Radial J48 more noise than Hi-Z Input?

[Wonks]

What is the Apollo connected to? A lot of noise issues are caused by using laptops with no or high resistance ground/earth paths due to double insulated PSUs. This stops the normal screening properties of cables from working correctly, with a resulting increase in noise pickup.

[Wonks]

Also, have you tried using a different guitar, guitar lead and XLR-XLR cable, just to rule out any of those as causing the issue?

I presume the recordings were done prior to adding the Fortin Cali plugin?

Add a hi- gain plugin that may be adding 60dB of gain to any input signal and the background noise will be brought right up. E.g. add 60dB of gain to a signal with a background noise level of -95dbFS and the noise level will now be -35dbFS.

This is why noise gates and downward expanders are used so much to process modern metal guitar sounds.

Almost every distortion and overdrive pedal has a high pass filter that rolls off the low end to remove as much 50Hz/60Hz noise as possible. Any pedal with diode clipping can boost the signal to the point where even a small amount of 50/60Hz hum is boosted to the signal clip level, making it the same amplitude as the guitar signal and the clipping adding in harmonics of 50/60Hz that aren’t related to the guitar signal. A plug-in that models diode clipping should do the same thing (but it should also model that hi-pass filtering). But a high-gain valve amp can do a similar thing (but without such extreme clipping), but is unlikely to have the hi-pass filtering, and a model of it will be the same.

So it may be worth trying a hi-pass filter before the amp plug-in set to roll-off the low end. You may notice it playing solo, but you won’t in a mix and the guitar(s) will sound clearer.

You may already be doing all this, but we need to ask as only you know all the finer detail of your recording set-up.

[YusefG]

BTW, what are you trying to accomplish by using the Radial?

I got the Radial to use it like any other DI box, and I use it when I only record DIs because I dont like the thought of having 2 different signal chains for DI sounds. This is the first time I ever noticed that the Hi-Z input has much lower noise, because I never tried it out. I figured, if Periphery use the J48 and it's good enough for them, then it's good enough for me.

[Hugh Robjohns]

The J48 is a very good active DI box. I have a couple gear and use them often... and I've never had a noise problem.

I think the only time I've used the pad option was with an active bass.

[YusefG]

What is the Apollo connected to? A lot of noise issues are caused by using laptops with no or high resistance ground/earth paths due to double insulated PSUs. This stops the normal screening properties of cables from working correctly, with a resulting increase in noise pickup.

The Apollo is connected to my 16" Macbook Pro 2019. Unfortunately, I have no other possibility to test this exact signal chain with, because my Windows PC has no TB3 support.

[YusefG]

Also, have you tried using a different guitar, guitar lead and XLR-XLR cable, just to rule out any of those as causing the issue?

I presume the recordings were done prior to adding the Fortin Cali plugin?

Add a hi- gain plugin that may be adding 60dB of gain to any input signal and the background noise will be brought right up. E.g. add 60dB of gain to a signal with a background noise level of -95dbFS and the noise level will now be -35dbFS.

This is why noise gates and downward expanders are used so much to process modern metal guitar sounds.

Almost every distortion and overdrive pedal has a high pass filter that rolls off the low end to remove as much 50Hz/60Hz noise as possible. Any pedal with diode clipping can boost the signal to the point where even a small amount of 50/60Hz hum is boosted to the signal clip level, making it the same amplitude as the guitar signal and the clipping adding in harmonics of 50/60Hz that aren’t related to the guitar signal. A plug-in that models diode clipping should do the same thing (but it should also model that hi-pass filtering). But a high-gain valve amp can do a similar thing (but without such extreme clipping), but is unlikely to have the hi-pass filtering, and a model of it will be the same.

So it may be worth trying a hi-pass filter before the amp plug-in set to roll-off the low end. You may notice it playing solo, but you won’t in a mix and the guitar(s) will sound clearer.

You may already be doing all this, but we need to ask as only you know all the finer detail of your recording set-up.

Yes, I tried the following:
- different guitars
- different XLR cable
- different guitar cable

The recordings we're exported with the Fortin Cali Plugin active, so what you are hearing is through the amp sim!

Man this is making me crazy, I would love to know whether I am doing something wrong or maybe Periphery have the noise as well, but just don't care? Not knowing makes me crazy. If I won't be able to find out or solve this, I might just resort to just using the Hi-Z input...

[resistorman]

There is nothing wrong with using the Hi z input if you're close to the input... being an Apollo I bet it loads the pickup properly and sounds great.

[Drew Stephenson]

This ^^^. If the Hi-Z input works well, just use that.

[Wonks]

I’d try adding a good ground connection to the system to see in that improves the noise at all.

I’d also look at the noise levels before any amp sim. That’s the actual noise level from the DI box. Any gain from the amp sim will definitely bring up the noise floor.

You’d get very similar noise levels from miking up a similar style hi-gain amp.

Noise gates, or preferably downward expansion or level automation is what will be used in the studio. Jack Ruston who used to post here fairly regularly, has worked on a lot of this style of music (e.g. he did the last Judas Priest live album) and he was always saying how much level automation was needed to remove all the hiss between notes/phrases.

[Hugh Robjohns]

The Apollo is connected to my 16" Macbook Pro 2019.

Hmmm. As Wonks suggested, the problem is likely to be an absent ground since, AFAIK, most macbook mains power supplies are double insulated types.

Is anything else plugged into the Apollo, like powered monitor speakers?

[Sam Spoons]

My MBPs (2011, 2012 and 2020) all have a metal earth pin on the PSU, the short plug (which makes the PSU into a wall wart) connection to the MBP chassis is open circuit but if you use the extension lead it is connected to the MBP chassis but the resistance to ground is high at 1kΩ.

[YusefG]

The Apollo is connected to my 16" Macbook Pro 2019.

Hmmm. As Wonks suggested, the problem is likely to be an absent ground since, AFAIK, most macbook mains power supplies are double insulated types.

Is anything else plugged into the Apollo, like powered monitor speakers?

No, nothing, except my Sennheiser HD650s. I also tried running the Macbook Pro on the battery, but that didn't change anything.
The noise is also only very loud when phantom power is engaged. Could this mean that the DI box is faulty or something?