Dual Rectifier question (NAD) - New question added!

Maynehead

***Long post alert***

Ok so I've been trying to get a good tone out of this thing for the past couple of days... channel 1 clean and channel 2 vintage sound great, but channel 3 modern has been a real pain.

The problem is, when I turn the gain up (2-3 o'clock, going for a Metallica sound), no matter what EQ and presence settings I use, there's a really gritty, buzzy treble tone that I can't dial out. It's like fizz but more coarse in texture, almost like a buzz. All this is performed at low volume as the neighbours have just had a baby.

At first I thought it was the valves, so I've swapped all the preamp valves for a new set. However this didn't make much difference and the buzz was still there. Tonight though, I finally made a breakthrough.

Out of curiosity, as it had been mentioned, I decided to try bypassing the FX loop using the bypass option around the back.... took it off standby and BAM! All the grittiness disappeared completely and it was instantly the sweet distortion tone I've been chasing for! I was amazed by the difference, even at the same low volume the tone was tons smoother, and finally sounds like the classic rectifier tone I know from all the demos on youtube.

But this leaves me with a dilemma: I actually need to use the FX loop.

Currently I use a joyo analogue delay and joyo EQ in the FX loop. The delay I guess I can stick in front of the amp but the EQ I'm using as a volume boost for solos, which I've come to rely on when gigging, and I can't think of a way around it.

The amp does have its own solo volume boost but that is also a part of the FX loop and gets disabled when it's bypassed. If I can figure out another way to boost the solos then I'm quite happy to keep it bypassed, but as it stands, I need to use all 3 channels for different tones so I can't use one channel as a boost.

So, this leaves me with 2 options to explore:

1. Use the FX loop and figure out a way to get rid of the buzz

2. Bypass the FX loop and find a way to boost solos.

As far as option 1 is concerned, I did notice that the more I turn up the ch3 master volume the more it starts to sound like the bypassed sound, basically the lower the master volume, the more buzzy it gets (strange that when bypassed, there's no buzz even with the master really low). However, I can't turn it up too much or it will be impossible to balance it with the clean channel volume.

With the master low, turning up the output volume doesn't seem to improve things. I haven't tried turning up both the master and the output due to volume constraints.

So, this is my situation. Ideally I'd like to find a way to make the FX loop sound the same as the bypassed tone, so that I can use the master volume and solo boost functions. Any ideas, comments, suggestions are most welcome.