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Old 15th September 2003, 12:42 PM   #1
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Default aleph p + attenuator

Hi All

There seems to have been some talk about an alternative methos of signal attenuation in the BOSOZ designs which relies on effectively placing a potentiometer between the +ve & -ve outputs. There by avoidong the complexity and cost of relay based or the precision 4 ganged stepped attenuators.

has anybody tried this on the Aleph P1.7 preamp design or have any comments suggestions.
What happens when the pot resistance drops to zero ( at minimum volume) ie effectivley shorting the +ve and -ve outputs together- is this a bad thing?

thanks and regards.
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Old 15th September 2003, 12:54 PM   #2
UrSv is offline UrSv  Sweden
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That would be a bad thing for the attenuator itself. Fortunately there is a 100 Ohm resistor on the output for each output that makes it possible giving a minimum of 200 Ohm across the output.
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Old 15th September 2003, 02:11 PM   #3
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There by avoidong the complexity and cost of relay based
16*2 Relays
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< 10 for resistors, transistors, PS
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Old 15th September 2003, 10:14 PM   #4
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Thank you Ursv & Till

I forgot about the 100ohm resistors, but still i wonder if thers might be a probklem as my understanding of the circuit implies there is usually a greater load on the outputs than i would be providing.

As for cost and complexity- I do not understand and therefore am uncomfortable with digital electronics.
Same problem trying to fix a car with electronic fuel injection compared to one with a carburettor (to me at least ).

Thanks

Any other comments out there?
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Old 16th September 2003, 03:02 AM   #5
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Default Hi George

For once in my life there is someone on the list who lives in the same city

Thus we are collaborating somewhat on this project and while I am less worried about cost (I already have my relays), the single attenuator across the output would simplify things considerably.

I have a working BLS to "play" with but I was wondering the best approach in terms of pot placement.

Alas, I posted to another thread:

http://www.diyaudio.com/forums/showt...994#post235994

Any comments from the learned ones .... !

regards
mark
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