[DIY BUILD] WHAMMY Headphone amplifier build

[DIY BUILD] WHAMMY Headphone amplifier build.


First of all, I want to thank everybody who participated in making this project available to the DIY community.

PCB was bought here:https://diyaudiostore.com/products/whammy
Assembly guide and help from the community here:https://www.diyaudio.com/forums/pass-labs/317803-whammy-pass-diy-headphone-amp-guide.html
Parts ordered via Digikey/Mouser/Audiophonics.


Schematics:

Careful, PSU configuration is either LED+C10 or R9+R10 (same for negative side)

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Build
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Hifi 2000 Galaxy GX283 Chassis 3mm front plate 80x230x230mm (Whammy would fit in smaller chassis)

Drawing the PCB/components placement before poking holes.

Manually drilling the whole for IEC socket.

Socket secured with some epoxy glue.

PSU gives the following voltages at each stage of the CRCRC circuit, before the regulator on positive line: 33.9Vdc (85mVac) 33.26Vdc (8mVac) 32.64Vdc (1.6mVac), which then exits at a +16.7Vdc after regulator. So with a 22V transformer, the regulators have a lot of heat to dissipate, but then PSU also has plenty of headroom before collapsing under load, which is good.

Ready for blind testing against JDS Atom:

Mod N*2 consists in:

• Removing input coupling capacitor, since the DC across them was always less than 1mV with all my sources. 
• Some 0.1uF film caps were added before and after regulators to better address high frequency noise.
• Decreased output resistors from 10ohms (60mA bias) to 6.9ohms (85mA bias)
• Beefed heatsinking
• Improved Op Amp local decoupling V+ to V- and V+/- to GND.
•  All coupling electrolytic caps on signal path were also bypassed by some WIMA MKP10 0.33uF.
• Capacitors C26 and C27 were also doubled to extend the low frequency response.