Marketing spiel:
Fuzz for the discerning tone seeker.ﾠ The Black Arts Toneworks Pharaoh is capable of tones ranging from a clean-ish boost to a good articulate OD, but the Pharaoh thrives in bringing open hairy fuzz to a clean amp. The Pharaoh's dual tone control is specifically designed to retain your guitar's tone and maintain the character of your pickups. There is no volume loss with this pedal's tone circuit, no drastic cuts or boosts leaving you wanting. The Pharaoh will leave your tone intact and add the soul-stealing doom you need to push your sound into the next world.
The fuzz control alters the amount of clipping. From a clean boost to a slight overdrive all the way to feedback mayhem the Black Arts Pharaoh covers all the bases. The Hi/Lo Input switch controls the first stage of headroom and clipping. With the switch in the Lo position the headroom increases, in the Hi position the clipping increases providing you all the growling fuzz tone your heart desires. The bottom switch is a three-way toggle to switch diodes (germanium, no diodes, silicon) adding even more versatility. With the silicon diodes in the circuit the pedal will add clip with less volume or add the germanium With the diodes out, the headroom increases with less clipping. The Black Arts Toneworks Pharaoh was designed with specific signal capacitors which pass all frequencies so none of your sound gets left behind.
The fuzz control alters the amount of clipping. From a clean boost to a slight overdrive all the way to feedback mayhem the Black Arts Pharaoh covers all the bases. The Hi/Lo Input switch controls the first stage of headroom and clipping. With the switch in the Lo position the headroom increases, in the Hi position the clipping increases providing you all the growling fuzz tone your heart desires. The bottom switch is a three-way toggle to switch diodes (germanium, no diodes, silicon) adding even more versatility. With the silicon diodes in the circuit the pedal will add clip with less volume or add the germanium With the diodes out, the headroom increases with less clipping. The Black Arts Toneworks Pharaoh was designed with specific signal capacitors which pass all frequencies so none of your sound gets left behind.
Update: I missed a cut from the vero so anyone already building this should put a new cut 2 rows directly below Q2 as shown in the updated layout.
Hi Mark,
ReplyDeletethanks for the layout
Is 1N34A a good candidate as ge diode?
thanks
Nic
Hi Nic, yes 1N34A's would be perfect.
DeleteWow, super fast reply!
Deletethanks
Hi Mark,
DeleteCan you tell me please which Ge diode can i use for this "beast"? :) Can i use whatever or is it somehow specificated?
thanks,
Petr
take a look at the notes on the layout. the notes will tell you what pots you need, what additional connections you will make with them, transistors and/or IC's and diodes you need in each position.
Deleteanyways, in the notes it says that D1-D4 are 1N914, if you don't have them and can't find them you can sub 1N4148 for them, D5-D7 are Germanium, which you can use pretty much any Germanium diodes you want, each will ad a slightly different flavor of clipping but should all sound fairly similar.
Hi ! Very nice work, thanks ! I'm wondering, is it based on a schematic ? I haven't been able to find one so far ... And also, have you tried it ? All the samples I've heard so far are awesome, but I've couldn't try it myself so far...
ReplyDeleteAnyway, thanks for your blog, it's just amazing !!
Cheers from France
Matt
Hi Matt. It's based on a schematic which was posted at the Freestompboxes forum. No I haven't built it yet, but I definitely will do. My to do list is pretty big nowand I do layouts much quicker than I can build so it's growing all the time! :o)
DeleteThanks for your comments.
Hey thanks for the (very!) fast answer ! I intend to build it myself as well, so I'll give you my feedback :)
DeleteThis comment has been removed by the author.
ReplyDeleteHi Mark, I built this baby up last night, but not without a few issues unfortunately. My sustain pot seems to operate in reverse, should it be a rev log, or can I just wire the two outer lugs of the pot, the other way around? (I have some 100k rev logs from my triple wreck build). Also, I don't know if I've ballsed something up, but the effect is really quiet and has no plums, until I remove Q2, then it comes to life. I've checked & triple checked for shorts & my layout, but everything seems to be in place and as per your layout. I did a silly thing and made this late last night whilst I was tired, so I'll have another look at it later and see if I can spot any anomalies in my building. Thanks dude, Matt
ReplyDeleteHow are you soldering your pots. This is the conventional method which is what I use in all my layouts:
Deletehttp://i76.photobucket.com/albums/j6/IvIark_2006/DIY/Pot20numbering.jpg
Based on that the numbering shown in the layout must be correct because it's wired in exactly the same way as a volume control. Maximum gain (maximum volume) in the far clockwise position.
