New 388 problem

  • Thread starter Thread starter famous beagle
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If you're actually sticking the probes into the jack socket, that's probably not a good idea. The best way to test a female jack IMHO is to get a male-to-male TRS cable, and use crocodile clips on the plug.

Oh, ok ... So you don't really test the jack; you test a cable that's plugged into it?

These are RCA jacks. Assume it would be the same process but just with an RCA cable, yes?
 
With rca it's super simple and easy. Just touch the inside with the pos lead and the outside with the neg lead.

Now for complicated (but easy), take a set of old multumeter leads, clup off the probes and solder them to an rca jack and plug it in. This has been handy to me for checking both contunuity and voltages on multiple jacks.
 
Oh, ok ... So you don't really test the jack; you test a cable that's plugged into it?
These are RCA jacks. Assume it would be the same process but just with an RCA cable, yes?

Sorry, yes. Obviously test the cable first to make sure you're not get a false negative.
Alternatively, if you have a spare RCA plug - one of the self-assembly ones, not moulded - you can open it up and attach probes to the solder tags.

Either way, if you're testing continuity or measuring signals from a socket, it's usually easier to plug something into it first and attach the probes to that.
 
Or in the case of an RCA jack, like jpmorris indicated for the TRS jack, just connect a male RCA to RCA cable and probe between the pin and the shield.

I don't go sticking probes into TS or TRS jacks since the ground and signal contacts are in the interior. In the case of RCA it's okay since the only contact inside a female RCA jack is the signal pin. The ground is outside.
 
Ok, I plugged an RCA cord into the left MON OUT jack. I wasn't sure if you still wanted me to send a tone to the monitor buss, so I tried it both ways.

Sent a 1kHz tone to the monitor buss with it registering at 0dB on the master meters and probed positive to tip and negative to ground on the other end of the plug.
with MONITOR knob all the way off (counter-clockwise): 3 mV
with MONITOR knob all the way up (clockwise): 328 mV

With no tone sent to the monitor buss, I got 3 mV regardless of the position of the knob.



Anywhere in between would fall somewhere within those two.
 
Right. The test tone is what you are measuring. If you don't send it to the MONITOR OUT jacks there will be nothing to measure.

Based on what your results are, your 388 is functioning normally.

The MONITOR OUT amp is a buffer amp. It is not a booster amp. You aren't going to get more signal out of it than what is going in, and it is nicely passing what is going in.
 
Well ... strange.

What in the world? It just seems odd, because in order to get what I would consider a normal listening volume out of the speakers, I'd have to crank the MON knob so high on the 388 that I'd blow my ear drums out if I put the headphones on.

That doesn't seem right, unless there's still some type of user error going on. But I would think that, with all the testing we've done, we would've noticed that by now.

Hmmm ... I'll mess around with it more this evening. Maybe it's not as bad as I'm remembering.
 
What amp and speakers are you using?

I'm using an Alesis RA-100 amp and Yorkville YSM-1 speakers. I have the volume on the RA-100 set at about 8 (3:00) on each channel. I also have a TC Electronic Level Pilot (just a big knob) that acts like a master volume for everything. Everything runs through that just before reaching the amp. So I leave the amp set the same and just control the volume from the Level Pilot.

I just did another listening test to confirm all this. Everything was being sent to the same amp/speakers. Maybe this will confirm for you that there's nothing wrong with the unit. Here's what I did:

1. Sent a song (Tom Petty's "Breakdown") to CH 1 and 2 of the 388, assigned both to 1/2 and panned them hard L/R, respectively. Monitor knobs for CH 1 and 2 are dimed.

2. Confirmed good level on the 388's CH and master meters. It was pretty much pegged in the red during the choruses, but the OL lights were rarely flashing.

3. Listened through the system without the 388 in the path at all (just listening off my CPU's soundcard) for reference. I set the Level Pilot at 9:00 and played a song with WMP. The volume was around 75% up in WMP. This is about an average listening level for me in my studio. Not waking the neighbors (or my kids when they're asleep for that matter), but plenty of volume to hear all detail.

4. Switched to the sound coming from the 388 using the STEREO OUT jacks. It was noticeably quieter, but certainly not prohibitively so. I could crank the Level Pilot to about 10:00, and the volume was pretty much matching the soundcard volume.

5. Switched to the sound coming from the 388 MONITOR OUT jacks. When I had the MON knob 100% cranked, the volume was the same (I think exactly) as that of the STEREO OUT jacks. But, of course, the sound coming from the headphones plugged into the 388 was almost as loud as the speakers at that point! I wouldn't dream of putting the phones anywhere near my ears at that level.

