I love these updates!
It’s fun to read all of these engineer’s tricks.
Thanks for the updates Alex.
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Chris its really close to being a “perfect” amp!!
LOL!
Alex
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Finally settled down with an Analog Devices AD746.
With Empys its a stunning overall sound.
Solid holographic sound, very realistic, airy, ethereal, live concerts are mind blowing nice…
Easy amp to build.
Wayne Colburn makes great stuff at PassLabs and his Whammy shows his prowess in design!
If its good enough for Wayne…well…
Alex
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Lovely looking Amp. Different look too.
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Thanks!
Its a wonderful amp, seriously good…Wayne Colburn of PassLabs has a great simple design thats well thought out…
The way the PCB sits in the case makes the volume knob mount below the center line of the front panel. The neutrik 1/4 phone jack is just above the center line so they are a little offset. I was too lazy to do a custom case where you can have more “Say” over where these things finally wind up.
Its a minor pain to swap out op amps, have to remove the front panel 4 screws, take out the top panel and the op amp is in between two electrolytic caps…
Some folks mount these caps at 90 deg to the board. A good idea I might take this apart and do this small adjustment some day.
I left the case open when I was trying different op amps. Then once I was done buttoned it up.
The lettering cost me $2.50 vinyl from a US company.
Alex
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Nice! How do they compare? The circuit looks very similar all in all, i expect that they are also relatively close sonically…
hmmm depends on the op amp and other mods I guess.
I have never seen a schematic of the HPA-1. But the Whammy is an op amp type of SS ciruit. The HPA-1 is pretty much totally discrete except for one op amp used as a servo.
So I cant say that the circuit looks similar unless I can take a look at the HPA1 schematic. Pass doesnt usually hand these out until the product is “end of life” according what I know.
Sound wise the Whammy is great, the HPA-1 is just greater!! lol
In what ways…well this is indeed subjective and you need to experience both personally.
IMO the HPA-1 has more overall 3d wide like soundstage and more of an overall spaciousness to the sound image…
Many folks would be very very happy with the Whammy with most headphones out there as well and u can play with op amps until the cows come home…
Alex
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Hi there I stumbled across this thread during my search for info on the whammy amp. I see on the diyaudio store they only have the PCB in stock and the parts are almost always sold out. Do u guys know how often they have the parts in stock or how else can I get my hands on them? Cheers
Good luck with this. Been waiting for months since the last go -around…I bought the pcb and just ordered parts from the BOM in the build thread.
Its a bit harder and laborious, but print out the schematics and you can use them as a guide or aid in the process and decide to change anything etc…the build thread is over 300 pages now…full of great hints and tips…
Example:
Mouser, Digi-Key, and Markertek are the places i use to get stuff…
Good Luck!
Alex
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thanks Alex, the only DIY kit i have done is the BH crack so i am not sure if i have the experience to shop the parts myself off the shelf… Im gonna wait for another couple of weeks if they still dont have the kit in stock i’ll try that!
Some of the parts are on weeks and weeks of back order right now. The 1K resistors are B/O at several sites…u can substitute…but with diy it indeed helps to know if the substitute will “FIT” on the pcb and function and not impede the design in anyway…
Alex
I ordered all parts myself starting from the bom in the first page from 6L6.
This allowed me to cherry pick certain components, add some more cap and resistor to experiment with extra psu decoupling and output bias options.
In addition you can better suit to your budget, but it s some work to search each component. In the end I just needed to order from digikey+ mouser to get a complete kit.
I can help provide my (now old) BOM it thats of any help.
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I’m in the middle of trying to build this. I found a mouser project link on diyaudio that everything except the transformer (digikey) and the alps blue velvet pot. I can post if interested.
I will say that even then, the “stuff” you need is incomplete. So far I have needed a random small machine bolt, lock washer, and nut for the ground/safety screw (2 nuts make it easier - tighten the first one, put ground on ring terminals, and tighten them down with the 2nd nut); 3 female wire disconnects for the a/c thing; 2 ring or spade terminals make your life easier hooking ground up; 2 random screws to attach the a/c power entry; and i still don’t know what i was or am supposed to connect the safety capacitor to.
If you follow the guide, step 4 involves drilling a hole for the rca connectors, one for ground, and using a jigsaw or something like that to cut out a hole for the a/c power entry. in hindsight, i should have cut out a piece of paper the size of the back of the enclosure and mapped out exactly where i wanted the a/c power and rca connectors (and power switch). i yolo’ed it which i’d rather change next time.
my first project was the pete millett nuhybrid (i really really like it) and in that kit you literally had everything you needed. i think the crack is the same (i hope to do it one day). this is definitely a step up. the instructions don’t hold your hand. what i’ve realized is that most diyaudio projects let you choose how to wire the headphone jack, rca jack, and power connectors to the board. that’s great, that leaves a lot of room for creativity in customizing your enclosure. but i know that can feel overwhelming. but, i’m stumbling through it, and you can too. if interested i can provide the “i have no idea what i’m doing” guide to this project, assuming i don’t kill myself when i test out the psu.
