Скачать с ютуб Ampeg SVT-2 non pro bias control and adjustment в хорошем качестве

Ampeg SVT-2 non pro bias control and adjustment

Thats my experience of adjusting the bias and phase inverter balance of an Ampeg SVT-II non pro. The amp has now to be retubed, so you see a mixture of four old sovteks and two old koch-labeled 6550s after one tube of the sovtek-sextett was blown. The 4 Ohm dummy load was made of eight 33 Ohm resistors in parallel with a nominal load of 400 watts all togehter. I could not get the 25 vrms across the dummy load, so i used the other peaker out. I made this video only for demonstration purpose, don't try this at home except you know what you are doing. These amps can really be self-destructing and powerful tube killers. I also replaced the main and standby switch because especially the standbyswitch made a harsh cracking noise in the cab, when beeing turned off. If you have a midrange control hum problem, try the power tubes in different positions and also a slightly mismatch of the bias or phase inverter. With some tubes i was able to achieve an improvement. But the best results i finally got with a perfectly matched set of power tubes. A specially shielded input tube doesn't help anything at all.