BZLS attenuation before output caps - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs

Pass Labs This forum is dedicated to Pass Labs discussion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 17th January 2003, 12:59 PM   #1
diyAudio Member
 
Join Date: Apr 2002
Location: Toronto
Default BZLS attenuation before output caps

My attenuator places one resistor at a time between the + and - signal of my BZLS or P1.7 via a 23 position Electroswitch.

This method seems to work best when placed after the output caps; however, my BZLS splits the output to a 120 Hz high pass and an all pass.
If I place the atennuator at the input I have to isolate it from my sources via 10K0. This causes odd attenuation at some listening levels.

Can I connect my attenuator ahead of the output caps, before the DC is blocked? The DC voltage seen by the attenuator should be very small. The 8R1 is the lowest resistor value which shorts beween + and -.
Will I have a problem if the drains are shorted?

The attached jpg is a very rough version of a modified BZLS; however, it sounds much much better than it looks.
  Reply With Quote
Old 17th January 2003, 01:56 PM   #2
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
If you look at the schematic of D1, you'll see that attenuator is located before the output caps http://www.passlabs.com/pdf/d1-srv-man.pdf
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 17th January 2003, 03:00 PM   #3
diyAudio Member
 
Join Date: Apr 2002
Location: Toronto
Default BZLS attenuation before output caps

Peter:

Thanks for the link.
What is the purpose of the 4.7 uF cap for on PL55 Volume Control dwg?

It looks like the shoulder frequency ranges from 1.1 Hz to 1.5 Hz.
Does the cap basically short out the unselected resistors for some reason?
  Reply With Quote
Old 18th January 2003, 05:01 AM   #4
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
Maybe the cap is there to reduce "pops" when switching.
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Output caps on DVD/CDP hafp Digital Source 0 14th November 2008 06:49 PM
Value of output caps for Aikido - how low is too low? cbutterworth Tubes / Valves 9 3rd September 2007 01:34 AM
Coupling caps in DAC output Sunsun22 Digital Source 12 13th July 2005 06:04 AM
Zen output caps apassgear Pass Labs 2 26th May 2005 06:38 PM
BG N/NX as tube output caps? possible? tone Tubes / Valves 4 21st July 2003 07:32 PM


New To Site? Need Help?

All times are GMT. The time now is 01:03 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2