Is this for me Zen? I do have a phase switch on my PS Audio Directstream DAC. When I'm at my most neurotic, I push it on every single track to check which is correct for any given track...
yup, to you
however , it's handy so do not desolder it
just find some nice cover for , to be able to ignore it most of the time
yup, to you
however , it's handy so do not desolder it
just find some nice cover for , to be able to ignore it most of the time
...way to feed compulsions
yup, to you
however , it's handy so do not desolder it
just find some nice cover for , to be able to ignore it most of the time
Ha! Finally sunk in that phase would influence soundstage depth...
...way to feed compulsions
And the switch for tying together the outputs has long ago been removed, so fortunately my mind is still in that regard. The switch for my dac is hiding right there on my remote. I'm never getting rid of it... Mind be damned.
eh ... if that be other than a placebo the button would be bigger than the volume knob
)eh ... if that be other than a placebo the button would be bigger than the volume knob
Certainly not a necessary feature, but you can also most definitely hear things move around (e.g., voices moving to a different place in the soundstage) as you flip the phase.
Does it make things definitively better or worse? Definitely not. Do most sound engineers worry about keeping every single piece of recording in the same phase? Also definitely not. Are placebos useful regardless of objective truth? Definitely.
Every once in a while there's a track where the lead vocals are clearly out of phase and can be corrected, that always feels good when it locks into place.
So when the lead vocals are in the correct polarity, everything else is backwards..... and maybe the desired effect was to reverse the polarity on the vocals?
To my view, this switch is to be used only when the recording company has a habit of recording with polarity reversed.
There are many positives, absolutely.
The negatives include -
Beat frequency interactions down into the audio band
Radiated noise (RF)
If one fails, the entire other rail will appear on your speaker as DC.
In the time being, issues such as this are why the linear supply will always be the standard.
These are not insurmountable issues, but do require some attention. There's been some look into it, and believe me, I'd love to see something like an interface board in the amp chassis that takes 2 of the external 24v 150w bricks that the ACA uses to make a bipolar, while providing filtering and shutdown protection. No AC wiring at all? That would be great.
However, as soon as you add complexity you add cost, and fairly soon the normal linear PSU doesn't look like a big deal anymore.
You mention a universal chassis where you don't have to worry about the supply - The last couple build guides have been exactly that.
There' no question in my mind that there will be a solution to use SMPS in these projects with minimum or no downside. I'm looking forward to that!
Looking at your linked PSU (MW LRS-200-24) I'm very tempted to get two and just try it.
Thank you 6L6, Zen Mod and Shawnstium for all the info on switching mode supplies. I have entertained the idea for a high bias balanced mono F4s, particularly after seeing Soulution amplifiers with massive switching psus (for what is worth they use Meanwell HRP-600 series with -I guess- RC filters with massive caps)
Life got in the way, no time to start the project. Still, this has been a great read! Thanks!
I just purchased the F4 boards. Now that I'm committed to this project, I have a few questions.
1. Will my preamp swing enough voltage? The specs aren't explicit about that. It's a Linear Tube Audio MZ2 OTL preamp (with LPS+ linear power supply) that I have used to inadequately drive my Omega speakers in the past. I want that sweet OTL sound amplified. The specs page says the following: "Voltage gain: (4-ohm load); 10.3dB, (14-ohm load): 12.4dB." I'm guessing it will work. Right? (Edit: I just realized I can probably just measure the voltage swing myself.) The MZ2 used as an amp puts out 1 wpc, if that is a better way to go, i.e. using the speaker posts versus using RCAs out. . . .
2: Do I need to put a pair of resistors between this preamp and the F4? If so, how best to implement that?
3. The transistors are out of stock at DIYAudio's store. Do I wait, or is there an alternative source, like Digikey or Mouser? I'm assuming I need to buy a dozen or two and then match 'em if I don't buy from DIYAudio.
I promise to read the whole thread over the next few days.
Thanks!
