But as a beginner (some knowledge left over from school), I'm having a bit of trouble getting parts together. I've been trawling the internet and tutorials etc. but I'm finding it ever so slightly overwhelming
So the capacitors I need are: 4.7nf, 47nf, 1nf, 47uf, 22nf and 5nf. I've searched on Maplins and such places, but it seems like there are a lot of different types to choose from. There are a few below that I've come across, but I'd just like to know if they would be suitable for this circuit? I'm just worried that I'll put it all together and then find that although they're the right values, they're the wrong type. Here are some I'm considering for 4.7nf:
Are you planning to build the strip/vero layout exactly as shown on that blog? If so, you'll need to choose not only the right type that will work, but also a suitable size to drop easily into the layout. You've got two "types" of cap in that layout: The small, nanofard (nf) value ones (all green in the stripboard layout), and a large microfarad electrolytic cap (47uF). The electrolytic has to be a radial type (i.e. both leads sprout from the same end of the barrel-shaped capacitor body) to fit the layout, and has to be a polarised (i.e. has a positive and negative terminal that is shown on the layout) electrolytic type to fulfil the job required of it. The nanofard value caps can be one of several unpolarised types: I like polyester "box" caps since they tend to have their value clearly printed on the large-ish body. However, that layout has three out of four of those caps spanning only two holes: Box caps naturally span three holes, so would require some fiddly lead-bending to make them fit, and would be a bit clumsy and untidy. I'd therefore choose ceramic disc capacitors which span two holes, or three with a minimum of fuss.
I can't read the datasheets for the caps you've listed to check the lead spacing (5mm is three holes, 2.5mm is two holes) on my phone, but the first one I looked at would certainly work (electronically) for the 4n7, but at 38p is probaly five to ten times what I'd want to pay. Unless you're wedded to the idea of buying from farnell, I'd get the parts from http://www.bitsbox.co.uk, http://www.doctortweek.co.uk or somewhere similar. They are way cheaper, and because they carry a smaller range, aimed more at the DIY-er, it's far easier for the newby or intermediate builder to find what they need and what is suitable.
modman wrote: ↑Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...
OK, I've had another look on my computer at the layout: Be aware that although C1 is 4n7 and 6 is 5n, in practice you'll usually not find 5n, and might as well buy 4n7 for both.
modman wrote: ↑Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...
Thanks so much for the reply! You've actually just cleared up an awful lot for me. I was just about to ask about the 5n as I couldn't find one anywhere, so I'll do as you say and get two of the 4n7s.
And those links are exactly what I've been looking for. Suddenly almost all of the bits and pieces I need are in one place! I think I'll order just about all of it from Bitsbox tonight. Do you know if their enclosures include the screws?
Just before I place the order, what would the benefits of trying different transistors be? The vero layout recommends the 2N4401 and the 2N5088, so I'll probably get one of each and try them both. But if for example I was to choose another transistor and put it in the circuit, what would happen? My trouble s that I'm eager to experiment but I lack the knowledge to really know how
Thanks again for the help, I at least feel like I'm heading in the right direction now!
Also one more thing, what is the ideal voltage for the 47uf Electrolytic capacitor? I have a choice of 10V, 16V, 25V, 63V or 100V. What difference will the voltage make, and which would be most suited to this circuit?
For a 9 volt circuit like this, 16v gives enough of a safety margin, 25v would be plenty. You're best off ordering parts rated for at least 20% higher than your expected working voltage (some power supplies put out a bit more than advertised) but don't go mad: Bigger rating means bigger components, the 63v are probably quite chunky parts and might not fit easily on the vero.
