Andromeda Tuning issue, Alesis will do nothing about it...

Miscellaneous
1

Date: 26 Jan 2008 18:19

Subject: ref, return - alesis andromeda fault report..

To: bbridges@neumark.com

Hi,

heres the fault report for my andromeda (ser no: (21) a10611045700***).

* I am experiencing some oscillator tuning issues whereby all of them

are drifting relative to eachother at an unacceptable rate (2/3rd

second and faster for a complete drift). This is in spite of observing

all matters concerning tuning & making sure the auto tune settings

remain on all the time.

This results in an audible phasing between sound elements which should

be in ‘perfect’ harmony. For instance, this can easily be seen/heard

when setting two oscillators in a voice to the same pitch, when in

unison with ‘0’ detune, in stack mode & when in multimode & layering

the same patch across all multi’s.

Also this undesired effect can clearly be heard when holding down

notes an octave (octave being 2x the lower note & sholdnt drift)

appart.

This anomaly is also significant enough to affect the musicality of

cords.. which just dont sound right.

The above effects are most easily demonstrated when using square waves

..the effects of the drift are quite startlingly obvious …and when

compared to another analog, which itself exhibited a little drift; it

was so small that it simply isnt audible compared to the andromeda.

* See the two attached mp3 files (a6.mp3 & other.mp3) for recorded

examples of this anomaly; both start with two sinewaves an octave

appart & then two squarewaves an octave apart.

The differences between the two synths drifting can most clearly be

heard with the latter squarewave section. Also it is advisable to open

the file in a wave editor, & scroll along to see the effect of the

drift (most easily seen with sine); otherwise an oscilloscope is a

better option.

  • Also goto User Bank; PROGRAM 12 on the andromeda (when it arrives)

for a patch already setup to demonstrate these problems. Additionally

see mix bank 00 to hear all 16 voices in unison & the effect this has

on the timbre.

Thanks.

Attachments: (links work here too)

http://homepage.ntlworld.com/nausicaa.valley/ucapps/alesis_andromeda/A6.mp3

http://homepage.ntlworld.com/nausicaa.valley/ucapps/alesis_andromeda/OTHER.mp3

Phoned them up after receiving it with exactly the same problem & the issue remains…

they failed to recognize that there was an issue at all..

stating they couldn’t hear a tuning anomaly ..in spite of having the problem described clearly as above…

and fascinatingly… they didnt even attempt to describe it as a ‘feature’ …would this be due to concern about acknowledging the anomaly ?

they allege that a ‘components added’ mod was done to the voice board for tuning issues in a previous service ..as for what this did tho…

Apparently other users have encountered this too.. and had the same issue with warranty servicing..

Be aware that all andromedas seem to lack the ability to tune all oscillators 100% & they just dodge this one…

(a fundamental ‘flaw’ in the custom chip design ?)

…shame; and shame on them.

2

I voted maybe, because it is the only valid option, because you didn’t include any information from alesis or give them an invitation to respond, so it’s impossible to say what they are doing.

3

http://mailman.code404.com/pipermail/a6/2003-January/000815.html

s&h quality depends on quality of capacitors , etc.  maybe you can tweak it yourself once they wont swap it eitherway ;D

4

i dont like honesty voicing issues on this forum therefore i wont vote. :-X

5

no problem..

i could invite them if they wished.. however they would probably just view it as harassment. if for some reason this did raise an eyebrow or two.. im sure they would comment if they wanted to…

i dont usually do ‘poll’ things.. however im just curious as to how other people view the handling of this issue.

Alesis didnt provide any information at all; their returns form simply states S1 - Recalibration..

and a polite phonecall just now, did not obtain a useful response or acknowledgment..

if you can think of a way for me to provide a more complete response let me know.

im simply letting other people know of the ‘minor’ problems im encountering here, so that they may avoid an issue with a product which will not be sorted & wasting time with customer support.

Im not the only one whos experienced exactly this; however i wanted to give them a clear chance to streighten it out before i published the problems on the web.

6

the problem looks like to be :

despite the 16bit DAC, the S&H section is not reaching anywhere near this resolution . With new TI opamps and expensive caps I think its possible to get closer to that bit depth.

7

unfortunately it would seem that most of the s&h circuitry is in those custom chips ..however i could be wrong.

8

uhuhuh now thats wrong  :o

9

heres the mods they did to this one prior to this return btw:

5x resistor mods around the cpu (bootup mods ?) …not the tidiest soldering iv’e ever seen.. tho smt is difficult by hand.

Oscillator section comprising of 2 voices / 8 oscs (each dac also serves another pair of ASO & ASF chips on the lower parto f the board)  resistor mod around Oscillator chip,.

A further closeup of the DAC section; burr brown 2134ua opamp on output dutys; presumably S&H onboard Custom chips.

..seriously ..one of these days im going to design and make a analog domain synth far more powerful & characterful than this.. which works as one would expect it to; just so i can go Nyaaaahhh ! :wink:

…well maybe.