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  • Originally posted by KernelG

    I have seen this issue reported on PowerBooks with PreSonus devices as well. Not sure what it is, but just so you know.


    Thanks for the feedback. I'm a bit leary of the presonus stuff as well, but more because I've heard they don't work well with powerbooks, they need a g5. CPU overhead? Too bad, the firebox is a sweet little box for super portability.

    Dang, I really want the 400f to work nicely as the pres are great and it's got almost the ideal feature set, but as it stands...

    Comment


    • Hmmmm...I've heard about the whine issue as well, although not in relationship to the Mackie. Maybe there's a relationship to power consumption, or lack thereof, given that the 400F is AC-powered?

      Does it change depending on whether you use batteries or the adapter? I recall reading something about that as well. Try it both ways, then try borrowing a self-powered FireWire hub (or daisy-chain with another FW device) and see if the problem persists.

      As to the download thing, there was a new Windows version on the web site when I received the 400F, so Windows owners would need to download the control panel/drivers too. I'm starting to think all companies should just give up trying to provide a current CD with any unit, and say either "Get the stuff from the web, or call us and we'll ship you the latest version of the software using 2-day delivery."

      Finally, about Gene's "hearing" thing...I tend to believe what people say. The big deal is to find out WHY. For example, there was an interview in Guitar Player with Eric Johnson where he talked about some batteries sounding different than others with effects. People had a field day making fun of him.

      But not so fast. Carbon-zinc and alkaline batteries have very different internal impedances, and when used with older effects that had shoddy power supply rejection, the battery type COULD make a difference in the sound. There may be something unique about Gene's setup which, if "decoded," might shed some light on how digital audio is perceived. There's no way whatsover I would describe the 400F sound as "piercing," but all I can speak to with authority is what I hear.

      On the other hand, the Sharpie around the edge of the CD ...I'm really not sure I buy that.
      CHECK IT OUT: Lilianna!, my latest song, is now streamable from YouTube.

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      Comment


      • I did a little googling around...seems the "firewire whine" is not an isolated problem, nor confined to any one interface.

        Here's a thread talking about the G4 "whine" problem with the MOTU 828 Mk II and Edirol FA-101 FireWire interfaces:

        http://www.macmusic.org/agora/forums/?s=〈=EN&act=ST&f=5&t=24040&st=0&#entry162096

        And one about G4 whines in general...one guy thinks it's related to the inverter used to power the backlight on the LCD, but I don't see how this would relate to FireWire:

        http://macintouch.com/pbg4reader24.html

        More about whines with bus-powered interfaces, with some interesting comments from a former E-Magic tech support person:

        http://www.bigbluelounge.com/forums/viewtopic.php?t=18138&sid=0391ea59712759cbfd0cdfdd 1e1e795b

        It's disturbing that no one really seems to have an answer.
        CHECK IT OUT: Lilianna!, my latest song, is now streamable from YouTube.

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        Comment


        • I need another guide for total ignorants. I've got a little money, and want a better interface for my G5 dual, G4 power book, and wintel computers.

          Back when the Spike first came out, I bought it, and was disapointed, except for one track recordings. Is the 400F much better than Spike?

          I'm more interested in Video productions now, than I was in audio only productions. I do think audio is as improtant as video in a production though.

          I'd rather be a producer, or talent, than an engineer. That is, I'd rather have the tools for many specialists to produce high quality multi-media productions than to be a specialist.

          I'm not a millionare, and the specialist, and talents, I am working with are not either, but I do want (and some degree have) equipment that qualifies me to sit in on courses on video production at a major university that I work for.

          Ok, I'm in the wrong place and will get flamed. I do hope I can get some info though. I'm just a grassroots independent film producer, (ok, i'm just a wanna be) looking for more info.

          I'm about ready to buy the 400F, but wonder if I'm making a mistake like I did with the Spike, when I had less money.

          I just want to raise hell, by lowering heaven, that is, I want to raise the street people to the ivory towers, and lower the ivory towers to the street people. I'm working class with a little more money due to an inheritance.

          Is the the 400F what I need to produce better sound on my computers? Thanks for the info so far. Is there another site I should go to?

          Thanks again,

          Comment


          • Originally posted by Pleasant
            Rodney,

            You gotta relax, man.

            Both Tadpole and I were being light hearted.

            I think the image of you sitting back listening to Stevie Nicks with your ears blown-off by the 400f DA IS pretty funny. That's all he meant.

            I read, enjoyed, and took seriously as did many here, your review of the 400f. It has been cited many times in this thread. That's why I, jokingly, referred to it as "infamous".

            We're all very impressed with your tenure on this and other forums.

            - P


            Thanks bro, I understand.
            I haven't actually read this thread...I just responded directly to the link invitation sent to me from Mackie.

            I happen to land on the thread to see one of the Mackie desingers say this..."This frequency dependent phase shift results (to our ears at least) in "fuzzy" sounds. Many people have become accustomed to fuzzy sound, and are surprised when they hear phase-aligned response, as it sounds brighter. Our opinion is that the D/A converter should reflect "truth", not a preferred sound. What good is mastering on sweet-sounding D/As when your mix won't translate to the masses?
            "...


            OK, I can accept the intent behind that post... But anybody in this business who say's.."it must be the users fault"...they lose credibility to me. IMO, It is OK that a project studio level device is not the very best thing out there or MAY exhibit some 'less than prefered' behavior...it is OK to me that it comes in at 'really good' or 'bargain for the money". That should be celebrated IMO. It was in my best interest (for other reasons not stated) that the 400F could replace my Fireface 800...but alas it could not...not on it's own.

            And to brother Craig...I would be surprised if I had a bogus unit (although I definitely got the first run of them). I also experienced a clarity and crispness that bordered on sterile ( that I was excited about at first)...but in the end it wasn't friendly at all...it was piercing. My Benchmark DAC-1 (which is KNOWN not to be flattering) has many of the same qualities, except the top end and upper mids sit correctly and smoothly with reference material...(I am positive that George Massenburg didn't overlook cymbals and guitars that bite your ears off)

            Not to mention my first experience with Mackie converters was with the FW card on the 1620 mixer..and that D/A was really scooped and bright. Not usuable for serious recording IMO.

            Also...and this is crucial...I was able to back to back the units in my own room (which is an excellent sounding room). This means I was able to hear the differences in an enviroment I am familiar with...and I WAS LISTENING for those 5% subtlties like the top end. That was my GOAL.

            As I have said in other posts...If I had the 400F only, it would not stop me from making great recordings..I would simply get used to it's sound like I have had to with my monitors, preamps, rooms etc...
            But I did and do have a better choice.

            I wouldn't expect this box to the answer to my prayers, but It would be insulting to think that it is not the answer to others.

            We each have our needs and opinions.

            Happy Sunday to everyone and I hope you all take the oppotunity to create today... and take a rest from talking about gear.

            Respect,
            "Most of our energy goes into upholding our importance...If we were capable of losing some of that importance we would free our energy from trying to maintain the illusory idea of our grandeur... and we would provide ourselves with enough energy to catch a glimpse of the actual grandeur of the universe"...

            Comment


            • Originally posted by Anderton
              Hmmmm...I've heard about the whine issue as well, although not in relationship to the Mackie. Maybe there's a relationship to power consumption, or lack thereof, given that the 400F is AC-powered?

              Does it change depending on whether you use batteries or the adapter? I recall reading something about that as well. Try it both ways, then try borrowing a self-powered FireWire hub (or daisy-chain with another FW device) and see if the problem persists.


              The whine persists whether or not the powerbook is plugged into ac power or not. I've also tried putting a harddrive daisy chained between the powerbook and 400f with the same results.

              Thanks for the links. Looks like this has been an issue with some other firewire interfaces. Too bad there isn't a solution out there.

