I think that, while the "forum" format is great for discussions, it's really cumbersome to gather "final status" of designs. In this case, one needs to go through 3500+ posts to see if capacitor X is better left on or off, if this opamp works and what people think about it. Heck, even to see my own notes about my opamp rolling I need to do searches.
I wish we could have a sort of sticky in the beginning of the thread that resumes changes, and that has, for example, a complied list of tried opamps and different user's opinions about them. Obviously it won't be a "final word", but if you read that 10 users vouch for a particular opamp, it means it's a safer bet.
Maybe I can do a script that can do this? I'll look into it.
I wish we could have a sort of sticky in the beginning of the thread that resumes changes, and that has, for example, a complied list of tried opamps and different user's opinions about them. Obviously it won't be a "final word", but if you read that 10 users vouch for a particular opamp, it means it's a safer bet.
Maybe I can do a script that can do this? I'll look into it.
Great idea, Rafa. I also find that the current format is cumbersome for updates as a design evolves over time, or even when searching for specifics.
Maybe the forum migration will help alleviate some of this too..?
Edit: I'm sure the team has had their hands full with the Sony VFET project, but I'm still so stoked for the Whammy chassis pre-orders, whenever they do come around.
Maybe the forum migration will help alleviate some of this too..?
Edit: I'm sure the team has had their hands full with the Sony VFET project, but I'm still so stoked for the Whammy chassis pre-orders, whenever they do come around.
I'm done rolling opamps in Whammy. Time to screw the lid on permanently. hah
OPA827 sounds a bit more "open" and has a bit more emphasis on lower frequencies compared to OPA1656. OPA627 is very similar, but I keep going back to OPA827, without being able to pinpoint why. I think OPA827 is a bit more fluid up high?
For what it's worth. Differences are quite small, and all three opamps are incredible
You rolled some premium op-amps Swifty, good to read you found one you like. Listen to some music for a bit mate
I recently used the OPA1656 in Bonsai's X-altra amp and it sounds very nice, smaller soundstage than the whammy but a lot of punch and drive. The OPA627 is 25 years old??? and I rarely read a bad review on its sound still today.
You learn a ton when skimming the forum, granted it's time you never get back and I fully agree it's can be a pain but there are gems hidden in the pages. To be fair the design has not evolved in any way, you build like Wayne suggests, period. Only the pot and op-amp influence the actual musical performance, changing gain and bias current can help capabilities for certain head phones.
Here are my thoughts after building 4 Whammy's -
None of the caps matter to sound, use the best you can correctly rated. 100uF is enough for the op-amp
C2/C7 Feedback compensation caps are important if you need them, Jfet op-amps will not need these caps usually - this would be the handiest info if someone could sweep various op-amps and their bandwidth measurements. Otherwise use ears and check op amp heat for oscillation.
Use 1% metal film resistors Dale RN55 , Vishay MBB0207, Koa Speer all good
Buy the best 10k - 20K Volume pot you can, this component matters more than you think. Alps are poor sounding compared to TKD 2500. Electronic Muses are superb.
Use 6.5K for R4/R8 to get a bit more gain without too much noise. Reduce C2/C7 to 39 - 47pf if needed.
Spend some money on a good op-amp - these all sound great:
Muses - 02 / 8920 (BJT's)
OPA2107
OPA627 x 2
OPA827 x 2 (Swifty recommendation)
OPA1642
OPA1622
Discrete op-amps are definitely good if you can afford them or spot one in the sales
I'm hoping to collaborate with someone to do a smaller better layout of the whammy. SMD melf resistors and separate op-amps with an upgraded power supply hopefully. All my current whammy kit is for sale.
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I am about to start this project. Any big time-saving tips or headache-avoiding knowledge that would be good to have before I buy the parts? Do I really need to read through this whole massive thread?
Which transformer is optimal?
Also, I'm interested in good options for upgraded volume pots. I assume the one in the list is decent but I wouldn't mind spending more on a premium part, if it would be worth it.
My plan was to order the board and build a mouser list from the BOM in post 5. (I caught the teaser pics for the chassis to come and will await those with excitement). Any other wisdom I could get from you folks would be appreciated. I have all the necessary tools listed in the diyguide. Thanks!
Which transformer is optimal?
Also, I'm interested in good options for upgraded volume pots. I assume the one in the list is decent but I wouldn't mind spending more on a premium part, if it would be worth it.
My plan was to order the board and build a mouser list from the BOM in post 5. (I caught the teaser pics for the chassis to come and will await those with excitement). Any other wisdom I could get from you folks would be appreciated. I have all the necessary tools listed in the diyguide. Thanks!
