Hi -- I've read through quite a bit of the info posted & I have a couple questions related to the new build (complete kit released last month) kit I've assembled.
I'm new to this so forgive me if the answers are obvious 🙂
If I want to hook up the pre-amp out RCA's -- do I just connect them to the other side of the headphone jack's 3 connections & should I connect the ground rings of the RCA's to the same grounded capacitor I used for the input RCA's (which are grounded to the chassis).
Also -- if I want to add a blue LED as a power on/off indicator -- and I don't want it too bright -- can you please suggest the parts I need and where & how to hook it up on the board for the most effective use.
thanks a lot
Bart
I'm new to this so forgive me if the answers are obvious 🙂
If I want to hook up the pre-amp out RCA's -- do I just connect them to the other side of the headphone jack's 3 connections & should I connect the ground rings of the RCA's to the same grounded capacitor I used for the input RCA's (which are grounded to the chassis).
Also -- if I want to add a blue LED as a power on/off indicator -- and I don't want it too bright -- can you please suggest the parts I need and where & how to hook it up on the board for the most effective use.
thanks a lot
Bart
The LED is easy. Pick the one you want and connect it via a series resistor across any of the large 3300uF caps on the power supply. Be sure to get the polarity of the LED correct.
The series resistor is up to you but would be in the 4k and higher region. The exact value depends how efficient the LED is and how bright you want it. You might get as high as 50k or 60k if it is very efficient and you want it pretty dim. So trial and error on that. A quarter watt or higher rating is fine for the resistor.
The ground question is best answered by those familiar with the boards but normally input and (preamp) output grounds would be connected to the same points whereas the headphone output ground may be different. Although electrically they all connect together, the low but finite resistance of PCB tracks and wiring determines which is the correct option for minimal interaction.
The series resistor is up to you but would be in the 4k and higher region. The exact value depends how efficient the LED is and how bright you want it. You might get as high as 50k or 60k if it is very efficient and you want it pretty dim. So trial and error on that. A quarter watt or higher rating is fine for the resistor.
The ground question is best answered by those familiar with the boards but normally input and (preamp) output grounds would be connected to the same points whereas the headphone output ground may be different. Although electrically they all connect together, the low but finite resistance of PCB tracks and wiring determines which is the correct option for minimal interaction.
This is what I just did on the complete kit. Not sure if root cause of my issue: input only with headphone = cannot get output unless phone jack is not fully inserted and what I do get is on the weak side, thin sounding. Troubleshooting to follow my day tomorrow.
For the preamp out, search this thread on the topic and you'll find a schematic shared by Mark Johnson. (Edit: post #2380)
You'll ideally want to place resistors inline with the preamp out due to expected impedance loads (for most amplifiers), and you may want to also have some resistors in parallel going to (signal) ground... Credit to avdesignguru's post on the following page.
I'm on my phone so I am limited on my ability to share links to all the relevant posts, but they're there. 🙂
As for LED, see my questions several pages back, and the advice from 6L6. I attached a low current LED (like 2mA) to one of the 3300uF caps, and used like a 30k Ohm resistor to dim it down. If you do go with a low current LED, you may want to try even a 40k-50kR in series for a more reasonable brightness. Standard LEDs may need only 10kR.
Here's an image of how I wired mine up to the Neutrik switching output jack. It's not a great image, nor am I the most tidy, but may give you an idea.
You'll ideally want to place resistors inline with the preamp out due to expected impedance loads (for most amplifiers), and you may want to also have some resistors in parallel going to (signal) ground... Credit to avdesignguru's post on the following page.
I'm on my phone so I am limited on my ability to share links to all the relevant posts, but they're there. 🙂
As for LED, see my questions several pages back, and the advice from 6L6. I attached a low current LED (like 2mA) to one of the 3300uF caps, and used like a 30k Ohm resistor to dim it down. If you do go with a low current LED, you may want to try even a 40k-50kR in series for a more reasonable brightness. Standard LEDs may need only 10kR.
Here's an image of how I wired mine up to the Neutrik switching output jack. It's not a great image, nor am I the most tidy, but may give you an idea.
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Are you using the complete kit? Does the output jack you're using have 6 solder lugs (3 on each side like in my picture)? If it does, it's a switched jack and you'll need to wire it a specific way for it to work. I believe Neutrik uses the same wiring scheme for all of their models, which would mean having the the output wired on the left, and pre-out on the right with the solder lugs facing up like in my photo.
