The simple answer is that you need a high current amp not just a high wattage amp. Some examples of amps that are stable into low impedances are Sanders, H2O, Wyed4sound etc all high current other examples are Krell, Pass, Coda,Bryston, Rowland, Musical Fidelity etc.etc
Most of the high end amps people favor on this forum would fit the bill.
I would doubt that the type of the vintage amp you are using now,-have the capacity to drive low impedance speakers to high volumes with some notable exceptions of course-like McIntosh perhaps the bigger Sansuis and the mid fi "Show Off" flagship/statement pieces.
In order to get something that will let you blast your speakers you are looking at a major expense over your current amps cost.
What is your budget?
It would be helpful if you can tell us what you have heard and what you like or don't like. It would be helpful if you can tell us what you have heard and what you like or don't like.
Most of the high end amps people favor on this forum would fit the bill.
I would doubt that the type of the vintage amp you are using now,-have the capacity to drive low impedance speakers to high volumes with some notable exceptions of course-like McIntosh perhaps the bigger Sansuis and the mid fi "Show Off" flagship/statement pieces.
In order to get something that will let you blast your speakers you are looking at a major expense over your current amps cost.
What is your budget?
It would be helpful if you can tell us what you have heard and what you like or don't like. It would be helpful if you can tell us what you have heard and what you like or don't like.