Tascam 312B Project

Forget ratios of mic to line level sources. Hook up your mics. Hook up your line level sources. That’s your ratio, but that figure is inconsequential. And you can have dynamic mics connected to an actively phantom powered mic input. So don’t worry about mixing and matching there with your condenser mics. You just don’t want to have balanced line level sources connected to an actively phantom powered mic input.

Yes you certainly can have 12 mics connected to the 12 mic jacks, and simultaneously have 12 line level sources connected to the 12 1/4” TS “LINE IN” jacks and switch the source to the mixer channel using the LINE switch as needed, but there is a caveat: line inputs 1-8 have two places you can connect sources, either the LINE IN jack, or the TAPE IN jack. The TAPE IN jack is what is normalled to the LINE source for channels 1-8. You break that normalled connection when you plug into the LINE IN jack. That’s why I suggested you connect your line level sources to mixer channels 9-12...then your tape returns are always available at three points: 1. the monitor mixer for you as the engineer during tracking or overdubbing using the TAPE RTN source switches, 2. the LINE source for channels 1-8 (when it’s time for mixdown)...and 3. as cue feeds during overdubbing using the LINE source switch at the AUX 1 control. In your case maybe, since you are sticking with 4 tracks at this time, use channels 1-4 as primarily tape channels, channels 5-8 for mics, channels 9-12 for line level sources, and connect your tape deck outputs to tape return jacks 1-4. This will have your tape returns normalled to mixer channels 1-4 for mixdown and cue feeds and this will maximize functionality and minimize any source crowding since channels 5-8 would be for mic or line level source overflow.

Maybe time for another video? This is a lot of info.
 
Maybe time for another video? This is a lot of info.
Click to expand...
That is a lot of info...... I'm going to look at it against the manual to try to understand it.

I'd never turn down a video from you, but I understand the time it takes to make those too. If time is tight, don't worry about it.... I'll just bug you by asking you questions... :) .

I ended up downloading that M-106 video. It's helpful even now. When I start to get confused on busses or even the 234 monitoring system I refer back to it. That video probably helped me start getting down the basic concepts more than anything that I read.
 
When you have a chance check this out:

YouTube

You’ll need the better part of a half hour...I rambled a bit...but at the very least I think it will clarify some things which will generate more questions all toward the end of having a better grasp of how to operate and utilize the console with your setup.
 
That was great!!!! I finally got a chance to watch it... the first of many times I'm sure..... I have to get out of my "portastudio" mentality when it comes to these mixers, I am a little lost on the advantages of normaling tracks 1-4 with the corresponding tape in.... I will watch it again in the next couple of days. Right now we are in the last room of our floor remodeling project. (actually its my wife's project.... I would have been just as happy with the 1970's shag carpet).
....but get ready..... I see alot of submixing and normaling questions in your near future......

Thanks again for doing that. I have a feeling in the next couple of weeks I'm in for some "aha" moments..... :)
 
Alright..... it seems a problem has snuck up on me in the monitor section of the 312. I haven't taken it apart yet, but I thought I'd tell you what was going on when the problem occurred. I was listening to music online and ran a line from the computer headphone jack to the EXT IN RCA jack. I probably had this setup for two days like this and then right while I was listening, it suddenly got quiter with a lot of static.
I've started looking over the schematics and ran a test signal though a couple of different ports. I have not tried to reseat the buss yet, I am doing some studio deconstructing and constructing and want to get it cleaned up a bit before I start working on the mixer.

My question is..... Did I do anything wrong here? I think the computer is line level and the EXT In's should accept line level inputs right?

Thanks,
Brad
 
You didn't do anything wrong.

You have verified its the EXTRA IN that is the problem? Taken an alternate known good line level source and connected it to that input and it still isn't working right?
 
sweetbeats said:
You didn't do anything wrong.

You have verified its the EXTRA IN that is the problem? Taken an alternate known good line level source and connected it to that input and it still isn't working right?
Click to expand...
.
Right!! I also tried EXT 2 because they were both furthest down the line (according to the block diagram). I also tried the SUB IN L-R. All three had the same results. The headphones received the signal but when I turned the headphone volume it was very staticy with intermittent lower town than the signal that would last until I turned the headphone volume lower or higher. Also around 1/2 volume and up, the volume in the phones never changed. I barely heard the signal even at full volume through the monitors and that was after adjusting volume to full blast.

