" Powerful, rich, good treble detail"
• 35 dB gain
• Punchy rich sound
• Balance between fatness and treble definition
• Evokes the BM sound of mid 1970s Queen albums "Sheer Heart Attack", "A Day At The Races" and the Brian May 1980s live concert sound.
Adding volume control to the output may be worth a try... (that's 100K log pot, board output to lug 3, lug 2 is your new output and lug 1 to ground...)
Would anyone have a guess how this would go with a BC249?
ReplyDeleteWell, tag it :P Works fine. Not really fond of treble boosters, but I liked the "original" concept of this one: no switch, no control pot, always on between your guitar and amp.
ReplyDeleteNice ffect to emaulate Brian May... if you have a VoxAC30 too, of course :P
BR
Excellent, nice one mate
DeleteYou're welcome!
DeleteJust a question, any special reason to use 2x 10pF instead of just 1x20pF?
BR
* a 5pF I mean
DeleteNo idea :) That's just how the original has it.
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JaviCAP- sometimes it is easier to ask than to waste time and resources building :p
ReplyDeleteAfter comparing datasheets and getting no useful reply here, I built it using the lowest rated 249 I had, and it needs a 239.
Dennis,
DeleteIf I'm not wrong, the BC249 does not exist, or l least, I can't find not the slightest reference anywhere.
The only one I've foound info is the BD249, and this one is a power transistor. If so, it hardly can work on this circuit.
Are you sure that you hace a BC249?
BR
I don't know what resources you're using, but I've got a bag of them, they're used in a lot of projects, and the first three results in Google are datasheets. Thanks anyway.
DeleteYou only get a useful reply Al / Dennis if one of us knows the answer. When it comes to suitability, as long as the transistor you're using are the correct polarity then give it a go. But like Javi I've never heard of it either, and the first 3 results on google aren't datasheets, the first two "imply" there is a datasheet but there isn't one when you go to the page linked. Alldatasheets shows a number that contain the characters "BC249" but one is a burst fire controller and the other three are solid state relays, and datasheetarchive are just material lists which contains reference to the BC249 but no information about them.
DeleteThis site encourages DIY absolutely, and that will often include trying things to see if they work and certainly finding your own datasheets if you need to refer to them.
Are their alternative transistor options for this? I haven't any BC239...but some 2N5088/89 and some other general purpose...are they interchangeable? I'm still gathering my knowledge on transistors :)
ReplyDelete2N5088 or 2N3904 will be fine. You could try any NPN Si transistor in there. Just mind the pinout. 2N transistors are more commonly EBC, while BC ones are CBE.
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Thanks Miro,
DeleteSo I'm trouble shooting this thing with a probe...and it's blowing my mind that I'm having issues with what should be pretty straight forward. I get audio signal from the both ends of the 6.8nf and the 1K but only from the top of the 100K and 1nf. The 2.2k, the 22k, and the 47uf all have signal at the top but none at the bottom and there's no signal getting to the right side of the board...my traces and cuts appear to be fine, ran a razor between the lines and reflowed...any idea what might be causing my signal to die off?
My bad - the 2.2, 22, and 47 DON'T have signal at all, top or otherwise.
DeleteSo you don't have a signal on the base of the transistor? Usual suspects would be wrong value or one component place to wrong holes. You should be getting the signal to the base via that 1K resistor. Then it should come out amplified at the collector...
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Man! I've been all up and down this thing and it's killing me...resistor values check out, caps checkout, placement checks out...the signal gets to the Base, but doesn't go from the Emitter or Collector...I'm just going to build a second one from scratch and see if that works then go back and follow that signal path.
DeleteAre you sure about the transistor pinout? What voltages are you reading on base, emitter and collector?
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I checked the datasheet for direction...I switched direction just to be sure. The datasheet showed CBE would be the flat of the 2N3409 facing right according to the layout. I made a second and it's doing the exact same thing...I must be making one incredibly obvious error or something, but appear to be powerfully oblivious to it. The voltages all read in the same area but I'm not sure if I'm doing it right. I socketed the transistor...that wouldn't matter right?
DeleteNo. It should work as intended with a socket.. You should not have the same voltage on all the transistor pins...
