< or = $700 Linear Power Supply Comparisons

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JohnR

Re: < or = $700 Linear Power Supply Comparisons
« Reply #40 on: 5 Mar 2018, 10:33 am »
I've just done some preliminary measurements on a DAC that has a switchmode supply and the audio measurements are astonishly good. I can't help feeling that adding $$ linear PSUs without knowing what exacvtly it might improve is just stabbing in the dark (while burning money).

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #41 on: 5 Mar 2018, 10:48 am »
If the DAC has inside a very good regulation then you do not need a great external PSU.

Which DAC?

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #42 on: 5 Mar 2018, 10:52 am »
$249. 5V.

Review and Measurements of Topping D50 DAC

https://audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-topping-d50-dac.2403/

The new DACs have better internal regulation. Expected is the widespread use of LT3402.

I am waiting the measures and graphs of RME ADI-2 DAC and RME ADI-2 Pro.

http://www.rme-audio.de/en/products/adi_2-dac.php

http://www.rme-audio.de/en/products/adi_2-pro.php

JohnR

Re: < or = $700 Linear Power Supply Comparisons
« Reply #43 on: 5 Mar 2018, 10:58 am »
I doubt that you will be disappointed with the RME measurements. I have to say that I'm not entirely convinced by the output spectra (of the D50) at your link tho. Anyway that isn't related to this thread.

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #44 on: 5 Mar 2018, 01:46 pm »
RME ADi-2 DAC, in the box you can see the big SMPS.

[IMG] https://s5.postimg.org/p3y819x6v/9_B67374_F-56_CC-4_DEC-9_F95-0_AB5_A640_D700.jpg

JohnR

Re: < or = $700 Linear Power Supply Comparisons
« Reply #45 on: 5 Mar 2018, 02:15 pm »
Well, technology advances! I can only assume that RME have specified the supply fairly precisely, altho it certainly doesn't look like much.

fado

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Re: < or = $700 Linear Power Supply Comparisons
« Reply #46 on: 5 Mar 2018, 03:42 pm »
In late March KECES will replace their DC-116 with a  new model, the P3, which will be ~$350.

fado

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Re: < or = $700 Linear Power Supply Comparisons
« Reply #47 on: 5 Mar 2018, 03:49 pm »
I've just done some preliminary measurements on a DAC that has a switchmode supply and the audio measurements are astonishly good. I can't help feeling that adding $$ linear PSUs without knowing what exacvtly it might improve is just stabbing in the dark (while burning money).

Absolutely, that is why it is so hard. I have three reviews that say the linear power supply improves the sound quality of my Acoustic Plan Digimaster DAC but most do not say it brings it to a whole new level. The good thing is that some LPSU manufacturers do offer a trial period after which the their unit can be returned so I would just be out the shipping. This option may very well dictate which ones I try.

wushuliu

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Re: < or = $700 Linear Power Supply Comparisons
« Reply #48 on: 5 Mar 2018, 04:12 pm »
No amount of speculation will beat listening for yourself and comparing. All the resellers should have 30 day return policies. If there’s no perceptible increase in sound quality just return the supply.

JohnR

Re: < or = $700 Linear Power Supply Comparisons
« Reply #49 on: 5 Mar 2018, 04:44 pm »
True, but I'm not sure I see how a liberal return policy justifies taking leave of reason either. $2000 for an add-on supply to a device that has umpteen internal supplies (some of them most likely switch mode) derived from that seems, well, kinda crazy.

wushuliu

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Re: < or = $700 Linear Power Supply Comparisons
« Reply #50 on: 5 Mar 2018, 04:46 pm »
True, but I'm not sure I see how a liberal return policy justifies taking leave of reason either. $2000 for an add-on supply to a device that has umpteen internal supplies (some of them most likely switch mode) derived from that seems, well, kinda crazy.

I agree. The pricing for some of these is nuts.

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #51 on: 6 Mar 2018, 12:25 pm »
About the RME ADi-2 DAC

[PDF] https://www.rme-audio.de/download/adi2dac_e.pdf




Measures and graphs: page 53, 54...

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #52 on: 6 Mar 2018, 08:05 pm »
With LT3045.

http://www.linear.com/product/LT3045


Quote
Features

    Ultralow RMS Noise: 0.8μVRMS (10Hz to 100kHz)
    Ultralow Spot Noise: 2nV/√Hz at 10kHz
    Ultrahigh PSRR: 76dB at 1MHz
    Output Current: 500mA
    Wide Input Voltage Range: 1.8V to 20V
    Single Capacitor Improves Noise and PSRR
    100μA SET Pin Current: ±1% Initial Accuracy


FS: „Ultra Low Noise“ Power Supply, LT3045 based PCB’s

http://www.diyaudio.com/forums/vendor-s-bazaar/310402-fs-ultra-low-noise-power-supply-lt3045-based-pcb.html

