Good idea with true bypass wiring. However, I think that you cannot increase the blending pot - at certain value it will start having influence on the frequency characteristic of the next stage (or amp). But this can be easily corrected with a few resistors connected to the ground. I will try to find such a schematic - I've see it lately.
At the moment I plan to build the ROG circuit with small modifications and later I will think what the finial wiring will be. E.g. I can omit the phase switch or add true bypass (as you suggested).

Mark

Hi Armstrom,

I also plan to build the circuit for use with a DSP module. And of course I need it in cases when only "wet" signal is provided from the module. I plan to build the circuit from ROG as it is (with one small correction on the output). I want to be sure that I can get only "dry" or only "wet" signal on the output. With your version you cannot be sure of that. Also if I use 2 pairs of input-output, the circuit will be more flexible (for 2 DSP modules??). Please note that one output can be shorted to the input in a jack so I even wouldn't need additional jack-jack cable. Do you want to build it as a stomp-box?

Mark

What do you think about this effect loop: http://www.runoffgroove.com/splitter-blend.html ? I think it meets my requrements (as long as effect provides only "wet" signal" - the second signal path may be just shorted).

Mark

The amp is in the design phase  but the plan is to have one channel only - this is for a bass guitar. As I said, I want to avoid sending whole signal through the DSP module. Signal level will be ~0.7V. And yes, I want to do a wet-dry mix. As Teemu wrote - in some cases it does not make sense (eg. compressor). Maybe I should consider a parallel-serial switch.

Mark

Teemu,

It seems that, as you say, there are more drawbacks than benefits. The main reason for the idea of using a parallel loop was to avoid sending whole signal through the DSP module. But you are right that in case of most of effects (compressor, equalizer, phaser) it makes no sense to use such a loop (although in some cases the effect already uses a parallel loop internally). It makes sense only for effects like delay, echo, which send only the "wet" signal to the output.

Mark

Thanks Teemu,

The basic idea is to take existing amp and plug in the effect between preamp and the power amp. So the signal levels should be typical - between 0.7 a 1V. I intend to simulate preamp and the effect loop in LTSpice before I build it (guess who convinced me to use the tool ). Your statement about effect based on varying frequency response not working well made me wonder whether the idea is correct. Do you suggest that parallel loop is not a good solution for some effect (like e.g. chorus)? And such effects should be connected in series? The DSP module that I'm going to use will operate with line level signals.

Mark

I'm looking for a good SS parallel loop schematic. I want to plug in a DSP effect just before a power amp input and to be able to mix the effect with the original signal. I could only find Marshall schematic but I've seen bad opinions about this loop (I'm not sure whether they are justified). Any ideas?

Mark

Nice booster. Can you tell something more about this piezo buzzer hooked as a pickup? I want to do something similar.
I have few suggestions regarding components:
C1 (10 uF) can be changed to 10 nF (due to high input impedance).
I'm not sure whether R1 (10M) is needed. I would at least try to remove it.
C11 (1000 uF) is probably too much. I would use 100uF.
Most probably C4 (330uF) is also too much. I would use 47 uF and increase the R10 pot value to 22k log.
The idea is similar to: http://www.scotthelmke.com/Mint-box-buffer.html

Marek

Since the article raised some interest on several DIY forums, it was translated into English - with huge help from Teemu.
Here it is: http://www.herby.kielce.pl/~piter/hexenew2/ie.php?c=cabsims_e&l=diy_e

Marek

Elwood,

For simple filters I would look at: http://www.herby.kielce.pl/~piter/hexenew2/ie.php?c=cabsims_e&l=diy_e
(translated by Teemu and me  ).
For more complex filters I would use any software that allows sound tweaking (e.g. SoundForge) to create required frequency response and then, having all required parameters, you can set up your analog filters or alternatively, you can implement the filters as a DSP circuit. For DSP you may take a look at: http://www.spinsemi.com/products.html or http://www.wavefrontsemi.com/products/AL3101pop.html

Marek