I've just been over the layout and did notice one slight error but it shouldn't make a difference. The Pharaoh 470n and diode feedback combination around Q2 seems to be back to front compared to how it is done by Skreddy (I used a Skreddy pedal as a template to do this from) - 470n to base, diodes to collector, which you will see in the newly uploaded layout above. But I can't see that causing problems. Everything else in the layout lines up exactly with the schematic.
Lin or log should be fine for the Sustain pot, Rev Log probably less so because all the gain will come in at the end of the rotation.
What transistors did you use?
Upload a high res front and back pic somewhere and post the links, and I'll see if I can see anything obvious.
Thanks Mark, I'll take & upload photos tonight! With re: to my pot wiring I do all my pots as per your photo. I'll need to go through it again & I'll try your update to see if that does anything, but if you think it won't is it worth it maybe? I just realised I used 5088's! Doh! I have them next to each other in my component rack!! (MPSA18 for Q1 though) Aren't the 5088's & 5089's quite close to each other with regards to values, or am I just assuming that due to there being only one digit difference between their respective names? I'm sure I read somewhere that they are (I guess data sheets are my friend).
ReplyDeleteThanks for your help buddy! Matt :0)
I don't think swapping the order of diodes and cap will have much affect at all, but of course if you want the scheme true to the original then it's a quick fix still. 2N5088s can get quite high gain, do you have a multimeter that can measure gain?
DeleteHi Mark, I didn't get round to trying it out again lastnight, will try tonight, but it's my wifes birthday today so.....
ReplyDeleteI have a hfe tester on my multimeter, that's what you mean right, or is there something else?
I have taken as high res picture as I can, but haven't uploaded them yet, can I just email them to you at the blog email please buddy?
Aah well you need to pamper her today then, maybe back to this tomorrow! :o)
ReplyDeleteYes the hfe tester on the multimeter is what I meant. Try to get 4 around 600hfe, and the tested will also confirm the pinouts.
Yes just email them to me and I'll have a look in the meantime.
Just noticed a missed cut which will be the cause of your problem mate. Make a new cut two rows and directly below Q2 as shown in the updated layout above. That should sort things out.
DeleteAces, thanks matey, I'm gonna check it out now, I'll report when I'm done! :0)
ReplyDeleteSure enough kiddo, it's now got some fuckin' plums. Awesome, thanks Mark :0)
ReplyDeleteYay! :o)
DeleteSo... can it be considered verified?
ReplyDeleteanother question for Mark: it isn't necessary to use a dpdt for the clipping switch, right? Is it ok if I use an on/off/on spdt wired like
this: http://i1116.photobucket.com/albums/k573/elflicho87/Immagine.png
(big red rectangles are Ge diodes, small ones are standing Si)
thanks!
Nic
Yes that switching looks fine to me, and I think Milkit has verified it.
DeleteThanks, once again!
DeleteSorry, yes tis' indeed verified. Sounds bitching!
ReplyDeleteHey man, built this from a layout over at Sabrotone. I didn't realise you had one too. Just wondering if you know whether there is supposed to be a huge volume difference between the diodes? I realise there will be somewhat of a difference, but the one I built doesn't seem right. Anyway, I might try your layout if anyone can tell me whether it is supposed to be like that or not.
ReplyDeleteYou will find more of a volume drop when the germanium diodes are used compared to silicon.
Deletewhere are the pads for in/out? where am i connecting a footswitch? this seems incomplete. sorry for the noob questions. never built with vero before..thanks.
ReplyDeleteYou'll see the input is on one of the switches, and then the Sw1 wire takes it to the board. The output of the board is the Level 3 wire, with the Level 2 wire from the pot being the actual output to the stomp switch.
Deletethank you sir. i suspected as much, but as ive never seen a pedal wired this way, i thought i'd ask. have i meantioned the quantity of balls this blog rocks btw? you may remember my enthusiasm from the wampler post. thanks again.
Deletehttp://www.youtube.com/watch?v=D64bPCL8OoM&feature=plcp
ReplyDeleteThis thing sounds massive, even with low gain 2n2222.
