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    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Attenuation for 0.5dBs

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How can calculate the voltage divider to attenuate 0.5dBs, my tube preamp have an input impedance of 50K or 100K because I use two separate volume pots. Using L-Pad calculator:

L-Pad.gif



50K L-Pad
R1 2796.96
R2 843828.8

100K L-Pad
R1 5593.91
R2 1687657.61

Can I use these values?

TIA
 
or just add a single resistor in the feed to each channel.

For a pot the required added resistance would be
{1 / [inv log (0.5/20 +-)] -1}* pot value
[1.05925-1]*50k or 100k
2963r for 50k or 5925r for 100k.

But can you hear a -0.5db reduction?
 
Hi,

I don't understand it either. Do you want to attenuate a driver unit in your speaker(s) or do you want to replace the pots in your preamp by a switched attenuator?
If the latter I can't see why one would use such inaudibly fine steps, there's a good chance L to R channel imbalance is already roughly that or worse.

Also when you say you have two pots, do you mean one for each channel and if so you need to know their exact impedance 100K log or 50K log?

Ciao, 😉
 
Why are you concerned with a level difference of .5dB?

I only want to be sure isn't any difference. Because the rest of the system can increase or cancel the difference.

Ola,

Assuming these are stereo pots and one channel is miss tracking by 0.5 dB over the entire track??

Adeu, 😉

Hola

Yes are stereo pots, both pots tracking well, the problem is the tubed preamp.

Do you speak Catalan🙂?
 
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