Tascam 388 question

Painful100

New member
So I took my 388 to a well respected tech In the SF Bay Area for repairs. I’m using LPR35 tape. I had a few issues that needed to be fixed, but also asked him to bias the machine and reduce noise/hiss if possible. He put a sticker on it saying “ 0 vu = +2db above 250n W/m” - and explained to me like this:

“When the recording signal registers 0 VU, the actual magnetic strength of the the signal going on to tape is a little (2dB) hotter than it would be with the factory operating level.
This means that the signal to noise ratio is 2 dB better for each track. Also, its a little easier to get tape saturation effect if desired.”

My 1st question is, is this a good upgrade for this machine? Has anyone done this, and is there any reason why you wouldn’t do this?

Second question is regarding some recent bass recording I’ve been doing. I’ve been getting distortion (with 2 separate DI’s, swapped cables, plugging into xlr and through line in, and plugging the bass directly into the unit). The frequency can be lowered at around 1.6k and this mostly eliminates the distortion sound I’m hearing. I have a few other things I want to try, different bass, etc. Any ideas what’s causing this? I don’t remember having this problem before getting the machine serviced. Could this be because of the upgrade I mentioned above?

Thanks for your help. Sweetbeats, hoping you will chime in!
 

sweetbeats

Reel deep thoughts...
I don't understand how the tech can call that an "upgrade". Its not really anything fancy. Its all relative. And in my opinion messes with the mind. For me, if I want to print a hotter signal to tape, then (assuming I have the machine setup to factory spec), I'll just track with peaks at +2 or +3, rather than having to track with peaks at -2 or -3 if I want to use the machine as intended. All they did there is make it so "0VU" is hotter than what 0VU would mean if the machine was setup to factory spec. I can do the same thing by just pushing the levels during tracking. Hopefully you didn't pay extra for that.

The other thing you'll want to be careful of, and I don't think you're in any jeopardy here, but understand the noise reduction and the amplifier electronics on that machine are all setup for 0VU = 250nWb/m. If you push levels, "bury the meters", you're likely to cause tracking issues for the dbx noise reduction. The machine sounds best using a +6 tape with the machine setup at 0VU = 250nWb/m. You may also clip the rec/play amps doing the whole "mash it" approach. It wasn't designed to be used that way and I can't understand why people continue to think you have to dump the throttle on a tape machine to make it sound good, or put +9 or ATR Master tape on it to get tape mojo. Tape distortion happens because you saturate the tape. Using a hotter tape only places the threshold for saturation further away, making it so you have to push levels even hotter, increasing the risk of dbx tracking errors and amplifier clipping. I'm telling you, there are people that think they are getting awesome tape distortion but its really the amps clipping...but they think its awesome because they drank the Kool-Aid that said use super high output tape and bury the meters...and it DOESN'T sound awesome...it sounds like opamps distorting. Which is generally non awesome. But if you're led to believe that something distorting is the tape, and that tape distortion is awesome, then when you hear distortion you assume it must be awesome. Tape saturation *can* be pleasing, and a useful tool in the signal chain, but if you *really* want to increase tape saturation on your 388 more than what you get if you *conservatively* push levels with the machine setup to factory spec, and still maintain the amplifier operation within the headroom range, and keep the dbx out of tracking errors, do not use higher output tape...use LOWER output tape. Set the machine up with some Quantegy 407 if you can find it...usual sticky-shed disclaimers...but setting the machine up at 0VU = 250nWb/m and using +3 tape, and then tracking with average peaks around 0VU to +3VU, your amps and dbx will get to handle signal strength as designed, but the signal to tape will be relatively hot for +3 tape... = saturation.

You don't run into this issue using a wider format machine at a higher tape speed and one with higher headroom amps, because those amps have the headroom to drive higher output tape to saturation, and with the higher output tape (= greater signal to noise ratio) and the better signal to noise ratio of the wider track width you don't need noise reduction. So no limitation of tracking errors, and amps that don't clip before the tape saturates. But those practices can't translate to operating something like the 388. Not all tape machines and formats are created equal. This shouldn't be read as something disparaging about the 388...my point is to know each tape machine, understand its format and limitations, and then wisely choose the machine setup and tape type etc. for THAT MACHINE to achieve the results you want. That's why I'm saying with a 388, if you want heavier tape saturation, rather than forcing the signal chain to operate outside of its limits, make that saturation threshold easier for the machine to reach by using a +3 tape and set it up to factory spec. The dbx will keep things quiet even using the +3 tape because you're still using the machine within the factory designed range as far as the level setup.

