Steampunk Modified Bottlehead Crack DIY Headphone Amp

If you're here you're probably a fan of steampunk, DIY audio, or hopefully both. I wanted to show off my buddy Greg's absolutely beautiful Steampunk themed Bottlehead Crack. I guess technically you might not be able to call it a Crack anymore given nearly every piece of the kit has been swapped out, but the amplifier section of the circuit the same, a simple tube buffer design. 

The Bottlehead Crack has been a popular staple for aspiring DIYers thanks to the lowish price and accessible build. Bottlehead includes step by step directions with pictures so you don't need to know how to read a schematic (although it's fairly easy for tube amps as they are typically simple circuits, so I recommend learning if you can). The stock Crack has very few parts and lacks output transformers so most can complete it in a single evening. 

That being said, many users like Greg like to customize their Bottlehead gear, so bespoke wooden bases or unique paintjobs aren't uncommon. Others choose to modify the internals to enhance performance.You will see the frequently replaced electrolytic capacitors with big honkin' film caps. Greg also designed a lovely pair of custom brackets to nestle around the Clarity Caps. 

Lots of audiophile goodies inside

You will see a small power filter near the power IEC socket, then a CRCRC high voltage power filter with Nichicon electrolytics, and near the front switch is a rectifier board. The stock crack has you mount the rectifier circuit on solder tabs around the transformer so this is a nice little improvement. Some people also elect to install ultra-fast diodes as another option. The tube sockets are replaced with the high quality CMC Teflon PTFE sockets which can help dampen tube vibration. These were directly soldered to however you can find PCBs on eBay or AliExpress to make things a little easier. CMC is also now making Bakelite versions of the socket if you are feeling especially vintage.

The stock Alpha potentiometer has been replaced by a higher quality Audio Note version, and Greg let me know he has ample real estate there to mount a larger stepped attenuator. You'll notice this Crack does not have the Speedball upgrade. While the Speedball enhances the performance of the amp as a constant current source for each channel, some people prefer the more "tubey" sound of the stock circuit. I can tell you they are two different flavors and each have their charm. I prefer to mate a Crack with the Speedball upgrade with some warm tubes and a I feel like it's a nice compromise.     

While there are plenty of improvements on the inside of the amp, the outside is the bee's knees. You'll see a polished copper chassis adorned with brass acorn nuts, a custom copper heatsink, the obligatory steampunk gears, and an old fashioned double pole knife switch. There is a reason why knife switches have been relegated to Frankenstein films and not household electronics; they are inherently unsafe and can arc when connected to high voltage. A shame as they look bad ass. This one is just for show.  

You will also notice there transformer is a little larger above. In fact Greg installed a dedicated heater transformer for the tube heater pins rather than requiring the single transformer from the kit to do all the work. 

An earlier version of the unit before the heater transformer was added

The whole unit is a work of art and has great personality. Despite being Steampunk, there were unique choices. For one much of the copper and brass is shiny and polished vs. aged/scuffed. I think it's great to not force yourself into one line of thinking; make it unique, make it you! Now Greg might have to make a pair of headphones that look equally amazing.    

For more steampunk related audio gear, check out this post.

Creator's Bio: Greg Ritacco started mis-wiring audio kits in the 1980's. Gradually fire became smoke and smoke became music. Encouraged by this, Greg briefly pursued a career in audio, first building speakers and later working for Threshold in the "lab". Family pressures and a desire to have his own back yard caused Greg to become more "serious" about his career, and as audio became the stepchild to home theater, and CD's washed vinyl away, Greg gave up and bought a Walkman. These days, he has rekindled his love of LP's and exploding electronics, built a few projects, and he and his daughter share their discoveries of new artists.

Please remember that building/modifying circuits can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a build or modification posted above and cause physical harm to yourself or your surroundings. Many electronics contain high voltages that can kill, and mods, if performed improperly, can be a fire hazard. 

Steampunk Grado with Turbulent X Drivers

I've heard plenty of good things about the Turbulent X drivers made to fit Grado Labs and Alessandro headphones, so I thought it would be fun to build a new pair. Anyone who's modded a pair of Grados and ran a few Google searches knows that there are hundreds of options out there, from Sennheiser pads to aftermarket leather headbands, to wood cups from numerous manufactures large and small. So if you don't want your Grado to look like everyone else's Grado, there's nothing stopping you from some serious customization.

I'm no stranger to modding Grados, my last being an Alessandro with custom wood cups and a cable made from Cardas copper. This time I decided to do something that I'm pretty sure no one else has tried, a Grado with copper leafed mahogany cups. Copper leafing is process where you put down a base coat of paint, sand, then put down adhesive sizing, then lay extremely thin sheets of copper down and burnish them onto the wood, then cover with some protective sealant. You'll see some other examples of this in my custom built tube amplifier bases.

I began with a pair of mahogany wood cups and performed the copper leafing process. You'll note that the look is not perfect, it has a unique weathered look that make it nice for a steampunk-esq look. It actually weathers over time a bit as well, which only makes it look better in my humble opinion.

