Audio Project Amplifier Speaker Loudspeaker Kit
diyAudio.com diyAudio Forums Archive > Top > Amplifiers > Pass Labs
 
2 questions on the aleph-p - Click HERE for Original Thread
jarthel
Hello. hoping you could help with the questions below :)

1. is this thread (http://www.diyaudio.com/forums/show...6414#post276414), Mr. Pass has said that it is okay to short the output to ground. Does it matter if it's before the volume control or after? I only intend to short the output to ground for a few millisecs after turn-on and would immediately switch back to normal output.


2. in the original aleph-p, is the relay attenuator comparable to series, ladder or shunt stepped attenuator? I did see the schematics on the service manual and it looks like a shunt. But I want to confirm.

Thank you for the reply. :)
Stefanoo
1. WHY?????? Why would you want to shor the output for a millisec?
You have to put a relay on the output and and timing circuit (RC or something else) to control the switching of it....and you definitely degrade the sonically quality.
If the initial bumb is what you're being concerned....you switch the preamp on first and then the amp and you figure this problem out without having to use those artificial methods.


2. the attuenuator is a shunt type, but you can implement a better ladder type....but i don't suggest you...is more expencive and it takes more time and space to implement it and it brings with it many issues.
I don't understand your first question....
jarthel
quote:
Originally posted by Stefanoo
1. WHY?????? Why would you want to shor the output for a millisec?
You have to put a relay on the output and and timing circuit (RC or something else) to control the switching of it....and you definitely degrade the sonically quality.
If the initial bumb is what you're being concerned....you switch the preamp on first and then the amp and you figure this problem out without having to use those artificial methods.


normally, the output is shorted to ground. on the same relay pin the pcb output is soldered, I have soldered the wires going to the rca/xlr connector. when the relay triggers the connection to ground is broken thus rca/xlr connectors work as intended.
Nelson Pass
Nevertheless, because the active stage is simply a current
source, it doesn't care what the impedance at the output is,
so shorting before or after the volume control creates no
issues.

:cool:
jarthel
quote:
Originally posted by Nelson Pass
Nevertheless, because the active stage is simply a current
source, it doesn't care what the impedance at the output is,
so shorting before or after the volume control creates no
issues.

:cool:


thank you very much

Page generated in 0.033392906188965 seconds with 17 queries,
spending 0.01663113 doing MySQL queries and 0.01676178 doing PHP things.

Powered by: Search Engine Indexer and vBulletin
Copyright ©1999-2009 diyAudio.com