DIYstompboxes.com

DIY Stompboxes => Building your own stompbox => Topic started by: BetterOffShred on March 23, 2018, 08:42:18 PM

Title: Want more volume on 78 Opamp Big Muff
Post by: BetterOffShred on March 23, 2018, 08:42:18 PM
Yeah so like the title says, I built a 78 opamp Big Muff using the tagboard layout, the uA741/4558 and tone bypass switch.  It's pretty loud, but not _really_ loud.. is the 741 stage controlling the overall max signal being sent to the tone stack and then volume?  What options are there for boosting output? I attached the schematic that the layout is based off, and all the notes about dotted line recommendations are taken into account.

(https://s9.postimg.org/8ak8d4grf/7fd0c4491aa83b8fe0acd5299604148f.png) (https://postimg.org/image/8ak8d4grf/)

So yeah just looking to boost output volume without stacking a boost or something.  Any ideas?  :icon_mrgreen:
Title: Re: Want more volume on 78 Opamp Big Muff
Post by: Derringer on March 23, 2018, 10:46:02 PM
I had the same issue with the one I built. It's not a loud circuit.

You could start by getting rid of R16, it's chopping of a smidge of volume and is superfluous anyway.
I think I got my volume a little more reasonable with a 500K volume pot.
A 500K volume pot will let some more low end through though too, so you may or may not like the tonal change.

Otherwise, you could try bumping R13 up, but I don't think it would make all that much of a difference since that stage is pretty maxed out. If you did bump it up, you might have to reduce C9 to get the same low pass characteristic.

Mine is a Frankensteined version of this, but I believe I did give in and just tacked a fet booster onto the end.

Title: Re: Want more volume on 78 Opamp Big Muff
Post by: BetterOffShred on March 24, 2018, 12:10:32 AM
Cool man thanks for sharing.  Yeah it's fantastic tone-wise, I'm super pleased but it barely pushes my amp. I will fool around with these ideas.  Thanks again :)
Title: Re: Want more volume on 78 Opamp Big Muff
Post by: BetterOffShred on March 24, 2018, 01:06:52 AM
I think I may just bypass the volume pot and run it straight into a Majikbox venom boost.  Then it'll have serious amp crushing power.     And jettison the superfluous 100k to ground there as mentioned above. 
Title: Re: Want more volume on 78 Opamp Big Muff
Post by: duck_arse on March 24, 2018, 09:55:28 AM
in the "tone bypass" position, R18 and R19 form a volume control, set half-way. probably to match the level from the tone stack, but if you want volume over toans, reduce R18 or increase R19
Title: Re: Want more volume on 78 Opamp Big Muff
Post by: BetterOffShred on March 24, 2018, 10:00:49 AM
Ok that's good information.  I would like the bypass to be a bit louder.  I'll mess that with :)  thanks much sir!!
Title: Re: Want more volume on 78 Opamp Big Muff
Post by: BetterOffShred on March 24, 2018, 12:16:50 PM
So I whipped up a venom boost, and ran it in series after the volume pot, but instead of having the volume pot on the venom I put 2 resistors on a toggle, so you have loud and then throw the toggle and Loud AF.  Pretty happy with how it sounds.  Thanks for the  help guys  :icon_mrgreen: