Henry Bogdan

Henry Bogdan, bassist for Helmet, is noted for using the SWR SM-900 bass amplifier head, as discussed on TalkBass.com.

In the performance at Hultsfred Festival in 1997, Henry Bogdan's main rig, a Mesa/Boogie Bass 400+ Amp Head, experienced technical issues, prompting the tech to switch to a backup Ampeg SVT-II. Both amps are clearly visible behind Chris Traynor at the 23:33 mark in the video. I spoke to Henry in 2016 and he confirmed that he used Mesa/Boogie amps almost exclusively, except for briefly "trying out" a Harry Kolbe amp in 1994 on the Betty tour, and having a backup Gallien-Kruger head on the Aftertaste tour.

At 5:37 in the video "Helmet - Austin 29/07/1997 #2" by tooolest32 on YouTube, Henry Bogdan's bass rack is shown containing a Gallien-Krueger 800RB Bass Amp Head alongside a Bass 400+ and an SVT-II without their chassis.

At 5:37 in the video "Helmet - Austin 29/07/1997 #2" by tooolest32 on YouTube, Henry Bogdan is seen using the Mesa Boogie Stereo Simul-Class 290 Power Amp, placed under the Gallien Krueger 800RB. Henry was slaving his GK800RB into the 2:90 to achieve power tube distortion, similar to his SVT-II and Bass 400+ heads, which are also visible in the same rack.

Henry Bogdan was seen using the Ampeg SVT-II NON PRO during Helmet's performance at Jabberjaw in 1991. This amp, alongside the G&L L2000, was responsible for the main bass tones on "Strap It On" and "Meantime." Source image.

In 1994, Henry Bogdan began using the Mesa/Boogie 2x15 Diesel Cabinet and the Mesa/Boogie 400+ amplifier, continuing their use until Helmet disbanded in 1998. This setup is documented in a live performance by Helmet at Rutgers University on November 10, 1994, as captured in a YouTube video by markit aneight.