To match quad EL34 tubes

Yes, the price is fine, but as noted above, you'd have to buy a large batch to find a matched quad.

First, you don't need a matched quad of tubes for the Stereo 70. What you need is two matched pairs, as bias is adjusted by the pair. This usually makes it a bit easier.

In my opinion, the Simens are not particularly good sounding tubes, and for much less money you should be able to get very well matched pairs of tubes by JJ Tesla, SED, Electro Harmonics, etc.

ST70 manual>>>[http://www.curcioaudio.com/st7_mnl.pdf]

The two tubes on the left side need to be a matched pair,and the pair on the right need to be matched.The left side matched pair doesn't have to be the same as the right pair.The left half of the amp is biased up separately from the right side pair.Like Viridian says you don't have to buy 4 matching tubes.It can be two separate matched pairs.The pair on the left could be a different brand than the pair on the right.The left will sound different than the right if you did this,but it would work.The manual link may help.

Thanks for all your information. Are Siemens tubes better than Russian tubes?