New Tascam M308B.. + questions

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boyd_boyd_boyd

trial / error based
Hey folks
This is my first post.. nice to meet all of you. I just got a Tascam M-308B mixing board, and when I was researching I got a lot of valuable info from this forum. Sounds like there's some fans of the M-300 series on this site. Please forgive my inexperience with analog recording basics...

Anyways.. I love it so far. It sounds great! I like just standing back and staring at it.. The signal routing is super extensive, almost confusingly so for my level of experience. As far as I can tell everything works besides a couple meter lamps, no big deal there, and I think the BUS 1 XLR output is messed up. When I send a signal out of that output it's noticeably weaker (lower volume) than the same exact signal from the other XLR bus outs, and also weaker than the same output switched to unbalanced. I don't have the same problem when I use the RCA pgm outs. I would assume the balancing isn't working quite right, like it's sending one signal instead of the "double" signal in a working balanced output. If this is the case, I would guess I can try to clean the XLR prongs and if that doesn't solve it I may need to look at the soldered connections behind the back panel. Have any of you had this same problem? Any tips?

I found a pdf manual on ebay for $10, which has helped a ton. The signal flow drawings are awesome. Need to keep studying those..

In the meantime - I figure I'd ask for some general advice on using the 308B. In particular what are the most sensible ways to use outboard signal processing? What's the difference or preference between the aux vs effects sends? The aux outputs make sense to me, but the effects send isn't clicking in my brain yet. And I'm sure there are some slicker ways to use the aux sends than what I've tried first (returning them into an unused channel strip).

Oh yeah and one of the EQ knobs was missing - i emailed the TASCAM/TEAC parts department and they replied to just send me my address and they'd send me the part free... awesome.

I'll be playing around with this for a while, and will hopefully answer some of my own questions, but any and all help is appreciated!

Thanks

Boyd
 
The effect send buss is for sending out signals from the channel strips, post fader, to feed to a digital reverb processor and there are dedicated effect return inputs that feed to the Stereo buss faders for mix-down to a stereo recorder. The return knobs for level and pan are located in the master section of the board...right side, near the faders. So, you don't need to use the main channel strips for that.

The Aux sends are normally used for setting up cue mixes while you're overdubbing but, if you switch them to the post-fader position via the switch on the channel strip, they'll behave the same as the effect buss, in effect giving you a stereo effect send, if you use both busses to feed a stereo reverb unit. This can broaden your mixing possibilities during mix-down to create more unique panning presentations of the wet reverb sound against the dry sound.

Cheers! :)
 
Welcome!

Yes, big fan of the 300-series here. :)

Like Ghost said the EFF send gets its signal AFTER the channel fader so say you are sending signal to a reverb or delay unit, and you pull the fader down to pull, let's say a guitar out of the mix, you wouldn't want to keep hearing the effected guitar sound which is what would happen if that effect send got its signal BEFORE the channel fader.

And, again, just restating what Ghost said, the AUX sends are usually before the fader for monitor or 'cue' mixes when overdubbing or as stage monitor mixes and you don't want changes to the channel faders (which you'd be adjusting for the recording or the house mix) to make changes to the monitor mixes...having pre-fade sends gives you independent control over the levels.

Tascam gave you options since one of those AUX busses is switcheable pre or post fade. ;)

I'll take a peek later at the schematic and see what I can come up withb for your group 4 out issue. You might be right that it is running unbalanced all the time which I *think* would cause the oujtput to be -6dB compared to the other balanced outs (if monitoring via a device with balanced inputs).

If you have a multimeter you can put a test tone through the board to group 4 and measure between pin 1 and pin 2 of the XLR out, and then pin 1 and pin 3. Set the multimeter to AC voltage. The two tests should measure the same.
 
while mixing, i tend to think of AUX as just another effect send, and there are lots of artistic reasons to have a pre-fader effect (100% wet spring-verb backing vocals anyone? ...hard panned left of course:D) - for intros/outros & special effects it can be nice having independent control of the effected source and the source itself.

