Fifty/fifty distorting

[mojosteve]

Hi, I have an old Boogie fifty/fifty power amp that I run a Triaxis and a modded Studio c+ into. Whenever I run the power amp past 3 it makes a bad trebble distorting sound. After a lot of messing with different settings a I took the amp to a local tech and he checked the scematics of the 50/50 compared to the 2;50 or 2;90 and he noticed that the 50/50 has more than 3 times the input level. I'm no expert so I cant give more technical info but I was wondering if anyone else has had a simillar issue with the 50/50.

Cheers
Steve

 

[elvis]

I always ran mine with volume at 12:00, but also set the level more with the preamp master than the power amp knobs.

 

[crane]

50/50 and 2:90 have the same input tube with the same polarization. Input volume is located before the tube on the 50/50, so if not turn all the way up you should have less gain with the input tube on the 50/50... Anyway the 50/50 should not saturate with the TA or SP. Running in Hi or Lo power mode ?

What's your setting on the TA ? How is the output volume knob turned ? 12 o'clock ?

The input tube on the 50/50 can be faulty, or another component maybe. Does the presence work fine ?

 

[mojosteve]

Thanks for the reply, I have the presence completely off, the tech said he could mod the 50/50 so that it would have the same input stage as the 2:50. I canged the input valve and the two PI valves and the amp still sounds the same. It just seems to clipp far too easy.

Steve

 

[mojosteve]

Hey again just to clarify I'm refering to the old fifty fifty poweramp not the newer 2:50.

 

[elvis]

It's not in half-power mode is it? I switch mine occasionally without realizing it.