Should i go Boulder 1060 or Jeff Rowland 625

What is lacking with your Pass amp? Are you sure the issues reside with your amp? Pass makes very good equipment, so what is missing? More power needed? My recommendation is to find a good store, establish a relationship and borrow the Bolder amp and Rowland amp for a week at a time and take it home, insert it into your system, without changing anything else and listen. Then make your decision. Don't buy first without trying it.

A good store will take your credit card information and let you take equipment home to audition for a week. That way you can directly compare the amps with your existing amp in your home with your equipment. Again, just insert the amp and don't change anything else. Then if you like it, you tell them to charge your card. If you don't you return it and they don't charge your card.

This works for me all the time at my favorite store in San Diego. For expensive equipment, I don't buy until after I audition. If the store won't, then find another store that will or friends that will let you borrow it. Sometimes in rural areas this is not possible or you may have to drive some distance but, the worst thing is to listen in the store, take it home and it sounds terrible.

But, why are you considering replacing your Pass amp?

enjoy

Agreed, the Rowland 625 should be a good match with the Corus. That's a no brainer. The Boulder is a great amp, but imho needs a reference tube preamp to balance it out nicely. Good luck!

IMO ,Pass Labs and your B&Ws are not a good match,speakers are way too slow and bloated in the bass.If me I would keep the Pass as its a great amp and look for better speakers.For sure sell them if you go with a Boulder

Yup, it appears that this is the case when replacing speakers would be in order. Either you keep the Pass or get Rowland or Boulder later.

I echo Thesoundhouse's comment: "Until there is away to audition your speakers with both those amps you are only guessing."

It is hard to predict amplifier/speaker synergy - although you can eliminate testing some combinations by way of deduction. Perhaps the following experience may help you in the elimination process.

I have auditioned the 802D in combination with Classe, and separately the 802 Diamond in combination with Corus & Jeff Rowland Model 625.
Both combinations sounded good - but I thought the 802D + Classe had a bit better overall tonal balance whereas the 802 Diamond + 625 combination was a bit bright. I also compared the Model 625 to my Cambridge Audio Azur 840W amplifier. (using Wadia CD player and Corus preamp).
Unsurprising the Model 625 best the 840W in terms of detail, transparency, soundstaging, bass control and extension. However the 840W (which has slight warm bass and soft treble) was a better tonal match for the 802 Diamond. The reason for this is that 802 Diamond is brighter and has tighter (less bloated) bass than the 802D.

So based on my experiences a slightly lean amplifier (with good bass control) will better suit the 802D. But equally a more neutral speaker (802 Diamond?) than the 802D may better suit the Pass Labs.
So my suggestion is try different amp/speaker combinations, but if at all possible in situation where can directly compare the amplifiers or speakers - otherwise you guessing how well it will work.

BTW, I am happy Corus and B&W 803D owner.