              Any Mackie engineers care to comment, have they heard about this? I'm wondering if getting another unit will solve my problem? I do plan to get another powerbook soon (after MWSF), wondering if that would help?

              Comment


              • I came in here late, just following a link from a periodic mailing that I received from Mackie. I've been following comments about the 400F on the Mackie forum and it's interesting to see Craig's review unfolding, together with the feedback and side discussions. It takes a while to get very much said, though. Better if we were all sitting around a 400F in a bar.

                I don't have a 400F here, but I have a bunch of other Mackie stuff including an Onyx mixer with a Firewire adapter card, and an 800R. I'm basically an analog person - I mix with a real mixer and plug in real stuff to a patchbay, but it's hard to avoid at least using digital as a recoring and playback tool so I have a passing interest in what's coming along.

                I wanted to add a few thoughts to some of the comments here.

                Brittle Sounding A/D Converters
                What you hear is what you hear, and what you get used to, provided it's pretty decent, is often what you like best. I'd like to point out that digital stuff distorts in ways that analog stuff doesn't. While we can tolerate, and even find pleasant, certain forms of analog distortion, very small amounts of certain types of disortion unique to digital processing can sound pretty unpleasant. The fact that there is no apparent irregularity in frequency response doesn't mean that we can't perceive some annoying goings-on with the high end.

                While I hae heard plenty of differences in digital reproduction, it's been a while since I've heard something that really sounds bad, if the source is well recorded. I don't expect that I'd have a problem with the 400F, but then I don't record cymbals in ways that they'd tear my ears off if something wasn't right in the playback. I hope that this issue doesn't become a "bandwagon" and that people will be biased before actually listening.

                That said, there's some value to having one D/A converter (and appropriate switching and patching) through which you can listen to everything that you do in your studio. It's the only way you can accurately compare, for instance, a CD pressing with the original recording. So while I don't think it should be necessary to buy an outboard D/A converter before firing up your new 400F, it's something that you shouldn't toss of as a unit that you'll never need.

                Firewire Connector Adapter
                The 6-to-4-pin adapters that I've seen hanging on the rack in computer stores have been solid, a hunk of plastic about 2 inches long with a big connector on one end and a little one on the other. Attaching a fat Firewire cable with its large connector and then attached to the adapter puts a lot of strain on the tiny connector on a typical laptop computer (Mac users may gloat here - the only laptops I've seen with a full sized connector have been Macs). If the cable isn't well supported, as is often the case with a portable setup, it could fall out easily. Worse, the connector on the computer is subject to more stress than it was designed to take. Replacing it will be expensive.

                While it's generous that Mackie will be supplying such an adapter, I'd recommend that if you need a small plug to connect the 400F to your computer, spend the $15 for a cable with the proper connectors on each end. It's probably too late for Mackie to change gears now, but it would make more sense for them to supply a big-to-little cable and an adapter to convert the 4-pin end to a 6-pin plug. While the 6-pin socket will still have more than the normal strain on it, it's more likely to survive than a 4-pin socket.

                Jacks with Plastic Bushings
                Craig likes 'em. I don't. The box should be an extension of the cable shield, and the only way you can have this is for the jack to be solidly connected to the box. One of the things that Mackie has done right in the past is to use solid jacks, and Pin 1 problems are rare on their mixers.

                The box shouldn't be the only route to audio ground, and a reasonably heavy wire running directly to a common ground point is also important for noise-free operation. You indeed do need a solder tab for this. But you can't assume that the wired path to ground is direct and heavy enough to carry what turns out to be a surprising amount of current in some cases. When I get in a new piece of gear these days, I test it for hum that can be induced through its ground, and fix (or return) it if there's a problem.

                The AES has finally published a standard for design of grounding systems. You can read more about it by downloading a PDF copy of AES48-2005 here: http://www.aes.org/publications/standards/courtesy.cfm?ID=44

                That's the ideal, and in some designs, it makes sense not to implement all of the recommendations of the standards. Screwing jacks solidly to the chassis is easy to do, however, and almost always solves more problems than it might cause. I don't know if there's a problem, but on general principles, I would have preferred jacks with metal bushings. Plus it's one less piece of plastic.

