888/24 line noise

[Custos]

I have two 888/24 interfaces I purchased from ebay Ive tested both of them. one of them has line noise on every channel. Does anyone know what would cause that? the other one doesn't seem to have that problem at all. Just a faulty unit?

[Syntho]

Get out a screwdriver and calibrate the converters with the screws on the front.

[Custos]

Ahh OK . I'll have to try it out.

[Ed Redfern]

I'd agree with Syntho, but there is also the possibility of an issue with the built in PSU and this can happen at times, rare but does happen. this is where you could get a grounding issue. if calibrating the  channels does not remove the noise issue, it's time to open the unit, if you're skilled with a soldering iron, it may be the issue of a few caps on the way out, either on the AD board or the PSU itself.

I had one or two 888 boards in my time develop hickups but with a little help, those problems were fixed ready for on the road work, all that's some time back.

ed

[Custos]

Yeah it really sounded like a ground noise. I checked all the output channels and it was the same noise on all of them. I'll check it out after work today and report back.  Its really great to have you here ed. You seem well educated on the subject.

[Ed Redfern]

No problem custos,

I've 14 years background with ProTools TDM and LE as well as sampleCell so digidesign hardware is my speciality including installations, building G3 and G4 macs ready for ProTools, etc. TDM 5.13 in my opinion is the most comfortable as that's what I have been working with until the studio was stripped by a company who made me lose work.

the thing with 888/24 units is to ensure that you're using high quality XLR looms whether you're doing this to an analogue console or to a patch bay setup / stage box setup, ensure your connections in this type of setup give you clean balanced connections without any hassle.

if you're doing a 24 channel setup like I had and again will at some point do, depending on your needs and if you've a recording console with direct outs and tape returns, look for 3 x 882/20 boards and chain them together, 24 ins 24 outs. then protools becomes a direct digital tape. you can do what the heck you like from that point onwards but remember, your hard drives are what do the work. stick to SCSI and not IDE, unless it's a G4 then SATA via PCI controller but set up Protools to use a source drive for recordings and scratch data. RAID it.

let's put it this way. I've always had my head inside a mac of one sort or another and between college and university I was on hand to fix macs, at college I was asked if I'd take my official apple certification so I could be paid by the college to repair systems as they only had PC techs there. from then on, that was it, protools recording guy and apple hardware tech.

It's a pleasure being here and to receive help where it counts. I hope at some point my TDM setup will be reborn somehow. have the software, plugins, etc a g3 mac waiting for parts, all that's left is the hardware side.

so still looking for a mix core card, mix farm cards, ribbon interconnect cable, cables to connect to outboard boxes, either 882 or 888 boards, etc. basically to build a dsp based 24 tracker to load in a trolley with the G3 and go on the road, doing what I do best and scaring the death out of studio owners lol.

ed

[Syntho]

Are you sure it's ground noise? That's going to be 50hz or 60hz hum. If you're hearing 'air' or something that sounds like sucking or like something that's coming out of a hi-gain guitar amp, it's the converter calibration. I too thought my 888/24s were broken until I realized that the guy I bought the 888/24s from had the converters calibrated way too hot.

http://macos9lives.com/smforum/index.php?topic=751.0 - I posted this almost a year ago detailing it.

The noisefloor disappeared completely once I calibrated the converters to -18dbFS. When I sent a 0dbVU calibration tone into the 888/24 converters from an analog board, it was clipping to hell and back. Once I brought them down by over 18 decibels with a screwdriver it was as quiet as anything.

Just get a screwdriver and turn a channel counter-clockwise while listening and see if it disappears. I bet it does 

[Syntho]

By the way Ed, I'm curious as to how you get around on a computer and with all of your software and gear. How do you post on the forum?

[Ed Redfern]

Hi Syntho.

In my experience, I've heard both the "Air noise" and "Ground tone", this is why I stated both possibilities, without clear description of the tone in question or a sample to refer to, I assess both possible cases.

anyway, as to your question of my use of IT and studio gear. with Mac OS9.2, I use a screen reader called OutSPOKEN 9.2 which is now impossible to get hold of. it's a screen reader which echos keyboard and mouse movements to speech, as well as all screen contents such as text, icons, etc.

on the intel mac I'm using to use this forum, it's voiceover in OS X yosemite, Voiceover is so much better in terms of navigation and gets me out of the sticky stuff.

with the G3 / ProTools TDM side of things, outspoken is a life saver so trying to rebuild a protools tdm setup for the studio is rather important, so I've a real challenge on my hands. in terms of gear control, I used to use logic platinum 6 along with sounddiver 3 but I can't get that software as a full kit anymore with the dongle. just can't find it for love nor money. at least with that particular midi environment using sound diver, outspoken gave me spoken data of everything a sound odule, effect processor (via midi) or synth, etc was doing, what I could edit, etc.

having found UniSyn 2, that might be a help, worth a try lol.

