It is Pie Day so here is a layout of an old Ram's Head variant. Rarely cloned and some cap values is not found in any of the other vintage EHX variants. 220pF/680pF caps replaces the standard 470pF/500pF values and the tonestack has less mid scoop. Still added a Mid switch for some sligtly boosted mids.
Note that the FS36999 was house numbered 2N5133s. These varied in Hfe a lot, ranging between 100-800. So socketing may be a wise decision for the transistors.
...and a mojo layout with 1,2w carbon comp resistors for the purist...
Awww man , now look what you gone and done. Now I have another project. I’m a sucker for a muff. As always Thank you.
ReplyDeleteSorry!;-) Let me know if you give it a go. By looking at some of the cap values, it seems like a quite heavy version...
DeleteAs expected,I built it. This one is verified. I used PN5133 trannys from mouser and the pin out was 180 off so mind your pin outs. As you thought it’s a heavy version, like a lowend wrecking ball. It sounds great on bass as that’s what I play. I like the switch option and it has its place . This is a lot like the dope priest on steroids and to me sounds way better for my use. Thanks for posting this one.
ReplyDeleteThanks Matt! Tagged
DeleteYour description made prepare a board for a building session tomorrow.
I assume you did the small layout?
Also, interested in the Hfe of your PN5133s? Might order some...
I built the 1st lay out, non mojo version. I checked the hfe with my chepo DMM as it has sockets for npn and pnp trannys.
ReplyDeleteQ1=312
Q2=350
Q3=300
Q4=330
i ran it into my amp today. This thing is a Low end monster, lol.
when you turn the sustain up the lowend comes in even more. I cant wait to try it through my board into the PA with the Sub kickin . This to me is a bass players dream muff. This to me crushes the SS Bluebeard, which is based on a rams head muff. Im makin a box for it right now. Waiting for paint to dry.
I checked the pn5133 specs on mouser and the hfe can vary quiet a bit. They can range from a low of 60 to a high of 1000. Crazy.
ReplyDeletehaha, that's crazy. Luckily you got some within the useful range.
DeleteJust fired this one up...and it is a monster of a muff. One of the heaviest and unruliest of all vintage variants I've tried. Perfect for bass and doom I suppose. Used 4 x ME4003, all around 300hfe.
Just slapped together the mojo layout. Used a mix though of carbon and metal film 1/2 watt resistors (no carbon comp yet). Can't wait to wire it up this evening. Thanks soooo much for all the work you guys put into these layouts!
ReplyDeleteJust built this one used some transistors with somewhere around 340 hfe sounds great maybe my favorite muff that I have built Thanks fuzzhead
ReplyDeleteHey Fuzzhead, just wanted to say thanks for these layouts first and foremost. However, I do have a troubleshooting question. I built the top layout with BC547s and tried slapping it in a dual effect enclosure with the other side being a proco rat clone. The rat side of the board is fine, but the big miff circuit is super faint. I eventually clipped the board out, and tested it but seemed to get similar results. I reflowed all my solder joints but that didn't seem to fix the issue. I might try redoing the layout as it seems this one works fine seeing all the other comments.
ReplyDeleteOut of curiosity and frustration, I built the second mojo style layout, but used a combination of metal and carbon film (no carbon comps), yet when I went to test the board it just doesn't sound right and is all hissy buzzy and weird. It could be the darn alligator clips and all I was using (but the connections seemed solid). However after the issue withe first board I'm afraid of slapping this one in an enclosure to have the same issues repeat.
Would you have any advice on how to effectively troubleshoot? Would a higher hfe mess up anything?
Big bummer you have issues with both layouts.:-/ Built both myself and both works just fine. I doubt transistor hfe would cause the symptons you have. It is more likely you have a short somewhere i. e. solder bridges, bad cuts or copper traces.
DeleteDo you have an audio probe? It is the best tool for troubleshotting IMHO and you can easily spot the area when where the signal stop/gets weak. Often you will spot a solder bridge, cold joint, misplaced component/cut or a wrong value.
So my advice would be: build a simple audio probe.
Thanks soooo much for the quick reply! Good to know then that you were able to verify both layouts yourself and that they work (I figured as such).
DeleteThe problem I was having with the second layout is probably one of those stupid alligator clips I was using to test it. I'll check over things and put it in an enclosure and see if that helps.
Unfortunately I don't have an audio prob (yet), but after past debugs taking hours and even weeks, I should have just bit the bullet and made one by now.
Well, I really appreciate your response and I'm super happy oddly that the problem is me and not a mistake in the layout or anything. Guess I better head over to Jack Orman's site and build that audio probe. I'll keep you guys posted if you're ok with it!
Great, let us know if you can sort it out! Yes, an audio probe will save you hours and days of frustration. Measuring voltages for your Q's can also help to indicate what the issue might be.
DeleteHey man! So quick update...I had the 10K resistor in the top right of the layout off by a hole and was subsequently going to ground. Fixed this issue, threw in some BC337s around 300 hfe and it fired right up.
DeleteI haven't tried the second layout, but am pretty confident that it was the test cables I was using after inspecting everything. I'm pretty confident I'll be able to get it up and running as well. So good news! It's always something stupid like a misplaced component or wrong value or something lol
Hreat, glad you got it working!:-)
DeleteIf I wanted to build this stock without the mid boost switch what would I need to leave out?
ReplyDeleteThanks
Just omit the switch and the 4,7nF cap.:-)
DeleteThanks FuzzHead for the reply and that you do here.This is a great site I am sure that it takes a lot of time and work.If you ever get a chance I would Love a layout of the original Little Big Muff I don’t know if they would be a lot of interest in it or not.
ReplyDeleteIf you are interested, there is interest, right?:-) And one knob fuzzes is cool!
DeleteSo, Little Big Muff is the one with a tone selector switch and volume control. Not sure if it was an op amp or transistor circuit in it?
Need to do some digging...
Your to kind fuzzhead you may be the coolest person I don’t know
ReplyDeleteI’ve been looking forward to doing this one for a while. Just built the 30x14 layout and it fired right up with fuzzy goodness! I used 2n5088 transistors. Thank you fuzzhead for this layout and all the other ones I’ve enjoyed building. I completed this one in a few hours while attending a virtual teacher training workshop on mindfulness. A very peaceful day indeed!
ReplyDelete