I took a break from changing out the BUSS AMP PCB....... another 100 or so solder joints and I might get this solder sucker concept down...... :)
 
connect a source to any channel strip.

Solo the input.

Now monitor the output at the:

1. Headphones
2. Monitor Out jacks
3. Solo Out jack

What is the result at each? Clean or crappy?
 
By soloing the output I’m assuming you mean PFL. I did that. Headphones are a clear good signal. Right/Left monitor and mono are a good signal. Solo out was a clear good signal
 
Yeah...the PFL/AFL switches feed the SOLO buss.

Okay.

Stay tuned. I'll probably have other things to try/test.

Look at the block diagram and see if you can figure out why I chose to have you check how audio sourced from the SOLO buss sounded through the offending outputs...
 
So, in the monitor select switchrack...out of all those choices of sources (stereo, ext1, ext2, effect, aux1, 2, 3 & 4), which ones of those sound like garbage?
 
They all sound weak and have a lot of static when I take it off PFL. EXT 1 and 2 sound bad too
 
Look at the block diagram and see if you can figure out why I chose to have you check how audio sourced from the SOLO buss sounded through the offending outputs...
Click to expand...

Well... you took the whole master pcb section out of the test.....and the switches.... and I guess since the headphone and monitor are still in line and working when soloing, those can be ruled out as being the problem
 
Nice! The key thing I was doing was taking the monitor output and headphone amps out of the list of suspects. We narrow down where the problem manifests, and then work upstream. I assumed the monitor and headphone amps weren’t the problem, because the issue is global to both of them (not impossible for both sections to have the exact same problem, but would be odd), but now we know.

I’ll take a look at the block diagram to see if there is any more narrowing down we can do, or if it is time to get into the schematics.
 
sweetbeats said:
But audio is clean at the Aux, effect and stereo out jacks, yes?
Click to expand...

Howdy,

Yes, Audio is clean on Aux Outputs 1-4, Stereo Output Right and Left, Mono Output, and Effects Output.

I also checked individual channels for grins. All were clean except channel 9 which was clean but a significantly lower strength than the others at the same settings. There I sent the signal into the individual channels line in and listened through the insert.
 
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I don’t want to get too sidetracked from the monitor amp issue, but am I understanding correctly channel 9 has diminished level relative to the other channels when monitoring the line input at the insert send?
 
sweetbeats said:
I don’t want to get too sidetracked from the monitor amp issue, but am I understanding correctly channel 9 has diminished level relative to the other channels when monitoring the line input at the insert send?
Click to expand...

Yes.... I have found three problems so far.

1. The Monitor section issue
2. This channel 9 issue
3. and here's a weird one..... I installed the BUSS PCB and everything works except the meter switch works opposite all the others. I took it out again and checked everything to see it was hooked up the same as the others and the old one (I took a picture....) ....and it is. All the PGM meters work except 1/4,2/5,3/7 switches are in the down position,,,, and the 4/8 meter switch is in the up position.
Last night I put the switch in the other Buss pcb. I might swap it out. even though it works, it will probably drive me crazy. :D
 
Double check something...

On monitor mixer channel 4, when you press the TAPE RTN switch there, does that happen to be sourcing TAPE IN jack 8 and not 4?
 
sweetbeats said:
Double check something...

On monitor mixer channel 4, when you press the TAPE RTN switch there, does that happen to be sourcing TAPE IN jack 8 and not 4?
Click to expand...

No it only sources 4.

Is this in regards to the meter problem
3. and here's a weird one..... I installed the BUSS PCB and everything works except the meter switch works opposite all the others. I took it out again and checked everything to see it was hooked up the same as the others and the old one (I took a picture....) ....and it is. All the PGM meters work except 1/4,2/5,3/7 switches are in the down position,,,, and the 4/8 meter switch is in the up position.
Click to expand...

because in this case, the meter switch worked the same as the others. When the switch was unlatched and in the up position, the signal showed up on all four meters which corresponded to the tape returns I was using. I'm going to see if I can duplicate what I did last night and tell you exactly how I did it.
 
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