Handy Tip for ARCHON 100w with EL34's (fuses)

Discussion in 'Amplifiers' started by HANGAR18, Jun 7, 2016.

  1. HANGAR18

    HANGAR18 Not buying any more guitars. Again.

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    Before I forget, I've got a tip regarding the fuses in the Archon amp for those of you who have replaced the stock 6L6's with EL34's.

    I was on a mission at the Experience PRS event to talk to someone about cabinets and amps as I have stated previously. Mission accomplished. I wound up speaking at length to Doug Sewell and one of the little tips I got from him which I thought would be handy to some of you Archon fans is this...

    If you have replaced the stock 6L6 tubes with EL34's, also replace the stock 10 amp fuses with 15 watt fuses. It's not a real big problem, so to speak, but in my own layman's terms, there is a bigger spike of power that happens when the EL34's get kicked on and over time, it could cause the 10 amp fuses to fail a little prematurely. He pointed to the back of the Archon and said something like, "If you turn on the amp and then see the light kick on here and then go out right away" that was apparently a symptom of the stock fuses having trouble. That is a really sloppy explanation so, let's just say that if you've got EL34's in a 100 watt Archon, replace both 10 amp fuses with 15 watt fuses. I think he also said they sell them in the gift shop too. Anyway, that's all I've got for you.
     
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  2. Boogie

    Boogie Zombie Two, DFZ

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    Hmm...you just answered something for me completely unrelated to the Archon (EL34 based Super Dallas, though). I thought the gem light burned out...maybe not. Thanks!
     
  3. vchizzle

    vchizzle Zomb!e Nine, DFZ

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    Hmmm, interesting. Will have to remember that if I ever have issues. I've been running 34's in my Archon at home without issue. I remember someone else stating awhile back something about using slo-blo as well.
     
  4. elvis

    elvis Hamfisted String Banger

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    Makes sense. Many fuses are bimetal, where one metal melts early and the other later. With short current spikes the lower-temp metal can migrate away and leave only the higher temp metal, altering the fuse significantly.
     
  5. Boogie

    Boogie Zombie Two, DFZ

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    You have to use slo-blow fuses on my Booigie or you'd blow it every time you fired it up. The spikes are common so you don't want the fuse to protect it unless overload is continuous. It depends on the amp's design. I'd do whatever Doug recommends.
     
  6. vchizzle

    vchizzle Zomb!e Nine, DFZ

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    I'll have to look at what's in there now. I emailed customer service before I put el34 in, because I heard a forum member had issues and they told me I didn't need to change fuses from what was in there. I think I specified I was using el34bstr, maybe that had something to do with it. I agree with going with what Doug says, maybe I'll grab some to be safe.
     
  7. vchizzle

    vchizzle Zomb!e Nine, DFZ

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    15 watt? Or 15 amp?
     
  8. HANGAR18

    HANGAR18 Not buying any more guitars. Again.

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    15 amp fuses go in the 100 watt amp.
    Yea... I think that sounds right.
     
  9. Bluesverb

    Bluesverb Currently in a long term relationship with myself!

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    15 amps???? That is crazy. 3 amps (Rarely/Possibly 5 amps) are normal for 100 watt amps.
     
  10. Bluesverb

    Bluesverb Currently in a long term relationship with myself!

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    Use slow blow 3 or 5 amps. If it still does it, change the tubes to something different than the ones you have in there.
     
  11. Dusty Chalk

    Dusty Chalk alberngruppenf├╝hrer

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    Nothing personal, but this came from Doug Sewell, himself, I think I'd rather listen to him.
     
  12. HANGAR18

    HANGAR18 Not buying any more guitars. Again.

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    You read the part about the amp coming from the factory with a 10 amp fuse, right?
     
  13. Bluesverb

    Bluesverb Currently in a long term relationship with myself!

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    No disrespect meant nor intended.

    Having 5 PRS amps myself, I find them beautiful works of art as well as being good sounding amps.

    I am a retired Air Force Avionics/Electronics teacher.

    It is hard to "Arm Chair Diagnose" a problem, especially with no schematic to reference.

    BTW - Was the amp new or 2nd hand?

    Without having a schematic or seeing the inside of an Archon, than I will stand aside. There could be multiple fuses throughout the amp. That said, I would also need the rated voltage of the fuse, the amperes, slow blow, and where it is placed electronically.

