Electro-Harmonix 6H30pi Gold vs Sovtek 6H30pi eb

In answer to your first question, I've not compared the electro harmonix's to the sovteks but I have compared them to the 6h30 dr's and they compare very favorably particularly when you consider price. The 6h30 dr's are better but not $250 a pair better!not even close. I can live with the electro harmonix's they sound very good!!
I purchased mine from the tubestore but can't remember whether they were matched or not, all I know is they sound great.
I would talk to audio research and see what they recommend as electro harmonix is their stock tube for all of their equipment.

I have a set of Sovteks and EH Gold Pins for my BAT VK-51SE. Sovteks are new. I'm waiting for them to break in. They have about 50 hours, which is probably enough but to have a piece of mind I will let them run for a total of 100 hours. So far from what I remember the EH Gold Pins possibly had a bit more bass and just a tad more midrange lushness and also highs were a bit softer. But then again, until I swap them this weekend, I won't know.

Sovtek are fine tubes though. Probably a bit more durable than the EH and less noisy. May be a bit more neutral.

Anyway, I'll report back if you're interested.

Electro harmonix 6H30pi gold,sounding more sweet and a bit warm than Sovtek ,but sovtek have better transparency & more dynamic.