[g3rain1]

Will GR Research sell all the parts (or as a kit) needed to build the high-pass filters that you place on the signal lines that Danny talked about in a recent video? 

[Hobbsmeerkat]

We're considering it, but we would need to source the housings as well as the connectors for both RCA and XLR connections. (Not to mention a variety of small value caps.)

But the thing is, they are 100% dependant on your system.
You will almost always need to have a separate amp & preamp in order to get the results you're looking for.

And if you change your amp, you will need to change the capacitor based on the input impedance of the new amp, or find another amp with the same input impedance.

It will probably be easier to just make a dedicated video/videos explaining how it works and how to make them.

[Beerbellydad]

We're considering it, but we would need to source the housings as well as the connectors for both RCA and XLR connections. (Not to mention a variety of small value caps.)

But the thing is, they are 100% dependant on your system.
You will almost always need to have a separate amp & preamp in order to get the results you're looking for.

And if you change your amp, you will need to change the capacitor based on the input impedance of the new amp, or find another amp with the same input impedance.

It will probably be easier to just make a dedicated video/videos explaining how it works and how to make them.

Would love to see this!

[mlundy57]

You can make them a number of ways. I've used PVC electrical boxes that I got at the big box stores and metal boxes from eBay. I've used Cardas connectors I got from SonicCraft

electrical box.


https://www.lowes.com/pd/CARLON-Gray-Weatherproof-Pvc-Junction-Box/1000975650

Metal box





https://www.ebay.com/itm/Steel-Project-Box-4-1-2-x-4-3-4-x-2-3-8-Pre-Punched-for-6-D-Series-XLRs/261808804730?hash=item3cf505537a:g:liwAAOSwfcVUEdB8

[g3rain1]

You can make them a number of ways. I've used PVC electrical boxes that I got at the big box stores and metal boxes from eBay. I've used Cardas connectors I got from SonicCraft

How do you calculate the value of the caps you need to use?

[Hobbsmeerkat]

You need to know the input impedence of your amp, and the roll off point you want. Then that is used to calculate the value you need.

And you can use this calculator to get the value.
Though I usually play around with cap size to get the roll off point.

Example: you have a 100,000 Ohm input impedance and want a 80Hz roll off, you'll need a tiny 0.02 uF cap.

Here is a calculator you can use: (make sure capacitance is measured in micro farads)
http://www.learningaboutelectronics.com/Articles/High-pass-filter-calculator.php

[Hobbsmeerkat]

.

[wgraft5]

.

[lokie]

Are you hearing any level loss or other differences w and wout?

[jparkhur]

https://www.audiocircle.com/index.php?topic=155682.msg1666094#msg1666094

[lokie]

Can you all recommend some caps with this low of value. Having a hard time finding something.

[Hobbsmeerkat]

We generally recommend sonicaps or Miflex copper caps
But in order to know what values you need
What is the input impedance of your amplifier and what do you want the roll off point to be?

[lokie]

Looking for 3000 and 4000pf give or take a few pf's.

Not a fan of Sonicaps but might give Miflex Copper a try.

Found some NOS Jensens at Parts Connexion, so, will be giving those a listen over the Holiday. 

Thanks

[Bonk]

You need to know the input impedence of your amp, and the roll off point you want. Then that is used to calculate the value you need.

And you can use this calculator to get the value.
Though I usually play around with cap size to get the roll off point.

Example: you have a 100,000 Ohm input impedance and want a 80Hz roll off, you'll need a tiny 0.02 uF cap.

Here is a calculator you can use: (make sure capacitance is measured in micro farads)
http://www.learningaboutelectronics.com/Articles/High-pass-filter-calculator.php

Using your example above with the 80hz roll off using a .02uf cap :
 - Is 80hz where the roll off begins ? Or is this a -3db or -6db at  80hz ?
 - Or are you better off using a .015 cap getting you a 106hz roll off starting point and ensuring that you are down 3 or 6db at 80hz?
 - Or are you better off buying both (.015 and .02 caps) and seeing which ones measure or sound best       
In other words are the roll off values shown the starting points ? And how shallow/steep is the roll off curve ?

[Hobbsmeerkat]

Using your example above with the 80hz roll off using a .02uf cap :
 - Is 80hz where the roll off begins ? Or is this a -3db or -6db at  80hz ?
 - Or are you better off using a .015 cap getting you a 106hz roll off starting point and ensuring that you are down 3 or 6db at 80hz?
 - Or are you better off buying both (.015 and .02 caps) and seeing which ones measure or sound best       
In other words are the roll off values shown the starting points ? And how shallow/steep is the roll off curve ?

80Hz is the -3dB point and the roll offs are 3dB per octave, then cross them at the -6db point.

Either way you'll be fine, you'll just need to adjust your subwoofer accordingly, just depends on where you think it would be easiest to
them over crossover.

[Bonk]

 Thanks Hobbs

[g3rain1]

Is there some easy way to determine the amps input impedance if the manufacture doesn't list it anywhere?

[corndog71]

Contact the manufacturer.  You could also look up reviews that measure the performance.