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Passive Preamp Project vol. II

I've opened that topic before so that's why it's vol II since I have a few more questions to discuss.

Would that help if there will be a resistor or selectable resistor bank added to output of attenuator to bring the input impedance of the power amplifier to at least 10x level? Will that solve the problem of attenuation bandwidth that is not realy usable with low impedance poweramps (bellow 30k)?
If you know any links or literature please, advise.
128x128marakanetz
4 responses Add your response
sean
6,231 posts
 
There are different types of attenuators. Some can maintain a constant input impedance to minimize "loading down" the source but still adjust the output level accordingly. Try contacting Michael Percy, as he can supply you with the parts and diagrams that you will need to do this. Keep in mind that Michael is typically over-run with business, so he might not respond very quickly. Sean
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justlisten's avatar
justlisten
489 posts
 
I am not very techincal, however my 1st passive, a Luminous Audio was connected with a 5k Caddock resistor and I had virtually not control over the volume scope (too much volume), I changed over to a 15k Caddock and my problems went away.
marakanetz's avatar
marakanetz OP
5,473 posts
 
Bingo! That's what I've ment! -- Right onto the point Justilisten!
tom_nice
387 posts
 
Besides MNichael Percy, who has recently moved and is VERY busy, try Arn Roatcap at www.goldpt.com. Email your question and I bet you'll get a useful answer. My guess is that your additional resistor idea isn't good. It may also be relevant that I've used 10K ohm ladder type passives with Pass Aleph 3 amps, whose input impedance is only 23K ohms. That 10X figure would be nice to have, but isn't necessary.
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