Hybrid Bass Amplifier Head (lamp and transistor preamp) develops 400 watts RMS.
I change light marshall (12AX7) tube with a groove, it's more like its hot, but I'm waiting for a Mullard make the difference,,,
the barnchements are simple,,,
the fine tuning, the equalizer gives good sound as well as the primary chart, I love the compressor makes good, the sound is warm round and fat as I like to do blues, ,

UTILIZATION

I use it on a cabinet Ampeg SVT 410 HE is good, though not quite as dynamic for some but I like,,
the sound is achieved very easily for those who seek a little,,,
when the manual is not helping,,,

SOUNDS

This amp is well suited to my style of play, and music, I used repeated enb,,, it avoids to walk my big SVT ampeg vintage,
I use a jazz bass deluxe U.S. acyive and an acoustic Takamine G series, it Up,,,
I like the sound of the preamp when it is switch on the lamp,,,

OVERALL OPINION

I use it recently but it's nice second head;
I bought this head in exchange for a head Hartke HA 4000 while transistor, one with whom I conduct this exchange is delighted, and I too, he sought at all and I trasistor of the hybrid, , I use the hybrid head Hartke 3500 and I admit that it stands out from the Marshall Hartke,,, and I recommend it,, is fun,,,,
In conclusion, I would not change my head Ampeg SVT in 1976, but I freely admit that I was able to marshall head sduire,,,