The two back tubes are the tall ones (EL84) and the two front tubes are the short ones (12AX7).
And it comes with a 1-amp fuse that you’ll need to install as well (in the back where the plugs are).
EDIT: Here’s a quick phone pic of the manual that came with mine:
Power tubes (rear socket tubes) you can use EL84, 6BQ5, 7189, 6P14P-EV tubes.
Driver tubes (front socket tubes) you can use 12AX7, ECC83, 7025, ECC803s, E83CC, E803CC, 6L13, CV4035, F6057, M8214, B759, 7729, 5751, 7058, 6681 tubes.
thank you so much I’m going to print this so I can keep it… I tried a quick search and didn’t see it available online.
Also beware of counterfeit NOS tubes. If they have a flying saucer getter, they are phony, regardless of what the brand stamp says. Flying saucer getters were only used in old Soviet Tubes and new production Russian and Chinese tubes. Below is a counterfeit Amperex tube (I circled the flying saucer getter in red).
So wait…at some point, a company somewhere, went through the effort of boxing and branding 6dj8/ecc83 tubes, well before they had any value past a few dollars each, and made them by the thousands in full production runs and sold them off as Amperex tubes even though availability of the real tubes was still plentiful? Why? Why would companies do this? These were being sold for TV and generl electronics use weren’t they? Did tv repairmen seek out Amperex tubes more than others? I’m confused why folks would have been counterfeiting tubes decades ago when availability was plentiful? I hate people🤬 Now i have to pull out my magnifying glass and inspect tubes all weekend😡
Thanks for that list!
I had some tubes leftover from old Lyr; do you know if any of the following tubes will work in either the driver or power tubes? I get confused by tube model # and families…
Reflektor SWGP Silver Shields (6N23P/6922)
Siemens E188CC
Mullard CV4109
Telefunken ECC88
Nope. What these con-men do is buy a surplus of current production tubes or old Soviet equivalents in volume, find the old brand stamp colors and create a cheap stamp. Old tube boxes are easy to buy, or even recreate as well.
The good thing in the case of 12AX7 tubes is that there is no old soviet equivalent tube (the 6n2p comes close, but has a different pinout). But new production tubes are used to make counterfeits as well. Always be careful if you have never purchased from a seller in the past…especially on eBay.
If they aren’t listed in the designations I cited, they wont work. Looks like the majority of what you have are 6922/6DJ8/6N23P family of tubes, which have completely different specs and pinout wiring configuration than the 12ax7.
Ahhh, the damned boxes, that’s what always throws me off the scent. The damned boxes 
Thank’s @Hazi59 !
Thanks… the pins looked very similar to both input and driver tubes… just didn’t want to start sticking incorrect tubes in the amp and turning it on.
The vast amount of which tubes can go where is very confusing so appreciate the help.
Thanks again for the detailed write up from mon and the help in this thread.
I think this is going to be a fantastic addition to my chain along with the hd800s.
I tried the QS last night and it has tons of power great control and pretty solid technical performance. Couldn’t be happier for the $ invested in it.
Your holo has a clear top? That’s pretty cool…
I think the circuit design is imprinted on the case top rather than having it clear.
After you’ve had some solid listening time, if there is something about the sound signature of the amp that you’d want to address (if possible) or tweak with tube rolling, just let me know. I’d be more than happy to give you some recommendations.
I still personally believe the Quicksilver is one of the best price to performance tube amps currently being made. It punches way way way above it’s price point.
You guys and the fact that it would fit perfectly on my desk are not helping.
Thought it might be good to pull the 5751 posts over to the Quicksilver thread!
I’ve gotten a little bit more listening time with the 5751s in my setup as well, and yeah, the Eikon is the only headphone so far that’s had that kind of night-and-day improvement (though these tubes really do sound fantastic with the Eikon).
I suspected that Focal headphones would see similar gains, but the only Focal I still have on hand is an Elex. And yeah, the Elex sounds good, but not amazing, though I’m guessing it’s being limited by the scaling ability of the headphone itself.
I expected Diana V2 would be noticeably worse, but in practice, it could kind of go either way? Diana V2 sounds a little less full and less thick on the 5751s, but honestly, it’s not a huge difference, and I could even imagine someone preferring it.
Moved my post to a better thread for it.
Those RCAs are supposedly the ones to chase for 6v6 tone. Supposedly they give a fuller sound and are very popular for fender amps, think early american rock and blues guitar.
Did they also smooth things out a bit? That is supposedly a 6v6 characteristic, getting out grit and grind as opposed to the UK variants.
I put some big-money tubes in my Quicksilver tonight, a pair of 1954 Amperex long plate foil getter 12AX7s. It’s too early for detailed impressions, but so far they seem to be just what I was hoping for coming from the 1960s short plate version. It might be expectation bias at work, but there’s some magic in the vocals using these tubes.
Yes, they definitely smoothed things out. But with the Quicksilver being a transformer coupled amp, you have to be extremely careful in using different tubes and adapters.
For me, the 6V6GT are the only ones I was comfortable using because they are basically 1/2 of an EL84 as far as specs go. Any other power tubes would probably put too much stress on the transformer, so you definitely want to proceed with caution.
Personally, I gave those 6V6GT tubes a try because as much as I like the 5751 tubes, with some headphones they can sound overly sterile. My hunch about the pairing was correct, it definitely balances out the 5751 tubes.