Soapbox speech over.

The other thing I would ask is how the tech set the bias on your machine. If she/he set it using the blind factory method (i.e. setting the bias level to 150mV on each channel), that's wrong for LPR35. The factory spec was determined using Ampex/Quantegy 457 which has a different bias requirement. I didn't know this until analog support specialists at Teac in Montebello, CA (before that department and its extremely valuable staff were disintegrated) told me some 8-10 years ago, and I did my own testing using the LF distortion "bias rocks" method using LPR35. It wasn't easy with the narrow format and 7.5ips tape speed, but my determination was that about 110mV was right for LPR35.

With your bass distortion issue, this is happening when monitoring the input to the mixing section, or when playing back bass printed to tape?
 
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Painful100

New member
Thanks for that in-depth response. I’m going to need to reread it a few times to understand it. But regarding the bass question. I’m not getting the distortion while tracking. It sounds very nice and clean at first. I’m getting it on play back through the headphone monitor.
 
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sweetbeats

Reel deep thoughts...
So how does it sound through the MONITOR OUT jacks, or the STEREO OUT jacks, or directly from the TAPE OUT jack?

What does the VU meter show for peaks during playback? And what does the average level look like on the meter? Any way you can post a link to a sound sample of the distorting bass track?
 

Painful100

New member
Haven’t tried through monitor outs bc I had house guests. Will year these things tonight and report back, maybe I can post a sample too. But the VU meters tend to average around 0 I think. But bc of the “upgrade” I’ve been wondering about where to aim for regarding VU meters.
 

sweetbeats

Reel deep thoughts...
Use your ears is always the best course for where to aim for on the meters. It will always depend on the setup, the machine, and the source and how it is EQed, and any input processing that is in the signal chain. I would monitor the track through those three outputs I mentioned earlier to see if the distortion is present there, and if it is you may be clipping something on the way in...I'm assuming it doesn't matter where you set the playback level? Like varying the level of the track playback results in the same level of distortion? And this is through the correspondingchannel in RMX mode, right? Because you said you could help the distortion with a cut at 1.6K? Honestly that sounds like an opamp distorting and you are getting higher order clipping because the LF content is overdriving something in the signal chain, but you would really have to be pushing the tape to get anything like that kind of distortion result from the tape...the rec/play amp would clip way before getting that kind of distortion on tape. So let's narrow down if the distortion is printed to tape (occurs on the way in), or if it is something on the playback side. If its printed to tape you'll still hear it even if you have the playback level set low, and it will be present in all outputs. Check all of them I mentioned. And if its printed to tape then try tracking with the level a little lower to tape. And tell me more about the signal chain...passive bass? Active bass? I'm assuming its a passive bass because you are using a DI. What kind of DI are you using? Any insert effect? How do you have the EQ set on the input channel for the bass?
 

Painful100

New member
It’s a passive P bass. I used a DI coming out of my orange amp head, then a separate Aguilar DI. Then again directly into the quarter inch cable. Tested on two different channels. I do have some affects hooked up to the machine, but those shouldn’t be affecting anything bc they are set in the off positions. Eq’s are flat. Yes I was testing through RMX mode on playback. Play back level doesn’t seem to make a difference. Although obviously it’s quieter when lower. I did have the volume on the bass turned all the way up/maxed out. I wonder if turning that down and the DI up could make any difference.
 
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sweetbeats

Reel deep thoughts...
Why are you using the DI between the amp head and the 388? That should already be line level coming out of the amp head...no need for the DI. You’d use the DI if you were going straight from the passive bass to the line in on the 388.
 

Painful100

New member
Sorry I used them separately not at the same time. My amp head has a DI out. I just tried them both out separately in case one was the problem
 
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Painful100

New member
I wasn’t able to test anything more tonight, but I will tomorrow. Thanks for your help. I asked about the bias question he did on my machine for the lpr35 tape, this was my response from the tech:

“The correct bias for that machine is in the range 85 to 110mV depending on tape oxide and headwear. The record EQ cal adjustment has only VERY subtle effect, so the bias is fine adjusted to get flattest record/repro frequency response.
I wouldnt try to re-set the bias for a particular value though without a DMM that has at least 100kHz bandwidth”

I’m not too sure what this even means. But I’m sure you do.

