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DIY Stompboxes => Building your own stompbox => Topic started by: Buffalo Tom on January 27, 2024, 02:58:38 PM

Title: DOD 565 Chorus Output Impedance
Post by: Buffalo Tom on January 27, 2024, 02:58:38 PM
Hi. Could someone please determine the output impedance for "Out 2" just by analyzing the schematic?

DOD 565 Chorus schematic
https://elektrotanya.com/PREVIEWS/63463243/23432455/dod/dod_565_chorus_sch.pdf_1.png (https://elektrotanya.com/PREVIEWS/63463243/23432455/dod/dod_565_chorus_sch.pdf_1.png)
Thanks!



Title: Re: DOD 565 Chorus Output Impedance
Post by: antonis on January 27, 2024, 04:54:26 PM
A couple of Ohms.. :icon_wink:
Title: Re: DOD 565 Chorus Output Impedance
Post by: PRR on January 27, 2024, 05:42:13 PM
Quote from: antonis on January 27, 2024, 04:54:26 PMA couple of Ohms..

?? It is not a naked opamp output. I see two 10K mix resistors, so 5k. And a 47k, so like 4.5k. AND 0.068uFd to 1K, so falling to 818 Ohms at some high frequency.

(https://i.postimg.cc/bGqmxwJ6/DOD565-OUT2.gif) (https://postimg.cc/bGqmxwJ6)

Or to be a wise-ass: "same as OUT1". But that's no help.
Title: Re: DOD 565 Chorus Output Impedance
Post by: antonis on January 28, 2024, 06:40:55 AM
Quote from: PRR on January 27, 2024, 05:42:13 PM?? It is not a naked opamp output.

Indeed.. :icon_wink:
(I've got it as INPUT..)
Title: Re: DOD 565 Chorus Output Impedance
Post by: Buffalo Tom on January 30, 2024, 09:18:14 AM
Quote from: PRR on January 27, 2024, 05:42:13 PM
Quote from: antonis on January 27, 2024, 04:54:26 PMA couple of Ohms..

?? It is not a naked opamp output. I see two 10K mix resistors, so 5k. And a 47k, so like 4.5k. AND 0.068uFd to 1K, so falling to 818 Ohms at some high frequency.

(https://i.postimg.cc/bGqmxwJ6/DOD565-OUT2.gif) (https://postimg.cc/bGqmxwJ6)

Or to be a wise-ass: "same as OUT1". But that's no help.

Thank you! The reason for my question is that I am currently using a 1:1 transformer to isolate output two. However, I am experiencing a loss in volume and treble due to the impedance of this particular transformer, which is 2k4. Initially, I assumed that the output impedance from the chorus device was lower and a 2k4 would work. However, with an output impedance of 818 ohms, I now understand that changing to a 10K transformer is necessary to prevent any further signal loss.