2N5088 and 2N4401 are both middle gain silicon npn transistors. They will sound pretty similar, if not indistinguishable in that circuit. If you had a three or four transistor fuzz circuit, the difference between using two different types might be exaggerated to the point where you could actually hear it, but then again, a filthy fuzz circuit might also hide component differences... You could try a 2N5088 for medium gain, a 2N2222 for low gain, and a BC109c (my favourite) for high gain. Generally, with simple booster and fuzz circuits, you can often try any silicon npn you've got to hand, and you will get pretty much the right sound. Some circuits are picky about hte gain level of transistor used, but here at FSB, that information will often be posted alongside a layout/schematic. In this circuit, the transistor is set up at a fixed "amplification level": The guitar signal goes in at the base (middle pin of the transistor), it is boosted by a large-ish amount, sent out throught the collector (upper pin) and the volume control acts as a voltage divider on the output to set the amount of boosted signal that is allowed through to the output. Changing transistor type will likely just affect the maximum boost level available, although if the transistor introduces some dirt to the signal itself, different types may clip more easily. Buy all three, use a socket and you can swap them around to find out.
One word about pinout: You should always look this up before you solder a transistor in. Different tranny types have different arrangements of pins - The 2N5088 AND 2N4401 have the pinout arranged so that layout is perfect, i.e. flat side faces the right as you look down on the top (i.e. non-copper side) of the vero. Other types have the pin-out reversed, or different again. The BC109c/2N2222 are both metal can types, so they don't have a flat side: The emitter has a metal tag next to it: This pin would need to go at the bottom of the three holes.
If I was going to tinker with the circuit, I might start by fiddling with the input cap values on the switch: The bigger the cap, the more low end is allowed through. The layout doesn't specify the type of switch: You could use a simple DPDT on-on type, which would give you an input capacitor size of 9.4n in one position (4n7 with 4n7 in parallel = add the values) which is a fairly small value and is going to give treble boost, or 26.7n in the other position (4n7 + 22N), which will be a bit fatter. If you get a three position on-off-on, you'll get 4n7 (centre/off), 9n4 and 26.7. See which sound you like, and maybe try swapping the 22 for a 100n for a full range boost.
modman wrote: ↑Let's hope it's not a hit, because soldering up the same pedal everyday, is a sad life. It's that same ole devilish double bind again...
Ahh brilliant, thanks so much! I've gone for the 25V. For the transistors I've ordered a few you suggested and I'm going to pick up one of the sockets from eBay.
This reminds me of when I first started tinkering with guitars, its getting exciting! I can see this turning into another hobby. I think I'll stick around!
Sorry to reopen this post but I too am a novice who can use a soldering iron and I have also decided to build this treble booster. Firstly, thanks for the advice given as it has helped me out a great deal too. Anyway, I have put the circuit together as per the instuctions and it works really well. But, I am getting a ground loop type buzz that disappears when I roll the guitar volume off. I have tried an assortment of guitars, leads amps etc but the result is the same. I've double checked the negative link and it seems fine but I did, as suggested, use the bc109c transistor. Could the extra gain be causing the hum?
It buzzes on the clean channel aswell so I know its not an overdose of gain thats causing it.
HELP!!!
Paul
Is the circuit in a metal box ? This helps to screen it from radiated noise (eg, from fluorescent lights, transformers, etc).
You mentioned "an assortment of guitars" - does that include humbucker equipped ones ? Single coils are very susceptible to noise.
I have a varriable temperature soldering iron that radiates all kinds of crap into my guitar pickups. The noise disappears when I turn off the iron. Try turning off everything that's not needed for the testing.
The extra gain from the 109C will be amplifying the noise a bit more, but you need to eleiminate the source of noise before chucking out the transistor (he's only doing his job)
”Sex is great - but you can’t beat the real thing !” - The Wanker’s Handbook
Thanks for your reply.
I tried it with both style of pickups and I even stood in another room.
The chassis is metal but it has a plastic top (which holds the pot and switch) as its being wired into a customized pedal board but I sent all of the grounds to the chassis and then earthed the pot itself.
I'm preparing to strip it down tomorrow and trace the problem a stage at a time.
Thanks for your advice
Ok, I sorted the problem and it sounds sweet but, I want to connect it to my dc daisy chain but the booster just squeals when I try that. Battery powered is fine but I don't want to keep relying on batteries when other pedals on my board are mains powered and have no problems. I have followed the various wiring diagrams for a dc input and it makes no difference. Would it help if I changed R1 (100r) to a bigger resistor because I assume that one is a power drop? Like I said earlier I am a beginner so dumb it down for me
