I understand your viewpoint, that's what got me involved in the first place.
I did trash a few items early on, and needed a solid year of professional work in the field of what's now antique electronic construction techniques to get good enough to tackle other people's guitar amps and keyboards.
Things are even worse now I reckon, but.........
As the item in question is a generator, rather than a serial processor, like an amp or effects unit, you can't inject a known good signal, so I'd start at the output and work backwards.
Use a straightforward patch in the Matrix with no fancy modulation, jam a key down carefully with something jammed between two keys to provide a constant signal.
With the oscilloscope, you should AC couple its input and discharge the probe tip by touching it to the chassis before each test probing.
Any poor contact or reduced value capacitor in line with any signal path will degrade it. Look for poor contacts on connectors, though the Matrix is usually fine here, unlike earlier synths.
Start with the output socket and adjust the scope for a clear display of whatever note is playing out of the Matrix, I'd play a low one, then look on the circuit diagram to see where the signal has come from just prior to this.
By gradually working back through the circuit, you might find a place where the level is much higher at low frequency.
The original coupling capacitor has been chosen to be a large enough value to allow a full range signal to pass, allowing for its load impedance. If the capacitance drops or the load drops, the low cutoff frequency will change. Like turning the bass control down on your listening channel.
There are other problems that can cause a similar symptom, but in this particular set of circumstances, the cap or the load are usually it.
A common example of low load impedance can be heard by plugging a strat into the mic input on a laptop or pc. Guitars are higher impedance than keyboards, but you can hear what the symptoms are like.
It's easier to find something if you can recognise it.
Good luck, but don't start with a soldering iron just because you have one.
--- On
Wed, 17/10/12, Loveslap! Recordings
<loveslap@...>
wrote:
From: Loveslap! Recordings <loveslap@...>
Subject: Re: [oberheim] trying to diagnose generall weakness of my matrix 12
To: oberheim@yahoogroups.com
Date: Wednesday, 17 October, 2012, 11:20
i definitely have a reliable monitor system/room/.. as well as other synths which easily shake the room without the aid of eq/compression.
"Poor low frequency response can be caused by coupling capacitors drying out, but this isn't usually the first place to look, and unless you have all the information, test equipment, tools,expertise and parts"
what is the first place to look
I have scope, multimeter, proper soldering/desoldering rig.. my expertise is a solid medium (i've fixed juno106 problems (pots, sliders, chips, outputs, leds, I've never rebuilt a power supply)..
i'm in Brazil.. shipping tech in and out of the country is a big hassle so I'd prefer to fix things here myself...
On Wed, Oct 17, 2012 at 7:00 AM, Les Lambert
<
les_lmbrt@...
>
wrote:
It's possible that the samples you are comparing it to have undergone change after they left the instrument, either accidentally or by design.
EQ is the first thing people try, but isn't usually the right solution.
Compression is usually the next thing, but........ditto.
If you have a known good audio monitor system a working xpander should make be able to make the dust fly out of the speaker cab ports. Just like one of your CDs turned up loud.
Poor low frequency response can be caused by coupling capacitors drying out, but this isn't usually the first place to look, and unless you have all the information, test equipment, tools,expertise and parts you need, it could end badly.
The internet is encouraging us towards this kind of activity, but it's not a sensible option for the inexperienced, who can be prone to mis-diagnosis in the first instance, and careless work these fine instruments do not deserve.
It's possible to degrade the frequency response by shunting the output of most audio devices with a low impedance.
--- On
Tue, 16/10/12, Loveslap! Recordings
<
loveslap@...
>
wrote:
From: Loveslap! Recordings <
loveslap@...
>
Subject: Re: [oberheim] trying to diagnose generall weakness of my matrix 12
To:
oberheim@yahoogroups.com
Date: Tuesday, 16 October, 2012, 23:05
thanks for answering...
i find myself always wanting to boost the low end... also normal
it is normal for there to be a world of difference between RES=62 and RES=63
On Tue, Oct 16, 2012 at 6:39 PM, synthwalker
<
synthwalker@...
>
wrote:
Matrix-12 / Xpander are great synths, but they don’t have balls like Memorymoog / Prophet-5, they have boobs instead…
Resonance to 63 means filter self-oscillation and yes this is normal.
Hello
I have a Matrix 12 (Voice 1.4) (Main Software 1.1)
I like it but when I listen to online samples they sound much better..
Mine seems to lack "balls".. I have no trouble with any tuning.
But my low end doesn't seem to be there and many of the factory presets don't really impress.
Once thing I've noticed is that when I adjust the VCF resonance, there is a HUGE difference between 62, and 63.. in fact resonance=63 is the only time the synth grows a pair... 0-62 is wimpy, 63 is burly.
Is this normal
I really want to get this thing sounding good!!!
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Loveslap Recordings
http://www.loveslap.com
Galaxy Group - Ease Back (w/ BSC and 1200 Warriors Remixes)
http://www.traxsource.com/index.php
act=show&fc=tpage&cr=titles&cv=33653&alias=downloads
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