Everything I do is a process of tactile control and audio feedback, 14 years of being in studios, touring, installations etc has given me methods most sighted people don't dream of. but that gives me a hidden edge in my work.

anyway, re the 888 trim, tone generators are always useful things to have in your toolbox.

ed

[Custos]

the noise only seems to be on my farm card. I switched the cable over to my Mix core and the noise disappeared. At this point I'm thinking its either the cable or the farm card.  All I did was install pro tools and then hook everything up. Does the farm card need drivers or does protools already have them? I did run the digi test and everything passed.

Noise description: Buzz/clicking also the audio coming out is garbled.

[Knezzen]

You don't need any additional drivers, they come bundled with Pro Tools (DSI & DAE).

Have you used the Digidesign control panel and specified what interface is connected to which card?
Strange shit happens if you don't specify your stuff in there

[Custos]

You don't need any additional drivers, they come bundled with Pro Tools (DSI & DAE).

Have you used the Digidesign control panel and specified what interface is connected to which card?
Strange shit happens if you don't specify your stuff in there

Yeah that was the first thing I did when i hooked everything up. Does it matter which order the cards are inserted in the pci slots? I had to move my cards a slot away from graphics card to keep os9 from hanging on the boot screen. I'm using a 1.25ghz dual mdd btw

[Knezzen]

In this order from the top

1. Graphicscards
2. Any hard drive controllers (SCSI, SATA etc)
3. MIX Cards (Core cards first, then Farm cards)
4. Any other "lighter" I/O (USB, serial port cards etc)

You are using a Dual CPU MDD. Have you moved the "Multiprocessor" folder out of the extensions folder? With it in place I get random freezes and strange problems in Pro Tools.
Digidesign does not support multi processor systems at all, so that might be a part of the problem.

Removing the Multiprocessor folder from the extensions folder disables one CPU, and makes your machine a single processor supported system.

[Custos]

No I haven't moved it out of the extensions folder. I'll try it out. thanks for the tips knez

EDIT: I moved the multiprocessor folder out of the extensions folder and restarted the computer. The buzzing/clicking noise is still there. The 888/24 only makes the noise once the computer starts booting. Right when it starts loading extensions at the start screen it starts making the noise. Only seems to make the noise when its hooked to the farm card. When I hooked it to the core card it worked perfectly.

[Knezzen]

Have you ran DigiTest to determine if theres anything wrong with your Farm card?

[Custos]

All my cards passed the digi test.

[Syntho]

So by hooking the same interface to different cards, one of the cards give noise and the other one doesn't, correct? That's really weird. I wouldn't think a PCI card would give off any 50/60hz hum. I can see the interface doing it though.

[Knezzen]

Does loading both the cards with TDM plugins work? Im thinking it might be a dodgy TDM ribbon cable.
Do you have a spare one you could try? I have had a lot of different problems and they all seemed to relate to a dodgy ribbon cable. When I replaced it, all problems went away.

[Ed Redfern]

a thought has just hit me and this happened to a chap who had a similar setup to me once.

ok here's what I could do with knowing, I'm assuming that you're running more than 1 888/24 with digilink cables to the core and farm cards. at the same time, are you syncing the 888/24 boards together via wordclock? are all running at the same sample rate and clock? are all 888/24's running in 8 channel mode XLR or are you using AES/EBU?

Is this noise being generated on any other 888/24 units? or just the one? if it's generated by all units via a card in question, it has been known for a farm card to fail, this is why the mix system was dropped for HD and never supported.  the mix system is still a great system but with it being rather old these days, take care of it.

if the noise is being generated by the 888/24 as a single unit there are some possible issues to examine.

firstly, what is your configured setup? as in... how are you using the 888/24 units for recording? is this via an analogue mixer board with direct outs and returns? or are you using them as direct interfaces and mixing via surface or on screen? I'm trying to eliminate audio possibilities.

have you inspected the inside of the possibly offending 888/24 unit for loose or out of line ribbon cables? etc.

this is what I'd be examining. as the digitest passes all, it doesn't necessarily mean the card's absolutely fine, digitest doesn't check for ground loops or the possibility of failed resistors, etc, I would doubt on the ribbon cable but do check it's a firm connection from master to slaves, all cards are in the correct order, etc. condition of your digilink cables is in tact, etc.

ed

[Custos]

I dont have them running in sync. I still got to get a word clock cable although I do have a sync device. It just seems to be just my farm card making the noise. I get the noise on either 888/24 if I switch which device is connected to the farm card. The ribbon cable connecting the cards seems secure. I dont have a spare ribbon cable.

EDIT: I just purchased a ribbon cable on ebay.