Awesome thanks for the link
DeleteI try to get videos up... When they work... lol
ReplyDeletewhat's a pulldown resistor?
ReplyDeleteIt's a resistor that connects from where the input wire connects to the board to ground. Usually 1M or 2M2 but I've seen 5M resistors used for it, I think that really anything above 470K would be ok.
DeleteIt's designed to combat the popping that you can get with some of these effects due to leakage current from the input capacitor. There isn't one on this layout but if you wanted to add one you'd put the resistor from the negative lead of the 10u cap where Sw1 connects, and ground. Or you could mount the resistor directly on the switch, from the lug where the input wire connects, to the ground lug for the LED.
So my build sounds kinda weak in the gain department. I measured my transistors and found that my mpsa18's are only measuring around 530hfe and my 2n5089's only 510hfe. Are these hfe's? or is it something else possibly?
ReplyDeleteWell.. I think you have something else wrong in there. That's basically a big muff, so it should be loud as f, regardless of the transistors used.
DeleteIs it loud, or just missing in fuzz?
+m
Sorry I misused the word "gain". It is plenty loud. But it doesnt have as much fuzz as a typical muff. It does have some fuzz, enough that it could be considered a fuzz, but every muff I've played has tons with the fuzz knob at minimum, I'd say this is a light fuzz with the knob maxed. any ideas?
DeleteOk. You could double check the transistor pinouts, as that has been known to cause similar symptoms. Next thing that comes to mind is a wonky component somewhere..
Delete+m
...
DeleteI'm not suggesting that you've got it wrong. I just recall someone tackling with wrong pinout that was causing low volume on some BMP or derivative... So that could be one viable explanation.
DeleteCan't find the post, but there was some confusion how it could have worked at all with transistors in reverse.
+m
So i just noticed that i'm getting more dirt out of the 1n914 side of the clipping switch. and the 1n34a side has a pretty major volume drop. should i be getting more fuzz out of the 1n34a's or the 1n914's? This seems weird because if i'm getting that huge of a volume drop shouldnt they be dropping more voltage and therefore be even more distorted and compressed?
ReplyDeleteGermaniums dump more signal to ground than silicon diodes - making it quieter. So that is working like it should.
ReplyDelete+m
yeh i know germs will drop volume, but doesnt that voltage drop equal more dirt usually? especially with the 3 of em compared to 2 1n914's? i find it strange that the germs have less dirt than the silicons
ReplyDeleteI had a question about the diodes switch and the Highs pot. Do I need to have a wire coming from the PCB "highs 1 & 2" that goes to the diodes switch and then to Lugs 1 & 2 on the Highs Pot?
ReplyDeleteI built this but its unfortunately not working. I was wondering if this might be the issue.
One wire from the diode switch connects to Sw2 marked on the board, the other wire needs to be soldered to lug 1 and 2 of the High pot, or on the board where the High 1 and 2 lug connect. There is a gap to the right of the collector of Q3 so you could solder it there if you wanted to.
Deletesweet man, thanks! fixed it
DeleteI just built this with mpsa18 for Q1 and 5088's for the rest.
ReplyDeleteI get no fuzz :(
all of the knobs and switches seem to be operating properly. Level(volume) and Sustain(fuzz) both act like volume controls anyone have any ideas on what I need to do?
Any help is appreciated thanks much.
Well I fixed it looks like through a combo of a few beers and being tired I missed the 10k resistor that feeds the collector of Q1. I just put it in and sure enough it fired right up. this thing is a beast :). I am currently out of 250k pots for the tone is there a different value that I could sub? Right now I have it wired with a 500k pot with a 470k resistor across lugs 1 and 3. which as I am sure you all know gives a pretty weird taper to the pot
ReplyDeleteI'm having issues with the "high" B25k pot. It has very little effect on the sound and it's hard to believe that's normal operation.
ReplyDeleteIs there anything I can do to make it more pronounced? Different value pot? Caps change? Anything...
The thing is boxed so I can't really experiment but if anyone has a reasonable suggestion, I'll take it apart.
Anyone? It's probably not even a pharaoh-specific question but a tonestack one...?
DeleteI'd check the wiring between the high and the pots to make sure it's solid. If you're after a little light reading on the big muffins tine stack, try this: http://www.muzique.com/lab/tone3.htm
DeleteThat was obviously meant to say Big Muff tone stack. Stupid frickin auto correct.
