"WHAMMY" Pass DIY headphone amp guide

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#4,281
sennfan said:
I just finished my second whammy-build and would like to share the result and some ideas. The 22 V transformer outputs around 30 V. The spec for the regulators is max. 35 V. So it is within limits. But next time I would consider the 18 V transformer even with the LED reference PSU because in my build, the regulators get quite hot. 60 C /140 F. That‘s okay, but just not necessary. The Burson Vivid sees +/- 15.6 V (measured) which is just perfect. It gets slightly warm: 40 C / 100 F. Perfect temperature for an electronic component. Current to the vivid is 2x 11 mA.
I used a 50 K log POT which has higher resolution in the low-volume-range. So if there is no specific reason to use 100 K, I would rather recommend 50. This provides enough input impedance for most applications.
I also tried the MUSES 8920 opamp. Also very good sound, but personally I prefere the VIVID.
The feeder is a modified IPod 5.5. I removed the internal SMD decoupling-cap and connected the DAC-out to the whammy via two Mundorf evo-oil 22 uF-caps. Nothing else is in the signal-path. The sound-files on the iPod are ALAC and stored on a 512 GB sdxc-card. I replaced the original harddrive by the card.
The whammy sounds great and I am very happy 🙂
Click to expand...
Wow that's an interesting Ipod mod. Do those caps make a lot of difference?
 
#4,282
JermNZ said:
Wow that's an interesting Ipod mod. Do those caps make a lot of difference?
Click to expand...
Compared to the stock smd-caps they do. The 5.5 generation iPod has the wolfson WM8758 DAC installed. This DAC provides very high audio quality compared to the DACs used by apple in later iPods. Perhaps any good PP-cap (like Wima MKP10) will do as well. I live close to the Mundorf factory and have already used them in several projects. So the Mundorfs are my first choice.
In my first whammy build I installed two EVO-2.2 uF-caps for decoupling. But not between the POT and the OPA because this causes POT-„scratching“ if there is DC at the input. I put the caps before the POT just after the RCA sockets.
 

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#4,286
No "official" Gerbers are available to the best of my knowledge (for what should be obvious reasons). However, there are quite a number of people that have created their own versions of the WHAMMY board layouts. They may even be created from the same schematic. Perhaps one of them will reach out to you. Alternatively... someone may be willing to ship you a board as a "gift", but that's up to you, your conscience, and your customs agent. 🙂

Edited to add - See, someone already beat me to it.
 
#4,297
Is there nobody else to help mrfunk on this topic?

Maybe the outline could be created manually? I tried this by modifying the outline from B1 gerbers, see attachment. The coordiantes would maybe still need some fine tuning by a few mils.

For the bottom soldermask I just made a copy of the top mask. Then I renamed all files according to the guide of JLCPCB.

https://support.jlcpcb.com/article/29-suggested-naming-patterns
This is looking better now in the gerber of viewer JLCPCB but I am not sure if this is ok to produce the boards.🤔
 

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#4,300
Hello guys,
I'm back here because of a big transformer problem.
After 4 months of beautiful work of my Whammy, now it seams completely dead.
My blue led is not working and D5 + D6 red led are both off.
I checked current on the main cable, checked the fuse and the Schaffner power inlet but current is there.
My transformer is a Talema ta50E 70065K 22V + 22
The only thing I did yesterday morning was to listen about 3 hours of music, I kept the Whammy on for lunch and when I come back for some more listening, after 1 ore of music it was completely gone, I mean dead.
I don't know what to do in terms of checking and measurements, my idea is that the transformer is friend but I'm not scientifically sure.
Could you guys help me on this in order to be sure that the problem is with transformer?
I have warranty for that so if the Talema is defective I will ask for a new one. BTW attached a pic, but
I can't see any signs of burn here.

Thanks in advance for your time and your patience.

IMG_1757.jpeg
 
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