Modified ROG Splitter/Blend schematic - feedback and a few basic questions

[kvandekrol]

This is the first time I've made significant modifications to a circuit beyond just adding switches and changing component values, so I wanted to see if I could get some feedback. I'm still a beginner when it comes to making these types of modifications, so your help is very much valued!



Basically, I took the ROG Splitter/Blend and added a LPB-1 right after it to give me a boost that I could then control with volume. Instead of a blend, the voltage divider is balanced so both signals are combined equally. Right before the divider, I control each channel's level independently. The boost is basically a LPB-1, a bipolar common emitter amplifier.

But I think I made a few mistakes, and I don't have the experience yet to know what they are. I've done a lot of reading and looked at a great deal of schematics in trying to figure out how to do this, so I think I have at least some of the terminology down, but my knowledge of theory is basically nonexistant. Here are my specific questions:

1) Coupling capacitors. This circuit is made for a full frequency range so I put a 1uF cap between IC2 and the gain stages. Is this right? Most of the common emitter schematics had a 0.1uF cap here. Also, I have a suspicion that the C8/C10 10uF caps are in the wrong place and that the volume control should be after it, since most of the circuits I looked at had the cap between the transistor and the pot... but I don't know if that applies here. And should I even be using a 10uF cap here, or could I get away with another 1uF?

2) Am I inverting the signals by adding the boosts? If so, is this an issue?

3) Will lowering the value of R20 and R24 change the overall gain of the boost stages - essentially setting a max volume? I don't want to boost it any more than I have to, and I don't think I will need nearly as much gain as this configuration has on tap, so I thought about putting 1k or 5k trimpots here and lowering it as much as I could. No point in a gain of 20+ if I will only be using 10, but I would want to tweak it to find the maximum volume I would reasonably need.

4) Is there a better way to do what I'm trying to do? My main issue, as I mentioned yesterday, is that the balance control in the original split/blend isn't working well - some of my parallel chain effects have low output (wet delay and reverb, modulation effects with no Level controls), so by the time I get the mix right using the balance control, the overall volume is way below unity. I'd rather not use a separate booster if I can just build boosts into the circuit. But it occurred to me after I finished the above schematic that maybe all I need is a single boost that comes after the Blend control to bring the overall volume back to unity. Set the balance to where I want it, then boost it as needed.