I owe you pint or whatever your poison is. Your video was not only as informative as it could possibly be but your breakdown of the circuit gave me a breakthrough on understanding the flow of energy through the circuit. I am indebted. Greetings from St. Louis
Excellent stuff. Thanks :) ... It also increased my own understanding of the circuit too. I'm planning on making one on the transistor-based EHX BMP soon, it'll be several parts , but the output stage is basically the same as the LPB-1 and the other three stages are similar.
@@MusicTechknowledgy I will be tuned in! I have decided to cut my teeth on this circuit and the rest of EHX's 1969 offerings - high boost, low boost and Muff.
tremendously informative video. it's a bit above and beyond my scope at the minute but i will rewatch it a few more times and take some notes. thanks again for the in depth explanation and analysis.
I built one of these after I built myself a Fuzz Face, since I had all the parts. Well, I just used some common transitors, the 2n2222a, I believe. On the Fuzz Face, I used a BC109C in Q1 and 2n2222 in Q2, IIRC. The 109C has something like 800 hfe. I've swapped it with 2 of the 2n2222a's but I don't remember it sounding much different. Guess it's time to pull it out and get it going so I can swap those out and see what it sounds like again. Unfortunately these are both on breadboards. I've tried using a couple of different types of thru hole boards to solder the circuits up but I never can get them to work. I tried the one with separate dots for each hole AND the boards with solid copper connecting every hole in a column so theoretically you should only have to cut traces and not solder each hole to each hole like the single hole board.
Nice combo on the Fuzz Face driving that second stage. BC109 is a good choice, I have some metal can style BC109C (and 108s) in the the growing stash of transistors ... at the other end of the scale. I also have some leaky GE Soviet era one's with hFE of 35.
This video helped me a lot. If I were to make a real pedal with this, what should the capacitor values be for C1 and C2? What value potentiometer do you recommend for RV1? Thank you!!
In the original pedal they are both 100nF and the potentiometer is a 100K A type. I’d start with those. A linear pot will also work on the output but give a slightly different response. Changing the values changes the frequency response - th-cam.com/video/Abb0t9PWKEI/w-d-xo.htmlsi=ASjw9nDxIqbXkgh4
Hi, for calculating Vbias how did you work out the base to emitter voltage drop of 0.6v? I can't see how you got to this figure in the video. Thanks and hear from you soon.
Excellent question. 0.6 to 0.7 volts is needed to turn on the silicon PN junction in the transistor. Just like a silicon diode. I just chose to use 0.6 volts in this example. Also worth knowing that Germanium is lower at around 0.3 volts.
Ok, thanks for letting me know. I have built a couple of these boost circuits from pcbs and recommended components. But I wanted to use different resistors to reduce the voltage gain.
@@johnr7303 Decreasing the value of RC will decrease the amplification, increasing RE will result in less gain. Try 1k as RE for a gain of roughly x10 Also note that in some common emitter circuits RE is (AC) bypassed using a capacitor in parallel with RE, and doing that massively increases gain, as the emitter is then effectively grounded for AC signals.
Hi, I wanted to use a smaller sized door bell type battery that has 12v instead of the larger and more common 9v battery. Would this work or would all of the resistors need changing for different values? Thanks John
Feeling a little bit overwhelmed by the math and science of it all upon my first watch. As a complete beginner, does it get easier as you go? Hoping eventually that it just clicks
Hi Allan, Firstly, that feeling is completely normal. I very often feel that way too, especially researching these videos and trying to get my knowledge to a point where it's good enough to try and show others. It does get easier though. A few years ago I didn't fully understand all the technical stuff myself, but I still built loads of pedals by copying designs I found on the internet and that actually helped loads. My advice is just to stick at it, the passion for making pedals is the key thing and the science clicks eventually. Plus, I'll be making some more videos aimed at beginners soon too 👍.
@@AllanHathaway Great question. Resistors come in "preferred" values based on a series of values called the "E Series". The E24 series is most common these days. So in that part when I calculate 400 ohms for the Emitter Resistor but pick a 390 ohm resistor, it's because 400 ohm is not in the E24 series but 390 ohms is (and 430 ohms is also an E24 vlaue, but 390 is closer to 400).
![[TH] FS vs BME - VCT Ascension Pacific - Lower Bracket Final](http://i.ytimg.com/vi/wnygqsR2Fig/mqdefault.jpg)
I owe you pint or whatever your poison is. Your video was not only as informative as it could possibly be but your breakdown of the circuit gave me a breakthrough on understanding the flow of energy through the circuit.