DeleteWell nothing wrong with the actual wires, I have continuity between the pot pin and the next component on the board so the wires and the connections on the board are fine.
DeleteI'll take a look at your link tomorrow morning. Thanks!
Is there any way to wire the 2 way switch as a stomp switch? I'm sure there is, just asking how and what kind of stomp switch to buy. Thanks guys!
ReplyDelete
DeleteSure thing. Just get a normal 3pdt footswitch, don't use the third pole and wire the other two exactly as pictured.
Make sure you get a latching switch and not a momentary (i.e. get the exact same one you would use for an on/off stomp).
Alternatively, you can get dpdt switches in latching footswitch version and just wire as-is.
This comment has been removed by the author.
Deletei'm getting a loud, high frequency hum when the pedal is engaged, and not a lot of fuzz. plenty loud, but not very dirty, almost muffled (no pun intended), kinda muddy. germ side is almost quieter than unity. any ideas?
ReplyDeleteWhatever happened to the 3position dpdt image? The one I have on file doesn't have the wires coming in on the same lug...?
ReplyDeleteIt doesn't. That happens sometimes with DIYLC because of "sticky points". I hate them! :o)
DeleteI'll update the layout, thanks for the heads up.
Just built the circuit, sounds f*** great but it doesn't fit in a 1590A :P. This one will get boxed soon, really liked the included switching options.
ReplyDeleteBR
Damn, forgot to order 10n caps. Will the circuit crap out if I use 22n instead?
ReplyDeleteMorjens kato...
DeleteThat'll affect the highs and tone controls. I think you'll end up with more middle and bass frequencies. No doubt, it will work.
+m
Teres! Sun kanssa ollaankin kauppoja tehty pariin otteeseen :)
ReplyDeleteThanks for the help! I think I'm gonna socket it and test run with the 22nf and get some smaller ones later on.
Got this thing running and Jesus christ it sounds amazing! By far the best Muff-derived pedal I've ever played. Still waiting for the MPSA18 to arrive, currently using BC108 instead and even now it sounds incredible. Let's see how it changes after I get the MPSA18. Craploads of fuzzy gain on tap.
ReplyDeletesooooo.... i tried to build this like a year and a half ago and could NEVER get it working, which rarely happens with me. I was looking at the board i kept yesterday and thought how the HELL did I mess up this board this badly and not notice it after checking it over like 20 times. this layout has been updated (even though it was supposedly verified when I tried to build it), so is this layout verified?
ReplyDeleteDid you read the post Goran posted above about the DPDT switch? If I remember the edit properly, one of the wires on the switch was attached to the wrong lug which happens sometimes when you move things using V2 because of the "sticky points" feature. It's something that some people may not have even noticed because they are already clear about how the switches are wired themselves and so only looked at the switch layout fleetingly.
Deletei have the original layout saved on my computer and it is quite a bit different. I did manage to get the board that was in the bin working! but it required about 12 changes- 3 new ground jumpers, 3 new cuts, and completely changing what pads teh pots were going to. its all good though, glad i got it working. now to try to implement a tone stack bypass!
DeleteJust checked it and I still had the original version saved. The new version was done purely to add the ground links so you don't have to make two connections. I did this for most of the muff type layouts I did where I omitted the link to keep the column number down.
DeleteThere were a few other things shifted about to make the layout more user friendly (ie the 1K minimum gain resistor moving to the top of the board so you didn't have to add the Sustain 1 wire underneath the link. And a couple of things shifted to accomodate the links plus the main power supply filter cap moving to a better place.
The first layout was still fully working though, nothing was "fixed" with the new one
I feel like this circuit is darker than the actual pharoah. So i started looking into the circuit and I was wanting to add a mids control. The pharoah schematic I found does have the 470k resistor going from lug 3 to ground. But every big muff schematic i've found shows that resistors value being 8.2 to 39k or so... This is the resistor that you replace with a pot to get a mids control. Of course I'm a newb so I'm not sure what the purpose of this is. Just thought I'd bring it up
ReplyDeleteCan i just omit the switches
ReplyDeleteWell you could but it wouldn't be a Pharaoh. That would omit clipping diodes entirely.