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Hello, have you fixed that issue? I just built this, checked like 200 times everything. But with volume on guitar maxed, I only get clean sound. Tried different trannies, checked resistors. Everything seems to be fine :/ I built much harder projects, but this simple one is somehow mystic :D
DeleteThanx
Done qnd working, I used a BC550C. It works and boosts well, although I find it's non properly a treble booster, high frequencies are not so clear as expected. Maybe a capacitor, I used a 47uF in place of 33uF:-(
ReplyDeleteI've just built this and it sounds fantastic! Many thanks!
ReplyDeleteI built a version of this recently, but using the layout of the Brian May Boost from Paul in the Lab. I substituted a 10kA pot for the 6.8k resistor, similar to the GGG Brian May Boost or a Rangemaster. I also used a NOS BC182L as in the original Brian May schematics. It worked OK but distorted a lot when the guitar volume was up all the way, and not in a good way. The hfe of the BC182L was around 160, which seemed reasonable, but I experimented with higher and lower gain parts. I finally settled on a 2N2369 with hfe around 55. Sounds great now, with a bit of grit when the guitar is up all the way. Good grit. The slope of the roll-off doesn't seem as steep as other treble boosters, so it doesn't sound as thin.
ReplyDeleteI added a switch so I could disconnect the 180k and 4n7 from the output, to be more like the original Brian May boost. These parts filter out some of the fizz when the circuit is driven hard, but disconnecting them adds a bit of sparkle when the signal is clean. This switch would go in place of the far right jumper on this layout.
Do the value of the electrolytics really matter? Or are they just filter caps?
ReplyDeleteNo. Those are just ripple filters. 1x 100ยต should be just fine. Circuits like these are usually prone to supply ripple noise..
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Okay cool. Two things, the 10pf caps, can those be omitted? I can't find any laying around and this is the only layout I've seen with those included! Also, would a 2n2222 be the best option for the transistor? Works well in the naga viper... I do also have BC108's, 2n3904, 2n5088, and a few others...
DeleteThey're included to filter some noise out of your input. You can change the top left cap to a link and just use a small value cap for the right one. 33pf e.g.. OR leave them out altogether and see how it sounds but being a treble boost it's probably worth putting something in there.
DeleteAs for your transistors...use a socket, mind the pinout and go to town. Thats the joy of DIY.
Good luck
So to omit them would I just leave them off? Or jumper the top left one?
DeleteYes you can just omit them and it'll work fine. But if you want to add a single cap instead of 2....replace one of them with a link/jumper and the other with your desired cap value. Doesn't matter which.
DeleteWould you all recommend BC239B or BC239C? Thanks!
ReplyDeleteI honestly suggest using a trimmer instead of 22k. Something like a 100k trimmer.
ReplyDeleteAnd use it to get 7v on the collector of the transistor you choose.
Also, I would suggest using a socket, and after that you can tune your own booster.
As for bc239 and bc238 they are easily obtainable in my country.
And bc 184 is very similar to bc239>
I am currently using AC187 ( germanium NPN ), 7,01v on a collector. Beautiful, rich sound. Not as grainy as the youtube videos, but it is very nice and nasty <3
I don't have a lot of knowledge about electronics but I get the basics. I'm more of a tinkerer who succeeds in making a plan.
ReplyDeleteI've built a fair amount of OD's over the past five years, all in good working order.
This built however doesn't really feel right, despite the simplicity of the lay-out. I've built this one twice but it is very noisy
I've got an awful lot of hum when I'm not playing. It's the typical 50Hz/100Hz hum with some added overtones. So I guess there's a problem with the ground?
I'm playing it through a completely cranked AC30 like BM would do, but I have the same problem with all my amps
Is there any way to resolve this issue? At first I thought that it was inherent to this booster, but then again, no one would really use it. Further more, there's a simulation of a BM trebble booster in my Helix(the original range master and this one should be an upgraded one, as far as I understand) and that one is almost free of any noise
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DeleteJust finished this one up yesterday. Added the volume control, and used the suggestion from a user above and replaced the 6.8k resistor with a 10k pot wired as a variable resistor. Works like a charm. Basically gives volume and gain control over the circuit. Put it into a slightly broken up 5e3 and got some great sounds.
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