                ASIO Driver Update
                It's good to hear that the next generation of the ASIO driver will accommodate stacking multiple units. A well infomred little birdie told me that TI was going to (or already has) decided to get out of the audio interface chip business, so there wasn't much incentive to pursue new driver development on a wide scale basis. Kudos to Mackie for taking this on. Hopefully what comes of this development will allow the 400F and 1200F to work together in the same system, making Dan's suggestion to "buy both" more reasonable.

                Mic Preamps and Ribbon Mics
                Someone asked whether the preamps were appropriate to use with ribbon mics. What mics, and on what source? The usual things we think about with ribbons are that they have somewhat lower sensitivity than condenser or other dynamic mics, so they require more gain when used with a quiet source. The 400F has about 60 dB of gain, and I find that to be a bit on the shy side when I want to use one of my Beyer M160s on an acoustic guitar or fiddle at a distance greater than a couple of feet. The Royers are about the same. I haven't tried any of the latest batch of copies, but reports I've read don't indicate that their sensitivity is typical of other ribbon mics. A Coles 4040, on the other hand, is a pretty hot mic.

                A lot of people get uncomfortable if they have to crank the gain all the way, and if the preamp noise comes up significantly at full gain, that's a problem. I don't find that to be the case on the 800R or Onyx mixers that I have, so I presume that the 400F is similar. So if that's enough gain for your mic on your source, no problem. The buzz a few years back was that ribbon mics should see a low impedance load, and a number of preamp manufacturers responded with switchable input impedance. The 800R has an input impedance switch on two channels, and I find that most most mics sound best at the highest impedance setting. So I predict that if the gain is adequate, the 400F preamps will work fine with any modern or even vintage ribbon mic.

                I guess that's enough ranting for now. I'll probably dropo back in now and then to see what else turns up.
                --
                "Today's production equipment is IT-based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson, Resolution Magazine, October 2006
                Drop by http://mikeriversaudio.wordpress.com now and then

                Comment


                • Hi there everyone. Thanks for all the contributions that are making this such a great thread! Here's some answers to some questions that have popped up since the last time I posted.

                  Referring the idea of controlling the 400F with a Mackie Control, Imagodel asked "I really dig this idea. Any way to have a single MCU control multiple 400F's at once?"

                  Good question, we'll see. We are still working out the details of MCU mode and I am not yet sure if this would be possible. It would require the user to make a "daisy chain" of the midi cables going between the MCU and the (2) 400F's, and we'd have to see if there are any technical gotchas to that route. With a single 400F and MCU, there's only 2 midi cables between the two pieces and we know that works.

                  Spectacular G inquired about multiple unit support, asking " For instance was this unit designed with this feature in mind from day one? Will I need to run two instances of the control panel?"

                  We've had this in mind for a while. You will not need to run 2 instances of the control panel. The control panel, upon launch, will sense if there are 2 units on the chain, and if so, will generate "tabs" on the left hand side to allow you to choose which unit you are controlling. Clicking on a tab will also flash the unit's lights so you know which physical unit goes with which tab.

                  "How much DSP horsepower is still yet to be used?"

                  We've made sure leave some available for effects. I will be honest though, that the existing mixing functions use a lot, so what's left might be more appropriate for "meat and potatoes" stuff (useful for giving you the channel and effects loop stuff you'd want in "MCU mode" rather than super DSP hungry top shelf effects (like people have been saying they want). But, time will tell.

                  I would like to stress again and be frank that "MCU mode" and adding effects might or might not make their way into this product, depending on customer demand and available resources, so please make sure to buy the product on its own merits as it stand today and not for features that we all hope might show up. Multi unit support though, is coming.

                  Ticohans asked " Speaking of which, are there any updates coming out soon, for which I should hold off my purchase?"