DeleteDone two of these and it just keeps kicking major ass. Maybe it's time to shoot for a 1590B build.
ReplyDeleteThis is a 1590B build :P
DeleteYeah, should be no problem at all. I've been lazy and did both into BB's.
ReplyDeleteHi. Layout is much apreciated :) Any advice for a novice trying to squeeze this into a 1590b?
ReplyDeletein regards to placement of components i mean. Im gonna try to fit in a 9v battery as well, but leave out the 9v jack.
DeleteIf you mount the board upside down in the box, and so with the soldering facing you when you open it up, you'll find there's plenty of room to get this in a 1590B with the switches and pots underneath it. Just try to lie the electrolytic and polyester caps to the side to keep the profile as low as possible
Delete:) Thats where my error was. I allready solderet it, before i found out how little a 1590b is (got it in the mail from china). But the only things to tall are the switches, so i guess i will just stuff em somewhere out of the way. Thanks anyway :)
DeleteI built this and omitted the diodes clipping switch. To confirm - I don't need to have the switch 2 wire attached to the board, since I'm not using the switch.
ReplyDeleteI used a 50k pot for the Highs control, it doesn't really seem to do anything. The circuit works fine otherwise...
Correct you don't need the Sw2 connection, and the 470n cap is also unnecessary, but then you have no clipping at all in the second clipping stage. If you've swapped the 25K High pot for a 50K then that is ok too, but you may want to swap the 22n cap at the top left for a 10 or 15n to compensate, and even then the response wouldn't be exactly the same. But even with a 22n still there you should get a noticeable change in the frequency response, so if it isn't doing anything obvious I think there must be an error somewhere or a problem component.
DeleteI used this layout which is older ( I got it from here or FS.org). Is everything still valid on it? It works, but I'm wondering if it sounds as it should...
Deletehttp://i157.photobucket.com/albums/t54/Beedoola/BlackArtsToneworksPharaoh2_zps0698ab25.png
hi, as a silent observer i followed this website since 4 month now. this is such a great website. it gave me a point to start with this kind of box-magic and i always find all kinds of inspiring layouts beside fuzz-units. until now i built like a dozen effects starting from d*a*m designs. and now i finished the pharaoh. it took me a week and it fired up just after i found out that i forgot one bridge. WOW! Thanks to all of you guys!
ReplyDeleteExcellent, glad it worked for you and that you enjoy the site
Deletefinished my pharaoh witch beaten/etched enclosure. it was a pleasure.
ReplyDeletehttps://www.facebook.com/bratislav.methulsky
Looks great, nice job.
DeleteThis comment has been removed by the author.
ReplyDeleteYes the diodes always limit the signal to some extent
DeleteD3 & D4 are 1N4001 on the original pedal ;)
ReplyDeleteEveryone: the high pot only makes a noticeable difference when you have the tone knob set fairly low. It's function is to restore clarity if you're boosting the bass by turning the tone knob down. In some trebly settings you wil hear it do absolutely nothing and this is exactly the way it's supposed to work (i have an original)
ReplyDeleteHave you compared this build to the original? This one sounds much darker compared to the youtube vids of the original Pharoah. Is that the case?
DeleteHI I just finished the work on this pedal. And it works and sounds great.
ReplyDeleteI just notced that if I select one of the two diode settings, the volume goes down.
Is that correct, or Did I meess somethign up ?
Cheers Carsten
germanium diodes will give a volume drop so this is normal.
DeleteSame goes for the 1n914 ?
DeleteDiodes drop voltage by nature. One side of the switch has two diodes arranged in parallel. The other still has a parallel arrangement but one half of that has two diodes in series. This is what's causing your volume differences and is entirely normal.
DeleteHow do I wire the bypass switch in this schematic? It would be great to include this in the picture above.
ReplyDeletehttp://tagboardeffects.blogspot.co.uk/2012/02/offboard-wiring.html
Deletewhy is there no hi/lo switch?
ReplyDeletethe hi/lo input switch???
Deleteit's there.
look in the layout.
Oh, so where's the on/off switch?
Deletethe on off switch is not in this layout. you use the offboard wiring diagram for this.you can find it here
Deletehttp://tagboardeffects.blogspot.gr/2012/02/offboard-wiring.html
those 2 switches shown in this picture are toggle switches.
for the on/off you'll need a 3pdt footswitch
hope i helped
Thanks a lot! Will any led work in d1? And do I wire 9v from adapter spicing them in the wires for the battery?
DeleteMan, 25k pots are rare-ish, can I use a 20k or 50k?
ReplyDeleteI'd use the 20K. What country are you in?
ReplyDeleteThe stores have them but only plastic ones and in my opinion they aren't suitable for a device you sometimes operate by foot.
DeleteNot trying to stalk you btw, just curious because if you're in the US I can recommend about 10 places to buy 25K pots :P
ReplyDeletesmallbearelec.com has just about every pot you'd need
ReplyDelete20K will be close enough though
I am thinking on building this, but twiking it a little bit to suits the "pharaoh supreme"
ReplyDeleteIve got a 6 position rotary lorlin switch lying around, so no problem with the added clipping stages.
The hi/low switch must be replaced by a pot; 500k maybe...¿
Last thing would be adding the extra "high" tone knob that the supreme has, but Im totally lost on this one.
Any ideas¿
Thanks in advance, Gilberto.
There are some other sites on the internet who have a Pharaoh schematic and the say 100µf for the big electrolytic cap instead of 220µf. is there any verification for the 220?
ReplyDeleteIt's just a filter cap so either will be fine and there be no audible difference (unless you get more noise with the 100u).
DeleteAfter some hours of work I finished the Pharaoh project but unfortunately it doesn't work. In bypass mode the signal goes thru but when I switch the effect on there is only white noise. the noise reacts on the level and sustain knobs but there is no guitar signal coming thru.
ReplyDeleteI checked all connections and tracks as written in the Faults text. I just checked the voltage along the circuit. At the end of the circuit at the 10µ cap thats before level 3 there is 5v at the plus side of the cap but at the Level Pot which is last in the circuit before output there is no voltage on all three lugs. Is this normal? What voltage should be there?
Hi there.
ReplyDeleteCapacitors block DC voltage, the whole point of that 10u output cap is to prevent any DC voltage from being present at the output. So there's no problem with that
Also the fact that the bypass works is irrelevant here, because that's unrelated to the layout in question
It's really best to test the circuit out before you wire it into the enclosure, that way you can check that the circuit actually works and you can rule out any issues with offboard wiring
It's difficult to tell anything without looking at your build, but if your knobs are working and you hear noise when the pedal is engaged, the first thing I would check is that your input is making it to the board. Follow your signal path from the tip of your input jack through the circuit and see where your mistake is
It maybe a stupid question, but how do I follow the signal thru the circuit. As you said Caps block the signal. I can't check the signal Path with the multimeter do I?
Deletewhen i check the signal from input jack onwards I have signal (peep sound on the multimeter :) till the input of the first 2DPDT. On the output behind the 39k or 390k resistor there is no signal. Is this normal due to the resistors?
ReplyDeleteBuilt this a few weeks ago and it seems to work as it should, but the sustain knob adds a loud hum as I turn it up. Same kind of hum as when the cable from an amp is not connected to an instrument. Guess it has something to do with the grounding but I can't figure it out. Any ideas? Broken pot?
ReplyDeleteI built this and it sounds great but the tone control doesn't have any noticable effect. Everything else is fine, including the high control
ReplyDeleteCool effect, this has got major balls this one. Used 1N60ps for Ges and the volume drop although still there seems less than with 1N34As.
ReplyDeleteyou're going to get a volume drop with the Ge diodes due to their lower forward voltage.
DeleteHello all! Built this and it sounds great. For me, one of the best si muff type circuits I've built. Tried the g2 but could never get the thing to sound any good:( this has restored my faith in the muff circuits...thnx, all for the help and dedication until we try again:)
ReplyDeleteHi there. I finished my "pharaoh" and everything works except sustain control. I can not fix it for 3 days. Сhanged the wires, checked board, pot "sustain" changed, but nothing helps, what could be the problem? http://smages.com/index.php?group=yqlvh30x images..
ReplyDeleteBuilt it today and everything works perfectly has volume drop on ge setting but if it's such a issue for anyone you know your amp has a volume knob you turn it clockwise and volume increases. It's such an evil vicious sounding fuzz I think my fuzz quest may be over ........ for now.
