Riviera duetto amplifier,info needed

[huggygood]

hello
I had the opportunity to buy a pair of Riviera Duetto mono blocks and I am looking for information about these devices.
they are not at home yet, they are supposed to be broken down with a ground noise which is above the sound.
I did not find anything on the net, just one flyer on hifiengine.
View attachment hfe_riviera_concerto_praludio_duetto_flyer_de.pdf

 

[huggygood]

I received my two monsters and I'm not sure what to think about them.
It looks like a quality German construction with few low-end components but I can't find an equivalent diagram based on final 845 = 6j5 / GU50 / 845.
for the moment I found the two 6j5 cooked and pumped.
they are on order, I will see for the future.

 

[disco]

Frequenzgang bis 28KHz... that's not very wide, even at 0dB. 845 are nice bottles but must be paired with nice outputs to shine. Mend it and take some FR measurements, see how HF behaves at 28-100KHz. Draw up your own schematic, there are only few parts in

 

[huggygood]

I'm already going to make them work then listen to them to get an idea and then see if I redo everything
with another diagram.
the unknown is the quality of the opts, I'm going to dismount a cover to see what they look like