                  The only update that is definitely in the pipeline is the 1.06 driver and control pnel which will add multi-unit support. No need to wait until it comes out to buy though, it will be a free download for you when it's available.

                  Ironbuddha asked " Any idea on how this product compares to the audiofire units from the 400f's co-designers at Echo? The design of the 400f appears to be a direct sibling of the audiofire 8, save only 2 different mic pres and 96khz as opposed to 128kHz. I'd be interested in how these two units compare."

                  The audiofire 8 is a great unit, as is all the stuff from the fine folks at Echo. Some differences are:

                  -Audiofire 8 has a street price of around $100 less than the 400F, so it is somewhat more affordable.

                  -Audiofire 8 is a bit narrower than the 400F, so although it can be rack mounted, it is a bit more portable than the 400F for stowing in a bag.

                  -400F has 2 more mic pres, 1 more headphone out, and a control room level pot

                  -Comes with Tracktion 2 (Audiofire 8 comes with 1.6 but users can upgrade to 2 for a reduced price)

                  -400F goes to 192k, Audiofire 8 goes to 96kHz.

                  -Audiofire 8 has a different mic pre design, it's not the Onyx pres (although knowing the guys at Echo I bet theirs sound great as well)

                  Sutoman asked " Am I crazy, or is it too much to ask that adapters be included with the Onyx series so their product can be used out of the box immediately after purchase?"

                  A fair point, and we are looking at doing a running change where we'll add a 4 to 6 pin adapter. Another post (later in the thread) mentions how these adapters can put a strain on the actual motherboard's Firewire connector, and this is true, so in the end we'd maybe consider the included adapter as a way to "tide you over" until you can order a 4 to 6 pin cable.

                  While we'd love to include both a 6 to 6 and a 6 to 4 cable in the box, it's just too expensive.


                  Freen then had some questions on MCU mode and the DSP mixer, asking

                  " It would be very useful, indeed. Especially if it meant being able to create super-low latency headphone/monitor mixes while tracking. Presumably this feature would also be included on the 1200F?

                  -If an MCU mode comes out, we would also try to have it for the 1200F. With it's superior channel and mic pre count, we agree that it would be especially useful for that product.

                  That's where it would really come in handy. Two questions related to this:

                  1. Would these interfaces be able to function in this MCU controlled mixer mode while simultaneously handling DAW I/O?

                  Not sure yet, we'd have to see what is technically possible.

                  2. While controlling the interface (400F or 1200F) in this mixer mode, would the MCU be unavailable to control whatever DAW was being used? Or could it somehow switch modes and control both the interface mixer function and the DAW? Bank switching with some banks controlling the DAW and some controlling the interface's mixer functions?"

                  The MCU would probably not be available to the DAW at the same time, you'd most likely have to choose one or the other. While your banking suggestions is a good one, keep in mind that for that to be possible, it would mean that each software company would have to go back and re-do their MCU implementation to allow for this. I don't see them doing all this extra work to help us sell a certain piece of Mackie hardware better.

                  Jameswood asked " What kind of firewire does the 400F use? Is it 1394a (up to 400Mbps) or 1394b (up to 800Mbps?) Does this really matter?"

                  It uses 1394a (although as another posted, the 400 stands for 4 mic pres, not Firewire 400F). And no, it does not matter, because Firewire 400F was fast enough to satisfy the product's goals, which was 10X10 at 192kHz, plus MIDI.

                  The only 1394b interface out there I am aware of is the RME Fireface. It has a very high channel count so it might need 1394b to achieve what it does, or on the other hand, they could just use 1394b to make people think their interface is cool. Stranger things have happened

                  Controlling the 400F's DSP mixer from within DAW software.

                  That is not something that we had been considering, but I am reading all the posts about it to learn of what you guys have in mind. I should say that this type of thing is sometimes hard to do, because you have to convince other companies (like Steinberg) to do work on their code, to ultimately help sell your company's product. That's often a hard battle to fight and I am impressed that M Audio was able to make it happen.

