered is a tiny, TINY band of the frequency spectrum and is NOT Rocket Surgery by a long shot. Designers have been building FINE audio gear Xfor far more then half a century.
Many STILL oooh and ahh over and search high and low for certain gear from the '50's, '60's, '70's, etc.
And guess what? LOTS of that gear will still function perfectly fine AS IS (caveat; for a given application).

In our current world of digital, where we are nearly splitting atoms with our obsession over higher and higher bitrates (really?!?!) that are WAY over the threshold of human hearing discernment, it may seem "obvious" that we also want our analog components to be as nit-picky (technical term).
Do remember; MOST listeners are now using earbuds (or phone speakers?) that cost maybe $.75 cents to produce!
Regardless, do let your ears be the guide and do NOT discount older gear offhand as "requiring all new caps", etc.

Just some perspective when someone pooh-poohs your purchase of that cool, old, vintage mixer.
Click to expand...
That's some of the best perspective I've come across. After not doing any recording for quite a while, I got one of the new TASCAM Model 12 machines with the SD Card recorder. Looked like something digital that I could relate to. I work on the computer all day. I don't relate music and computers in my mind. I'm 62. But it was still not what I wanted, so I got a TASCAM 388. An actual music recording machine. But, still not what I'm looking for. I had a studio in SF with 8 track Studers and a 2" 16 track 3M machine so I whine about digital like Neil Young. Now I'm thinking about an Otari MkIII 1/2" 8 Track. I need to hear that sound and it doesn't come off of 1/4" tape and a 1" 8 Track machine would heat up my room too much. By the way. That TASCAM 388 that the guy wrapped in bubblewrap and put in a box and shipped to me in PVD from N. Carolina.....worked just fine. It's heads gave me the last music they had in them, but that happens, but it worked. I made songs. Sure, I could send it to Bob Shuster to have it rebuilt, but why? It's only ever going to be a 1/4" 8 Track.
 
I love my Tascam M3500 32 channel and 16 track 1” Tascam MS-16. They’ve both been easy to work on, and sound larger than life without DBX.
 
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