I am indebted. Greetings from St. Louis
Excellent stuff. Thanks :) ... It also increased my own understanding of the circuit too. I'm planning on making one on the transistor-based EHX BMP soon, it'll be several parts , but the output stage is basically the same as the LPB-1 and the other three stages are similar.
@@MusicTechknowledgy I will be tuned in! I have decided to cut my teeth on this circuit and the rest of EHX's 1969 offerings - high boost, low boost and Muff.
Aaaaayyyy been waiting on this one
tremendously informative video. it's a bit above and beyond my scope at the minute but i will rewatch it a few more times and take some notes. thanks again for the in depth explanation and analysis.
I built one of these after I built myself a Fuzz Face, since I had all the parts. Well, I just used some common transitors, the 2n2222a, I believe. On the Fuzz Face, I used a BC109C in Q1 and 2n2222 in Q2, IIRC.
The 109C has something like 800 hfe. I've swapped it with 2 of the 2n2222a's but I don't remember it sounding much different. Guess it's time to pull it out and get it going so I can swap those out and see what it sounds like again.
Unfortunately these are both on breadboards. I've tried using a couple of different types of thru hole boards to solder the circuits up but I never can get them to work. I tried the one with separate dots for each hole AND the boards with solid copper connecting every hole in a column so theoretically you should only have to cut traces and not solder each hole to each hole like the single hole board.
Nice combo on the Fuzz Face driving that second stage. BC109 is a good choice, I have some metal can style BC109C (and 108s) in the the growing stash of transistors ... at the other end of the scale. I also have some leaky GE Soviet era one's with hFE of 35.
This video helped me a lot. If I were to make a real pedal with this, what should the capacitor values be for C1 and C2? What value potentiometer do you recommend for RV1?
Thank you!!
In the original pedal they are both 100nF and the potentiometer is a 100K A type. I’d start with those. A linear pot will also work on the output but give a slightly different response. Changing the values changes the frequency response - th-cam.com/video/Abb0t9PWKEI/w-d-xo.htmlsi=ASjw9nDxIqbXkgh4
Hi, for calculating Vbias how did you work out the base to emitter voltage drop of 0.6v? I can't see how you got to this figure in the video. Thanks and hear from you soon.
Excellent question. 0.6 to 0.7 volts is needed to turn on the silicon PN junction in the transistor. Just like a silicon diode.
I just chose to use 0.6 volts in this example.
Also worth knowing that Germanium is lower at around 0.3 volts.
Ok, thanks for letting me know. I have built a couple of these boost circuits from pcbs and recommended components. But I wanted to use different resistors to reduce the voltage gain.
@@johnr7303 Decreasing the value of RC will decrease the amplification, increasing RE will result in less gain. Try 1k as RE for a gain of roughly x10
Also note that in some common emitter circuits RE is (AC) bypassed using a capacitor in parallel with RE, and doing that massively increases gain, as the emitter is then effectively grounded for AC signals.
@@MusicTechknowledgy thanks for the heads up on this. John
Hi, I wanted to use a smaller sized door bell type battery that has 12v instead of the larger and more common 9v battery. Would this work or would all of the resistors need changing for different values? Thanks John
Hi John, 12V is well within spec. of a 5088, so the bias would change slightly but it will absolutely still work.
@@MusicTechknowledgy thanks very much for the quick reply. Much appreciated. John
Feeling a little bit overwhelmed by the math and science of it all upon my first watch. As a complete beginner, does it get easier as you go? Hoping eventually that it just clicks
What makes some values “not preferred”? I may have missed something
Hi Allan, Firstly, that feeling is completely normal. I very often feel that way too, especially researching these videos and trying to get my knowledge to a point where it's good enough to try and show others. It does get easier though. A few years ago I didn't fully understand all the technical stuff myself, but I still built loads of pedals by copying designs I found on the internet and that actually helped loads. My advice is just to stick at it, the passion for making pedals is the key thing and the science clicks eventually. Plus, I'll be making some more videos aimed at beginners soon too 👍.
@@AllanHathaway Great question. Resistors come in "preferred" values based on a series of values called the "E Series". The E24 series is most common these days. So in that part when I calculate 400 ohms for the Emitter Resistor but pick a 390 ohm resistor, it's because 400 ohm is not in the E24 series but 390 ohms is (and 430 ohms is also an E24 vlaue, but 390 is closer to 400).