Increase input impedance

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi all

For my active horns I want to run 2 amps feed from the one DAC, each amp has an input impedance of 10k this means that the combined load maybe too great on my DAC. I want to include a passive volume control in the mix, if I feed the DAC into the volume pot, say 20k that would be a constant load on the DAC, yea? The output of the pot (wiper) would then go to both amps or should I have a dual gang pot where 1 wiper goes to each amp?

Appreciate your thoughts and other possible solutions.

Cheers Dave
 
AX tech editor
Joined 2002
Paid Member
Two comments:

I do not know of any DAC that has a problem with 5k load. It's not that heavy.

Second, if you add a pot and want a 'good feel' to the settings, the rule of thumb is that the pot impedance is 5 to 10x lower than the load. That means a pot of say 1k to 2k, which makes the load on the DAC much heavier.

So if you don't need the pot, don't use it and just use the DAC and power amps as is, no problem!


BTW A pot is not a constant load to the DAC, the load depends on the pot setting. The impedance the DAC 'sees' is the top part of the pot, plus the parallel impedance of the bottom part of the pot and the load. So the total depends on the post settings and is not constant.

Jan
 
Last edited:
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.