hi, I just started building the whammy and completed the PSU today. While taking the measurements I noticed that the negative rail is off by quite a margin, it’s -11,7V. The positive rail seems like expected.
Is this something I need to worry about? Any tips on how to continue troubleshooting?
That is not right. To begin, please verify it's a 7915 in the U2 position.
See:Which version is this?
https://www.diyaudio.com/community/threads/whammy-pass-diy-headphone-amp-guide.317803/post-7731199
And:
https://www.diyaudio.com/community/threads/whammy-pass-diy-headphone-amp-guide.317803/post-7731267
And:
https://www.diyaudio.com/community/threads/about-op-amps-use.274575/post-4361276
That is not right. To begin, please verify it's a 7915 in the U2 position.
Thank you, I overlooked this when assembling the board and only looked that the 7815 went into the correct place. It turned out that my friend, who collected and sold the parts, had accidentally collected two 7815’s and not one of each. I didn’t pay enough attention it either. So I’ll need to replace the wrong component.
Ok thanks Mooly.
I went through my parts stock and found Muses02 that i had forgotten i had.
Was it so that it requires some modification to the stock cofiguration to work properly? I run stock led configuration on Whammy.
I tried searching the forum but i didn't fing the post where it had been mentioned.
I went through my parts stock and found Muses02 that i had forgotten i had.
Was it so that it requires some modification to the stock cofiguration to work properly? I run stock led configuration on Whammy.
I tried searching the forum but i didn't fing the post where it had been mentioned.
This was it.Muses 02 - C2&C7 = 68pF
1kHz & 20kHz
Need to get those caps.
As we chat I stick the Signetics NE5532 into the Whammy. By far the best bass I've heard from the Whammy. The highs are not too sharp, in a strange way it suits him. Bought second-hand from the Chinese. Plucked from who knows what device.

You've never tried the ceramic version of the the Signetics NE5532. Come to me, and I'll give it to you as a gift. I have some extras.😀
P.S. I sold the Muses02 after seeing how well ceramics match here.
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Your copy of the amplifier does not have to be identical to mine. The 68pF for the Muses 02 was determined by an oscilloscope to be a pure square wave at the output. Output transistors - IRF610/9610.This was it.
Need to get those caps.
Ok. So do you recon i should modify anything for Muses02? I don't have any measurement equipment other than multimeter.
That's the problem with rolling opamps. Sometimes it goes without a problem, and sometimes it oscillates or is not properly compensated. So I bought a simple USB oscilloscope with a function generator.
So this is the FFT I got from the Whammy I was loaned.
It’s not bad of course.
But that is with the spikes below 1khz and the harmonics odd thickness structure if that makes sense
Cheers. And no offense.
It’s not bad of course.
But that is with the spikes below 1khz and the harmonics odd thickness structure if that makes sense
Cheers. And no offense.
Pardon. I didn’t mean to offend anyone posting the FFT if that’s what ‘ stopped’ the thread.
Apologies.
Apologies.
quite contrary, no one is having anything against
it's just rhythm of universe, give it time
it's just rhythm of universe, give it time
Thanks man. I didn’t want to offend anyone.
And mind you this is done with my Focusrite and a DAC3 feeding the 1khz signal.
So the Focusrite isn’t the best of course
And mind you this is done with my Focusrite and a DAC3 feeding the 1khz signal.
So the Focusrite isn’t the best of course
Just something a little different. I have a great selection of knobs, but so far, this one stands out. Also, I decided to use a thick brass disc in the pit, 'cuz that is my mark. I have another on order to fit the headphone jack too. We will see how that looks.
Attachments
Ahh yes, the ceramic version of the Signetics NE5532! The ceramic version was what was used in the SSL 4000 series recording console. I was a recording engineer and maintenance tech in the Nashville area in the '80's. This was where subbing out an NTE generic replacement part got noticed and I was called out for that. They do sound better than all 5532s and for people who's job is to listen to music all day and be aware of changes, you can't fool them. Also noted was a break in period where the sound of the op amp improved.View attachment 1439049
You've never tried the ceramic version of the the Signetics NE5532. Come to me, and I'll give it to you as a gift. I have some extras.😀
P.S. I sold the Muses02 after seeing how well ceramics match here.
