Mini-mixer new thread

[garfo]

I've built a simple mixer from GGG and I want to make some changes in order to make it sound as I would like.I've built the minimixer from GGG.
Basically I want to run two signals at the same time.One signal is clean(bass); and the other one is Turbo Rat.What I get with the stock project is some bass loss and definetly a lot of difference of volume between processed and unprocessed signal.My idea was to change the 100nf caps that come after the 10k pots to 330nf to let more bass in.
Second is to increase level on the clean channel.Well, this is where things get rusted in my head.I've read in forums that raising the pot to 500 or even 1M plus raising the 100k resistor to match the raising of the pot would do the trick.But in my mind it doesn't make much sense.And also I think that on the schematick the cap and the resistor are creating some kind of filter(are they???).
Maybe someone can help figuring out what is the best way of raising volume and bass response and not loosing treble either?

Here's the link to project:http://www.generalguitargadgets.com/projects/15-boostersrouters/68-mini-mixer-project

[garfo]

Anyone please!?

[jtn191]

yeah try raising C1-C4 depending on which inputs you're wanting to have more bass. Play around with values until you get something that sounds good.

And GGG says

The value of R10 can be lowered to increase the overall gain of the mixer.

[garfo]

Yeah, that I know, thanks.The thing is, I want to only raise one of the outs since I'm blending clean signal with distrted signal.So, baring that in mind, r10 is not an option.

[stecykmi]

basically any time you have a series capacitor, like the 0.1uF caps, you're forming a high-pass filter (a capacitor has high resistance to low frequencies and low resistance to high frequencies). However, if you choose a capacitor that is large enough, the lowest frequency that can pass through it (without getting attenuated) is so low that audio frequencies are not affected.

since the mixer is in the inverting opamp configuration, you can increase the gain of one input by decreasing the 100k resistors (R5-R8).

[garfo]

Thank you stecykmi.So, there's not even necessity to raise up the value of the pot?
The reason why I ask this is because I've read people talking about raisining it to 500k to see eye to eye with the guitar clean signal.
Let me guess, maybe .33 is not enough to let all bass through, right; perhaps 1 uf would be ideal, am I right?

basically any time you have a series capacitor, like the 0.1uF caps, you're forming a high-pass filter (a capacitor has high resistance to low frequencies and low resistance to high frequencies). However, if you choose a capacitor that is large enough, the lowest frequency that can pass through it (without getting attenuated) is so low that audio frequencies are not affected.

since the mixer is in the inverting opamp configuration, you can increase the gain of one input by decreasing the 100k resistors (R5-R8).

[stecykmi]

ya, perhaps 10k is unsuitable for guitar signal, raising the value maybe more effective. the other option (perhaps better in a lot of ways) is to add a buffer before the pot. if you need only 2 inputs, you could build the whole circuit with only 1 quad amp.

[garfo]

Well, I experimented putting the buffer before one of the outputs, but I have also change the pot to 1M.The result was horrible.
I assume that If I place the buffer there, the pot should still be the 10k, am I right?

[garfo]

I've never designed a circuit, I have no idea nor any tools to do it.Tha's why I used this one instead

ya, perhaps 10k is unsuitable for guitar signal, raising the value maybe more effective. the other option (perhaps better in a lot of ways) is to add a buffer before the pot. if you need only 2 inputs, you could build the whole circuit with only 1 quad amp.

[stecykmi]

how did you implement the buffer? what about it was horrible?

with a buffer, the value of pot shouldn't matter very much.

[garfo]

I connected the out of the mixer channel to the in of the buffer.The out of the buffer to lug 2 from the pot.Lug 1 is connected to the out tip.
It didn't work out.sound comes out very little, almost non-existing.

[garfo]

i was thinking of powering this unit with an 18volt supply.how would this benefit this build?
the reason why is because i think this wsy the opamp won' distort as early.am i right?