PRS Archon FX Loop Noise Solutions

Discussion in 'Amplifiers' started by METAL123, Jun 29, 2020.

  1. METAL123

    METAL123 New Member

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    Hey everyone. So after spending quite a long time trying to find solutions for the noisy Archon loop, I thought I'd made this thread for anyone else experiencing the same issue. I've done a lot of research online, been in contact with PRS several times, and have been to an authorized PRS dealer, and an amp tech.. I'll go in order from the most obvious solutions to the less obvious ones.

    1) Power supply, cables, and pedals
    Before you blame the FX loop for noise, make sure that it's actually the problem and not your pedalboard. Try just one pedal at a time running on a 9 volt battery. Also try using different cables. Poor shielded and poor quality cables can cause noise. Generally speaking, it's a good idea to get higher quality cables and an isolated power supply.

    2) Cable placement
    Where you place your FX loop cables and where they come into contact with other cables and parts of the amp can introduce unwanted noise. Make sure that your FX loop patch cables aren't touching any power cables or speaker cables. In fact, try to have them as far away from these cables as practically possible. Also, make sure your FX loop cables are away from the left side of your amp (the side closest to the power on/off switch). Tying you FX loop cables together can help cancel out noise.

    3) FX Loop Mod
    In late 2014 models, PRS began modding the loop to prevent noise. Models of the Archon built prior to this will not have the mod done. You can often tell which year that your amp was built by the first 2 numbers in the serial number (located on the back of the amp). It's best to email PRS customer service with your serial number and they can tell you if the mod has been done or not. They can also provide you a PDF of the loop mod which you can take to a local tech to see if it needs to be done or not. If your amp doesn't have the mod, getting it done should help.

    4) Tube Driver
    The stock tube in the Archon that drives the FX loop has 100% gain. I had that tube replaced with a Mullard 12au7 Blackburn (which is around 20% gain), and noticed a significant drop in noise. It may be worth taking your amp to a tech to try out different tubes that drive the loop.

    5) Volume Pedal
    I've heard others say that the Archon's FX loop is before the pre-master volume and that the noise of your effects are amplified at 100%. To combat this, I've heard of people cranking the master volume and putting a volume pedal at the end of the loop to act as the master volume. I can't speak for the efficacy of this or if it's a good idea or not, as I've never tried it. But thought I'd mention it nonetheless.


    I hope that this helps anyone experiencing this issue. The solution for me personally was the cable placement and tube driver swap. Now, on the lead channel, the loop for me is quite quiet. The clean channel still does have a bit of noise, but way quieter than before. I'm happy with it nonetheless. It's worth noting that FX loops will introduce some noise to a degree. The problem with the Archon's loop is more of an issue at lower volumes. When cranked, the natural tube noise will hide any loop coming from the loop often times.
     
    bodia, Roy and Black Plaid like this.
  2. Black Plaid

    Black Plaid just another Alan

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    #5 -> That's my solution so far.

    About the FX driver tube, is it only on in the FX loop?
     
  3. METAL123

    METAL123 New Member

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    Yes, there is a single tube that only drives the FX loop. Doesn’t affect the sound of the amp, only what goes through the loop.
     
    #3 METAL123, Jun 30, 2020
    Last edited: Jul 1, 2020
    Black Plaid likes this.
  4. andy474x

    andy474x Knows the Drill

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    Just to add one to that list, I’ve had that problem with a couple other PRS amps as well (MT15, Custom 50) and the Ebtech 2 channel hum eliminator works very well. The problems I’ve had seem like some kind of grounding (or ground loop) issue, and the Ebtech unit really cut that down, and I don’t feel it effecting the tone.

    I’m referring to the HE-2, which has 1/4” jacks, not the popular “Hum X” wall wart, if anyone goes looking.
     
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