Pardon. I didn’t mean to offend anyone posting the FFT if that’s what ‘ stopped’ the thread.
Apologies.
Heavens no, sometimes a post is authoritative enough the thread stops because everyone is "well, there it is" 🙂
The spikes below the 1 kHz fundamental are 60 Hz and its odd harmonics: 180 Hz, 300 Hz, 420 Hz, etc. That's why I modified the power supply to a choke-input, with the accompanying change of power transformer, of course, especially since I biased the outputs to about 200 mA each channel.
The board doesn't fit in the default box but that's okay since my rig has a preamp stage & Khozmo volume control. A 2U Modushop rack mount chassis does the job just fine.
As we chat I stick the Signetics NE5532 into the Whammy. By far the best bass I've heard from the Whammy. The highs are not too sharp, in a strange way it suits him. Bought second-hand from the Chinese. Plucked from who knows what device.
Bypass a 5532 properly (about which I have more to say anon) and they do a fine job, just like most opamps. I suspect "differences in sound" could be related to how the devices react to power supply impedance, and in many cases the standard 0.1 uF on each rail doesn't cut it.
So far, I actually have two Whammys. Fell into one after another. To house this board, a non-standard chassis is required. I mean to say, it will be a bit more difficult than what you will normally find. Having said this, each Whammy that I have is perfectly housed, one in a before there was a chassis for the Whammy sort of thing, where the chassis actually allows the circuit board to slid right on rails into the chassis. Then, I couldn't help myself but to go a head and buy the DIY Store chassis especially made for the Whammy. At first, I thought it to be a bit expensive, but quickly realized that this has all of the holes ready, and more important to me, the lettering. Let's not forget my favorite part though, the front panel. Nice and thick. Pretty damned easy to make this kit look its best too. In fact, it took a bit of thought to make one that might stand out just a bit from the rest.
In the very near future, I will get to hear one Whammy with a 2134opa and the other with an authentic 2604opa that I found. Turned out that I had 'sparked' the original one that led to some strange behavior with volume and distortion. Also, this week, my SPL Phonitor will be arriving back from the shop. Interesting tale there, but I hope it to be well when it arrives. Let the races begin.
I do have a piece of advice about the small nuts that are slid into the top rails in order to hold the top and bottom panels. I used a small piece of sticky putty to get the damned things to stay in place. Somewhat tedious to do all 8 but well worth not having to get the magnet out to locate them on a dirty carpet. I will also add that I don't accept any chatter in a chassis when thumped and so to end all doubt to bottom plate is sealed with a very reliable silicone type adhesive from front to back. As I go along I add damping sheets and use soft silicone feet. It really is just the way that I am that will never change. When complete, you end up with a real brick. Now, back to soldering.
In the very near future, I will get to hear one Whammy with a 2134opa and the other with an authentic 2604opa that I found. Turned out that I had 'sparked' the original one that led to some strange behavior with volume and distortion. Also, this week, my SPL Phonitor will be arriving back from the shop. Interesting tale there, but I hope it to be well when it arrives. Let the races begin.
I do have a piece of advice about the small nuts that are slid into the top rails in order to hold the top and bottom panels. I used a small piece of sticky putty to get the damned things to stay in place. Somewhat tedious to do all 8 but well worth not having to get the magnet out to locate them on a dirty carpet. I will also add that I don't accept any chatter in a chassis when thumped and so to end all doubt to bottom plate is sealed with a very reliable silicone type adhesive from front to back. As I go along I add damping sheets and use soft silicone feet. It really is just the way that I am that will never change. When complete, you end up with a real brick. Now, back to soldering.
I currently have a Signetics NE5532 inside and listen to it as a preamp, which is its primary purpose. I'm not much of a fan of headphones. I need to try a few more opamps (OPA1656, OPA1642A, OPA1622, Muses 02, Sparkos SS3602 and a few more), so whatever works best stays. But right now I'm doing something else, so Whammy is waiting. I hope it will be better than the 6N6P buffer, but it is unlikely to happen. 🤣Bypass a 5532 properly (about which I have more to say anon) and they do a fine job, just like most opamps. I suspect "differences in sound" could be related to how the devices react to power supply impedance, and in many cases the standard 0.1 uF on each rail doesn't cut it.
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