RCA are those red and white cables. One for left and one for right channel. They carry audio in or out. So you could connect a dac and amp together by connecting an rca cable to the DAC’s rca out and the other end to the amp’s RCA in.
AUX ports are essentially headphone ports. Like where you plug your headphones into a computer. So an Aux in would mean you could input audio signal from another device, like an ipod or another amp, using a male to male aux cable.
Good man, I couldn’t address those points.
To add, the “RCA OUT” would take the audio signal in and allow you to control that signal out via the volume knob to connect a power amp for speakers (or powered speakers) or even a solid-state headphone amp that you’d like to “dirty-up” the sound of with the tube preamplification.
Still struggling to understand the Element 2 problem that C.A.T.H mentioned earlier today — is it possible you were trying to run the dac/amp from the iOS device rather than from the wall? I doubt this, cause that unit doesn’t even use USB power. The connection of the MT-602 will be different, requiring a dongle or other DAC device (then a 3.5mm male from dongle → rca male connection to plug in RCA IN on back of MT-602 // or a 3.5mm male to 3.5mm connection if you simply want to plug it into the front AUX IN port of MT-602)
I get concerned about new setups when so many questions remain about the previous device. The Element should have just had USB signal running into it from the iOS device, and power into a wall. Then headphone in. There’s other ways to get audio in, but this is what you’d do to get what you’re paying for. “Too much power for the device” is concerning. What happened?
I ask because now we’re playing around with tubes, though the MT-602 is a very flexible, easy unit. I type this while listening through one.
Not sure what changed, but my iPad Air now works with the Element 2!
For context, my Element is powered by its own power brick, and I connect the Element to the iPad via a USB-C adapter (to my surprise, a USB-C dongle from Amazonbasics actually worked!)
Here’s a snippet of the error message I used to receive:
Update on the original topic: Just traded for an MT 602. Looking forward to my first TUBE experience!
Thanks to everyone for their input.
i-devices are weird 
Always been android, bought an iphone and it won’t charge off my car’s USB port xD
Happy you found your solution!
Anyone tube rolling yet on this amp?
Got 4 Voskhod 6J1P-EV’s coming for my MT-604 they’re on the way but I’m not sure I’ll get them as Paypal didn’t seem to list my full address correctly for some reason 
defo not the Ukraine sellers fault, they’re not expensive in fact you can get 10 for circa 20 bucks so if I don’t get them I’ll reorder with an edited address 
Can I ask why you settled on the Voskhod?
I will probably pick one from the list Nr48 linked which adds treble+soundstage.
No real reason I’m just going to work my way through a few different makes.
I’ve got General Electric 5654W, Siemen 5654w and Mullard M8100 for my Little Dot ll and out of those the Siemen’s are best for treble the least “tubey” if you like
Thanks! Will try the siemen’s first 
Yup. Tried a few. I have some voskhod and GE tubes. After switching back and forth, I ended up leaving the GE tubes in. To my ears, they have a little more width and smoothness, which is what I want out of a tube amp.
And thank you for reminding me I’ve just ordered 4 siemen’s for my MT-604
Interesting, I will look into those too! Thanks for your input.
Lol I just ordered a matched pair too 
I got 6AK5 Sylvania’s. Thick, warm and wide!
Just as I was bitching the Voskhod’s arrived even with an incomplete address 
Siemen’s to follow next week
Just chucked them into my 604…
yes they do…think you’ll like them way better than stock, will interesting to hear your thoughts
Oh so nice! And glad to hear your early impressions, and yep I am a treble head so I think I will enjoy them 
Will def include my thoughts once they arrive around the 20th from Europe.
By the way, do you or anyone else know what the life expectancy of these tubes are? The 6J1, just asking if I should stock up on spares thats all.
Not 100% sure but tubes slowly burn out and depending on usage power tubes maybe a couple of years depending on use
TLDR; Don’t worry about it…
I’m pretty sure they’re not really pushed on these hybrid amps so they’ll probably last a lot longer than spec’d.
I’d say most tubes have a life expectancy of 5000+ hours (in use of course) and some are even longer when run at spec.
Which specific tube are You talking about?
We can probably find the spec for it… 
EDIT: Wrong spec sheet. I’ll try to find it
EDIT2: I think I’ve found it:
https://electronbin.com/sheets/190/5/5654.pdf
Pretty cool site:
https://electronbin.com/