Copper leafed Grado cups

Inside the cups, I'd be using some unique grating I had powdercoated a copper color. This was cut for a tight fit and affixed with adhesive.

Powdercoated grates

Since Zynsonix is known for it's audiophile quality wire, I wouldn't be using any run of the mill cable, but some really impressive wire that was custom-made for Zynsonix, particularly for headphone and portable cable applications.

Custom Zynsonix Trebuchet wire

This is a special 24 gauge wire with high flexibility and low memory properties called the Trebuchet. It uses a high-flex clear PE dielectric and ultra pure ohno continuous cast copper for the finest sound quality. 

The mini connector is the well-made Amphenol 3.5mm. Unlike many other mini connectors, it works well with portable DAPs and iPhones in thick cases. This was braided into a litz, then into two twisted pairs, one for each cup. 

Each wire was run into the cup, soldered directly to the Turbulent X driver, then test fit to verify where the wire would fall. The wire was then secured with a zip tie and some hot glue. If it's good enough for Grado, it's good enough for me ;) It is nice to use hot glue as it is removable later for future mods. 

Turbulent X Drivers - Green marks positive in this case

I needed a donor pair of Grados, this would be a pair of used SR-60s I located online.

Some of the best value cans out there, the SR-60

The headband was removed with a twist of the plastic, then the Turbulent Labs headband was installed. This is much comfier than the stock headband, although not the finest Grado headband I've used. That honor would go to JMoney. I do like the color on this one though. 

Next was the process of removing the stock SR-60 cups and installing the copper leafed cups. The forks on the stock unit needed to be dremeled down a bit for adequate clearance, but other than that, pretty straight-forward.  

Well now I have a very unique Grado build with some great sounding Turbulent X drivers and the superlative Zynsonix Trebuchet wire, a match made in heaven for my ears. The sound is crisp and detailed yet full-bodied and dynamic. 

Please feel free to contact Zynsonix if you'd like your headphone recabled with the Trebuchet wire, or if you'd like a custom cable made from it, you won't find it anywhere else.

The Fine Print: The above steps detailing the recabling of a headphone are for entertainment purposes only, and not to be performed under any circumstances. The owner of this blog and all associated parties can not / will not be held responsible if you attempt the process posted and cause physical harm to yourself, your surroundings or your property. Please keep this in mind.

Steampunk Art & Design

I wouldn't necessarily call all of my electronics work my own creations; many of the amps and preamps were existing circuits or kits that I may have modified the parts list or made a few minor circuit changes. As enjoyable as it is to build them, it's preferable for me to stick with tried and true circuits created by the experts and not come up with new schematics of my own volition. There tends to be more enjoyment in the final presentation, the color scheme and the chassis work and even the way the inside looks. A number of people have told me that my builds have a Steampunk look to them. I'm familiar with the movement, and I wasn't even aware of the fact that my design choices tend to follow that look, but perhaps was subconsciously making the design decisions with Steampunk as an inspiration.

Steampunk?

I suppose my designers manifesto is that I feel that amplifiers with older technology like vacuum tubes should have a vintage look and patina, even if they are being assembled in the 21st century. Vintage has a different look for different people, but I tend to think of copper and polished brass, gold plating, brown and copper hues with a crinkled / hammered texture, wood and metal grating and leather. These seem to be the same facets that find themselves in the psuedo-Victorian era Steampunk movement of design. I'm not sure that future projects will have the telltale brass gears and non-functional pipes that Steampunk gear tends to have, but I may think up other embellishments as time goes on.

I think that the main inspiration for vintage electronics was a company called Moth Audio that produced a number of designs from 1996 to 2007. There are many purveyors of audio gear that make really beautiful work, but in my minds eye, the aesthetics of Moth Audio gear is second to none. Craig Uthus was the head of Moth and at the time, the work was considered to be "retro-styled", the designs were highly distinctive and still highly sought after today. Craig's partner at Moth was Joel Marshall, a Hollywood prop designer, who designed the beautiful chassis you'll see below. 

Moth Audio NiteLite with 15E Radar Tube

Moth Audio Sphinx balanced line-out amp and phono preamp

I almost feel that these amplifiers belong in an exhibit somewhere. Perhaps someone out there could open up an audiophile museum one day, the cable section alone could take up a whole wing ;)

There is at least a few audio builders out there that fully embrace the Steampunk aesthetic; Aevil at Coppersteam Labs put together the best looking S-5 Electronics K-12G I've ever seen. I'd imagine there's more money invested in the copper than the amp itself, it's a real beauty that looks like it came right out of Bioshock.

AEvilMike's K-12G Amplifier 

I also found a lovely "effect-pedal" if you will made by Peter Groenewoud at Hilltree Productions called the Steampunk Doomsday Machine. The top features two 230V DC bulbs that carry the music signal and create the effect. Lots of wood, brass and copper in this Steampunk design. Peter will not share a schematic on this device as the 230V DC going across those lightbulbs is fairly dangerous.

