ART Tech (Yorkville) - Cleanbox LOUSY ! - Improved

[Artesia]

I recently adquired some art technologies "pro" balanaced to unbalanced converters from a kit clearout.. given that a friend needed to use them to convert his desk outputs to drive some long cables; i figured i should check their performance.. listened to and measured below.. i was shocked and not at all impressed..

for an accessories company which is a division of a pa company (yorkville sound).. this is unbeleiveabably careless :/

however excercising some braincells, a soldering iron and changing some components.. the response was tuned to perfection ;)

http://www.artproaudio.com/products.asp?type=90&cat=13&id=77

Here is a plot of the frequency response of the unmodifyed box (blue) and the pink trace is the tweaked one over a 10db range; each line represents a 1db step.

mod vs original, freq response 10db range:

mod vs original, freq response 2db range:

mod vs soundcard loopback, freq response 2db range:

as seen in the 2db range magnifycations, the modifyed version now essentially follows the input signal to total perfection, actual deviation is a fractional percentage ;)

and further comment from the 10db range, the response on the original slides down by roughly half a decibel from 5-10k ..and without checking it ..probably drops a whole decibel by 20k ! ..okay, well whilst that may not be 'major', the sag on the bottom end is criminal; it starts rolling off at 300hz & is down by 5.5db at 30hz !

...someones bound to come up with a b.s. argument that this was done in the 'interests'  of 'protecting' your speakers & reducing 50/60hz hum ..but really, is it eq that you asked for - or where told about ? :) ..amazingly Their website makes no meantion of this, the frequency response ..or anysuch things.

okay, so thats frequency response, so what about phase drift and distortion ?

Original Phase Response:

Modded box Phase Response:

:]

Mod vs Sound Card, THD distortion:

As seen here, the distortion floor on the soundcard, although low, can be considered to still be higher than that of this box now ;)

Mod vs Original Thd distortion:

Actually, this one just shows how the old box seems keener to run into distortion..

heres being fair to it & driving it lower down:

ony thing, is this only takes into account the addition of unwanted harmonics & ignores the collosal deviation of volume level over the circuits range ..if that was factored into the distortion measurment, it would look really ugly.

All in, im appauled that they could call this the result of 'applied research & technology'..

My CV available on request ;)

components replaced where 1uf caps with some 100ufs i had handy, green ones of a small value likewise & the jrc 5538's (a modern dual version version of an old, trashy opamp - the 741; but supposedly jrc 'improved it') ..with some 5532's i had to hand, low noise & fast :)

[stryd_one]

Good mod!

Don't forget, ART is a budget audio manufacturer....

[Artesia]

sad thing is it doesnt actually cost any more to get good response; just using the right values ;)

muppets :]

mind theres also a unit identical down to the last component made by rolls; someone copyed someone elses bad design along the way :)