WHAMMY Headphone Amplifier
Description
The WHAMMY Class-A headphone amplifier
Wayne Colburn, the genius at Pass Labs who for the last 25 years has designed essentially all the things that aren't speaker amplifiers, wanted to make a fun, high-performance, fantastic-sounding, Class-A, DIY headphone amp for this community. We call it:
Wayne's Headphone Amp Must Make Yourself
Yes, it's a silly name. But it's cute. And it explains a lot about it. So it stuck.
Given the explosion in the popularity of headphones, as well as the unbelievable amount of choice and variety in the market, it seemed that a simple and great-sounding headphone amp would be a great addition to the DIY community.
Because there are so many choices of headphones, from Planars to IEM's, high impedance or low, this amp will drive any headphone you want to throw at it (Well, not electrostatic headphones directly, no amp like this will, but it will happily drive a step-up transformer like Stax).
Wayne wanted a universal headphone amp for his desk. This is the fruit of that idea. It’s made to be made in an afternoon or an evening and it has no builder adjustments, so it’s going to have a high likelihood of success and completion for beginners and experienced DIYers. 
It's an all in one PCB, just wire the AC & fuse, input and output jacks. Add a selector switch if you like.
Class-A output stage with enough current to drive anything. It also makes a wonderful line stage with about 14db of gain.
Your choice - PCB or PCB plus parts kit
We are now selling both the a WHAMMY PCB by itself, as well as a parts kit that includes the PCB, and everything else you need to build the WHAMMY other than a chassis.
- We are working on a chassis for the future and will definitely release one, but we aren't going to rush it
- 6L6 has done a great WHAMMY build guide and the supplied parts will match the build guide, more or less
- We have now seen multiple successful builds of this new kit, and are now opening pre-orders for the kit, shipping January 11th 2019
PCB Details
- 218mm x 160mm (8 5/8" x 6 5/16")
- Black with gold immersion traces
- 70oz Copper
Kit Details
The kit includes everything to make the amp except the PCB and chassis. All components are of the highest quality.
- Dale RN55 milspec resistors
- Panasonic FC & FR series capacitors
- Elna SILMIC II capacitors
- Solid aluminum anodized volume knob
- Alps "Blue Velvet" potentiometer
- Neutrik RCA connectors
- Schurter filtered power entry module with spare fuse
- TRS Headphone Jack
- IRF610/9610 Power MOSFETs
- Texas Instruments RC4580 op amp
- Teflon insulated silver plated copper milspec wire for I/O connections
- Silver bearing eutectic Kester 44 solder for I/O connections
- All nuts, bolts and standoffs to attach external connectors and the PCB to a chassis
Illustrated build guide
Most of the info you need to complete this project can be found in the first 6 posts this thread, a well-illustrated guide showing how everything goes together.
- Step by step WHAMMY build guide on guides.diyaudio.com
- WHAMMY build guide and general discussion thread
- Rough Bill of Materials (this is not the BOM used for the kit)
Video
Here's a video of Wayne talking about the Whammy at Burning Amplifier Festival 2017 -- Wayne Colburn at BAF '17
I wanted a high-quality HPA and didn’t wish to pay over-the-odds for sub-par consumer designs. As it was designed by a pro from a proper hi-fi company, I saw it as a bit of a no-brainer decision. The build took me about six days to complete with cutting chassis etc and making a few mistakes along the way. As it was my first time I wanted everything to be correct and my fussiness paid off this time - On Power up all was perfect and I was pleasantly surprised. Would definitely recommend this build to those who appreciate real hifi and music-lovers who don’t want to break the bank. I am a music-lover not an Audiophool.
It was a very helpfull guide and I spent a nice time building the WHAMMY preamp.
A very nice design. Enjoyed the build, was straight forward and not too pricey of a BOM. Excellent sound. Going to play around with a couple different OpAmp (almost like tube rolling).
I bought the both the PCB and parts from DIYaudiostore, and soldered all the parts during two evenings. The instructions were easy to follow. I acquired a suitable aluminium enclosure, which required some metalworking (drilling holes and making threads). The amplifier is driving my 600 Ohm Beyerdynamic headphones with ease. Very satisfied with the sound, and it was fun to build!
Wayne's design of the headamp is simple but excellent and so is the parts kit provided by diyaudiostore. Only high-quality-parts. Fast shipping. I only changed two parts: the headphone-jack (I used a Neutrik which is isolated from the Chassis) and the opamp (the red part, it's the burson V6 vivid). Chassis is Hammond. It perfectly fits the PCB.
Al in all an outstanding headamp.
I bought the PCB from DIYaudiostore and manually selected the parts from Digikey/Mouser etc.
PCB is of high quality and once assembled, the amp worked right away.
Sound quality is great, clearly above my JDS Atom, but I advise to play with input coupling caps and Op Amp to get the best synergy with your other gears.
I went for a slightly bigger chassis (Hifi 2000 Galaxy GX283 80x230x230), and it gives plenty of space to play around.
Be aware of the extra cost due to customs (shipped from US to EU, +33E in my case).
Highly recommended!
A really nice pcb. Follow the directions on diyaudio, and you'll have a great-sounding amp. Drives both my Grados and Sennheisers with ease. Looking forward to some op amp rolling. Thanks for making this available to diyers!
Everything except heat paste was in the box. Excellent instructions, but two things to watch - this project is not like the amp camp amp and starving student II, which were made for anyone and everyone to build safely - you can electrocute yourself with this project. To death. Perhaps before turning it on cover the 120/240 volt ac live track parts with beads of hot glue? Someone else will have better advice. Second thing, the instructions are excellent, but I still needed to remove some resistors I had put on the board after successfully leaving them off earlier in the build - look at and compare the assembled board picture when you've finished yours, before turning it on. As a preamp for the amp camp amps it is truly special. I thought the ACAs were having serious bass run-on, but there was just more, a lot more, happening in the bass department, all of it clearly defined, and the concert bass drum reverberations were supposed to happen. Happy building.
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