When I reduce the MON knob on the 388 so that the headphones are at a comfortable listening level, the sound coming from the speakers is extremely quiet -- so much so that I have to crank the Level Pilot to almost 3:00 to achieve the same volume as the STEREO OUT jacks at 9:00. To give you a reference, I've never even approached 12:00 on the LP when listening off the computer soundcard. That would be ludicrously loud.

So ... is that normal? I mean .... are the headphones supposed to be unlistenably loud (and distorted) when you need a good control room listening volume out of the monitor jacks?

Am I doing something wrong here?
 
Doesn't it have a seperate HP volume?

No it doesn't. That's the crux of the problem. The same knob that controls the headphone volume also controls the level coming out of the MONITOR OUT jacks on the back. In order to get a usable listening volume out of the MONITOR OUT jacks, I have to either have the headphones set at an unusably loud volume or crank my amp up to a dangerous level.
 
From the manual.
 

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What headphones are you using? Bear in mind the MONITOR OUT amp is not a booster amp...the headphone amp IS a booster amp. And if your headphones have high sensitivity it's going to exacerbate the discrepancy in comfortable listening level between the MONITOR OUT jacks and the headphones. Furthermore, the unbalanced STEREO OUT jacks are driven by two 2:1 boosters...one before the fader and one after...those outputs have gain...the MONITOR OUT jacks do not.

If you are going to use the MONITOR OUT jacks for your control room monitoring, and unless noise is an issue, I would turn the level knobs up to full clockwise on the RA100. Those aren't really "volume" knobs but input sensitivity adjustment attenuators. By setting them at 3:00 you are attenuating the input to the amp.
 
I've always run my power amps full bore. They like that better. I believe it gives then full headroom.
Listening level is controlled by the mixer.
 
Thanks y'all for the tips regarding the power amp running full. I didn't realize that!

Still the 388 design seems odd to me. I mean ... why wouldn't they separate the headphone and monitor out jacks? Or why not make the MONITOR OUT jacks output a line level signal like the STEREO OUT jacks?

Oh wait ... actually ... I just read in the manual that the MON OUT jacks do provide a line level signal. And the STEREO OUT jacks supposedly send a -10db line level signal. I'm confused ... maybe I just don't really understand the concept of line level.

In other words, why isn't the output of the MON OUT jacks boosted the way the output from the STEREO OUT jacks is? You have the monitor gain knobs on the 388 to control the level. Am I missing something?

What's the point of having the MON OUT signal be so much lower than any other signal that might possibly be sharing the same power amp and speakers?

I just tried again, with the power amp running full out. With the 388 MON knob at a comfortable level for headphone listening (I tried three sets: AKG K240, Tascam TH-300x, and Behringer HPS3000 -- the Tascams were the loudest but not by much), I had to crank the Level Pilot all the way (dimed) to equal the level coming straight off my soundcard with the Level Pilot at about 8:45 or so.

In other words, with a comfortable headphone listening level on the 388, I had to run my 100 watt power amp full out with no attenuation in order to get a decent (not even really loud) listening level out of the MON OUT jacks. And this is with a signal in the 388 that's pegged in the red! If I were to switch to my soundcard's output at that point, I'd probably blow my speakers.

If this is the normal operation mode, then I must be missing something because ... what the hell?

And just to clarify, I'm not trying to be a smartass. I'm sincerely asking, "Why did they design it that way?" There must be a reason that I'm not seeing. I mean ... I know Tascam aren't dummies, so I'm obviously the dummy. But I'm not getting it.
 
Ok, here is something that I'm finding odd. You keep on mentioning soundcard. Do you have this tied into your computer audio in some way?

It would seem that the monitor outs would go straight to your monitor amp and the stereo outs go to a mixdown deck.

If using headphones when tracking, turn to a comfortable level. When mixing (with monitors) turn to a comfortable level.
I don't think it was designed for both being used at the same time, so you wouldn't have to worry about one being too quiet or one too loud.

As far as line level, my understanding is that all three (0db, -10db, and +4 db) could all be considered 'line' level for that particular piece of gear.
 
Ok, here is something that I'm finding odd. You keep on mentioning soundcard. Do you have this tied into your computer audio in some way?

It would seem that the monitor outs would go straight to your monitor amp and the stereo outs go to a mixdown deck.

If using headphones when tracking, turn to a comfortable level. When mixing (with monitors) turn to a comfortable level.
I don't think it was designed for both being used at the same time, so you wouldn't have to worry about one being too quiet or one too loud.

As far as line level, my understanding is that all three (0db, -10db, and +4 db) could all be considered 'line' level for that particular piece of gear.

Thanks for the reply.

When I mention the soundcard, I'm talking about something that's not tied to the 388 at all. I have my power amp wired into my patchbay, so I can send whatever I want to my speakers. So when I'm talking about my soundcard, I'm just talking about playing a song on my computer (whether it's just playing a wav file with Windows Media Player or it's playing a project in my DAW, Reaper) and hearing that through my speakers. The 388 is not involved in any way.