Fascinating reading your explanation about why using +3 tape makes the most sense bc that’s how this machine was designed. I read that lpr35 tape was good to use, so that’s why I had it set up for that. But I had been getting artifacts using dbx, especially on bass frequencies. A “pshh” sound surrounded the bass notes. Is it possible that using +3 tape and biasing to factory would get rid of that?
 
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sweetbeats

Reel deep thoughts...
Yes, that does make sense what your tech said, and IMHO the tech is spot-on.

Back to tape selection and operating level, LPR35 IS good tape to use. It is the BASF/EMTEC/RMGI/RTM equivalent of the tape type the machine was designed to use; +6, 1mil class tape. So you're good there. I'm just bringing the whole +3 thing up because, as an option, if (with a proper setup) you wanted to experiment with ways to achieve higher tape saturation with minimal impact to the amplifiers and dbx circuitry, the easiest and best thing to do is just use a tape that saturates easier. It doesn't mean you *should* do that or *have* to do that. My recommendation is use the machine as it is setup with the LPR35 you have...experiment with tracking hotter and see what it does. Drive it for awhile, and then if you find there is anything lacking, THEN ask the critical questions and seek options to address those limitations if they even exist at all for you.

But I had been getting artifacts using dbx, especially on bass frequencies. A “pshh” sound surrounded the bass notes. Is it possible that using +3 tape and biasing to factory would get rid of that?

First of all, your statement about using +3 tape and biasing to the factory 150mV is tying two things together that aren't necessarily related. All the tape type and its designated operating level (i.e. +3, +6, +9, etc.) means is at what level over the original Ampex standard (+0 if you will) the signal to tape distorts to 3%. So "hotter" tape can handle more signal before it distorts. Generally speaking, the higher the operating level of the tape, the more oxide is on the tape, and the more bias signal is needed to do its job. By the way, if you didn't already know, all "bias signal" is is a high frequency signal that hits the tape ahead of the record head when recording. Why? During the dawn of analog audio tape recording it was realized that frequency response drastically increased and distortion drastically decreased if the magnetic particles in the oxide on the tape were "excited" or prepared for receiving program signal by a high frequency signal just prior to program signal hitting the tape. I think the frequency of the bias tone on a 388 is 150kHz. Too little bias signal during record and distortion is not abated. Too much bias signal and you diminish the HF response. Every tape has an optimum bias signal requirement to maximize frequency response and minimize distortion. So that's why we set the bias on the machine when we put new tape on. There can even be slight variation in bias signal requirements between different batch runs of the SAME tape brand and type. Professional studios made it common practice to set the bias on the machine with each new reel of tape regardless of the make and tape type.

Now to hopefully address your question, yes, if you switched from LPR35 to some +3 tape (like 407, which is a +3, 1mil class tape) you would certainly want to reset the bias, but neither the standard operating level (i.e. "SOL", the +3, +6, +9 designation) of the tape nor the bias setting may have anything to do with your issue your experiencing with your bass track. My gut-hunch is what you are hearing is possibly dbx mistracking artifacts, or a bias issue, or a combination of both. Might you fix that by plopping different tape on the machine and blindly setting the bias to 150mV? Maybe. Probably not. If you left the operating level of the machine the same as it is currently and otherwise continued tracking at the same level, you would be distorting the tape more (saturating the tape more...right? Because if you left everything else the same and put tape on the saturates easier you will instantly have more tape saturation), but that in itself may increase the potential for dbx tracking errors (the dbx circuitry may have issues dealing with the distortion), AND if you put that +3 tape on the machine, which typically would require LESS bias signal than the factory specified +6 tape (remember what I said above? Generally speaking, a "hotter" tape has more oxide requiring more bias signal level, and therefore the converse is generally also true...a less hot tape generally requires LESS bias signal level) but you INCREASED the bias to 150mV, my hunch is you would have an over-bias situation with compromised HF performance as a result. In summary, it might sound like ass. Or you might like it. Only your ears will tell you the truth relative to YOU. BUT...here's what I'm thinking...you might just try tracking your bass a little less hot and see if that addresses the issue. I don't know how you have your bass setup, how full it is on the bottom end...since your tech set the machine up at 250nWb/m = -2VU, if you are running your average levels on the bass track at around 0VU or something a little more, and your bass tone is full, you might just be causing some dbx tracking artifacts. So start there, see if taming your average levels a bit helps with the "pshh" sound. If that doesn't do it, I would try increasing the bias 10mV at a time on the bass track only to see if that helps. I'm not sure where your tech actually set the bias level. You can ask your tech, and it sounds like he/she possibly set it a little different for each track in conjunction with the record EQ control to maximize frequency response which, IMO is okay...the whole point of the bias and record eq calibration controls is to line up the frequency response of each track and get them all within factory spec...IIRC that's +/- 3dB from 30Hz to 16kHz on the 388. But maybe your bias level is a little shy overall which is helping the HF response but on the bass track the LF content and dbx processing is revealing some distortion. I don't know. But those are the things I would try if it was on my bench, FIRST just easing up on how hot you are tracking to tape. And by the way if you DO decide to mess with your bias level I totally agree with your tech you want to use a multimeter that is acurate to at least 100kHz. Why? He/she says that because, remember, I said bias signal is high frequency. Maybe I'm wrong on the frequency of the 388 bias signal...maybe its 100kHz and not 150kHz...I don't have the manual in front of me. But anyway your tech's point is that if you are going to measure/set your bias level you need to use a meter designed to measure that high of a frequency. That makes sense, right?

