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DIY Stompboxes => Building your own stompbox => Topic started by: RDV on November 13, 2004, 08:27:23 AM

Title: How do you reduce gain in inverter stages?
Post by: RDV on November 13, 2004, 08:27:23 AM
...like in the Double D's Bounce channel? I'd like to make it a touch less bouncy. What I don't know is whether the resistance across the inverter  should increase or decrease for less gain.

RDV
Title: How do you reduce gain in inverter stages?
Post by: Nasse on November 13, 2004, 09:00:59 AM
feedback resistor smaller or input resistor bigger I would say puts gain down

(does the stage have an input resistor :oops: )
Title: How do you reduce gain in inverter stages?
Post by: B Tremblay on November 13, 2004, 09:05:20 AM
So, you want to throw a corset on her?

The inverter stages work pretty much the same as inverting op-amp gain stages - reduce the feedback resistance for less gain.  Try a 270k in the first stage and if that doesn't do enough, you could also reduce the second stage to 180k.
Title: How do you reduce gain in inverter stages?
Post by: RDV on November 13, 2004, 09:11:13 AM
No, actually a breast reduction!

Thanks a bunch! It's funny how little info there is on this on the web.

RDV
Title: How do you reduce gain in inverter stages?
Post by: RDV on November 13, 2004, 10:11:48 AM
I put a 220k in the first stage and viola! A perfect 36C!

RDV
Title: How do you reduce gain in inverter stages?
Post by: B Tremblay on November 13, 2004, 11:03:04 AM
Beautiful!  You know, they say more than a handful is just a waste...
Title: How do you reduce gain in inverter stages?
Post by: WGTP on November 13, 2004, 11:42:44 AM
I thought it was mouthful.  I never believed that anyway.

Rick you were talking about fizz reduction in another post, you can increase or decrease caps in the loop to deal with that as well.   8)
Title: How do you reduce gain in inverter stages?
Post by: RDV on November 13, 2004, 11:56:28 AM
Quote from: WGTPI thought it was mouthful.  I never believed that anyway.
Rick you were talking about fizz reduction in another post, you can increase or decrease caps in the loop to deal with that as well.   8)
Well, more than a double handful is wasted anyways. :wink:

I was just comparing the Double D to the Thunderchief, and there's a whole lot more treble to the Double D. I've not tested either one on the big amp yet, so I'm wondering if I'll be able to use either one of them with my rig. I left a space between the 4 pots on the DD for a Tone control if need be and with as much output as it has I don't think there'll be any problem there. I'd rather include a tone control than put non-adjustable filtering on there cause it sounds so good with the Ruby I'd hate to lose that. A tone control like I just put on the HMP5 would be good cause at 0 there would be no filtering at all. The fizz isn't that bad really, there's just a lot of high-end.

On the Thunderchief, I'm gonna test it with the Marshall before I change anything as it might be just fine as is, if it needs changing I'll remove one of the filters at the end.

RDV
Title: How do you reduce gain in inverter stages?
Post by: WGTP on November 14, 2004, 01:29:49 PM
I meant to add that changing the resistors in the loop also changes the roll off frequency of the caps.  If you half a resistor, it doubles the roll off freq and if you double the resistor it halves the roll off freqency.  You probably already knew that.   8)
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