1. Will my preamp swing enough voltage? The specs aren't explicit about that. It's a Linear Tube Audio MZ2 OTL preamp (with LPS+ linear power supply) that I have used to inadequately drive my Omega speakers in the past. I want that sweet OTL sound amplified. The specs page says the following: "Voltage gain: (4-ohm load); 10.3dB, (14-ohm load): 12.4dB." I'm guessing it will work. Right? (Edit: I just realized I can probably just measure the voltage swing myself.) The MZ2 used as an amp puts out 1 wpc, if that is a better way to go, i.e. using the speaker posts versus using RCAs out. . . .
2: Do I need to put a pair of resistors between this preamp and the F4? If so, how best to implement that?
3. The transistors are out of stock at DIYAudio's store. Do I wait, or is there an alternative source, like Digikey or Mouser? I'm assuming I need to buy a dozen or two and then match 'em if I don't buy from DIYAudio.
I promise to read the whole thread over the next few days.
Thanks!
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Not pro enough to answer most questions, but for #3. I bought from punkydawgs here: Toshiba 2SJ74 + 2SK170 LAB MATCHED QUAD to 0.03mA AND 4mV (7-8ma range) | eBay
More expensive, but confirmed genuine parts and great matching. Note that regardless of where you get them, you need the B type (Idss ranging from 6.0-12.0). I failed at that myself the first (non-diystore) time around...
More expensive, but confirmed genuine parts and great matching. Note that regardless of where you get them, you need the B type (Idss ranging from 6.0-12.0). I failed at that myself the first (non-diystore) time around...
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Soldersmoker: a few reactions to your questions:
1) the gain from your preamp should be enough to work with the F4, but this will depend on how loud you like to listen and the efficiency of your specific speakers. My BA-3 preamp build delivers about 14dB of gain (I reduced its output to work with a variety of amps) and works great into my F4.
2) I'm not sure about this at all, I'm hoping someone else can guide you here
3) Yep, you can buy the output mosfets at Digikey or Mouser. If you purchase more than you need, you'll have an easier time matching them. I think if you order 25, they'll come in the original plastic sleeve from the manufacturer, so you'll be getting 25 from the same die lot, which will GREATLY increase the likelihood that you'll have close matches. This will certainly cost more, but will also leave additional matches for a future project. If you don't end up building another amp, you can sell your matches to someone else in the Swap Meet forum. If you need to know how to match your mosfets, click on the "Aleph-X Amps" link in my signature and do a search on "Matching Mosfets." I've got a fairly detailed procedure there.
1) the gain from your preamp should be enough to work with the F4, but this will depend on how loud you like to listen and the efficiency of your specific speakers. My BA-3 preamp build delivers about 14dB of gain (I reduced its output to work with a variety of amps) and works great into my F4.
2) I'm not sure about this at all, I'm hoping someone else can guide you here
3) Yep, you can buy the output mosfets at Digikey or Mouser. If you purchase more than you need, you'll have an easier time matching them. I think if you order 25, they'll come in the original plastic sleeve from the manufacturer, so you'll be getting 25 from the same die lot, which will GREATLY increase the likelihood that you'll have close matches. This will certainly cost more, but will also leave additional matches for a future project. If you don't end up building another amp, you can sell your matches to someone else in the Swap Meet forum. If you need to know how to match your mosfets, click on the "Aleph-X Amps" link in my signature and do a search on "Matching Mosfets." I've got a fairly detailed procedure there.
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And for #2, unless I'm mistaken about how the LTA works, you'd only need resistors if driving the F4 from the speaker outputs. Traditional line-level RCA outputs will connect via normal cables.
Realizing now that I was only talking about input JFETs and that both the JFETS and MOSFETS are sold out at the diystore.
I bought my MOSFETS from alweit on ebay. Shipping takes a while as he's in Isreal, but again, he's well reviewed from folks around here... genuine parts and good matching. He sells matched quads here, just buy three sets and ask for 4 matched trios in the notes: 4 X IRFP240/IRFP9240 (Matched quad) | eBay
I bought my MOSFETS from alweit on ebay. Shipping takes a while as he's in Isreal, but again, he's well reviewed from folks around here... genuine parts and good matching. He sells matched quads here, just buy three sets and ask for 4 matched trios in the notes: 4 X IRFP240/IRFP9240 (Matched quad) | eBay