16.5V. but the OP amp do not see the full railvoltage. Most OP amps are in the max voltage range +/-15-18Vdc.
Yes. This Whammy ran with standard 15V regs and LED circuit for a while plus other types of regulators have been tried. The one type I did like were the rare Xen discrete regulators from EUVL, very neat and didn't break a sweat.
It could have been here that I read, 'if you can hear a difference in a change to your power supply, there is something wrong with your power supply'. It's a fair point and Wayne has already given us a great linear supply that eats up ripple nicely, as the measurements show on the first page here.
So it's nit picking to try and do better... but what the else we gonna do? 🙂
A USB scope is really needed to see any ripple improvement so at this stage I will say that it works very well indeed and has the benefit of adjustable output. In terms of effect to the sound, all I can say everything sounds brilliant. I tell you this amp can take a tweak or two.
Also on the table for people with 18 or 22V transformers, is the option to run the output stage with the MX at higher voltage and a separate 15V regulated supply to the op-amp. Sod it, why not. Push the envelope...
So, this 994Enh discrete op-amp jobbie is a beast. Kind of left the amp on overnight and today things opened up for sure even with the Xfeed. But the xfeed does indeed veil some music, so out it came and back in with the DACT stepped ebay attenuator, they are very clear neutral pots IMO.
Had a little swap between the 994 and OPA627BM's and those 30 year old Burr Brown op-amps actually hold their own, still damned good. The 994 has all the clarity, space and scale of the 627's but a sweeter more musical tone it has less sibilance on female vocals but all the texture of the sound. Plenty of depth and control to the bass, lovely mids. The Focals are loving it man.
This Whammy sounds bloody astonishing boys, fair play. If anyone can handle a nice bit of electronica, then get hold of Trentemoller, The Last Resort on FLAC or WAV. One of the best produced albums in the last decade. Naughty bass lines 😉
For what it's worth I spent far too much time tinkering again and improved the first Cap MX layout. This time to give more space around the TO-220 transistors I hacked the end off a board and turned it 90 degrees, sneaking it in front of the main filter caps. The supply is now just CRC before the MX, the last 5.1R resistors replaced by wire.
DC Voltage after CRC into the MX is +/-20.5V - Running the amp at +/-18V, leaving just over 2V dropout for the MX. So far so good, wish I had a few extra volts to play with. Will probably try some low noise regs to the op-amp at some point knowing me...
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I don't understand why you removed the last caps to make the PSU on the whammy CRC. The last RC is where the magic happens and gives the flat line reading on the scope. Wouldn't it make more sense to leave the CRCRC intact and tap off from the rectifier bridge to your MX board? Great work by the way looks impressive. 🙂
Absolutely Gaz, no doubt. CRCRC is a slayer of ripple alone. The last RC is critical, your best caps should go at the end I believe, the circuit only 'sees' the last component.
Hopefully, the theory would suggest, the MX takes on the role of the last RC here and cleans any naughty ripple nicely. I would have used the MX on-board reservoir caps as the last RC but really needed some sinking and space around the transistors for peace of mind, this hack was a compromise to allow that I guess.
If you have a scope Gaz, I'll send you one... you tell me mate 😉
Nice one that would be awesome thank you. I'm still learning how to use a scope properly but I have one that works well for what I want it for. I'll send you a couple of my PSU boards to play with although you will have to build them yourself. 😀 Drop me a PM with your address and I'll get them posted out in the morning. 🙂
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Will do Gaz, PM sent. Those PSU's look neat, good to hang an CapMX off 😉
I'm being a cheapskate and want to grab a decent second hand 25 or 50mhz USB PicoScope, heard they are good and a British company. Missed out on a couple but have my eye on one.
I'm being a cheapskate and want to grab a decent second hand 25 or 50mhz USB PicoScope, heard they are good and a British company. Missed out on a couple but have my eye on one.
Basically the same as the whammy PSU but without the config options. LEDs near output are for dummy load. Single rail one makes my NuHybrid sound insane! I paid £180 for my scope second hand it's a 2 channel GW-Instek not a bad bit of kit.
