Author Topic: Klon + Boost  (Read 133 times)

Mixa

Klon + Boost
« on: April 08, 2021, 04:24:04 AM »
Yet another experiment gone south, sorry guys 😀

Basically, I tried to implement this simple boost circuit:



into my Klon clone, between R2 and the opamp.

Doesn't work 🙂 no sound with pedal on or off



antonis

Re: Klon + Boost
« Reply #1 on: April 08, 2021, 06:04:11 AM »
between R2 and the opamp.
Doesn't work 🙂 no sound with pedal on or off

1. No bias (+4V5) for U2A non-inverting input (pin 3)..
2. Delete R2 on "boost" circuit..

Mixa

Re: Klon + Boost
« Reply #2 on: April 08, 2021, 06:51:01 AM »
between R2 and the opamp.
Doesn't work  no sound with pedal on or off

1. No bias (+4V5) for U2A non-inverting input (pin 3)..
2. Delete R2 on "boost" circuit..

Yes, I get it, thank you! All in all, I'll be better off inserting the boost after (or before) the R1... Maybe even after the C1 because the C1/R2 HP filter doesn't really affect the sound, it is below the audible spectrum.
Then again, I'll place it after (or even instead of) the R1, because in that case I can remove the 100n from the boost circuit... just thinking out loud :-) :-)

« Last Edit: April 08, 2021, 07:03:21 AM by Mixa »

antonis

Re: Klon + Boost
« Reply #3 on: April 08, 2021, 08:07:41 AM »
Although it should be better to place booster after U2:A, it should be complicated a bit so implement configuration below :


Mixa

Re: Klon + Boost
« Reply #4 on: April 08, 2021, 09:48:04 AM »
Although it should be better to place booster after U2:A, it should be complicated a bit so implement configuration below :



Wow, thank you Antonis, much appreciated!
Of course, I would like to learn about the reasons for the modifications you made to the boost circuit, so if it is not very complicated, please :-)

antonis

Re: Klon + Boost
« Reply #5 on: April 08, 2021, 10:32:24 AM »
1. There is no need for R2 (100k) in practical circuit..

2. By implementing 2k2 Source resistor, you obtain a more stable bias (due to its negative feedback action) and by implementing 4.7μF Source resistor bypass cap you obtain maximun stage gain..

Of course, 6k8 and 2k2 reesistor values are arbitrary somehow 'cause you'll have to trim them according to your very particular J201 item.. :icon_wink: