After 57 hard-rocking years, Black Sabbath will play their final “Back to the Beginning” show on July 5th at Villa Park in Aston Birmingham, which is the exact place the band was originally founded in 1968. This massive sendoff concert will feature the original lineup of Sabbath, consisting of bassist Geezer Butler, guitarist Tommy Iommi, drummer Bill Ward, and Ozzy Osbourne together again for the first time since 2005. Everything about this concert is distinctively huge—from the venue and sold-out crowd size, to the list of legendary opening acts like Metallica, Tool, Pantera, Guns N’ Roses, Slayer, Alice in Chains, Soundgarden, and a rock A-list supergroup consisting of 25 instrumentalists—and most importantly to us, Geezer Butler’s bass rig is of absolute enormity.

For decades, Butler has relied on Ashdown Engineering to tailor amps to his exact specifications to ensure that his distinct bass tone has come through in every arena he’s rocked. Ashdown founder Mark Gooday and his son Dan, who serves as the Managing Director, took great care in working with Butler to create his very own Head of Doom, which boasts 600-watts of power with a 9-band EQ, and enough headroom to reach the outer walls of any venue. Paired with their ABM 810H-EVO cabinets, these amps have become part of Butler’s distinct signature sound that has made such an impact on generations of bass players.

However,  for this final show, Butler and the Goodays knew they would need something special, so they got to work months before the announcement of the concert to come up with a rig that would send Sabbath out with a bang. The subsequent brainstorming sessions resulted in a one-of-a-kind wall of amps that matches the grandiose nature of this farewell event in both stature and sonic range. Rather than us explaining it, we sat down with Mark and Dan in the weeks leading up to the show to get the inside scoop on this final rig of doom.

How did you first begin working with Geezer in designing his amps? 

Mark: Many years ago, Geezer came to us and wanted something that had his old-fashioned sound, so we got together and we got his old rig and listened to it, and then we took one of our old ABM’s and modified everything to suit him. We took out the compression and some parts of it that he didn’t like. Because he uses multiple cabinets, we had to put extra transformers into it to stop ground loops. He was linking about eight amps together all in one huge system and running it in a bi-amp format. We ended up making a very special amp for him. At the end of the day, it’s one of our ABM amps, but once you start putting more transformers in there it sounds different. It’s an animal. It has so much headroom.

Tell us about the special rig you created for him for this show.  

Dan: Geezer wanted to run two 15s with two 12s on top. Working this out to be efficient in terms of impedance to be run from four of his signature Heads of Doom, they needed to be 16 ohms. We opted to go with B&C drivers for their efficiency and power handling. The rig was designed to produce 2400 watts into eight cabinets in total to ensure the rig could run correctly. So all up, there are four custom 2×12 cabinets and four custom 2×15 cabinets.

Mark: It’s retro and vintage and just huge. Listening to it is painful. Geezer’s a lot like John Entwistle in how they both play with all of the hammer-ons and their attack, so the sound of it is simply massive.

What did Geezer specifically ask for in regard to the specs of this rig?

Dan: He needed to hear it, and for it to be at ear level. We were given relative freedom in terms of design. Geezer’s long-standing tech Terry Welty made sure everything was on point prior to production.

Mark: Geezer has worked with Terry for years and he contacted myself and Dan and we got down to fine tuning the sound. It didn’t take much messing around once we built them. It was actually a very easy process. The hard part was building the crossovers internally and the extra transformers. It’s a serious system and it took a lot of extra work to do that. If I’m honest, the power section in this is something I’ve been building for 45 years. It was in the early Trace-Elliot stuff that I built.

These certainly have a unique look to them too. How did the artistic design come about? 

Mark: Dan went nuts with the design, the color, and the big symbol on the grill. It was a lot of work and I wouldn’t like to add up how much it cost to build these.

Dan: Terry sent us the Black Sabbath “Henry” logo to use and wanted it to match the aesthetic of the Heads of Doom. The black-on-black silk screen worked very well. We were asked if we could make the logos a little more subtle for the stage, as the standard Ashdown red and cream logo, beautiful as it is, stood out a little too much for the dark stage. So we decided to go that little extra and make a custom ‘Sabbath’ logo in black and purple colors. These were hand-painted in-house, and we think the logo really puts the icing on the cake. It’s the attention to detail we build into our products on every level.

What is going to happen to this amp after the show? Will Geezer keep it?

Dan: Yes, we’ve been informed the rig will go back to Geezer’s house after the show. There might be something in the works for those who fancy one of these beautiful creations, but you’ll have to keep an eye on our website for more news on that.

What has it been like working with Geezer for so many years and having him be such an integral part of the Ashdown family?

Dan: Honestly, an honor and a pleasure. They say never meet your idols, but that couldn’t be further from the truth with Geezer. His wife/manager Gloria, and his tech Terry, they’ve always been such an inspiration and nothing’s changed. This is a very proud moment for us. Being a small family business and getting to be a part of such an historic event is a true honor. We can’t wait for the show and to share this very special rig with everyone.

Mark: He’s just so lovely. He and his wife are wonderful, wonderful people. You couldn’t find easier people to work with. To be involved in it on any level is huge. Having Geezer as an innovator in bass playing on a world stage, we couldn’t be more proud that. What a night it’s going to be.

Does it feel bittersweet for the Ashdown family for this to be the end of Black Sabbath?

Mark: To be honest, we haven’t had a chance to take it in until being asked  this question. It might be the last show, but Black Sabbath will continue forever in our hearts and in their recordings. So in the words of Ozzy: Never Say Die.

For more on Ashdown: Click Here

Stream the farewell concert: HERE