Pass Labs Whammy - Solid State Class A Headphone Amp Kit

Hi All,

I just came across this the other day, and it looks really cool, and like a great value. Nelson Pass, is quite a big name in the speaker amp world, and is known for some amazing designs. I would love to know, if anyone has heard or seen one of these Whammy amps in person?

The amp is a Class A Solid State and the few reviews I have seen, say this amp can hang with amps costing over $1000.

I look forward to hearing what ya’ll think!

Happy Listening,



I have one finished minus drilling some holes in the case sitting on my bench.
I’m not really expecting anything mind blowing from it.
I’ll post impressions next week if I can get a few hours to finish it over the weekend.


I’m kind of partial to everything Pass Labs. I have their 260.8s monos, XP-22 Pre amp along with their HPA-1 Headphone Amp. Though my amps are class A/B they are Class A to 34 watts which I haven’t been out of yet. The HPA-1 Headphone Amp is Class A and with Focal Utopias just awesome …

Box 8


You should build one and send it on a tour.



Well it works, and my initial (got 10 minutes to listen to it before having to cook dinner) listen was very positive.
I’ll post more detailed impressions after I get a chance to listen to it.


Nice! I found out about the Whammy, from the a guy I know that professionally builds Bottlehead Crack amps, and he says the Whammy punches up there with amps costing much more. He also did a bunch of opamp rolling and settled on the OPA2107AP. It is nice to get some more opinions.

Out of curiosity, what DAC are you using the Whammy with?

Thanks for your time, and I would love to see some pics.



6L6 Build Guide:

Wayne Colburn 2017 Youtube:

Diyaudio Build thread:

Have Fun and welcome to the Diy world!



Using the whammy with a Gungnir multibit right now, feeding into Focal Elex.
When I first turned it on it was a D10 into HD598’s, since those were “expendable” if I’d messed up. I also briefly tried some Ether CX and HD6XX’s on it. I don’t really have anything “hard” to drive here.
I picked it up out of curiosity, “how good is some of the DIY SS stuff?”. The pass labs connection was also intriguing.
I did get a couple of hours listening in last night, and my impressions are still very positive, right now I’d probably take it over my Jotenheim, I still prefer the Liquid Platinum to it, but they are very different amps.
Detailed impressions when I’ve had a day or two to listen.

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Just so your know Pass Labs has about a 4-6 week burn in time. You haven’t heard it at its best yet …

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I still only have about 8 hours listening on it, so it’s really still just a preliminary impression, I’ll keep listening, and if my overall impressions change I’ll update. But my ZMF Eikons arrive tomorrow, and while I will listen to the ZMF’s on it along with my other amps, it might be a week or two before I get back to “listening to the amp”.

The bulk of listening was done as follows Amazon Music HD -> USB -> Gungnir Multibit -> Whammy -> Focal Elex. I did try a number of other heaphones, the whammy had no problems driving any of them including the T50-RP2 (11 on the volume dial, so plenty of headroom).

I built mine from the Kit supplied by DIYAudio, the kit is complete (minus a chasis) and they are high quality parts. You’ll want to sort and label the resistors before starting, with my aging eyes and the tiny text, that required magnification and about 45 minutes.

The build itself is straight forwards, you can build the power supply section in 3 different ways, and all of the parts for all 3 are in the kit (the build guide covers these), you will have components left over when you are done. I used the LED reference design, so I ended up with some extra resistors.
The build guide has you build and test the PSU first, that’s what I did, after that it’s pretty much put the components in the right holes, the only thing you don’t populate is the isolation caps in the feedback circuit. Note that the power circuit is dealing with mains voltages, and you need to be comfortable with that.

I used a Hammond 1455T2201BK enclosure, it’s basic, the circuit board is designed to slide right in, you need to ensure you drill the hole for the volume pot in the right place, and cut the hole for the IEC socket slightly above the center line (I think mine is offset 2mm vertically), so it can’t interfere with the resistor it’ll end up being close to. I like the amp enough I’m considering making up a custome facia for it.

Total build time for me was about 4 hours to put everything on the board, another 3 maybe messing around with the enclosure, but I 3D printed test plates to ensure I had clearances, if you just used paper templates, it’s probably an hours worth of work to cut the holes and finalize the I/O wiring.

The Amp takes a long time to get to a stable temperature, the Voltage regulators get hot, the FET’s in the amplifier, not so much, I left it on overnight, and it stabalized at about the same temperature as the Gungnir.

