Why doesnt MOTU release any ACTUAL specs for thier gear

[1nput0utput]

how am I supposed to push my gear to the limit without knowing these specs

You have these appendages on your head, one on each side. They have evolved to allow you to sense minute air pressure fluctuations. Some engineers might suggest that you use them to help you make good recordings and get the most out of your gear.

[kassonica]

Err specs are overated tis not the gear bit the ear but if you want specs but prism converters.

http://www.mercenary.com/prsodradstwi.html

All the specs you'll ever need there.

[michkhol]

I've got all specs I needed for 896mkIII by phone (like maximum input and output, mic gain, type of A/D/A converters, etc.). By publishing them MOTU could save on phone calls....

[EMRR]

The volume control on the front of a 2408mkIII, for instance, can push the main analog output into clipping. 0 dB FS should be marked on that knob, and it's not. There's no clipping indicator, and it's very easy to overlook subtle occasional peak clipping. It's very difficult to align a system for maximum undistorted output when no info is given.

Can the gear successfully drive 600 ohm inputs, or lower? Hard to know without test equipment.

[producer4000]

Can the gear successfully drive 600 ohm inputs, or lower?

My twenty day old impedance question, was answered (this morning via sporadic techlink) like this:

input: 10k ohms
output: >100 ohms

Test equipment would probably be useful.

[EMRR]

>100 ohm output only tells you one rating, but not recommended load impedance with regard to rated level and distortion.

[Phil O]

Well, regardless of where this thread belongs, the OP's question is valid for somewhere on this board. I recall having a question about specs when I got my original 828. (I think I was looking for input impedance.)

The word specifications doesn't even appear anywhere in the manual's index. The person I spoke to at MOTU gave me all the info I wanted, but I thought it was odd that they didn't simply publish the specs in the manual. For whatever reason, it's MOTU's policy and that's that. But, if you need something specific, give them a call.

Phil

[producer4000]

>100 ohm output only tells you one rating

I suppose... in a rather broad and sort of open ended way
Some testing would clarify, as you previously suggested.
The ability to drive 600 ohm inputs properly would be heavenly.

[Bill O'C]

Apogee doesn't normally publish specs (at least with the two products I have: a Mini-Me and an Ensemble.)

I've read posts of representatives of their company freely giving dynamic range on internet forums when asked. In one forum an Apogee representative said they go for the sound, not the specs. And, and if I recall correctly, he said their highest level converter boxes don't sound as good to many as their Rosettas--one level down price and spec-wise.

Mind you, I am not comparing one company to another, just pointing out that not giving specs is not necessarily an attempt to conceal something.

Regards,
Bill

[thashobs]

NICE
Now we are getting somewhere. I really appreciate when someone can look at the gear with the same perspective as me. I know some people may think these specs are trivial but it's just piece of mind for me to know these sorts of things.
It's like trying to figure out how to get more horsepower out of an old muscle car: by installing a 360 stroker kit. with 2 inch headers. a 3.73 rear-end ratio.

Or an aftermarket cam with a 3mm offset to get more fuel flow by adding more rocker arm clearance to get better fuel atomization for 50 more horsepower.

I am the kind of person who likes to know what the people who design gear know.

[EMRR]

I measured the actual MATCHING output impedance of the 2408mkIII tonight, and found it to be in the 150-200 ohm range. This, of course, will probably be at a diminished maximum output voltage level and an increased distortion figure. Seems to be no real problem driving 600 ohms. Testing of a 200 ohm passive mic mixer with Spectrafoo shows no significant erratic frequency response issues related to low-Z loading.

I have not opened a unit up to see what build out resistance, of any, exists to set a minimum output impedance, while protecting the output driver circuit. There will surely be something, even if it is imbedded within an IC and consequently not viewable.

[producer4000]

Thanks for doing the testing, Doug. Since you're set up for such things, do you think
you could test the frequency response for the inputs being driven by a 600 ohm output?
I think we know what should happen, but it would be interesting to see what really happens.
Also, what version of Spectrafoo are you running and is it pretty stable for you?

Thanks again.

Chris

[EMRR]

Chris,

Not sure as to the exact revision of Spectrafoo Complete OSX, standalone version. Have had it a few years. It is pretty stable. If I shoot a lot of response curves and do a lot of manipulation with them at the same time it will shut down, but it's never quit or frozen with a full assortment of metering in use. In fact, it never freezes, just shuts down, and rarely.

I test other gear all the time, and never see any frequency response variations with any impedances tested. I get a reasonably flat line when testing lots of modern transformerless gear. I would expect distortion differences when you get so close to a matching load (MOTU 200 ohm actual out driving 600 ohm load), but I've not delved into measuring them. Not really sure you can do comprehensive distortion testing with Spectrafoo easily. I derived output Z with a 60 year old General Radio power level meter, which has a variable load impedance switchable in decades, and a decade switchable meter. When you get maximum power registering on the meter through switching of the variable load, you have a matching load, and that tells you the actual impedance. Then you can find maximum output level with that matching load impedance.

[thashobs]

sweet, thank you. I appreciate the effort. By the way i was reading the last post and I was like how the hell does this guy know my name:?: it was weird until I figured out Producer4000 is also Chris