Mario
When I read you writing the Classic 30 driving the ProAcs were 'tense' I thought you meant too sizzly and strident, not too bassy and slow. I misunderstood but no problem.
Given the actual problem you have I would definitely retube the amp first. I suspect the tubes are old and dulled. The Classic 30 should NOT sound dull into a high line ProAc! Suggest you get KT88 instead of 6550 power tubes for more bass control. I think modern Russian replacement small signal tubes should be fine as they are a little brighter than most older tubes. Be sure to re-bias the new power tubes upon installation.
Good luck.
When I read you writing the Classic 30 driving the ProAcs were 'tense' I thought you meant too sizzly and strident, not too bassy and slow. I misunderstood but no problem.
Given the actual problem you have I would definitely retube the amp first. I suspect the tubes are old and dulled. The Classic 30 should NOT sound dull into a high line ProAc! Suggest you get KT88 instead of 6550 power tubes for more bass control. I think modern Russian replacement small signal tubes should be fine as they are a little brighter than most older tubes. Be sure to re-bias the new power tubes upon installation.
Good luck.