The noise floor is pretty good, there is a slight audible hiss when the volume knob gets past the 3 oclock position with no input, given most of my listening was closer to 9 oclock, it’s not really relevant.

Overall I really enjoy listening to the amp, it’s a very Neutral/Natural sounding amp, with perhaps a hint of warmth.
I like the tonality, bass has impact and control, the trebble has good extension, but isn’t fatiguing, and I liked the timbre on vocals.
The dynamics were also a standout for me, it resolves details really well without shoving them in your face.

It’s a really good sounding SS amp, better than any other SS I own, which is limiting my ability to give a complete review.

If your comfortable building the amp, and you don’t need the additional features they provide, I’d take the whammy over a Jotunheim, or any of the THX amps I’ve heard, how it competes with higher end SS amps I can’t really say, because I just don’t have a reference.

I do still prefer my Liquid Platinum, but it’s not a very interesting comparison. It’s a tube hybrid, and it’s balanced out of the Gungnir, which does make some difference. I just prefer the additional body and warmth the tubes impart and the increase in soundstage the LP provides.


Thanks for all that great info! It is nice that we have the same gear, so that really gives me a good idea of the sound. I have heard opamp rolling can change up the sound a bit as well, so that seems it could be fun to tweak the sound a bit, and overall it sounds like a really great value.

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I have a Burson V6 Classic opamp on order, to see how that sounds.

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Thanks Polygon, for sharing. I’ve been eyeing the kit and wonderibg

Nice! The professional builder I know has tried lots of the available op amps in the Whammy, and recommends this one, OPA2107AP. One of these days, I am going to build one of these. . .

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The higher end Burson OpAmps are actually discrete implementations of an op amp in a package that will fit in an 8 pin DIP socket.
I got mine earlier this week, unfortunately it overhangs the socket by enough it won’t fit between the 2 Caps on either side of the socket. I need to order a couple more caps to replace them and leave some leads so they can be bent out of the way a bit.
Opamp rolling is even less interesting to me that tube rolling TBH, but id like to at least understand if there is a significant impact.

The Whammy itself is very much in my regular Amp rotation, in fact with the Aeolus I prefer it on SS (specifically the Whammy) to the tubes and hybrids I have.


I use the WHAMMY for the last few months (since COVID19 started)- and I own the Bottlehead Crack OTL with SB- the WHAMMY is what I use for my OLLO Reference S4X, Kennerton Magni and Gjahallahorn headphones, but for my HD600’s I prefer the OTL Crack BUT the WHAMMY does a straight up job- just not as euphoric as tube crack - It really is a match made in heaven w/HD600. For Critical Listening I prefer the PASS. I used the OPA2017, OPA627 (two), LM833N and maybe one other. I settled (like not at all) with the OPA627 which is the most dynamic and clear with no analytical harshness. I love the amp and have not found anything I could afford under $1K that can compete. You will love it I think.


These are the op amps I’ve tried in order of preference (with my notes for the two I REALLY didn’t like lol):

RC4580 - Dull, lifeless, no dynamics.
AD823 - Not feeling it. lifeless. tired. don’t want to listen to it. dirty. constipated.

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Well i finally ordered a PCB that other day and will build this amp over the winter months…waiting for the parts package…makes things easy in chasing parts…



Parts on order!!



Sorry, did I push you over the edge, there? :smiley:

So how did the V6 classic sound?
Which Op Amp sound best to your ears?

I did some comparison last year but it would need a refresh I think now that I listened to some more Op Amps and got a better grasp on the differences.

My main complain about the V6 vivid is the slightly harsh / gritty treble, otherwise it is truly excellent.
In comparison, V6 classic is very non fatiguing, more euphonic, less sterile.

Here’s a picture of my WHAMMY amp, used with Bifrost 2, Sennheiser HD58X modded and DIY speaker system:

Since hat picture I did some more mods.

Oh, and I did some measurements with Audio Precision APX555 and a scope, and the amp performs pretty well:

THD at 1kHz, OPA2107(not best), 8Vpeak (amp can output 10V):

10kHz square wave:

OK, one last measurement: I zoomed in the transient of the square wave and observe different transient behavior across op amps:


Burson V6 classic:

Burson V6 Vivid:






Op Amp PSU’s decoupling is way overkilled (which is good), so I believe that we really see the behavior of each Op Amps, rather than the system oscillating.