EL34 equivalent tube types

I've had a Coincident Dynamo 34SE sitting around for my bedroom system, and I just on a lark decided to hook it to my main system for some 100% tube/analog listening sessions. I'm actually amazed at the sound this 8 watt amp is putting out.  Right now it's equipped with the (I believe) stock EL34 tubes (from tubedepot). Just looking around, vintage tubes seem to be extremely expensive, but are there equivalent drop in replacements that I could be looking at? Just to play around with, nothing serious.

This is also making me consider a more powerful tube integrated (my speaker makes recommend at least 30 wpc tube amps), but similar topics already exist so I wont create another thread for it.
The Genalex Gold Lion reproduction KT-77 is  in my opinion, and many others, the best EL34 variant currently available. They are night and day better than anything else I have tried.
Ok - that is what I will try, the Gold Lions. Thanks everyone!
jond speaks the truth. I’m loving the KT77’s based on his say-so.
These are simply matters of taste, but I prefer the JJ E34L to the Gold Lion KT77s. More importantly, if you want a linear sound with plenty of punch then go with the Lions, if you like a tubier, more liquid, presentation then the JJs are for you.
I had bad luck with JJKT77s in that they don't cut the sonic mustard compared to the KT88s (either surprisingly great sounding no longer available Sovteks or newer Gold Lions) currently in my SEP "Fire Bottle" HO. I might try the GL 77s, but...meh…the amp sounds so damn good I kind of lost interest in 77s…go HO!
I have a Dynamo 34SE MKII which has more grunt than the original.Have used Black Treasures,Siemens and Gold Lion KT77s'.All good but my favorite is the KT 77's.
@wolf_garcia "I had bad luck with JJKT77s in that they don't cut the sonic mustard."

You're right about that.  Not sure why, but JJ did a poor job with this tube.  Kind of a head scratcher, as their E34L (as Viridian / Marty pointed out) and EL34 sound very good.

I also think the Shuguang EL34B will surprise a lot of people, and sound fairly close to the JJ EL34.  And though I'm generally not a fan of most Russian tubes, for a bigger and robust yet easy to listen to sound overall, the ElectroHarmonix Big Bottle 6CA7 make me happy
Joe, here here, the Shuggie is a fantastic tube, and one of the very best values out there. Super call.

I still have a quad of the welded plate EH 6CA7s and while I am not partial to them, I can see how some will go crazy over them. A beam power tube has a different sound quality than a tetrode does, and I think those that like the 6550 will enjoy it’s uptown cousin the 6CA7. The later, crimped plate, EH 6CA7 has a subtly different sound to it.

In my collection I have a big bottle Sovtek 6CA7 quad from the late 70s or early 80s that seems to be repurposed 6L6 variants. Very interesting, but not so good. But we’re not talking vintage here or I would bring up my favorite Teslas.
Would a 7581a work? Tung Sol have a new tube out that is real nice. Super bass and crystal highs. I replaced a quad of 6L6GC with them.
+1 for GL KT77. Smooth and non fatiguing
Some folks like 6L6 variants as a sub for EL34s. The Dyna ST70 manual actually says to use these in a pinch. So 7581/KT66/6L6 would all work.

They are certainly not electrical equivalents of the EL 34 family, and should not be considered direct subs, but some will like the distortion spectra and your power transformer should run a little cooler.
I also like the GL kt77 the best in new production lines of new tubes. Smooth and clean with good details. It just lacks little punch in lower region, so voice is not as rich as NOS  tubes. 
I just retubed with the Mullard EL34 repops and 12ax7s and they really sound great in my Quicksilver Mid Mono amps....