Double check the wiring from your input and to your output, and make sure your opamp is installed correctly -- pin 1 & 8, or the dot on the opamp, should be facing to your left if you orient your board the same as my picture.
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Great call outs, TY!
Complete kit, switched TRS jack (6 contacts).
First off, opamp not fully seated (not it, but likely would have been next hurdle). 2nd, based on Jim's guide, appears I have I/O reversed (in my haste to make magic, did not consider). Will swap, rinse/repeat. Thanks again.
Complete kit, switched TRS jack (6 contacts).
First off, opamp not fully seated (not it, but likely would have been next hurdle). 2nd, based on Jim's guide, appears I have I/O reversed (in my haste to make magic, did not consider). Will swap, rinse/repeat. Thanks again.
Progress on my balanced Whammy
Here is the progress on my Balanced Whammy.
Decided to try this just for the fun of it.
Have some optimistic plans for the build based on ideas from this thread.
Khadas DAC
Muses Volume
OLED display
The case is tighter than I expected so will have to see.
Anyway, hope to test for sound this weekend.
Any comments and suggestions are welcome.
Here is the progress on my Balanced Whammy.
Decided to try this just for the fun of it.
Have some optimistic plans for the build based on ideas from this thread.
Khadas DAC
Muses Volume
OLED display
The case is tighter than I expected so will have to see.
Anyway, hope to test for sound this weekend.
Any comments and suggestions are welcome.
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@ fatdad
Had the same issue. Just piggyback the connections on the jack with the L/R/GND that go into the board.
Had the same issue. Just piggyback the connections on the jack with the L/R/GND that go into the board.
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TY @MEGA_amp. Phones working, but without pre wired. ACA and ACP+ under my belt, but still green as not clear to if pre outs need resistors or not (complete kit does not have resistors for this) as i've seen both ways. Just wanting to try as pre to ACA at some point.
It does not need them, but it's a good idea. You can absolutely try it without them, but I'd add them at some point.
Value isn't super critical, 22ohm or 33ohm 1/4w metal film.
A kit like this is a great thing for all DIYers to have, It will save your bacon in future projects, the resistors are great quality, and the price is about what shipping a pair of resistors costs from Mouser or Digi-Key...
https://www.amazon.com/dp/B07P3MFG5D/ref=cm_sw_em_r_mt_dp_ZWDSXT25BR1ZNSJKAX6S
Value isn't super critical, 22ohm or 33ohm 1/4w metal film.
A kit like this is a great thing for all DIYers to have, It will save your bacon in future projects, the resistors are great quality, and the price is about what shipping a pair of resistors costs from Mouser or Digi-Key...
https://www.amazon.com/dp/B07P3MFG5D/ref=cm_sw_em_r_mt_dp_ZWDSXT25BR1ZNSJKAX6S
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Nice find, Jim!
I ended up going with 100 Ohm for my pre-out, so a bit higher but I imagine would still do the job just fine for most power amps.
I ended up going with 100 Ohm for my pre-out, so a bit higher but I imagine would still do the job just fine for most power amps.
I just bought a 300 pack of Zener diodes from Amazon for $7.99. It was cheaper than buying qty=1 of the specific Zener I actually needed, from Mouser or DigiKey. Free shipping for Amazon Prime members.
https://www.amazon.com/gp/product/B07BTKVRG8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B07BTKVRG8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
100ohm will work very nicely.
These resistors are just a very small load for the Whammy output section to always have something to look into when there's nothing attached. Nice to have, make no impact on the sound or normal operation.
hello all - new to the group and the hobby. I'm building my first project, the complete Whammy kit purchased a few weeks ago, and am at the PSU stage. Wondering if I'm missing parts or if I need to source independently....the screw and lock nuts to attach the mosfets to the heat sinks. I guess I will need 6 total. Was this supposed to be included? Obviously I can easily source, but more concerned if they were packaged with any other parts I might need. Thanks all in advance, and looking forward to learning.
Yes, should have been included, and you should have gotten a follow-up email from the store sending you some, or perhaps they were just sent automatically.
Check your PM.
Check your PM.
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 🙂
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 🙂
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Everyone should build whammy, its such a great sounding headphone amp, and preamp too. Easy to build. I built two for me, and soon one for a friend.
I use mine with external power supply with whatever voltage i desire, +/-12 or +/-15 volts.
This allows me to use burson or any opamp. Lots of fun to choose.
Cheers.
I use mine with external power supply with whatever voltage i desire, +/-12 or +/-15 volts.
This allows me to use burson or any opamp. Lots of fun to choose.
Cheers.