Tubes for Archon 100

daveNOTW

PRS Pulse Artist
PRS Pulse Artist
Joined
Jan 31, 2018
Messages
6
Just picked up a used Archon and it's sounding great.

Being the third owner I was thinking about having it serviced. I know the power tubes are Ruby and the pre's JJ... anyone recommend anything different?

Cheers.
 
Yes.

What sort of tone are you going for? For clean tones, you want "late breakup" tubes; for dirtier tones, you want "early breakup" tubes. The archon has both clean and dirty channels, so if you're not going primarily one way or th'other, then just get normal, middlin' breakup tubes.

How many tubes does it take? If 2, then you want to get a matched pair; if 4, then you want to get a matched quartet. Trust me on this. The bias controls all four tubes, you don't want something that would merit individual biasing.

The pre's probably don't need replacing, but tube-rolling is fun and expensive, so have at if you have money burning in your pocket. Check all channels and whatnot, see if there's any noise or microphonics. If there isn't, then just leave it alone. Get used to it, tuberoll later.

I don't remember which position, but if you're going to tube-roll the pre's, there's really only one position that matters. Perhaps try "Archon position". A good NOS Tungsol shouldn't be too expensive, but I haven't priced NOS in a while. Don't go down the NOS path until you've proven to yourself that you can hear the difference. No-one else matters! If you can't hear the difference, then that's just money out of your pocket, and it's not going to PRS, so you're better off saving it.

For power tubes, you can actually plug in one of four different types -- it should say right on the back of the amp. I would stick with that recommended list.

I would actually disrecommend the Groove Tube 6L6-R (I think it's the Russian one, the Chinese one is fine...I think) -- it's actually a 6π3C, which freaked out my Archon.

If you're happy with the Ruby ones, then stick with that!
 
The archon 100 has 4 bias points on the back...are you saying that you cant bias each individually via that? Full disclosure I have never messed with an amps bias before.
 
4 bias points to observe the bias values of the 4 tubes individually, but only 1 bias adjustment to actually change them all.
 
Dave, if it sounds great, and everything works, it doesn’t need servicing.

I’m an advocate of using NOS tubes, if possible. They’re smoother, less ringy, warmer, less harsh, and most of them last longer.

But if it sounds good, it is good. Dusty’s right. Play it for a while, and get used to it. Tweak later.
 
Congratulations on the new amp. So I was just in the same position - I bought a second hand purple Archon 100 and should have got it checked over. One power tube failed catastrophically and caused a bit of collateral damage - only about $100 though. I put in Svetlana winged “C” power and some new Mullard style pres from a UK supplier - I was mainly looking for smoothness and retaining the clean headroom as there is plenty of gain going on! I’m pleased with these tubes compared to the originals.
 
I recommend the biggest tubes you can find. If you need to cut holes in the chassis to help them fit, all the better.
Actually, PRS disrecommended a certain tube because it was too big, and there'd be cooling issues.
 
For serious:

If you have the Archon 100, the power tubes are all headroom (unless you are trying to peel the paint from the walls), so any decent set will do.

For the 50, you may want to look more at the power tube character, as they may break up a bit in gig-level operation.
 
Awesome appreciate the insight guys. It does sound great so I'll leave it for now, just want to be prepared when the time comes.
 
Well, I spoke too soon. I'm getting some crazy noises out of the Lead Channel:


Only happening on the Lead channel at 100w. It went away when I switched it to 50, and nothing on the clean as you can see in the video.
 
Super weird. As always, try replacing phase inverter. Swap inside and outside power tubes.

Yes, and since this cuts off two tubes in half power mode (as opposed to the 50 watt head I have which switches from Pentode to Triode in half power mode) that means that chances are good it’s a power tube if it stopped in half power mode. If you switch the power tubes as Elvis suggested, it should be evident in both modes if it’s a power tube. The weird thing was not doing it in clean channel... did you leave it in half power mode when you switched to clean channel?
 
Any update? I've never heard noises like that come out of an amp, would love to know if you came up with any resolution.
 
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