                  One thing I would encourage folks to do, if you have a powerful enough computer, is to actually try turning the DSP mixer off and seeing if a 64 sample latency, going through the software, works for you. If so, then you can work purely in the DAW and not even worry about using the DSP mixer and how it interacts with the DAW software. I actually like to think of the DSP mixer as "plan B" for people who have a computer too slow to just work with a low latency, or for people who even the lowest DAW buffer is not good enough. But we should not assume you have to use the DSP mixer when tracking, we designed nice low buffers so that it is hopefully a choice.

                  Tadpole mentioned " I do wish that there was a way to group faders together so one could adjust two tracks at once if monitoring a stereo cue"

                  You can actually do this with the 1.05 console available on the website, just press the shift key while adjusting either one and they will move as a group. The 1.06 console will add a visual "link" button, since the current method is a little too "hidden knowledge" for our tastes (although this key command was put into the 1.05 release notes which I know you all read carefully, right ?

                  "I also notice that when you save a mixer setup as a .onyx400f program, the buffer settings and the sample rate don't get saved with it."

                  Thanks for bringing that to our attention, we will look into what we can do about that.

                  Madnoman mentioned " o Mac software on the disc!!! What the #$%^??? OK, reading through the Mackie forums, looks like there was a production issue with the disc. OK, guess I've got to download the control software from their website"

                  Unfortunately correct. It's a hybrid disc (Mac users only see Mac materials and same for Windows) and apparently our duplicator did not duplicate it correctly, only the windows side made it through (which is odd because we tested a test pressing and it was fine).

                  The situation is being corrected now for future builds, and all I can say is we apologize for the inconvenience in the meantime. The ironic thing is there's nothing on that disc you'd want anyway, the control panel, drivers, and version of Tracktion available on the website are all now newer than what's on that disc. I liked Craig's idea of just not including discs anymore, they always seem to be out of date by the time they hit your house

                  Regarding the high pitched whine, Craig mentioned " I did a little googling around...seems the "firewire whine" is not an isolated problem, nor confined to any one interface."

                  This is our experience as well, it's not an innate issue of the box itself (so far we have only had 2 reports of it out of hundreds of units sold). As far as we can tell it seems to boil down to some combination of the user's computer, electrical power in their environment, and unique setup. We want to figure this out as much as you want us to, and hopefully we will be able to.

                  As always, if there is any question someone has that I'm forgetting to address, speak up and don't be shy!

                  Comment


                  • Originally posted by Dan Steinberg
                    As always, if there is any question someone has that I'm forgetting to address, speak up and don't be shy!

                    AD spec's. On the Mackie site, I see specs for preamp + AD, but not AD. As a user who has decent external mic pre's, the AD is a bigger consideration, and -3dB seems drop in frequency response (between 10hz and 24 khz) seems much larger than competing products. Is this correct? Are there specs without the preamp, are there specs or graphs for 40hz to 18khz or numbers related to what listeners here?

                    Thanks in advance.

                    Comment


                    • Originally posted by Dan Steinberg
                      Regarding the high pitched whine, Craig mentioned " I did a little googling around...seems the "firewire whine" is not an isolated problem, nor confined to any one interface."

                      This is our experience as well, it's not an innate issue of the box itself (so far we have only had 2 reports of it out of hundreds of units sold). As far as we can tell it seems to boil down to some combination of the user's computer, electrical power in their environment, and unique setup. We want to figure this out as much as you want us to, and hopefully we will be able to.


                      Hi Dan,

                      So are you saying that if I return the 400f for another unit it likely won't correct the 'firewire whine'? You say you've experienced this 'whine' too. Can you elaborate? What setup do you guys have where you experience this whine?

                      Any other powerbook users on this thread have this issue?

                      I really want to like this unit, but small issues like this and other issues that mac folks have experienced are making me very hesitant keeping this unit.

                      Please let me know what I can do to help troubleshoot this issue on your end to help you better understand this issue.