I think the 308 is similar to the mixer on the 388 - i'm real happy about all the options for using the 388 as a stand alone mixer, but a question for those with intimate knowledge of both: compared to the 308B what's missing on the 388? (as a stand alone mixer, and besides the "B" phantom powered xlrs) - [hope this is still on topic...]

as for the effect & AUX returns, i'm sure you've got dedicated return ins on those (but you'd forgo the luxury of post effect eq or potentially dangerous (possibly "inventive"!;)) feedback loops that you would have when you route them back to another available channel.

ahh, now looking closer at a few pictures of the 308 it IS rather different from the mixer on the 388... quite.
- Fascinating possibilities you've got!
 
I'd ordinarily suggest to use main channel strips for effects returns when you can spare them as it's a nice way to print reverb environments to tape or in comped bounces but with only an 8 channel mixer, those channels are usually needed for other things.

I use two M312B cascaded together with an MS-16 and do use dedicated strips for effects returns and other channels as dedicated tracking inputs for different instruments but that's only because I have 8 left over channels to play with.

Otherwise, it's a lot of patching and a lot more work with just an 8 channel board.

Cheers! :)
 
You guys are awesome...

So the effects send ONLY comes back into the mix in the L-R Stereo master. For example if I had a signal in CH1, and had that bussed to BUS 1, the 'dry' post fader signal would go to the bus (and the stereo bus if I had that selected), and the 'wet' signal would come back into the L-R stereo master bus, with the level controlled by the master effects knobs. Right?

Sounds like the Aux channels would have a bit more flexibility if I use them as effects sends, but like you've said I'm limited with only 8 channels. I'll be using this mixer to record my own music and won't really be using it to mix a bunch of inputs at once, so I do have some freedom there. The biggest mix I can envision doing at once would be maybe 4 or 5 drum mics.

I'll be multi-tracking / overdubbing through either my 4-track cassette (HI-FI!!), or *sorry* a digi 002 into protools. Either of those will have 4 simultaneous inputs max (bypassing the digi pres leaves me 4 channels). I'll probably use the 4 M-308 balanced busses as my standard outputs - but if I'm understanding it right those would exclude the effects return. Correct?

Thanks so much for the advice, I'm sure I'll have a new batch of questions as soon as I mess around with it more..
 
sweetbeats said:
I'll take a peek later at the schematic and see what I can come up withb for your group 4 out issue. You might be right that it is running unbalanced all the time which I *think* would cause the oujtput to be -6dB compared to the other balanced outs (if monitoring via a device with balanced inputs).

If you have a multimeter you can put a test tone through the board to group 4 and measure between pin 1 and pin 2 of the XLR out, and then pin 1 and pin 3. Set the multimeter to AC voltage. The two tests should measure the same.
Click to expand...

Cool. That makes sense. I'll give that a try. Not that it makes a difference but the output I'm having problems with is the XLR PGM out for BUS 1, not 4 (or does group 4 mean something else in regards to the outputs on this board?). I'll let you know the results of the voltage test, if anything else comes to mind please pass it on!

Thanks!
 
LUNE, yeah, the 388 mixer is...I sort of think of it/see it as a baby brother to the M-308, though (obviously) the 388 mixer is an 8-buss. The M-308 is designed to interface with different systems and serve well live or in the studio, while the 388 mixer is very focused on serving the 388 transport, but Tascam was nice in the design and included features allowing the 388 mixer to function independently as well. But the M-300 series mixers have many, many niceties over the 388 mixer...doesn't stop me from lovin' the 388 mixer. Its perfect.

M-300 mixers have a PFL circuit, channel mute ("ON"), "ON" function for the EQ, independent routing of the TAPE returns to the AUX section or channel strip, 100mm throw on the faders, independent strips for the groups, comprehensive monitor section, inserts on the busses and main outs (L, R and MONO), and more.

Boyd x 3, do test the voltages. So the levels on the RCA jacks are consistent/okay?

My bad on group 4 vs group 1...DOH!
 
Boyd x 3, do test the voltages. So the levels on the RCA jacks are consistent/okay?
Click to expand...

Yes, the RCA bus output jacks are okay, all the same consistent level for bus 1,2,3 and 4. Which is definitely good news - I guess I don't know the wiring diagram but I'd assume if there is a malfunction with the BUS 1 XLR output it's pretty close (or at) to the XLR connection itself.
 
The balance amp is a whole separate bunch of guts that the signal goes through so the first step is to see what is coming off that XLR with a meter and test tone and then move upstream.
 
