Before I forget....LOL....
If you want to smooth out the recto tone/gain, which is famous for the fizzy/buzzy stuff, use an OD pedal in front. I'll try to explain as best I can....
Many use an OD pedal with the volume maxed, tone around 10-1 oclock and gain 0. This is great if you want the 'recto sound'. To smooth it out and this is based on my findings, I use a MI Audio Blues Boy Pro pedal and an EQ pedal after it. It's a great pedal, well made and I think better than the TS9 pedal.
There is a direct relationship between the amps gain and the pedals volume and gain. I'll leave the EQ out for now. Lets' start with some 'assumed' settings so we can 'see' what's going on. I won't talk about the pedal's tone control for ease of understanding. So.......
If the amps gain is at 12oclock and the pedal is set at Vol=max, gain=0, you'll get the classic Recto sound; fizzy/buzzy/full on. To smooth it out, turn amp gain down to say 10oclock, the pedal Vol down, to say 10oclock and pedal Gain up to 12oclock. This should immediately smooth out the tone. If it still sounds Recto-ish, turn the pedal Vol down further or the amps gain down. If there's too much overall gain, turn the pedal Gain down a little.
What you don't want is the gain from the amp overtaking the gain (not volume) from the pedal. In this particular case with the pedal gain up, the Recto sound from the amp is brought about two ways: the amps gain dial and the pedals Volume dial. If you turn up the pedal Vol higher, you'll push the front end too much and you'll start to hear the Recto sound. If you turn the amps gain up, you'll start to hear the Recto sound.
There is a balance between the three dials. Basically:
1. Set pedal gain say to 12 oclock.
2. Set amp gain say to 10 oclock.
3. Set pedal volume say to 10 oclock. Adjust to push or 'pull back' the front end. This push and pull will smooth out or increase the Recto sound.
If you feel that more gain is required, turn up the pedals gain. If you want a balance between the recto sound and a smoother sound, use the amps gain or the pedals volume.
Now, the amp may sound a little wishy-washy, a little flat or not quite right. This is where the EQ pedal comes in and the tone control on the pedal. I find that a tone control isn't quite great on most pedals (the MI pedal is good, though). They make an amp sound flat or dull. You really want more adjustment on the bottom and top end. On the MI pedal, I have it set somewhere around 12oclock give or take. Now the Eq pedal is where it's at, setup after the OD pedal. I boost the bottom end and top end a little. One or two sliders at each end by a couple of dB's (depends on amp settings). This makes the amp more alive and fills out the tone overall. Which EQ sliders you adjust depends on your setup/equipment.
Obviously, everyone's gear/setup and so on is different, so what may be OK for me, may not be right for you. All I can say is experiment with an OD pedal and EQ up front (I also have an EQ in the loop). Go to a shop and try it out and play for a while. You may find it's not for you. I don't suggest that my way is the best way or the right way or whether it will work for you. It's just another idea in the search for 'tone'.
OK..... my fingers and head a getting sore.....LOL.