ReplyDeleteBut all in all used everything in the layout and no problems so it's verified
am i correct that the first switch is basically a pre gain knob but in a switch form? like in the revelation super bass
ReplyDeleteYes
ReplyDeleteWas just building this and noticed that all coupling caps incl feedback caps are shown as 470nf here. Considering Pharoah was a modded clone of Ram's head, which had one 470nf right after Q1 and all the rest were 47nf's. King Tut from Rullywow shows the same. Does anyone know of a link to gutshots of an actual Pharoah to confirm the value of caps?
ReplyDeleteI built this and just noticed the 470nF caps instead of the 47nF-ones too. Since it's a rather old and verfied layout, I guess it should be fine.
DeleteHowever, I do scratch my head over a problem with the diode selector. I know there has to be some voltage drop when those diodes get switched into the signal path but compared to the bypass-position both options decrease my output volume dramatically (maybe in half) and there doesn't seem to be any mids/lows left. There is a strong increase in fuzz so it can't be all that wrong but it's no use without a proper signal strenght. What could be the problem here?
Clipping diodes will cut the output compared to having no clipping diodes, it has to do with the forward voltage of the diodes. Germanium diodes have a lower forward voltage than Silicon diodes. With this in mind with the switch in the Silcion position you will have some drop in output, but no different than a normal BMP, Germanium will have a lower output than the Silicon position, and with the diodes removes you will have an increase in output.
DeleteAs far as the coupling caps, they are correct for the BATW Pharaoh. The schematic used to create the layout was traced from the actual pedal. Additionally, as you both stated it’s a modified Ramshead BMP. Key word in that statement, it’s MODIFIED, not identical. The increased coupling caps allow more bass to pass through the circuit.
I do get that the diodes cause some voltage drop but I'm still wondering if the extent of it in my circuit is really normal.
ReplyDeleteWhen I strum my guitar and measure AC Voltage between the "High"-Pot (lugs 1/2) and GND, I get the following:
Bypass: ca. 4.0VAC
SI-diodes: ca. 0,5VAC
GE-diodes: ca. 0,4VAC
Is that much of a deacrease really to be expected?
No idea, I’ve never measured that. Did you compare your build to demo videos online? Might be a good place to start.
DeleteI've tried that but somewhow all the demos that I've watched, make it look like there's hardly any volume drop at all while, on the other hand, I keep seeing comments of people asking if it's normal that there's a significant volume difference between the diode settings. I know that it is to some extent but my specimen seems too extreme. There must be a fault somewhere. Unfortunately I can't find it.
ReplyDeleteTriple checked the board for errors but it looks ok. It's like whenever the signal is routed through the switch (the working middle position/bypass isn't actually going through the switch, as far as I can see), it lacks further amplification. The switch itself is wired correctly and different diodes don't make a difference. I'm starting to wonder if a bad Q3 could be the cause.
Might be or could be a bad switch or the wrong type of switch. I have an original early model and I can tell you there is a distinct volume drop, as I described above.
ReplyDeleteI can rule out the switch now, even shorting the wires that go to and from the switch causes the signal to go very silent. I also replaced the 470nF film cap between "Sw2" and the base of Q3 but it didn't change anything.
ReplyDeleteDuh... I found the error! It was a missing 2.2k resistor. So much for "triple-checked everything". Now the difference between the diode-settings is really tolerable. Thanks for your replies, Zach!
ReplyDeleteThe original pedal uses a sp3t switch for the diodes. They are jumpered in mid position an both caps are in parallel. You could achieve the same with a dpdt on-on-on and a jumper on the switch
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ReplyDeleteHi friends. Has anyone experienced feedback noise with this pedal? It works and there's good gain but when switch is in Hi position with all knobs kranked there's loud feedback noise when not playing guitar.
ReplyDeleteAfter checking points it seems like feedback appears on collector of MPSA18 and then getting louder after every stage. I've tried another mpsa18 and 2089 but it doesn't help.
I obviously don't need to keep it kranked all the time but this is first pedal built for the last 7 years and I want to make it work as it should. Thank you.
Most probably it's a wiring issue. The strong, low impedance high gain signal gets into the weak, high impedance input signal, via capacitive coupling. Use shielded wire for the input path (jack - switch - pcb). Keep it short, and as far away from the output signal as possible. Sometimes, a jumper wire on the switch causes the problem...
DeleteWhat happens if you place a pedal with a buffered bypass between guitar and Pharaoh?