Getting there...good weekend to get some stuff done
Got some of the chassis work done...rear panel contains Cardas jacks, NKK toggle switch, and 2 stage line filter. The hole where the temporary cord goes through will be for the fuse holder and the gland/nut ingress will go below that. A 1/4" polycarbonate front panel is on the way...may institute more of the "Swatch" approach. The 2 caps guarding the OPA2604 are underneath the board to make it easier to change. Nice to be able to accommodate 2 sources without manually unplugging. Was getting a little sick of that. Can also think of a couple other cosmetic touches...like wooden sides. Have a nice piece of cocobolla that would make some nice sides...stained and highly polished maybe.Too busy listening now.
Got some of the chassis work done...rear panel contains Cardas jacks, NKK toggle switch, and 2 stage line filter. The hole where the temporary cord goes through will be for the fuse holder and the gland/nut ingress will go below that. A 1/4" polycarbonate front panel is on the way...may institute more of the "Swatch" approach. The 2 caps guarding the OPA2604 are underneath the board to make it easier to change. Nice to be able to accommodate 2 sources without manually unplugging. Was getting a little sick of that. Can also think of a couple other cosmetic touches...like wooden sides. Have a nice piece of cocobolla that would make some nice sides...stained and highly polished maybe.Too busy listening now.
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Has anyone used one of these or one that's comparable
After building their WHAMMY and using it for a while. If not, I wish someone would try it...very simple to use..it wires in just before the transformer. But it should be attached and grounded to the case. I've just been a little surprised the before and after...well worth trying, but don't want to taint the results if someone does try it. FN2090-3-06 Schaffner | Mouser
After building their WHAMMY and using it for a while. If not, I wish someone would try it...very simple to use..it wires in just before the transformer. But it should be attached and grounded to the case. I've just been a little surprised the before and after...well worth trying, but don't want to taint the results if someone does try it. FN2090-3-06 Schaffner | Mouser
It was quite surprising and made me start thinking about what i had changed during the process of mounting the board. Not really anything of any importance..and then I remembered the filter. It'll be mandatory in anything else I build for sure. And I could see it influencing someone's choice of opamps or headphones even.
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Waaaaay back 30 years ago, Audio Amateur magazine published a short article from a guy who assembled 3 identical looking "power line conditioner" boxes. #1 was just wires from input to output. #2 included a CORCOM AC line filter, and #3 included an AC line filter plus three lightning suppressors (MOV -- Metal Oxide Varistors), (i) L-N; (ii) L-GND; (iii) N-GND. He published the statistics of listener preferences (single blind) who took the three boxes home for a week and listened to all three. A solid majority preferred the sound of box #3, which had an AC line filter and three MOVs.
For what it's worth.
For what it's worth.
I'm just amazed...everything I've played has improved audio. There's no MOV's, as this is just a noise filter. And for others, this definitely a YMMV situation. I have a certain level of RF in the room from small switching supplies...always on TV and CD, cell phone charger, laptop, etc. I discovered this from using an HF amateur rig on SSB. 2 S units of hash could be eliminated if I shut one power strip down. Undoubtedly some of this is sneaking into the power lines. I'll try to attach the data sheet if I can do that with a PDF.
My Whammy uses a Schaffner fused IEC/filtered inlet. My research finds that reducing the current capability of the line filter increases the filtering capability. So I chose a 2A device for the Whammy, rather than a 5A or 10A device:
FN261-2-06 Schaffner | Mouser
FN261-2-06 Schaffner | Mouser
Good to know. I ended up with this 3 amp version I think because at the time it was more available at Mouser than one I had used in one of my FM tuners. I was mainly looking for 2 stage units that weren't too large to fit inside. That's not a problem with the chassis I'm using for this project though. Is there a more optimized filter to be used here? The change in AQ was immediate and noticeable...and I would recommend anyone building to include one in their parts list.
They should be very decent, AMB make some nice kit. The AMB versions use the same regulator IC's as LDOVR's Regulators, which should be a bit cheaper and output is configured manually- -
TPS7A4700
TPS7A3301
He also does LT3045/LT3094 versions.
ebay shop -https://www.ebay.co.uk/sch/alexey.ivanov/m.html?item=253306361665&ssPageName=STRK%3AMEBIDX%3AIT&rt=nc&_trksid=p2047675.l2562
John I was looking to use a switched fused filter in a project and was recommended the FKID 2 stage type as being the one, damned expensive though -
4304.5022 | Schurter,2A,250 V ac Male Panel Mount Filtered IEC Connector 4304.5022 | RS Components
I found the Sigma 11 and Sigma 22 to be better, but made for much higher current/voltages - quite large and you would need a separate case but you also have a wider choice of components...