And here's a little tip...there's nothing wrong with experimenting with your bias level outside of that sweet spot of minimum distortion and maximum frequency response. That's right. You never know. Maybe your kick drum might actually sound better if on the kick track you lowered the bias a little...the extra bite of a little more distortion and increased HF response might actually sound good. That's part of what makes working with a tape machine pretty great. Between bias settings, tape types, operating levels, record levels, etc., there's a diverse palette of things a tape machine and its tape can do to compliment your source material.

Hey, anybody, its been a little while since I've mind-barfed this stuff, so if any of my information is backwards or otherwise incorrect PLEASE correct me.

Thanks.
 
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Painful100

New member
Well, I certainly appreciate you taking the time to write all of that. It’s starting to all make more sense. It seems possible that my tracking is too hot. Also wondering if I’m used to clean digital tracking, and there is just some noise I need to get used to as well. I’m going to try all the things you suggested and hope to post some samples here. I know I won’t get to it for a few days though (prob early next week), so stay tuned.
 

Chilljam

transitional phase
I personally wouldn't be trying to push the levels to tape on any machine with DBX as that noise reduction system inherently exacerbates any peaks and troughs in the frequency response and also any distortion ie. any subtle tape saturation you are trying to achieve will very quickly become not so subtle.

The Fostex machines used Dolby C which I understand handled tape saturation better as that system doesn't do much at higher tracking levels.
 

rorohello

New member
I just got my 388 back from the same dude. He's in Berkeley correct?

I went ahead and had him do the +2 adjustment and he cleaned/demagged/biased for SM911 which was my choice for tape.

I've never used my 388 with the DBX off, because I don't record bass heavy or in-your-face type stuff. But as my heads are approaching the end of their life, and I'm going to be switching to my Otari MX5050 more for saturation (and the beauty that a 4 track forcing mechanism imparts on songwriting) I'm planning to slam drum tracks from a drum brain into it now and see what kind of results I get.

Also, both Sweetbeats AND this tech are knowledgable and friendly/supportive dudes. He's not in business to rip anyone off. Believe me.
 

Painful100

New member
For sure. I felt good about that tech I just didn’t understand the concepts yet, yeah he’s in Berkeley. I think I was pushing levels too hard,
It’s sounding better to me now.

If anyone is checking in on this thread, I got another question. So I have drums on tracks 1, 2,3. (Kick, oh-l, oh-r). I’m patching in a
Roland space echo re-201 into the global effects send/receives). I want to effect the overheads on tracks 2 and 3 (but keep kick clean) and bounce all 3 over to a stereo mix on two channels (7,8) - panning each overhead accordingly. I can’t print the effect unless I go plugging the re-201 directly into the channels (7,8) right? Then all 3 tracks are effected. I’m thinking it may not be possible to do what I’m trying to do...due to there being one out on the space echo, and trying to effect 2 out of 3 of the tracks I’m trying to bounce. Hope this makes sense.
 
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sweetbeats

Reel deep thoughts...
Glad dropping the level helped.

Your question about printing the RE-201 effect makes perfect sense.

Here's what I would do, since the effect returns on the 388 are not assignable (i.e. EFF RTN 1 and EFF RTN 2 are internally patched to the main STEREO L-R buss...you can't assign the effect returns to any other busses):

Instead of bringing the RE-201 back to an EFF RTN channel, bring it back to any other open mixer channel, and assign that channel to PGM 7-8 with the PAN control set to center. You'll have complete control of the balance of wet to dry you are printing to tracks 7-8 by adjusting the RE-201 channel's fader, plus you'll be able to use the EQ if you need to shape the output of the RE-201. Just make sure you keep the EFF send knob turned all the way down on the channel you use to return the RE-201 or you'll create a feedback loop.

