G-SSL Side-chain (Stephen's HP + Dual Thrust HP filter) !

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Purusha

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Tested yesterday my finished Stephen - Thrusty overkill HP filter based on Clintrubber's schematics http://home.hetnet.nl/~chickennerdpig/FILES/API/API-Thrust-HPF-circuit_20060310.pdf

I used 1x12 rotary for 8 steps SC Filter. Measured only from 20Hz up to 250Hz. You can see the GR curve bellow.

CLICK ON THE PICTURE FOR BETTER VIEW :shock:

HP-filter.jpg


Many thanks to Greg for Stephen's HP PCBs and Peter Clintrubber for expanded schematics :thumb:
 
Hmm, looking at the graph I just noticed that there is no big difference between the 60Hz and 90Hz HP curve. It doesn't look right to me. Can anyone of you experts chime in?

Maybe someone of you who has the Stephens SC board installed make some tests so we can compare the curve responce. I used 10dB of GR when SC was OFF. Maybe I did something wrong :?

Another thing. I tweeked the trimpots on the fiters to match GR for all settings at 600Hz.
 
Double check your capacitor values.

Also, it's a first order filter, so the knee if very broad and not very precise. Did you give a listen, too?
 
I can do it, but it won't be any time soon. I've got my full-time engineering job, and on top of that I defend my graduate thesis on the 21st. And I've got a few paying racking gigs that are keeping my electronics obsession fulfilled. Maybe someone else can come through on this one.
 
[quote author="Greg"]Double check your capacitor values.

Also, it's a first order filter, so the knee if very broad and not very precise. Did you give a listen, too?[/quote]

Is it possible to adjust the knee?
 
I just checked the capacitors on my SC board:

60Hz = wima MKS4 220nF
90Hz = unknown small and round 150nF
130Hz = square unknown brand 100nF
200Hz = wima red 63nF

It looks like I have all the right capacitors...

Anyone out there willing to test their own HP filter?
 
And the Thrust filters both qualify probably best as 'half order filters'.
A sweep will be easy & simple - once it's all connected & powered-up. :grin: Will definitely do so, but like Greg, it won't be very soon I'm afraid.

But aren't we reversing things ? This stuff should in essence just be like the filter-simulations predict. These are not the kind of circuits that are very sensitive to details. Opamp+R+C should behave straightforward. So are easily predicatable with a sim. Make curves, compare with breadboard.

Bye,

Peter
 
Hey Peter, thanks for stopping by. Do you have any idea why are my curves of the 60Hz and 90Hz HP so close? Should I change some capacitor?

I know sweepable would be nice but I have to finish my G-SSL with the overkill, just need to fix the 60/90 thing asap if possible and move on.
 
Purusha: There's only one variable unique to the 90Hz that's not used by another part of the circuit, and that's the capacitor. I would first change the "unknown small and round 150nF " with something else then run the test again. C'mon man, use your noggin'. In filters, I like to use polyester or polypro caps. Also, some caps have a large tolerance, so that could be the problem. I don't think anyone can help you out here.
 
[quote author="zitoune"]Is there a pcb for this side chain ?

Thanks
Olivier[/quote]
You mean the whole thing ? Yes, IIRIC there have been some PCB-designs posted recently, do a search. (12rafael ? sonicwarrior ?)
Or if you mean the added Thrust-stuff, then no, but there are some pics around that show an easy beardboarding route.

Bye,

Peter
 
[quote author="zitoune"]Is there a pcb for this side chain ?
[/quote]

If you didn't found it, here they are:
http://www.groupdiy.com/index.php?topic=16113

My layout IS NOT YET TESTED!!!
When I have the time and finished the basis of my GSSL
I will test it and if there is enough interest I will
do a groupbuy and order some professionally made PCBs.
But for this to be worth while there has to be at least an
interest in 20 PCBs. The more PCBs the better the price
of course (it will be the cost price only!).
 
Ok, so far there is interest in 13 PCBs (mostly from the Synthesizerforum), not that far from the 20. :wink:

I expect the PCBs to cost only cost 7 Euro including 19% VAT when 25 pieces are reached. 20 will cost 9 Euro per piece.
 
[quote author="sonicwarrior"]Ok, so far there is interest in 13 PCBs (mostly from the Synthesizerforum), not that far from the 20. :wink:

I expect the PCBs to cost only cost 7 Euro including 19% VAT when 25 pieces are reached. 20 will cost 9 Euro per piece.[/quote]

Hey sonic sign me up for 2.
You can contact me here, acidcode or midibox onder the same name ;)
 
[quote author="Twin-x"]
You can contact me here, acidcode or midibox onder the same name ;)[/quote]

Yes, the DIY world is small. :wink:

I'm getting a prototype at anytime and will test it first.

Edit for myself: Remember tommypiper per PN!
 
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