Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

How To Make Passive High Pass Filter?
How To Make Passive High Pass Filter?
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 30th October 2017, 12:57 AM   #11
cacao ambiance is offline cacao ambiance  United Kingdom
diyAudio Member
 
Join Date: Oct 2015
Quote:
Originally Posted by ceulrich View Post
I worked up a little spreadsheet to calculate the capacitance needed for the known input impedance of the power amplifier.
Hello too, ceulrich
Do you have a copy of this spreadsheet? i would be interested in a copy please.
Thanks

Last edited by cacao ambiance; 30th October 2017 at 01:00 AM.
  Reply With Quote
Old 30th October 2017, 01:44 AM   #12
ceulrich is offline ceulrich
diyAudio Member
 
Join Date: Jan 2016
Location: Mid Ohio
Default Spreadsheet

Hello cacao ambiance,

If you can work with Excel V14.7.0 for a Mac, send me your e-mail address off forum at dwpharma2@gmail.com and I will send you a copy.

Cheers,

ceulrich
  Reply With Quote
Old 30th October 2017, 02:22 AM   #13
Muskrat54 is offline Muskrat54
diyAudio Member
 
Join Date: May 2016
Quote:
Originally Posted by cacao ambiance View Post
Here is are photos of the original transformer from the speakers from when they where 100v ones. it had this 15uF kerpen cap and parallel 220R resistor in series with what i guess(?) was the ground of the user/installer connections to the speaker transformer.
Can this cap be used for a speaker side/post amp passive low freq filter? or did it do something else to do with it being a 100v line speaker?
To block lows, 100-200uf non polar capacitor in series with speakers, if 8 ohm. Double that if 4 ohm. Should be $3 or so. 63volt or 100. 6 db high pass filter
  Reply With Quote
Old 30th October 2017, 10:31 AM   #14
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by cacao ambiance View Post
How to i create a passive line-level 90hz high pass filter? I want to be able to filter off the low end limit of my speakers (90hz) before it goes into the (class d, tpa*) amps...............
I don't understand your question.

The amplifier goes before the speaker in the audio system.

Do you want to filter the signal going into the amplifier, or do you want to filter the signal after passing through the amplifier, i.e. at the speaker?

The filters for these two alternative duties are very different !
__________________
regards Andrew T.
  Reply With Quote
Old 30th October 2017, 02:10 PM   #15
cacao ambiance is offline cacao ambiance  United Kingdom
diyAudio Member
 
Join Date: Oct 2015
Quote:
Originally Posted by AndrewT View Post
I don't understand your question.

The amplifier goes before the speaker in the audio system.

Do you want to filter the signal going into the amplifier, or do you want to filter the signal after passing through the amplifier, i.e. at the speaker?

The filters for these two alternative duties are very different !
yes, iím (now) interested in both.

When i started this thread i was just thinking about passive before amp filter. then i started to think and remember about a post amp, internal to speaker passive filter as i would then not have to match the amp impedance for a before amp line level passive filter. So later in the thread I ask about speaker post amp passive filter.

Sorry for the confusion. i should really start a new thread regarding post amp passive filters, in a more correct forum category...
  Reply With Quote
Old 30th October 2017, 02:18 PM   #16
Pano is online now Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: SW Florida
How To Make Passive High Pass Filter?
If you want to do the high pass before the amp, this should be very helpful.
TLS.org | Passive Line-Level Crossover

If you want to do it after the amp, you'll need large value caps for a 90Hz high pass. There are many online calculators, this is a good one.
2-Way Crossover Calculator / Designer
__________________
Take the Speaker Voltage Test!
  Reply With Quote
Old 30th October 2017, 07:34 PM   #17
cacao ambiance is offline cacao ambiance  United Kingdom
diyAudio Member
 
Join Date: Oct 2015
ok i think i finally understand it. in the speaker crossover calcs. Even-though the high pass cap is intended for the treble speaker, i just put the cross over at 90hz 4ohm for both treble and bass speakers and use the cap it calculates for treble speaker for my mid,bass speaker! i always thought the high pass cap was only for the treble speaker for some reason! arr at last.

so i have extracted some 100v+ 100uF,330uF,470uF caps and been playing around with them seams to do they job.

Interestingly i think there is some distortion in the base with the bigger values still... but 100uf while on its own is ok, compared to 330uF i hear how much bass im losing and in a open bigger space, i suspect ill notice more. i wonder how 200uf would sound... need to find a cap...

I wonder if maybe i damaged the speakers for driving them on the hard side, with low freq they where not designed for. :/ I tried quite a lot, to not over do it... but i guess its hard not too...

next is to pop these caps into online calc to see what the high pass filter freq is with each one. need to find the track list for my freq test cd too kinda hard to tell which freq is which from the test cd without it! or ill use gnu/linux cli SOX software to generate new test freq files. maybe even dare to approach learning hot to use scope to see whats happening...

also wondering how a 2rd order high pass would affect things? cus when i turn the bass more than i normally would to see what happens it distoruts in a unpleasant bad PA way and so i wonder if that is something to do with the sharp cut off?

Thank you all!!! Huge Help

Im still have an interest in trying out passive line level pre amp filters... after i face up to working out how to find out amp impedance. Looks like i will end up using post amp speaker filters for there genericness, efficiency wise my problem is putting to much power into them so i can live with a few % loss. I can put the caps on the spare speaker terminals so i have future choices of with and without

Last edited by cacao ambiance; 30th October 2017 at 07:39 PM.
  Reply With Quote
Old 30th October 2017, 07:49 PM   #18
Pano is online now Pano  United States
diyAudio Moderator
 
Pano's Avatar
 
Join Date: Oct 2004
Location: SW Florida
How To Make Passive High Pass Filter?
Good, glad you figured it out. I didn't mention that part about using the tweeter section as your woofer high pass, hoping you would figure it, and you did.
A 2nd order just rolls off the bass twice as fast.

What kind of caps are you using? For speaker crossovers you'll need to use non-polarized caps, since the signal is AC.
__________________
Take the Speaker Voltage Test!
  Reply With Quote
Old 30th October 2017, 11:18 PM   #19
cacao ambiance is offline cacao ambiance  United Kingdom
diyAudio Member
 
Join Date: Oct 2015
muskrat54 also said non-polarized caps yet the diagram had a polarized/electrolytic cap symbol. so i used electrolytic. searched RS, Aliexpress and Farrell but the only 200uF,400uF non-polarized caps where something like £60+!. Where does one find them for $3?
  Reply With Quote
Old 30th October 2017, 11:21 PM   #20
cacao ambiance is offline cacao ambiance  United Kingdom
diyAudio Member
 
Join Date: Oct 2015
yea it was only because people had suggested i use the online cross over calcs to work out what i need, i then rethinked and expand the question of why are they confidant that this is my answer, i was then able to think of what i had not considered before.
  Reply With Quote

Reply


How To Make Passive High Pass Filter?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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Passive high pass filter to prevent excessive excursion SpartanX58 Subwoofers 5 3rd May 2017 11:08 PM
Passive high pass filter before Topping TP22 7V Class D 4 22nd October 2016 01:14 AM
Passive high pass filter app. 60 hz emosms Multi-Way 12 4th February 2016 01:27 PM
Passive line level low and high pass filter help Matttcattt Multi-Way 54 28th July 2015 09:46 PM
RL passive high pass line level filter noviygera Analog Line Level 11 9th March 2012 05:13 AM


New To Site? Need Help?

All times are GMT. The time now is 04:01 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright ©1999-2017 diyAudio
Wiki