You might be able to find a one-box player that beats your current three box combo for $500. DACs have advanced significantly at lower price points. The discontinued $120 ART DI/O beat the Theta Pro Basic II (a 15 year-old design) in my comparisons.
One other thing to consider: Theta "rewards" customer loyalty and original purchasers, i.e., Theta punishes second-hand owners by charging them higher rates for repairs and upgrades than to customers that have original proof-of-purchase.
One other thing to consider: Theta "rewards" customer loyalty and original purchasers, i.e., Theta punishes second-hand owners by charging them higher rates for repairs and upgrades than to customers that have original proof-of-purchase.