    My humble recommendation is to re-verify with Dough himself.

    Personally, I would try a different brand of tubes, preferably new from an actual Tube dealer.

    Please note the following as reference only as general rule of thumb
    .

    Guitar amps are inherently inefficient. The power draw, from your wall, is say 400 watts on a 120 watt (speaker output max) from the amp. Basically, you lose 70% of the initial input power due to Heat, Inductance, Insertion loss.....

    That said, a "Main" fuse on an amp would be 3 amps slow blow (due to cap/tube) current draw, I would expect to see 3 amps. Consider that P=IE. On a main, say voltage is 120 VAC from the wall which is the E in the formula. 15 amps is the I in the formula per the fuse rating. Therefore, P= 120(15), which is 1800 (watts). Ergo 1800 watts = 120 vac x 15 amperes. Now, go to your Circuit breaker panel in your house. The common breaker that you will find for a typical 14 gauge wiring is 15 amps. In effect, that fuse would have to take the entire load of that circuit before it blows the fuse, which should trip the breaker.

    As an example, this is why you will never (typically) find a hair dryer or curling Iron rate over 1800 watts (usually around 1500 watts).

    Again, I DO NOT CLAIM TO KNOW where it is and all the particulars.
    Depending where the fuse is in the circuit, OHM's law can be manipulated so that it would make sense for a 10 amp fuse, somewhere in it. ELI the ICE man.......LOL. That comes into play as well.

    Again. Without having a schematic or seeing the inside of an Archon, than I will stand aside. There could be multiple fuses throughout the amp. That said, I would also need the rated voltage of the fuse, the amperes, slow blow, and where it is placed electronically.
     
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  14. HANGAR18

    HANGAR18 Not buying any more guitars. Again.

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    There are times when too much knowledge can get you into trouble.
     
  15. Bluesverb

    Bluesverb Currently in a long term relationship with myself!

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    Absolutely!!! It is interesting though.
     
  16. DreamTheaterRules

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    True. I know a little (I'm sure not as much as you) and have built and modded a few simpler tube amps. Built some pedals also. I know enough to sometimes be dangerous, but not enough to be taken seriously by anyone who really knows their stuff. :)
     
  17. rising farce

    rising farce New Member

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    That was me, and yes, the 10A slo-blos worked just fine. (I even ran it by Matt King at PRS to be sure.) Mine was a very early production model, however, and I wouldn't be at all surprised if they made subsequent changes to ensure that the EL34 swap was more of a "turnkey" operation.

    On an unrelated note, I'm looking forward to getting back in the Archon saddle after having foolishly sold off mine awhile back. I found an obscene price on one of the limited-run violet/flame heads, and it should be here early next week. Such criminally underappreciated amps.
     
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  18. vchizzle

    vchizzle Zomb!e Nine, DFZ

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    I emailed customer service again and they told me it was ok to put in 15 amp slo blo fuses in. I did & everything is running fine. Prior to putting them in, I had a minor scare firing up my amp one day. Turned on from standby, heard an outrageous him, turned back to standby and everything went dead with a loud pop. The mini 4 amp fuse in the power cord socket blew. Luckily there's a spare in the little tray that pulls out. When you open that little tray, the one closest to you is the spare. That's what prompted the email to PRS. Not sure what caused the issue, but figured I'd go with the 15 amp slo blo to be safe after I heard back from PRS. Both my Archon's are from the very first run FWIW.
     
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  19. boardn10

    boardn10 New Member

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    Question guys...

    Is this fuse problem only with older Archos? I've run 6CA7 tubes which are EL34type tubes, without issue.

    Assuming since mine is a 2019, they have the fuse issue resolved!?

    When I emailed PRS, they said there is nothing to do, other than plug in the EL34tubes and bias it like 6L6 tubes.

    Surprises me since my other amps all require me to flip the switch to 6L6 or EL34, depending on what I'm using, so how do they get away with a 30mV bias for both tube types?
     
  20. HANGAR18

    HANGAR18 Not buying any more guitars. Again.

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    It's not always a problem and I never wound up swapping out the 10 amp fuse for the 15 amp. But I was glad to know that I could do that if I wanted to.
     

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