Your running (89dB/4 ohm) speakers with a Cayin A-50T?
It's a miracle your driver tubes lasted as long as they did!!! What a load.
Power handling capability according to the manufactor is 40-120 watts. If there was ever a case of pulling a rail car (your speakers), with a Shetland Pony (your Cayin), instead of a 1/4 horse, or better yet a draft horse, this is it.
It's a good thing you are using a tube amp instead of a SS amp, because the likelyhood of you clipping your speakers to death by now is very high.
$1000-$2000 isn't much of a budget to drive (89dB/4 ohm) speakers, unless you go used, & even then.
In a SS amp look for something with a massive power supply, with 120-200 watts of power. Not only will this give you impact at any volume, low or high (caveat, SS amps have a smaller sweet spot than tube amps), it will also give you the safety of "head room" so you don't clip/(damage) your speakers, or your amp.
If you can find a used Bryston B100 Integrated Amplifier, or a Krell KAV-300i Integrated Amplifier, you will have an integrated SS amp that will realize the Stradivarius violin potential laying in your Reynaud's, that can safely run those thirsty speakers for years to come.
Enjoy the experience.