Fair enough.. but the numbers dont lie.. you want low impedance over a large spectrum, pssr is way better , noise figures also tell no lies..
All theese figures ensure your circuit runs optimal..
Heres an audiophile description of those 7815. Just for Fun.
“With the 7815’s warmth coursing through the circuit, the treble unfurls like dawn-dew on copper leaves; there’s a buttery glow around the cymbals, as if every transient carries its own tiny candle.”
“The bass line doesn’t merely throb—it breathes. Picture standing inside a barrel of smoked oak, each 40 Hz swell stroking your ribs from the inside out.”
“The midrange bears the amber heft of a sunbeam through a jar of honey; vocals hang in the room like silk, lightly crinkled by that analog-sweet hiss.”
“And the quiet passages? Like listening to country night-air: you hear the darkness itself, a subtle choir of electronic stargazing
All theese figures ensure your circuit runs optimal..
Heres an audiophile description of those 7815. Just for Fun.
“With the 7815’s warmth coursing through the circuit, the treble unfurls like dawn-dew on copper leaves; there’s a buttery glow around the cymbals, as if every transient carries its own tiny candle.”
“The bass line doesn’t merely throb—it breathes. Picture standing inside a barrel of smoked oak, each 40 Hz swell stroking your ribs from the inside out.”
“The midrange bears the amber heft of a sunbeam through a jar of honey; vocals hang in the room like silk, lightly crinkled by that analog-sweet hiss.”
“And the quiet passages? Like listening to country night-air: you hear the darkness itself, a subtle choir of electronic stargazing
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Of course, the numbers don't lie. But neither do the ears.
I'd accept a little more noise for better sound quality, but of course, to each their own 😀
I'd accept a little more noise for better sound quality, but of course, to each their own 😀
78/7915 can do a decent enough ripple rejection for a high psrr device like an opamp but one has to take care of the hf noice from rectifiers, possible switching PSU’s and induced on cabling, coils etc before it reaches the ldo. While it rejects 60-70 dB up to hz-khz range it lets almost all above 100 k straight thru.
Decent job yes... So why spend stupid money on external ultra low Noise regulators, umbicillical cables and what not, just to throw into a decent regulator?
Hello PEARL 3 - builders,
I have used LT1085 / LT1033 - regulators after a CRCRC- filter in my PEARL 3- PSU with very good results. I decide more earwise.
Measurements and datasheets are important.The LM317/LM337 are 'oldtimers'. But still good.
Never tried LT3045/LT3094 till now. Would be worth a try.
Cheers
Dirk
I have used LT1085 / LT1033 - regulators after a CRCRC- filter in my PEARL 3- PSU with very good results. I decide more earwise.
Measurements and datasheets are important.The LM317/LM337 are 'oldtimers'. But still good.
Never tried LT3045/LT3094 till now. Would be worth a try.
Cheers
Dirk
It all starts to get a bit academic now.
The reason for using better LDO´s is for me just to prove excellence, (which is fine btw) but is it audible??
In my listening position, when volume turned to approx. 2/14:00 o´clock, I have over 100dB SPL (depending on which LP I play).
When removing needle from the groove, I can hear absolutely no hum, hiss or other nasties,
The 7815/7915 works perfectly for me 😉
The reason for using better LDO´s is for me just to prove excellence, (which is fine btw) but is it audible??
In my listening position, when volume turned to approx. 2/14:00 o´clock, I have over 100dB SPL (depending on which LP I play).
When removing needle from the groove, I can hear absolutely no hum, hiss or other nasties,
The 7815/7915 works perfectly for me 😉
My point is.. could you still get good results with a simpler (cheaper) pre psu and change those 7815 7915.
I read many used super regs, myself included, and i have now wondered if they indeed are a waste of time and money,
They cant regulate anything, the cable, the capacitance prohibits their design features
I read many used super regs, myself included, and i have now wondered if they indeed are a waste of time and money,
They cant regulate anything, the cable, the capacitance prohibits their design features
One can only wonder (or try it out)...
As I wrote in #5.692
"One of my previous builds had UDP-like psu´s adjusted to 19 volts before "hitting" the Pearl. No lack of PSSR.