I'm just mentioning it because the level coming out of my speakers when I do that was my guide before I wired the 388 into my rig.

So ... if I'm understanding you correctly, you're meant to only use headphones throughout the whole tracking process? I mean .... shouldn't you be able to listen through the speakers if the talent is recording in the next room or something? That seems to be a very common practice in most studios. And in order to do that with this setup, I'd have to turn the headphones down to a comfortable level for the talent, which means I have to crank the ever-loving piss out of my amp to get a decent listening level out of the speakers.

I guess I'm still not understanding. I'm used to being able to throw headphones on or off at any point and not have to majorly readjust my listening levels.
 
Ok, realize ive not owned one, but have had familiarity with most tascam gear.

If you had this in a control room behind glass with the talent on the other side, you wouldn't be monitoring on headphones. So they'd be out if the picture.
Only the talent would have a HP mix that was run off of a seperate HP amp.
If everyone was in the same room you'd not use the monitors at all, and chances are you'd use a HP amp as well .

Thanks for clearing up the question I had about the soundcard.

It sucks that it doesn't have a HP volume.

Now when you are using monitors, when everthing is at unity running around 0db on the meters, is it still too quiet?
Shouldn't be. Should have a healthy level.

I know with a 100 watt Bryston, if I turn up my output fader 1/3d of the way up, my NS10s are loud!! I don't dare push it up more.
With the Yorkies and the alesis, you should have some volume out of them.

Edit:is that TC vol control tied in somehow??

Just scratching ny head on this. It seems you should have similar volumes.

So forget about the hp for a minute. Can you get good volume out of the amp and speakers?
 
Ok, realize ive not owned one, but have had familiarity with most tascam gear.

If you had this in a control room behind glass with the talent on the other side, you wouldn't be monitoring on headphones. So they'd be out if the picture.
Only the talent would have a HP mix that was run off of a seperate HP amp.
If everyone was in the same room you'd not use the monitors at all, and chances are you'd use a HP amp as well .

Thanks for clearing up the question I had about the soundcard.

It sucks that it doesn't have a HP volume.

Now when you are using monitors, when everthing is at unity running around 0db on the meters, is it still too quiet?
Shouldn't be. Should have a healthy level.

I know with a 100 watt Bryston, if I turn up my output fader 1/3d of the way up, my NS10s are loud!! I don't dare push it up more.
With the Yorkies and the alesis, you should have some volume out of them.

Edit:is that TC vol control tied in somehow??

Just scratching ny head on this. It seems you should have similar volumes.

So forget about the hp for a minute. Can you get good volume out of the amp and speakers?

I can get good volume out of my MON OUT jacks (on the 388) going into my speakers as long as I turn the MON/PHONES knob on the 388 up all the way. Like I said, though, when I do that, the headphone jack on the 388 is completely unusable because it's ridiculously loud.

The TC Level Pilot is basically just like an attenuator before the power amp (I think). I don't know for sure, but basically it has the same effect as me reaching down and twisting the knobs on my power amp. If I were to take it out of the path, then, with my power amp on full, I'd blast myself to oblivion.

That's why I was a little confused by your statement about how you "always run your amps full bore" and "control the level at the mixer." I've always read that the best signal-to-noise ratio on a mixer is attained when most of the faders are near unity gain. If I were mixing a song and had all my faders around unity and fed that signal to my power amp without the Level Pilot in the path, it would be way too loud! It's hard to remember exactly, but I think back before I had the Level Pilot, I would run the output of my DAW through a little Behringer mixer before going into the amp, so I would control the level from that. In other words, I would use that to turn it down before it hit the power amp.

And while that sounds like what you were saying ("control the volume at the mixer"), that's actually a second mixer in that system, the first being the one in the DAW. If I were running a tape rig and using only one (main) mixer, wouldn't you want to run it near unity gain to get the best sound?

Or are you saying that you're controlling the level of the monitor mix (not the main mix) with another knob, and that's the one sent to the amp/speakers?

See, I think one of the main issues is that I've always made it a habit of just listening to the stereo mix -- not the monitor mix. I never understood how to do it back in the day ... and now that I'm trying to figure it out, I obviously still don't have a total grip on it.

It seems as though it should be a simple thing, but now that I'm trying to actually put it into practice on the 388 (and also the 246 --- see my other thread "Tascam 246 mixer questions" for another somewhat related issue on that machine), I'm running into all kinds of little bumps.

The 388 has an AUX BUSS and EFF BUSS in addition to the dedicated monitor buss. With regards to the statement about the talent having a HP mix off a separate HP amp, are you talking about using one of those (AUX or EFF) sends to create that mix? I have two headphone amps, so I could do that.
 
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