                      Thanks!
                      Mandoman

                      Comment


                      • I think there are two different types of "high-pitched whine" issues with the 400f. I am not experiencing the "firewire whine" that mandoman has. However, I am experiencing a high-pitched whine that comes out of the control room outputs. It is barely audible, but still loud enough to be distracting. This whine is not present at either the headphone outs or any of the line outs, so I'm wondering if it has something to do with the design of the control room volume pot. It is most noticeable when the control room volume is off, and it lowers slightly when the control room volume is at the halfway point.

                        Otherwise, I'm really enjoying the unit so far. The sound quality is excellent, and the asio driver performance at low latencies is almost as good as my Delta 1010. Just curious, if the 400f wdm driver worked better in Sonar could I use the 400f and the Delta 1010 at the same time? That might be a reason to improve the performance of the wdm driver in Sonar. Also, I'm looking forward to the possibility of DSP effects for the 400f's digital mixer - - that would be great. I'd especially like a reverb to use for monitoring the vocals wet while tracking. Also, I think it would be a good idea for the matrix mixer to allow the selection of which daw outputs get sent to a particular pair of outputs rather than having daw outs 1 & 2 hardwired to physicals outs 1 & 2, daw outs 3 & 4 hardwired to physical outs 3 & 4, etcetera.

                        Comment


                        • Wondering if anyone has A/B’d the 400f to the Metric Halo devices.

                          The 400f is a strong candidate (I own a Mackie analog 8bus and a pair of HR824s) but a buddy of mine is lobbying hard, suggesting either the 2882 or ULN. Raves about the MH converters and mic pres are hardly rare but I’ve yet to see a comparison to the Onyx pres or converters. Neither has the perfect feature set for my needs but I must prioritize quality mic pres and converters.

                          Thanks to all for this forum,

                          sr

                          Comment


                          • <<Craig likes 'em. I don't. The box should be an extension of the cable shield, and the only way you can have this is for the jack to be solidly connected to the box.>>

                            The box is grounded, and therefore is part of the shielding. It's like on XLR connectors, where the shield is separate from ground. There's a reason why it's done this way, but with 1/4" jacks, you don't have that "fourth pin" option. Hence the need for electrical isolation, so you can control exactly how the audio ground line will connect to electrical ground, and where it will connect.

                            <<The box shouldn't be the only route to audio ground, and a reasonably heavy wire running directly to a common ground point is also important for noise-free operation.>>

                            Except that if there's a difference in resistance between the shield ground going to ground through the box, and a ground wire running to ground, then for a given amount of current flow there will be a voltage differential. It may be very small, but when you're dealing with high-gain preamps, it can matter.

                            Now, I'm not totally against "ground plane"-style grounding where you have so many grounds in parallel that the resistance becomes very, very small. In fact I prefer it for line-level only devices, and that kind of approach may be solution to the whine issue, which is starting to sound more and more like it's ground loop related. But as soon as a high-gain mic pre makes it in there, the grounding issues become multiplied. One of the easiest ways to control this is by insulating a jack's ground sleeve and choosing exactly where the ground line is going to go. An additional advantage is that the ground wire is dedicated a particular jack; signals from other jacks aren't going to flow along it.
                            CHECK IT OUT: Lilianna!, my latest song, is now streamable from YouTube.

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                            Comment


                            • <<<<I should say that this type of thing is sometimes hard to do, because you have to convince other companies (like Steinberg) to do work on their code, to ultimately help sell your company's product.>>

                              Well I know that Steinberg and Yamaha are committed to the Studio Connections initiative, and I'm quite sure they recognize that the only way it will gain traction is if it gets 3rd party support. So your timing is excellent if you want to go for better integration with at least Cubase and Nuendo! I think they'll welcome you with open arms.
                              CHECK IT OUT: Lilianna!, my latest song, is now streamable from YouTube.

