NAD: PRS Archon Classic + PRS 2x12 Archon Stealth

[AlbertA]

Is it quiet for you? I’m getting a bad hum when I even just have a cable plugged into effects send/return, trying to figure out if it’s inherent in the Archon Classic or I just got a bad one.

Its... OK? Could be better I think.

Using a hum buster cable I rigged together for the return helped a bunch (as well as plugging both the Axe-Fx III and the amp to the same power strip.


I am thinking about redoing the cabling here to the loop to use shielded cables to reduce noise further on the send.

Also I may try a 12AU7 pre-amp tube (less gain) for the loop.

But as it stands, I don't really have an issue with it - (I use the noise reducer feature on the input block, set to about -55dB threshold on easy mode, that with the hum buster makes it basically silent).

 

[Fishbulb]

Really appreciate the feedback guys - gonna see what the sweetwater rep says and decide whether to keep or not!

 

[OrganicZed]

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That looks like a very service friendly layout and a robust build.

 

[Humbug]

Gut shots

You know it's serious business when the transformers have vent holes!

 

[Humbug]

Its... OK? Could be better I think.

Using a hum buster cable I rigged together for the return helped a bunch (as well as plugging both the Axe-Fx III and the amp to the same power strip.


I am thinking about redoing the cabling here to the loop to use shielded cables to reduce noise further on the send.

Also I may try a 12AU7 pre-amp tube (less gain) for the loop.

But as it stands, I don't really have an issue with it - (I use the noise reducer feature on the input block, set to about -55dB threshold on easy mode, that with the hum buster makes it basically silent).

Shielded wire is never a bad idea, and the heater wiring could be tidied up a bit. Hard to tell from the picture, but it looks like it's close to the wiring for the rear board. It also appears that the rear board may be connected to ground in two places on the main board which can also cause issues.

Edit: After looking at the other pictures the heater wiring probably isn't as close as I first thought, but it would still be a good idea to use something to keep it in place close to the chassis and away from other stuff.

 

[AlbertA]

Is it quiet for you? I’m getting a bad hum when I even just have a cable plugged into effects send/return, trying to figure out if it’s inherent in the Archon Classic or I just got a bad one.

How long is your cable? Well shielded? Try not getting too close to the power transformer.

 

[Fishbulb]

How long is your cable? Well shielded? Try not getting too close to the power transformer.

Had some 20’ ones running to the pedalboard and back in a loom, the nicest LiveWire ones. Even after cutting down # of pedals and patch cables etc and just running a cable straight from send to return with no pedals, still had that hum.

 

[AlbertA]

Wow, the Amp was biased very cold at 19mA.
I measured the plate voltage at 450V.

I’ve set the bias current to 35mA for now.

 

[2dor]

Wow, the Amp was biased very cold at 19mA.
I measured the plate voltage at 450V.

I’ve set the bias current to 35mA for now.

Mine hovered around 25 ~ 27 when I measured it. That's a very healthy plate voltage. Do you feel any difference in the room now that it's biased higher?

 

[Humbug]

Wow, the Amp was biased very cold at 19mA.
I measured the plate voltage at 450V.

I’ve set the bias current to 35mA for now.

It's probably not a bad idea to stay on the cooler side with today's tubes, but 19mA seems overly cautious.

 

[AlbertA]

Mine hovered around 25 ~ 27 when I measured it. That's a very healthy plate voltage. Do you feel any difference in the room now that it's biased higher?

Sublte but was a little smoother and a bit more compressed so I backed it down to 29mA - I think that's a good spot for me.