Does that make sense?

So you'll set channels 1, 2 & 3, to RMX, assign all three to PGM 7-8, but only turn up the EFF send knobs on channels 2 & 3 where the overhead mic tracks are being monitored. As a result only the overhead mic tracks will be sent to the RE-201.
 

Painful100

New member
Dude thank you! This is exactly what I was looking to do. Worked great! Follow up questions though....

Does it matter that I had the red assign buttons pushed in on tracks 1-2-3, and not the tracks been recorded to , 7-8? Just wondering what the difference would be if I had them pressed in on 7-8

Can I do this while a band is playing live? And it will print to their tracks and effect their instruments?

And what is up with the MON (PGM, CUE) when it comes to doing something like this. I watched a YouTube video where the guy said you have to have that pressed down to bounce tracks. Well I didn’t have it pressed down and everything went fine.
 

sweetbeats

Reel deep thoughts...
I hate to say it, but I’m having some difficulty understanding your post. I’ll try and answer what I can and ask clarifying questions for where I get lost.

Does it matter that I had the red assign buttons pushed in on tracks 1-2-3, and not the tracks been recorded to , 7-8? Just wondering what the difference would be if I had them pressed in on 7-8

So...the “red assign buttons”, you’re talking about the buttons that assign signal to the L-R main buss? And you’re saying you were able to record your kick and overheads that are on mixer channels 1, 2 & 3 to tracks 7 & 8 and you *only had the L-R assign switches latched?? All other assign switches were up/unlatched? If that’s what you mean I have NO idea how you recorded to tracks 7 & 8 without assigning any sources to PGM groups 7 & 8. :???:

Can I do this while a band is playing live? And it will print to their tracks and effect their instruments?

Sorry, man...do what while the band is playing live? Print what to what tracks?? Effect what instruments with what? Please spell it out in some detail. I want to help but I can’t see your machine, setup, band, have no idea what’s turned up, switched on/in etc., so you need to paint a complete picture with words.

And what is up with the MON (PGM, CUE) when it comes to doing something like this.

Doing something like...what? Look in the manual for the function of the PGM/CUE switch. Page 33. That switch defines the source of the monitor mixer channels 1-8. In PGM position it fixes the monitor mixer channels to whatever is present on PGM groups 1-8 respectively. When in the CUE or up position the source of the monitor mixer channels is defined by the position of the INSERT switch, and that has to do with auto-switching the source depending on the record arm switches...it’s for doing punch ins.

I watched a YouTube video where the guy said you have to have that pressed down to bounce tracks. Well I didn’t have it pressed down and everything went fine.

It does not need to be in the PGM position to bounce tracks. Again, look at the manual. It has nothing to do with what the tape tracks’ sources, it has to do with the monitor mixer channels’ sources and locking them in (PGM or down/latched position) to the PGM groups regardless of the track record and transport record status, or not (CUE or up/unlatched position) where the monitor mixer channels’ sources automatically switch from tape to input during a punch in. There’s more to it but that’s the basic overview.
 

Painful100

New member
Through experimenting I was able to answer some of my own questions. Sorry some of my questions were so unclear. Regarding the first question, I assigned the tracks using the pan/l-r knobs, and kept the red assign button down so I could eq the mix being sent to tracks 7/8. Everting went fine and I probably should have left it at that, but was wondering what the difference would be if the red assign l/r was depressed on tracks 7/8. Maybe that would allow more eq effect to print on those tracks. When I track a band, the red buttons are up and I mix the headphones with the monitor section. My friend records with the red buttons depressed. Maybe it’s the same means to an end?

Regarding the second question, I think I discovered my answer. Thanks for explaining the next parts.

I have another question that hopefully I can word well. So I have a m-1b line mixer. I read a recent post in which you commented, but there’s another poster who suggested using that line mixer to expand effect capabilities. Follow the instructions on that posting, I was able to hook up the line mixer with separate spring reverb unit. What I’m trying to figure out is can I have 3 or 4 global effect units hooked up to the tascam 388 ready for use without having to fuss too much behind the unit. Obviously the machine has 2 options, effect and Aux... but my limited understanding is that can be expanded with the line mixer. Is this achievable and if so, how would I would I wire things up.

And... can I hook up a second pair of external monitors to the M – 1B? I definitely will be experimenting with all of this as well.

Thank you very much
 
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