F-deck HPF Series 3

[masonsjax]

I am interested in building a high pass filter based on the F-deck designs. I have found a layout for the older series 2 version here:
https://tagboardeffects.blogspot.com/2015/01/hpf-technology-hpf-pre-2.html

The latest design, the series 3, includes 2 stacked 12db/octave filters. One is fixed at a 35hz corner frequency, the other is variable from 35-140hz. The older models would be useful, but the series 3 has been designed specifically with electric basses in mind.

The schematic for the series 3, along with a good amount of testing notes and JFET discussion have been provided by the creator, Francis Deck on his website here:
https://sites.google.com/site/hpftechllc/home/technical-diy-stuff

If any of you experienced folks would be interested in taking a crack at an updated stripboard layout for the series 3 design, I would be very grateful. Thanks!

[Zanius]

As an upright player I was looking forward to this schematic release as well!
Here is a first draft, I will let it sit for anyone who wants to double check and I will give it a try soon!

[masonsjax]

Excellent! Thank you so much for working this up!

I plan to give this a go when I wrap up the current projects on the bench. I have a couple of questions though...

The OpAmps specified seem to only be available in surface mount packages (and none are available via my supplier of choice, Tayda). Is there a reliable way to use these type of ICs on the vero layout as drawn? I may try using a TL074 and see if the performance is acceptable.

Also, for C8, R14, and R15, do you have suggestions for component values that would allow a touch of gain? I would probably be fine with unity and may build the first one without that section and experiment later.

Thanks again!

[Pavlos]

Regarding using SMD components on layouts made for through hole / DIL somponents then yes, you can use adaptor boards. A lot of us already use them for JFET's as the through hole versions are pretty much all obsolete and out of production now and almost impossible to find even at ridiculous prices for what may well be way out of spec and next to useless. So for a while now the only reliable way to use them has been to go SMD and use adaptor boards, which coincidentally has the advantage that the SMD versions are generally very consistant when measured with a tester


So depending on where you are in the world........

if you are able to buy from UK then Bitsbox is very reliable and has these SMD to DIL  adapter boards
https://www.bitsbox.co.uk/index.php?main_page=index&cPath=255_313
I've not used these particular ones myself yet but I often get parts from them and have never been dissapointed so far



if you also need adaptor boards for SMD JFET's so you can use them in an existing layout then Paul at DIY Guitar Pedals in Australia has these (Which I have used) really nice quality boards, fast international shipping at reasonable rates and a nice guy to deal with

http://www.diyguitarpedals.com.au/shop/index.php?main_page=product_info&cPath=1&products_id=286

[masonsjax]

I'm in the US, but this is great information, very helpful thank you!

I was trying to figure out how to do something myself with pieces of vero and creative cutting, bending, soldering pieces of leads, etc.  
These adapters look pretty slick!

[Pavlos]

Glad to be able to help

US has plenty of parts suppliers so you may well be able to get something suitable domestically. There is at least one thread on here about good /bad suppliers around the world, and also a few about SMD FET's and other componets so plenty of good ideas and advice available, and if you notice that DIY Guitar Pedals even has a video of one of the many ways you can deal with soldering SMD components on that link for the boards.

Might be worth having a read through some of the posts about compressors as as well. Quite a few use CA3080 which are sometimes not too easy to find reliable sources/quite expensive but there is an SMD version that even with an adaptor board would work out a lot cheaper, so even more info!

[Zanius]

So... turns out the layout above was super-wrong lol. I repaired it and got it working. It is now Verified and I will post it in said forum :)

[Zanius]

So turns out I can't post straight in the verified section :P  

Built it up, works like a charm. Super transparent and I'm using a TL074. It's going straight into the upright gig bag :)
Didn't look into the "more gain" deal, seems easy enough though. I guess some extra gain would be nice just to let you know "it's there".. If someone has some input it's welcome.


****UPDATED AND VERIFIED*****

[jabali]

Thank you Zanius (and Francis Deck for sharing), build and working perfect, ... great.

I decided unity gain, TLC2664 running at 12 VDC and omitting the protection diode. It is going to be part a EF86 preamp based (plus compressor, EWS Bass mid control, DI, and cabsim).

Saludos and thanks again.