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                              • Originally posted by Anderton
                                The box is grounded, and therefore is part of the shielding. It's like on XLR connectors, where the shield is separate from ground. There's a reason why it's done this way, but with 1/4" jacks, you don't have that "fourth pin" option. Hence the need for electrical isolation, so you can control exactly how the audio ground line will connect to electrical ground, and where it will connect.
                                There are two problems that we have to deal with. The electrical connection between Pin 1 (or the 1/4" jack sleeve) and the audio ground point is to prevent interference carried by the shield from getting into the audio. This is what's important when you have high gain circuits.

                                The other problem is EMI getting in from the outside world. An ungrounded jack essentially leaves a hole in the shielding. It wasn't a big problem in the past other than perhaps for gear installed close to a braodcast transmitter, but today EMI is everywhere. The AES standard attempts to address both the "hole in the shield" and the "Pin 1 problem."
                                Except that if there's a difference in resistance between the shield ground going to ground through the box, and a ground wire running to ground, then for a given amount of current flow there will be a voltage differential. It may be very small, but when you're dealing with high-gain preamps, it can matter.
                                Yes, this does indeed sound like a ground loop. And it's one of the reasons why, for any single product, strict adherence to the standard might not be the best decision. Sometimes it will be connected to a device that isn't properly grounded and/or shielded and things might actually work out better if the shield isn't carried through the box. We used to lift shields to mitigate this problem, but with today's great creeping EMI monster plus no longer having tape hiss to mask low level interference, we have to do better. Neutrik came out with a new XLR design that provides a better EMI shield to give manufacturers a new tool for applying the principles expressed in the standard. But like all solutions based on an industry standard, it will take a while before everything plays nicely together.
                                Now, I'm not totally against "ground plane"-style grounding where you have so many grounds in parallel that the resistance becomes very, very small. In fact I prefer it for line-level only devices, and that kind of approach may be solution to the whine issue, which is starting to sound more and more like it's ground loop related. But as soon as a high-gain mic pre makes it in there, the grounding issues become multiplied.
                                I love talking with Grant Carrington (Gordon Instruments - super tweak preamps) at AES shows because he's just so thorough. Last year he re-did the grounding on his preamp following all the recommendations in the AES standard and, at least when measured with his test equipment, lowered the noise (not just hum) by a couple of dB. Whether someone who connects a Gordon preamp up to one of the line inputs on a 400F will see this improvement remains to be seen.

                                As far as the whine, it could be a Pin 1 problem (which is not quite the same as a ground loop - re-read the June 1995 AES journal), and this isn't the sort of thing that can be solved by an isolated or solidly connected jack, if the noise doesn't come in through a jack. These are tough nuts to crack. It could be an internal radiated EMI problem, or an external one.

                                Is there a cell phone, cordless phone, Bluetooth device (wireless keyboard?) or computer monitor nearby? Maybe it's EMI from the computer. Maybe it's coming in on the power line, or the Firewire cable. It could be totally unreleated to the power supply. Has anyone observed that the whine goes away when the 400F is disconnected from the computer, or perhaps moved to a different room?
                                One of the easiest ways to control this is by insulating a jack's ground sleeve and choosing exactly where the ground line is going to go. An additional advantage is that the ground wire is dedicated a particular jack; signals from other jacks aren't going to flow along it.
                                Star grounding (what you're describing) is often a good approach, but it can get complex. Are there real wires there, or are the jacks mounted on a circult board, and the "ground wire" is a trace? And while using isolated jacks may indeed be the easiest approach (and this is really important to a manufacturer with a target price point) it may not be the best way. But that's a decision that Mackie made, and I hope they make it intelligently. We don't always need the best, but we always need "good enough"

                                I didn't mean to hijack this discussion over a cause, and how design decisions are made. I was just pointing out something that I, just on general principles, thing should be done differently. But then, Mackie doesn't pay me to design their equipment, or price it out.
                                --
                                "Today's production equipment is IT-based and cannot be operated without a passing knowledge of computing, although it seems that it can be operated without a passing knowledge of audio." - John Watkinson, Resolution Magazine, October 2006
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