Dumbleator In/Send/Return/Out Impedances

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phillygtr
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Dumbleator In/Send/Return/Out Impedances

Post by phillygtr »

Hi all. I would like to know what are the nominal in/out impedances for the in/send/return/out jacks. I'm not an amp builder so I can't read schematics. I'm just curious if anyone had these values handy (roughly speaking since I know there are some design variations).
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jelle
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Re: Dumbleator In/Send/Return/Out Impedances

Post by jelle »

Send in: about 18 M Ohms
Send out: about 600 Ohms

Return in: 220 K Ohms
Return out: 250 K Ohms

Hope this helps. Regards, Jelle
phillygtr
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Re: Dumbleator In/Send/Return/Out Impedances

Post by phillygtr »

Thanks. I didn't realize that the main In had such a high input impedance.
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martin manning
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Re: Dumbleator In/Send/Return/Out Impedances

Post by martin manning »

I think the Send and Output impedances will depend on the control settings, so with 250k 10% log pots set at "noon," those impedances will be about 25k. I get 11Meg for the input ;^)
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jelle
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Re: Dumbleator In/Send/Return/Out Impedances

Post by jelle »

11M.... With what values? I have calculated this a long time ago, so my memory might be fuzzy... :D
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martin manning
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Re: Dumbleator In/Send/Return/Out Impedances

Post by martin manning »

jelle wrote:11M.... With what values? I have calculated this a long time ago, so my memory might be fuzzy... :D
Standard circuit: 1M and 27K to ground at the input, 1k8 bias resistor, 260V. I got my number by running a sim... it's so high it doesn't matter either way!
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jelle
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Re: Dumbleator In/Send/Return/Out Impedances

Post by jelle »

I see. Thanks! :D
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martin manning
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Re: Dumbleator In/Send/Return/Out Impedances

Post by martin manning »

Jelle, just for grins and mental floss I ran the numbers by hand and got 10.8 Meg. I'm always happy when I get the same number two different ways!
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jelle
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Re: Dumbleator In/Send/Return/Out Impedances

Post by jelle »

Haha, I think I know what my brain did to me... 18 and 10.8M... Even a brainscientist gets fooled by his own brain....:lol:

I used RDH4 when I calculated it.... :D
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