Hilltree Productions Steampunk Doomsday Machine

Also, a new addition after the 2012 Bay Area HeadFi Meet was Frank Cooters amazing looking headphone amplifier. I don't know too many details about this one, but the glorious copper piping and top-plate and nicely figured hardwood really set this apart from other builds. Evidently all the work inside this beast is point-to-point, and Frank has a matching one that powers electrostats. In this photo it looks like someone has an Audeze LCD-2 headphone plugged in.

Frank Cooter's steampunk-styled headphone amp

In conclusion, I'm not sure that my builds are Steampunk. They may look like it to a certain degree, but it's nebulous where the line of vintage and Steampunk merge, intersect and share common facets. What do you think?

Looking for some steampunk-esq audio cables and equipment? Contact your friends at Zynsonix Audio.

The AMB Mini³ (Mini Cubed) Portable Headphone Amplifier

The AMB Mini³ is a cute little portable headphone amplifier designed by Ti Kan of AMB Laboratories in 2007. The size of the amplifier when completed is approximately the size of a pack of cigarettes, or perhaps a stack of credit cards ;) 

The AMB Mini3 Schematic

Available from the AMB Laboratories website is the PCB board, a few selected parts, and pre-drilled panels that fit the Hammond 1455C801 or1455C802 enclosure if you'd rather not make them yourself. I'm not a big fan of the unanodized rim around the FPE (Front Panel Express) panels so I'll be drilling them out myself, but if one doesn't have access to a drill press, the pre-made panels would save a lot of effort. 

Because of the size of the board, one has to mount some very miniscule parts, including 1/8 watt resistors and some SMD opamps. SMD stands for Surface Mount Device and means that the device or component is not through-hole, so it is soldered on the side of the PCB that it is mounted on. Most modern components are made by machines using SMDs, but when soldered by hand, care is required. As explained on the Curious Inventor website, solder flux is first placed on the component legs, then solder is added to the tip of the iron, then the solder is carefully added, please view the video here. 

AMB Mini³ PCB, the size of a credit card

Because of sizing constraints, one really can't drop in boutique resistors, capacitors or other such items, but one can manage a little bit of customization. I chose to replace the 1% metal film resistors with 5% carbon film as carbon films can tend to sound a little more natural. I purchased about 10x the amount of carbon films that I needed and measured them with the multimeter, keeping only the ones that fell within 1% and matching them on both the left and right sides. This is much more obsessive than one needs to be, but I like drawing out projects a little bit longer to get more enjoyment out of them ;) 

My populated AMB Mini³ Board

The Mini³ has a built in battery recharge circuit that runs off a wall adapter. The battery is a very tough fit in the Hammond case. I had to file down the batter contact pins, remove the battery wrapper, sand down the plastic around the battery AND file the top of the inside of the case and it all just barely fits. I chose the 9V CTA 325mAH NiMH rechargeable battery that was recommended, perhaps the latest models are a little larger than before. As you can see below, the fit is quite tight. I also re-snipped some of the soldered leads at the bottom of the PCB to ensure they wouldn't short to the case. 


I wanted to make my Mini³ unique, as there are many out there that have already been built by headphone enthusiasts on HeadWize and HeadFi, so I chose to dremel out a vent area (purely for aesthetics) and have the case powdercoated in a textured antique copper. AMB has a nice set of printouts that you can use to drill the holes in the front and back panels, I simply lined them up, taped them on and used the drill press to make the holes. The vent area was quite a bit more work, requiring four drill holes to be placed in the corners, a cutting disc to cut the area between them, and a metal file to de-burr and even up the cutout. 

Chassis Prep

Once this was complete, I trimmed a small piece of perforated metal and used a permanent adhesive to attach it in place. The grill area is colored with a bright copper powdercoat to provide an accent to the antique copper chassis.

Unit Front without panel on, input, output, LED and potentiometer

Unit back without panel on. LED, power inlet and battery

Completed Mini3 unit with brass hardware and aluminum knob

Antique copper textured powdercoat

One might wonder why I chose to build a solid state amplifier since nearly everything on the Zynsonix blog is tube-based. There are a couple of tube-based portable amplifiers out there. Todd the Vinyl Junkie developed one a few years ago and there's the DIY Oatley Electronics K272A for a mere $27 that people seem to like. I haven't tried either of the two units, but as tubes tend to be fragile and microphonic, I'd be a little concerned about them banging around in my pocket for extended periods of time, even with damper rings. The AMB Mini³ offers a nice warm sound without the tubes, so it is highly recommended in my book. 

The Fine Print:

Please remember that building circuits and performing circuit modifications can be dangerous to you and/or your surroundings and should only be performed by a certified technician. The owner of this blog and all associated parties can not / will not be held responsible if you attempt a build or modification posted above and cause physical harm to yourself or your surroundings. Many electronics contain high voltages that can kill, and mods, if performed improperly, can be a fire hazard. Please keep this in mind.