Aleph P.17 1st order high pass filter - diyAudio
Go Back   Home > Forums > Amplifiers > Pass Labs
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

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
Thread Tools Search this Thread
Old 29th October 2002, 04:35 PM   #1
diyAudio Member
Join Date: Apr 2002
Location: Toronto
Default Aleph P.17 1st order high pass filter

I want to change the value of the out put caps on my Aleph P1.7 so that it will act as a first order high pass filter at 120 Hz to drive ESL63s electrostatics.

My current power amp (3BST) has an input impedance of 10K to ground balanced. If my math is correct the 10K of the amp and the 4.75K of R49 of the AlephP approximate to 3K220. (Pass X is my next project).

If this is true then I think I can replace the 30uF in the Aleph P1.7 with 0.4uF to get the 120 Hz high pass. Am I correct with my math?

The 0.4uF caps will feed the power amp which drives ESL63s. The 0.4uF will also feed through a 30K resistors each the +/- inputs of an OPA2134 which I think will give a high pass of 13Hz. The OPA2134 will convert balanced to single ended to feed a Gradient 2nd order low pass with fc at 120 Hz this in turn will feed a power amp driving Gradient sub woofers.

Is my theory correct or have I made some fatal mistake with the above. Any suggestions as to a better method of achieving the high low pass at 120Fc would be greatly appreciated. I am anxiously awaiting the Pass crossover design.

Thanks to a great forum
  Reply With Quote
Old 30th October 2002, 01:19 PM   #2
diyAudio Member
Peter Daniel's Avatar
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
That is an interesting question. I'm thinking about similar setup with my preamp. To confuse things more, what about the volume control at the preamp's output?
“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 30th October 2002, 07:56 PM   #3
diyAudio Member
Join Date: Apr 2002
Location: Toronto

My volume control is now on the output. I think it is a shunt type (one resistor between + / - ). It works great in this configuration as it attenuates the same feed to both panels and subs.

I just replaced the 10uF with a 0.47uF and it seems to be working well although I am not quite sure the shoulder frequency is exactly 120Hz, but it must be close. All the low frequency load has dropped off the panels, but the bass feed to the sub woofers seems great.

I need to get some better quality 0.47uF caps., but I am really pleased with the sound and tonal mix. I have not yet checked the phase difference between the subs and the panels.
  Reply With Quote


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
low frequency, high pass filter memphissound Multi-Way 6 19th March 2007 10:11 AM
high gain 2nd order high pass active filter topology sreten Solid State 21 23rd March 2006 02:26 AM
3rd order HIgh pass filter - explanation? APaddy Analog Line Level 12 24th January 2006 09:06 AM
1st order low-pass filter, which cap ? Thmartin Parts 4 17th November 2005 09:37 AM
Low/High Pass Filter fatpower17 Car Audio 1 28th June 2004 09:45 AM

New To Site? Need Help?

All times are GMT. The time now is 02:52 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2