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Looks like you've made a decision for your friend. Excellent choice.
Unless you plan to pick a bunch of exotic parts based on your own preferences, or unless you have your own stash, I'd very strongly suggest going with the PCB + parts kit from the store. If you count your time as valuable, you'll not save much money or likely any at all if you source all your own parts. Also, you know that all the parts are "the right" parts. Lastly, you won't have to worry about out of stock parts or asking the group "is this part an OK substitute for that part?" when you inevitably find that some part or another is out of stock at your favorite supplier. These kits are a bargain, IMHO.
The only other advice is to follow the exceptional build guide to the letter.
Use the transformer in the kit.
Unless you plan to pick a bunch of exotic parts based on your own preferences, or unless you have your own stash, I'd very strongly suggest going with the PCB + parts kit from the store. If you count your time as valuable, you'll not save much money or likely any at all if you source all your own parts. Also, you know that all the parts are "the right" parts. Lastly, you won't have to worry about out of stock parts or asking the group "is this part an OK substitute for that part?" when you inevitably find that some part or another is out of stock at your favorite supplier. These kits are a bargain, IMHO.
The only other advice is to follow the exceptional build guide to the letter.
Use the transformer in the kit.
Yes. I like the idea of making this and having him test and evaluate it vs his current gear
Sadly the parts kit is out of stock. I did add a notification and may be willing to wait a little while. I would much prefer to purchase the kit from the store and agree it would save loads of time and be well worth it. I'm not interested in pinching pennies.
I may make a starving student amp in the meantime, while I wait on the parts kit.
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Thanks for feeling my pain. Yeah, after making a decision I was quite bummed to not be able to throw money at the kit. I then started hunting parts and just finding the transformer was more trouble than I wanted to deal with. I guess I'll have to practice some patience.
Well, if you're only down to the transformer...
You can try these folks. I've never used them, but if I were in your position, I might.
L01-6365 - Amgis - Transformers - IN STOCK - Hotenda.com
You can try these folks. I've never used them, but if I were in your position, I might.
L01-6365 - Amgis - Transformers - IN STOCK - Hotenda.com
I had only just begun at the transformer and digikey was out of those also. Thanks for the link. I might end up needing it. I hadn't been able to find it elsewhere yet. It's cheaper than digikey's price also.
You don't need a 22V transformer. I couldn't find one either and dug into this thread a little more. Turns out 18V is perfectly fine. I found plenty of those.
Thanks for the input. The transformer isn't a problem anymore as I have some options there.
I found a post from avdesignguru ( "WHAMMY" Pass DIY headphone amp guide ) that had the parts list BOM. Thanks for making and maintaining that.
The problem now is the 3300 Panasonic caps are backordered as are the Nichicon ones (647-UPW1V332MHD) from the BOM in post 5.
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Anyone see a reason these wouldn't be an acceptable replacement? Nichicon UPS1V332MHD (https://www.mouser.com/ProductDetail/Nichicon/UPS1V332MHD?qs=xhFoq8Y2Qkau3oh8X4rHVw%3D%3D)
I'm not happy about the much shorter life, but that was all I could find that seemed to meet the size constraints.
I'm not happy about the much shorter life, but that was all I could find that seemed to meet the size constraints.
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Yeah, less than half the life and almost the same price kind of stings but I am not a patient person
Are there certain opamps that there is some consensus about regarding being amoung the "best"? The suggested opamp (RC4580IP) is so cheap they are almost giving it away and then the AD823ANZ is 20 times the price. I highly doubt it's 20 times better but it is something I really should try? Any other "must-try" opamps?
I used the 18V Talema tranformer. No issues. My voltages are on the money.
Supply lines are problematic everywhere, and it seems to hit hardest on Semiconnductors and Electrolytic Caps. Still waiting for a shipment of caps from Digikey on their own expense because they thought they had stock, but they did not have. This is most probably also the reason the DIY Audio is waiting for their kits to get into stock.
Patience is required in these crazy times.
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18V is the optimal secondary transformer voltage to keep te regulators from getting too hot. Almost all opamps allow a max supply voltage of 15-18V, so any extra voltage is being converted to heat in the reglators.
A 22V transformer was originally chosen because Whammy was designed with the opa2604 in mind, an opamp capable of handling a supply voltage up to 24V per channel.
18V should be the standard transformer recommendation imo.
A 22V transformer was originally chosen because Whammy was designed with the opa2604 in mind, an opamp capable of handling a supply voltage up to 24V per channel.
18V should be the standard transformer recommendation imo.