[sdiy] Fet to short pedal input?

[Oren Leavitt]

Looks to me like a simple LDR (LED/photocell) may do the trick here. 
Given the LDR has sufficiently high "dark" resistance.

- Oren

On 11/28/25 5:47 AM, Tom Wiltshire wrote:
> I've checked the Arp Odyssey schematics (since it has one of these 
> inputs). The relevant part is attached below.
> 
> The Portamento input jack is a TRS jack connected across the ends of the 
> 1M audio-taper portamento pot. So shorting the Tip and Ring connections 
> disables the portamento. It's not a simple short-to-ground action as I 
> had thought it might be, but any bidirectional switch should work in 
> this position.
> 
> 
> 
>> On 27 Nov 2025, at 20:34, el macaco via Synth-diy <synth-diy at synth- 
>> diy.org <mailto:synth-diy at synth-diy.org>> wrote:
>>
>> Hi all,
>>
>> The portamento pedal input on arps has me thinking of using my midi to 
>> cv converter's velocity output (+5V) to activate a fet with the two 
>> pedal contacts on the source and drain.
>>
>> Can it be this simple?  The only power coming from the velocity 5v?
>>
>> Thanks,
>>
>> Ed
>>
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