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Yes, please post that project link.
for the BOM stuff: https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=F1AD28D424
- edit: the mouser project above above does not have all of the caps you need. You need 6 of the 220uf/50v caps and the link has 2. the link uses 647-UKT1V221MPD, increase the # you need to 6.
- I see 2 things out of stock. For the resistors, find something the same but 1/4 watt. There’s a post in the forum that the resistors are really 1/4 watt.
- For the Vishay transitor thingamabob, i can’t for the life of me figure out the difference between the one in the link above and https://www.mouser.com/ProductDetail/Vishay-Semiconductors/4N36/.
- Also, get the op amp you want. don’t just accept the default one in the project link above.
For the enclosure: https://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=304A2E96C6
- delete the power cord unless you want a super short one, you probably have 8 of these in a box somewhere
- the enclosure comes in different colors, switch it out if you want
- add a knob if you want
You will also need a transformer (https://www.digikey.com/en/products/detail/amgis-llc/L01-6365/2137091) and pot (ALPS 100K Blue Velvet - STEREO Potentiometer)
Other things I’ve needed to complete the enclosure so far:
- you will need 3 of these things for the a/c power entry for whatever wire gauge you have https://www.homedepot.com/p/NSi-Industries-16-14-AWG-Fully-Insulated-Female-Disconnect-in-Blue-50-Pack-IF16-250-3N/303994276
- you need a way to screw or bolt the a/c power entry onto the enclosure
- a random machine bolt/screw and nuts for the ground
- wire
- a couple of spade or ring terminals may make your life much easier
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Thanks. You just lowered the chance I burn my wife’s house down by like 4%.
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Gonna be a few days before I can work on this some more. But, I figured I’d start writing down what I’ve done and what to do. No pics yet.
The idiot’s guide to building the Whammy
Order all the parts
go to the guide on guides.diyaudio.com and read through step 4. everything below will walk you through steps 1-4.
Once you get all the parts, unpack the ac power entry (where you plug it in), fuses, red and white rca connectors, power switch, transformer, enclosure, and safety capacitor.
Put the fuse in the a/c power entry.
find a cardboard box you don’t care about or a piece of card stock, something a little sturdier than paper. cut out a piece exactly the size of one of the ends of the enclosure. put the pcb in the bottom of the enclosure and put the transformer on it. put the cardboard on the open end of the enclosure next to the transformer. that’s where you’re probably going to want to put the a/c power entry, the rca input, a ground, and maybe the power switch. the a/c power entry is huge, and you are putting the transformer on the pcb temporarily in this step so you can plan where things go and you don’t make a mistake planning where things go. also, congratulations, the power switch is on the back, you can apply to work at schiit. if you want to put it on the front, that’s cool too, just gonna take more wire. either way, i wouldn’t hook up the power switch yet. info on that below.
notice there’s not a lot of room between the transformer and the end of the enclosure. you’ll have to move the a/c power entry to the middle. tight squeeze for the rca input and that’s ok.
get the cardboard just like you like it. now mark off the spots on the real enclosure and drill and jigsaw. drill holes for the rca connectors, space for the jigsaw to cut the a/c power entry hole, ground, and maybe power. and you may want holes for where you are screwing in the a/c power entry.
if you have drilled a hole in for the power switch, you can screw it on, but ignore hooking it up for now. If you hook it up now the end of the enclosure is now attached to the pcb. we will come back to this. much later.
attach the rca connectors and a/c power entry to the enclosure end. attach a ground screw to the enclosure end (see the step 4 guide for sorta kinda what this looks like). using spare wire, solder the ground connectors on the rca inputs together. solder a wire that connects from that same connection to one end of the safety capacitor. solder another wire to the other end of the safety capacitor. connect that wire to the ground screw. This is why I recommend a ring terminal. One end of this wire will attach to the safety capacitor. The other can go to a ring terminal that you can easily screw on and not have to solder.
No I don’t know where the safety capacitor goes. I used some thermal paste to stick it on the side of the enclosure, but thermal paste isn’t really like glue. the capacitor is stuck but it slides around.
You need 3 female disconnects for the a/c power inlet. Crimp wire in them. Solder one to positive on the board, one to negative, and put a ring terminal on the other (so it’s easy to put on the ground screw/bolt). You’ll need to read the guide to remember which a/c hole on the board is positive and negative.
Now, here’s the cool part. Unplug the disconnects. You’ve got an enclosure end that is basically done except for the power switch, and we will wire that later. And you can disconnect the end from the board so you can solder stuff later.
Solder the wires in step 3 of the whammy build guide for the appropriate 120 or 240 voltage.
Take a break. Part 2 will basically be “follow the guide on wiring up the power supply and test.” Once it’s working, disconnect the a/c power entry and work on part 3, soldering all the pieces.
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Super cool!!
Post pictures if you can!!
Hang in there its a really awesome amp!
Alex
Thank you man 