Urgent: Hiwatt DR504.. what's going on with this?

[Helmholtz]

Don't forget the influence of the speakers. Marshall always used Celestions while Hiwatt mostly used Fanes AFAIK. Fanes sound way different from Celestions. I once had a Vox AC50 with Fanes and could compare to my AC30 with alnico Celestions.
This said, different Celestion models sound different as well but typically not as tight and percussive as the old Fanes.

[fred]

...and Fanes, too!! Thanks, Helmholtz, now I need to see a doctor.

[Leo_Gnardo]

...and Fanes, too!! Thanks, Helmholtz, now I need to see a doctor.

Find some oldies but goodies. Fane admits their current run of speakers sound nothing like what they made during their "golden age." Meanwhile musicians & reviewers have much the same to say about Made-in-China Celestions. Fooey! Wassamatta with these guys. They could do it - if they wanted to - I'm sure.

[olddawg]

Also don’t forget.. you have to be dimed on a concert stage. That’s what my point was. I couldn’t get an authentic sound out of a HW in a club. I could with a 50 watt Marshall.

[Leo_Gnardo]

Also don’t forget.. you have to be dimed on a concert stage. That’s what my point was. I couldn’t get an authentic sound out of a HW in a club. I could with a 50 watt Marshall.

Even more to your advantage, back in the day, most of those 50W Marshalls started clipping at about 30 watts. Plenty of volume, enough for almost anything. And tone for days... luv them old "50"s.

[vintagekiki]

Even more to your advantage, back in the day, most of those 50W Marshalls started clipping at about 30 watts. Plenty of volume, enough for almost anything. And tone for days... luv them old "50"s.

Clipping at about 30 watts because the rectifier components (transformer, electrolytic caps) was dimensioned "thin, poor", so with the drive increased, the high voltage declined rapidly and the amplifier fast go to clipping.
With a little knowledge and music there was a lot of sound.

[Helmholtz]

most of those 50W Marshalls started clipping at about 30 watts.

This is certainly true for the JTM45 with GZ34 tube rectifier, KT66s and (non-optimal) 8k plate-to-plate impedance.
But its successor, the model 1987 (introduced around 1967), employing EL34s, SS rectifier, zero! screen resistors and 3.2k to 3.4k plate-to-plate impedance easily puts out in excess of 45W before any signs of clipping.
Overall loudness was mainly limited by the relatively low efficiency 20W or 25W Greenbacks.