Archon loop fix mod

supplebiscuit

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Mar 26, 2016
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I have a pre-loop fix 50 watt Archon. Does anyone know what I need to do to clean the loop up? It is unusable in its current state... It is definitely the loop as when I short the loop with a short cable it is noisy, when loop is off the amp is silent. Does anyone have a schematic for the modification that will fix my loop?
 
I can email you a PDF if ya wanna message your email addy to me. You'll need a 47K/1W resistor. I could mail you one that I got from PRS(or they'll send it to you if you email them) if you can't source one locally.
 
I can email you a PDF if ya wanna message your email addy to me. You'll need a 47K/1W resistor. I could mail you one that I got from PRS(or they'll send it to you if you email them) if you can't source one locally.
I have a pre-loop fix 50 watt Archon. Does anyone know what I need to do to clean the loop up? It is unusable in its current state... It is definitely the loop as when I short the loop with a short cable it is noisy, when loop is off the amp is silent. Does anyone have a schematic for the modification that will fix my loop?

I also have a pre-loop fix archon 100.
Does the composition or the tolerance matter? Which kind does PRS send out?
 
when did the loop fix come in? Just curious as I'm looking to buy an Archon and the places that have on in stock have had these heads for quite a while
 
It's not a good idea to post your email address publicly since spammers might get ahold of it and start sending you junk you don't want. I'd edit your message to remove it and just send it through a private message to the right person.
 
It's not a good idea to post your email address publicly since spammers might get ahold of it and start sending you junk you don't want. I'd edit your message to remove it and just send it through a private message to the right person.
Too late, I already sold it off for $0.25 plus 10% of proceeds.

:D

I keed, I keed. Yes, a good idea to never publicly post an email address on a place that is easily harvested by bots, such as open-to-public-viewing forums like this.
 
Zombie thread alert!

So a year later, having not used my Archon nearly as much as I would like, and also not using the effects loop at all, I start mucking about again and notice the loop noise issue (again), which I never got fixed.

I was reading yesterday that amps with effects loops are somewhat expecting to have rack-mount effects put into that loop, not necessarily pedals. So last night I experimented with a rack-mount delay I have, and the noise levels dropped considerably. This is possibly attributable to the impedance matching better just as much as any other factor. I would be curious to know if the changes/fixes to the Archon effects loop made using the different resistor are impacting gain and impedance, or just one or the other...

So, I just found info on the impedance of my rack-mount delay - it is 10kOhm on input, 1 kOhm on output (and the unit expects levels at -10dB, does not say if dBv or dBu). But I lack info on the send and receive impedance of the Archon. I'm hoping I might gain some knowledge from the group as to what might be typical of a PRS amp, if nothing specific about the Archon is known.

(The very simplified Archon owners manual from the PRS website lacks much specific data...)

EDIT: one more thing:

Typical Boss pedals have input impedance of 1 MOhm (I MegaOhm), with output impedance recommended to be 10kOhm or greater. Thus, the rack mount is much lower impedance than a typical Boss pedal.
 
Last edited:
Zombie thread alert!

So a year later, having not used my Archon nearly as much as I would like, and also not using the effects loop at all, I start mucking about again and notice the loop noise issue (again), which I never got fixed.

I was reading yesterday that amps with effects loops are somewhat expecting to have rack-mount effects put into that loop, not necessarily pedals. So last night I experimented with a rack-mount delay I have, and the noise levels dropped considerably. This is possibly attributable to the impedance matching better just as much as any other factor. I would be curious to know if the changes/fixes to the Archon effects loop made using the different resistor are impacting gain and impedance, or just one or the other...

So, I just found info on the impedance of my rack-mount delay - it is 10kOhm on input, 1 kOhm on output (and the unit expects levels at -10dB, does not say if dBv or dBu). But I lack info on the send and receive impedance of the Archon. I'm hoping I might gain some knowledge from the group as to what might be typical of a PRS amp, if nothing specific about the Archon is known.

(The very simplified Archon owners manual from the PRS website lacks much specific data...)

EDIT: one more thing:

Typical Boss pedals have input impedance of 1 MOhm (I MegaOhm), with output impedance recommended to be 10kOhm or greater. Thus, the rack mount is much lower impedance than a typical Boss pedal.
It's ALIVE! :D
I can't answer your question directly, I'd imagine if you emailed cust serv you might get an answer. Both mine have been modded but I recall before modding, that my old Intellifex rack was dead silent in the loop.
 
Buy and Ebtech Hum Eliminator and run it with your pedal(s) through the effect loop.
 
Hey guys, didnt want to start a new thread.
i bought a pre loop fix archon 100 (MFG 4/14) and would like to fix the loop. If someone still has the pdf/schematics on how to fix it, please send me a pm.
I contacted PRS Europe customer support a week ago but im still waiting for a reply.
 
More news on my archon: i exchanged all the old preamp tubes for a new set of JJs, because of V2 making static noises. Turns out the tube for the loop was noisy too. After changing the 4 year old tubes the loop is dead silent. I had problems with the loop making a pop sound when engaging it via the footswitch, which disappeared as well after the tube change.
 
Glad to hear this! Now enjoy that thing to the fullest.
 
I can email you a PDF if ya wanna message your email addy to me. You'll need a 47K/1W resistor. I could mail you one that I got from PRS(or they'll send it to you if you email them) if you can't source one locally.
Hi there, new to this forum, I just bought a Nice archon 50 combo, second hand, sounds great but the fx loop is unuseable, would you email me the pdf file with the fix, thanks [email protected]
 
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