"WHAMMY" Pass DIY headphone amp guide

I have a whammy pcb coming this week, and after reading the whole thread I'm wondering what I'm going to fit it with. The following candidates are in play for the U1 position
  1. OPA1612 with soic/dip adapter (7€)
  2. OPA2107AP available at Digikey in dip8 (24€)
  3. BURSON audio V6 Vivid, Dual - through ELTIM (80€)
But for now, I'm leaning towards choosing the BURSON audio V6 Vivid, which is the best so far. This year I would like to finish both WHAMMY and CFA preamp/Headamp GainWire MK3 and I am already looking forward to a direct comparison of these two rivals WHAMMY with Burson Vivid vs CFA GainWire MK3 (from dadod) ;)
 

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The Burson V6 Vivid was provided unsolicited by John Garcia of Burson who wanted my to post pictures of their opamp in my builds. Both units are using Sparkos voltage regulators and one of them are using the Sparkos Pro opamp. The Burson appear to have tighter bass, but the Sparkos a more opened midrange. The Sparkos require about an hour to stabilize for DC offset adjustments. Since they are stacked, it took me a few days to get the Sparkos adjusted. The Sparkos are also sensitive to variations in ambient temps. DC offset in the Burson are not possible, but the opamp appear to be more stable in terms of DC offset.



The input capacitor 1UF_PP is not needed for OPA1612, Sparkos SS3602, Muses02 etc. because there is no DC offset at the input, or there is hardly any up to 1mV.

It won't interfere with the potentiometer. It colors the sound unnecessarily. You just need to put a jumper wire on it. Watch the video above where Wayne says it.

It's a waste of money to put Duelund there...

The two 100pF against oscillations are more important / of course nobody has them.

Has anyone read the Sparkos manual? "placing a 22pF capacitor across the feedback resistor (Rf) will cure any instability that may result. See the section called "Feedback Resistor Selection" for more info."
 
[Edited] I think I missunderstand your photo. Are you plugged into AC mains and using your voltmeter on VAC measure, and it shows zero VAC with a good fuse? The meter shows VDC on the screen. So something inside the entry module is broke. That's pretty crazy being those sell for 20-30 bucks each without the fuse drawer (another $5 additional fee).
 
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Yes, it was plugged in, but my hand obscured the cord. Also, after some time of inactivity, the select function (allowing switching between AC and DC) on my meter switches back to the default DC (took too long to hold leads and take a picture). I used another module with the same fuse and all is well; trying to get a replacement as this module was included in the WHAMMY parts kit at the store.
 
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Sounds like you got a dual fuse power entry module, but only the single fuse drawer and a single slow blow fuse. I'm sure the store will make it right if that's the case. Glad you figured out the issue. Those 1amp DD12 Schurter PEM are really nice and sell for $28.50 plus shipping without the fuse drawer, which is another $5. Just a little tricky to be sure that you get the right drawer that works with the PEM. Don't ask me how I know that....errr...I may have "learned through trial and error" on that front.

Who knew there were so many options for Power Entry Modules from just a single brand. It's overwhelming to try and figure it out, so thank goodness the diyaudio store does it for ya. Occasionally they might make a mistake too, but not very often. If they do, they have always made it right in my experience.