EHX Hogs Foot Small Layout

[rocket88]

so i've been planing on building an EHX Hogs Foot to put into a 1590a, and i purchased those tiny SMD electrolytics for builds like these, but found that they can only stretch between 2 rows. so to solve the problem i took marks posted verified layout and shrunk it as much as i could. so i got it down 2 rows and 2 columns. should now be an easy fit into the 1590a, and make a nice quick boost for those of us bassists out here or someone that wants a boost that helps retain/boost the low end.

[jsetov]

Nice man! I was thinking about this one pretty recently myself. thanks!

[rocket88]

Your welcome buddy. With the SMD electrolytics this should be super tiny. I'm even thinking about using the multilayer ceramics instead of the normal poly caps to really keep the height down, and the tallest part will be the transistor in the socket.

I'm going to build it today, when I get off of work, as it should be a quick easy build. It's not verified yet, but seeing that I pretty much just changed the spread of some of the parts on a verified layout, it should be good to go. Once I build it I will confirm that it's verified.

Also, stupid me I forgot to add the transistor pinout on the layout. I'll make that correction later today too.

[rocket88]

the layout has been updated with the transistor pinout. i'm not going to get a chance to build it tonight, but should be able to either tomorrow or thursday. i will still confirm that it works, but there's no reason that this shouldn't start right up.

[rocket88]

VERIFIED!!!!

Here's my build using SMD electrolytics. Now the tallest part on the board is the transistor.


One comment about this booster is there is a MASSIVE boost in the bass that it's very boomy. I'm looking at how to tweak it to help get more mids and highs through. Never thought I would be trying to do that since most of the time I try to do things to let more bass through.

[jsetov]

That's awesome man! Nice work. I've had an A box sitting around for a while. I think this might be a good use of it. But yeah, i made one of these a while ago and had the same deal with the bass. to at least have some trimmers for mid and/or highs would definitely be super useful.

[rocket88]

thanks buddy. it really turned out great. i've been doing a lot of research about this pedal since i built it and found a few things. first is that's just how it sounds, which is basically like you turned your tone knob all the way down rolling off all the highs. second, this is basically a modified version of the EHX Screaming Bird, which much larger input and output caps, and the addition of the 100nF caps inline from Collector to Ground, and Bass to Ground. i believe this is acting as a low pass filter, which is cutting all of the high end off.

i'm going to still mess with this and see if i can help gain some of the high end back. it really sounds great, there's like 20db of boost, and works great when playing old school R&B, reggae & dub, and i ran it into one of my fuzzes for massive doom metal fuzzy goodness. but, i still want just a tad of mids and treble back, cause by itself i think it can feel like you put your amp underwater. lol

[rocket88]

so thanks to induction, who validated part of my assumption about the circuit design, here's how to get rid of the boominess. the two 100nF caps are the issue. the one that connects the bass to ground acts as a low pass filter, if you lower the value of the cap you'll regain some high end. the second 100nF cap that goes collector to 9V acts as a selective boost for low frequencies, so if you lower it you'll boost different frequencies. you could also just remove them, but then you just have a screaming bird booster with larger input & output caps.

what i did was take the two 100nF caps out and put in sockets and started trying different caps in each. if you take both caps out, you just get a nice clean boost, not bad, but not what i wanted. from my experimenting i find that anything over 22nF for the one that goes collector to 9V it's boomy, not as boomy as the 100nF, but still too boomy IMHO, i ended up settling on 10nF which helped boost the low end just enough that you know it's a bass boost. for the cap that goes base to ground, you get similar results as with the other cap. i ended up putting a 1nF cap in there just to roll the real high end off, there's a slight difference between no cap and the 1nF, but it's just enough that i hear a difference. i may go back and put a higher value in, but i like it as it is now. the way it's definitely a bass boost, and it rounds the tone just a hair, and makes things sound a little warmer to my ears.

i think i might stick an NPN Ge transistor in there and see how it likes it. but, i've got other pedals i want to get a move on building.