### Author Topic: Will this boost circuit work with 12v?  (Read 131 times)

#### halloy

##### Will this boost circuit work with 12v?
« on: February 23, 2021, 01:05:30 PM »
Hi guys. I'm a complete noob to DIY stompboxes and I'm trying to make a built-in boost circuit for a tube radio which I've converted to an amplifier. It gives away a pretty nice clean tone at the moment but I'd want to be able to make it break up a bit more.

So I found the following video and ordered all the parts: https://www.youtube.com/watch?v=ANkNvOFgYKk

However, for various reasons I only have access to a 12v DC power transformer, and no possibility of getting a hold of a voltage regulator before thursday (for when the project needs to be finished).

So my question is, will the circuit function on 12v instead of 9v? What do you think will happen? I couldn't find a circuit diagram but I will post a print screen of the video showing the connections. I know I could use a 9v battery of course but it would be sub-optimal in this case. Thankful for any help.

#### Mark Hammer

##### Re: Will this boost circuit work with 12v?
« Reply #1 on: February 23, 2021, 01:25:38 PM »
Yes, it should work just fine.  Although I suspect the 830k resistor in the parts list is a misprint and should probably be 820k.

#### antonis

##### Re: Will this boost circuit work with 12v?
« Reply #2 on: February 23, 2021, 03:23:35 PM »
IMHO, with values shown it should be misbiased (saturated) for 12V PS..
(sorry Mark..)

{[(12*100k/920k) - 0.65] / 360}*10k = 18V drop on Collector resistance..

Replace 830k with 1M and 360R with 680R..
(results into 23dB instead of 28dB gain which is more sensible for a booster..)

"I'm getting older while being taught all the time" Solon the Athenian..
"I don't mind  being taught all the time but I do mind a lot getting old" Antonis the Thessalonian..