[sdiy] SOLVED RE: AX60 Voice Issue

[Adam Inglis]

Hey thanks for this - the resonance on this synth I often find rather  
annoying!

What value did you use and where?

Adam
On 29/08/2012, at 10:13 AM, gregory zifcak wrote:

>
> To be honest, I don't fully understand the schematic, but I'm  
> guessing the transistors are part of a muting circuit? I ended up  
> just probing the signal flow at various points and narrowing it down  
> that way. Bypassing TR2 restores normal behavior. I'd be curious to  
> hear insight from someone who understands the circuit.
> In other news, I took the opportunity to put a resistor in series  
> with the resonance pot to limit the voltage to a range closer to  
> what's recommended in the CEM3394 datasheet (2.5v vs. 4.13v). Now I  
> get a very smooth response, with self-oscillation when the slider is  
> at about 95%, instead of the typical 40%. Makes the synth feel much  
> less angry. I got the idea from this analysis: http://www.youtube.com/watch?v=B5ikCDzhFRA
>
>
>>
>>
>> ----------------------------------------
>>> Subject: Re: [sdiy] SOLVED RE: AX60 Voice Issue
>>> From: tom at electricdruid.net
>>> Date: Tue, 28 Aug 2012 20:42:54 +0100
>>> CC: synth-diy at dropmix.xs4all.nl
>>> To: zifcak at hotmail.com
>>>
>>> How's that work then?
>>>
>>> By which I mean; how does a blown transistor in the chorus circuit  
>>> come to generate the symptoms you reported?
>>>
>>> (Just curious)
>>>
>>> Thanks,
>>> Tom
>>>
>>> On 28 Aug 2012, at 18:57, gregory zifcak wrote:
>>>
>>>>
>>>> blown transistor (TR2) on the chorus board.
>>>>
>>>> ----------------------------------------
>>>>> From: zifcak at hotmail.com
>>>>> To: synth-diy at dropmix.xs4all.nl
>>>>> Date: Mon, 27 Aug 2012 16:55:48 -0700
>>>>> Subject: [sdiy] AX60 Voice Issue
>>>>>
>>>>>
>>>>> Hey all,
>>>>> Strange behavior from this AX60:
>>>>> In split modes 2-4 and 4-2, all voices work. I can  
>>>>> simultaneously hear 6 pitches when I hold 6 keys. the balance  
>>>>> slider functions normally, mixing between the two patches.
>>>>> In single mode and in split modes 6-0 and 0-6, only voices 5 and  
>>>>> 6 are sounding. I can hear the other four faintly in the  
>>>>> background. I have checked the CV going to the VCA, and it's a  
>>>>> consistent 4v across all CEM3394s.
>>>>> The signal paths for the mixed voices are split into two groups;  
>>>>> 5 and 6, and 1 thru 4. What I don't understand is why all voices  
>>>>> would be present in split modes but not in single mode.
>>>>> Any ideas?
>>>>> Service manual can be found here:http://manuals.fdiskc.com/flat/Akai%20AX-60%20Service%20Manual.pdf
>>>>> Thanks in advance,Greg
>>>>> _______________________________________________
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>>>>
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>>
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