Alright... Took me a sec to get my little meter to "hear" anything. It does look like there's an XLR balanced ouput problem. The voltage across pins 1+3 is about 0.5 V, but across 1+2 it's 0.0 V. All the other balanced outs (other PGM busses, L-R bus, etc) have equal voltage from 1+2 vs 1+3.

I'll keep troubleshooting and may open it up and look at the contacts and solder points, see if I can figure out how to check the balanced amp. Looking at the schematic, it seems like there's a pair of amps for each balanced output, right before the XLR pin connection? Anyone have any experience/tips there?

Any tips on troubleshooting is appreciated, I'll see what happens!
 
Little foggy on what you can get to easily, but pull the rear bottom panel off after you tip the mixer up on its side, and see if you can get to the backside of that jack. Put tone through it and start tracing back to where it hits the PCB and just as far upstream as you can get to see if you can get signal on the conductor for pin 2 somewhere along the way. That will at least narrow it does as to whether or not it is just a bad connection between the balance amp PCB and the jack. Report back. I'll still have spares of those assemblies (the PGM group boards) so if you end up needing one I can sell you one. PM me if we get to that, but let's see if it is something simple first.

Let me know if what I said above doesn't make sense.
 
Thanks Sweetbeats
By the way I've been going through a bunch of posts in the A.O. forum and you've shared some amazing information out here - kudos!! Now I want a 520..

But back to reality. Your instruction makes sense. After reading more in the manual and looking at other posts I can now see where the amp is (on the buss amplifier PCB), and where the jacks are (on the buss jack PCB). I follow what you're saying about tracing a signal back through the pin 2 conductor. I'll let you know how it goes. Might be a while, and if it goes anything like my car repairs I'll break at least one other thing while I'm trying to fix it.. No way!

And that's great to know you have PGM boards - if I need one I'll get in touch. I sent an email to the TEAC parts guys asking if they have the jack PCB and the buss amp PCB, but I imagine they're price would be the highest of anyone's, if they have the boards.

Thanks so much for taking time to help a beginner!
 
Thanks Sweetbeats
By the way I've been going through a bunch of posts in the A.O. forum and you've shared some amazing information out here - kudos!! Now I want a 520..

But back to reality. Your instruction makes sense. After reading more in the manual and looking at other posts I can now see where the amp is (on the buss amplifier PCB), and where the jacks are (on the buss jack PCB). I follow what you're saying about tracing a signal back through the pin 2 conductor. I'll let you know how it goes. Might be a while, and if it goes anything like my car repairs I'll break at least one other thing while I'm trying to fix it.. No way!

And that's great to know you have PGM boards - if I need one I'll get in touch. I sent an email to the TEAC parts guys asking if they have the jack PCB and the buss amp PCB, but I imagine they're price would be the highest of anyone's, if they have the boards.

Thanks so much for taking time to help a beginner!
 
Looks like it's the XLR jack itself... see the red arrow in the picture, it's blurry but you can kind of see that pin 2 is broken, separated so no signal gets to that output pin connection. The signal makes it all the way up to the break. I tried soldering it together, which worked for a short period but then my solder must have broken after I put it back together. Its tricky to get solder in there without melting all the black plastic.. (I need a better soldering iron..)

XLR_break.jpg


I think the easiest thing for me would be to just get a new XLR jack piece and then screw + solder that new piece into the jack board. I saw a post by Sweetbeats about soldering caps on these PCBs, and that you need to be careful not melt the board..

I'll see if TASCAM / TEAC has that little part. I see them on some electronics supply sites - any idea if these would be pretty universal, or do I need to get one designed for TASCAM stuff?

for example:
http://www.westlake-electronic.com/products/all/all/all/RDL10034

I'm open to any suggestions for a solution, I may be going about it wrong..

Thanks again
 
it works... 4-buss beats 3

one month later.. sorry so slow
got a replacement part from TASCAM, just the XLR connector that solders to the board. put it in there and it works.. science! Now I have all 4 buss outputs working properly.

Thanks for helping a new guy. I'm having fun with the 308B.. everything sounds better than when I mixed without it.
 
i love this forum

I love visiting you guys more and more everyday. Sweetbeats: not only have your beautiful hands brought to light (pun) the steps necessary to change the bulbs in my M308B's VU's, but you've just helped me understand how to properly send and return effects to my board, thus saving many headaches forever.
 
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