Despite that, this build sounds better, and is my most well sounding and most noise/hiss-frre build to this date."
Hey everyone - just finished up my Pearl 3 build - duel mono power with sweet murdered out black chassis from modushop.
Fired up power supply, had 24.8v on both sides. Power umbilical showed same. Plugged into Pearl amp chassis and turned on - Right channel showed 24 V at power block and for some reason Left only showed about 9 or 10V. Before I could scratch my head I heard a hiss and Cap 21 let the smoke out with a nice POP. The cap is a bulging for sure but everything else seems fine. Do you guys see anything fishy here or did I just have a bad cap? Measuring across L side R27 was 2.8 V so that's within spec at least.
The only thing I didn't do yet was wire up the front switch - the power inlet is switched for the time being but I'll do the front eventually.
Thoughts?
Fired up power supply, had 24.8v on both sides. Power umbilical showed same. Plugged into Pearl amp chassis and turned on - Right channel showed 24 V at power block and for some reason Left only showed about 9 or 10V. Before I could scratch my head I heard a hiss and Cap 21 let the smoke out with a nice POP. The cap is a bulging for sure but everything else seems fine. Do you guys see anything fishy here or did I just have a bad cap? Measuring across L side R27 was 2.8 V so that's within spec at least.
The only thing I didn't do yet was wire up the front switch - the power inlet is switched for the time being but I'll do the front eventually.
Thoughts?
Reversed cap just above U1 on the left board.
Well, it's all happy now! Ended up bumping R27 to a 820R to get 3.46mA and dang those LEDs are bright so went with 30k and might even go up to a 50k before its all said and done. My first attempt at a custom chassis. Nothing too crazy, just tweaked the original pearl3 chassis to be duel mono power and delete the bal outputs. Thanks again @Gianluca for the help and crazy fast turn around time!
So yeah, this thing sounds wonderful! @6L6 you were right . . . best phonostage I've heard! Even after just 1 record, the details and that "i've never heard that before" stuff was nuts! Thanks everyone for the encouragement, help and amazing generosity! And thanks @GKTAUDIO for the matched / modded 209's! Your boards are very slick, put together beautifully and worked perfectly!
So yeah, this thing sounds wonderful! @6L6 you were right . . . best phonostage I've heard! Even after just 1 record, the details and that "i've never heard that before" stuff was nuts! Thanks everyone for the encouragement, help and amazing generosity! And thanks @GKTAUDIO for the matched / modded 209's! Your boards are very slick, put together beautifully and worked perfectly!
That turned out great, @blue360cuda - congrats!
Yes, I made those boards really tiny to fit tight spaces, and nice to have matched JFETs.
Enjoy!
Yes, I made those boards really tiny to fit tight spaces, and nice to have matched JFETs.
Enjoy!
With family away for the weekend there was plenty of time for P3 building (single psu).
Still waiting on Mouser order with back panel parts, so no final wiring done.
I used mogami w2893 for the umbilical in the psu chassis and plan to use same for power in the P3 chassis pulling 2 of the 4 wires together as the ground.
If using 3 twisted wires as per the online guide is a much better way to go for power in P3 chassis please let me know.
Thanks in advance.
Still waiting on Mouser order with back panel parts, so no final wiring done.
I used mogami w2893 for the umbilical in the psu chassis and plan to use same for power in the P3 chassis pulling 2 of the 4 wires together as the ground.
If using 3 twisted wires as per the online guide is a much better way to go for power in P3 chassis please let me know.
Thanks in advance.
Attachments
They are still in my cellar room 🙂
They were used back in the "Mofo-days".
Probably a bit overkill for the P3 PSU filtering. They should be good for +20A DC without core saturation.
Induction is just measured at 3A DC (50 mH at factory). The person making the inductors was able to go a bit below 100 mOhm (73 mOhm).
As mentioned on here, I'm planning on using the chassi of a Rotel RQ970BX and retaining the current power stage in the Rotel (with a steel divider installed) which gives +/- 17VDC. I'm wondering where best to pick up the VDC and remove the rest of the PCB? (Please see the schematic of the power stage)