[Big IMG] https://cdn.pbrd.co/images/GFLPErp.jpg

[Big IMG] https://cdn.pbrd.co/images/GFLRnIR.jpg

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #53 on: 11 Mar 2018, 12:21 pm »
I had forgotten the acquaintance AMB The σ22 (aka sigma 22) regulated power supply!

https://www.amb.org/audio/sigma22/


Tech highlights

Quote
Low noise, high PSRR

A constant-current source feeds a zener diode as a stable voltage reference. A low-pass filter (with corner frequency of 1.6Hz) prevents zener noise from being introduced into the error amplifier. This is an effective yet lower-cost alternative to expensive voltage reference ICs. The low-pass filter also provides a soft-start characteristic.

The output noise (unloaded) is less than 10µV at ±30VDC output (measured using a Tangent LNMP (low-noise measurement preamplifier) and a Fluke 187 50000-count DMM in ACmV mode). The output noise is even less when the output voltage is lower. This is much better than the noise of an IC regulator based PSU tested under identical conditions.

The error amplifier is a discrete implementation of an opamp with a high open-loop gain of 102.5dB. The voltage supply to the error amplifier is isolated with capacitance multipliers to boost its PSRR (power supply rejection ratio). This greatly improves the line regulation performance of the PSU.

A long-tailed pair differential amplifier with current mirror and constant current source forms the first stage of the error amplifier. The second stage is the voltage amplification stage (VAS), also with constant current source load. The 3rd stage is comprised of the power MOSFET output devices configured as a source follower.

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #54 on: 12 Mar 2018, 12:07 pm »
The SilentSwitcher

https://linearaudio.nl/silentswitcher

Quote
The +/-15V linear regulators are fed by a dual switcher, working at a high frequency, so as to minimize radiated and conducted noise. Until recently this would not have been an option, but the linear post-regulators I selected have a PSRR of over 60dB at more than 1MHz! Absolutely incredible and exacty what is needed to clench what little ripple remains from the switcher. The 6/5/3.3 V source uses another dedicated high-frequeny switcher. It works in constant current mode into a relatively high decoupling cap and has low residual ripple.

I also put a lot of effort in designing the PCB to avoid excess radiation; very low impedance ground- and current paths, short traces, decoupling caps right at the source, etcetera, etcetera. More time went into that than into the circuit itself...

[Big IMG] https://linearaudio.nl/sites/linearaudio.net/files/connections%20final.png

Quote
[Big IMG] https://linearaudio.nl/sites/linearaudio.net/files/SilentSwitcherNoise.png

The +/-15V outputs of the linear post-regulators have 0.2uV (neg) and 0.02uV (pos) noise at 1kHz, and broadband audio band noise level of less than 40uV (neg) and 7.5uV (pos). That is impressive by any standard. (The baseline for the test amplifier is also shown).

[Big IMG] https://linearaudio.nl/sites/linearaudio.net/files/SilentSwitcher%20Zout.png

-> https://diyaudiostore.com/collections/kits/products/linear-audio-silent-switcher $89





maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #55 on: 7 Apr 2018, 08:29 am »
Verified, the RME ADI-2 DAC with a SMPS has very low noise <- super low linear regulators

Review and Measurements of RME ADI-2 DAC

https://audiosciencereview.com/forum/index.php?threads/review-and-measurements-of-rme-adi-2-dac.2582/

Quote
Note also freedom of low-frequency noise below 1 kHz, indicating exceptionally clean supply (external wall-wart is switching by the way).


poseidonsvoice

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Re: < or = $700 Linear Power Supply Comparisons
« Reply #56 on: 7 Apr 2018, 11:29 am »
I've just done some preliminary measurements on a DAC that has a switchmode supply and the audio measurements are astonishly good. I can't help feeling that adding $$ linear PSUs without knowing what exacvtly it might improve is just stabbing in the dark (while burning money).

+1.

Best,
Anand.

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #57 on: 22 Dec 2018, 03:06 pm »
Linear Power Supply Unit L-100 €178 - €200 + shipping from Bulgary (EU)

https://www.atlhifi.com/shop/fully-assembled-devices/linear-power-supply-unit-l-100/



Quote
Schematic description

The regulator has all-discrete topology. No Operational Amplifiers are used. This allows complete design control over all operating points and parameters for superior performance. Low noise, high PSRR.

There is a bridge rectifier block on the input which is filtered with a massive electrolytic capacitor on the output. This greatly reduce the ripple charge voltage and hence helps for better output filtering.

The error tracking stage is based on a differential amplifier built with dual transistors chip which ensures the excellent thermal stability and equality of its parameters.

The differential amplifier is cascoded which greatly reduce the input noise influence over the error (differential) amplifier and Erly effect.

A Zener diode is used as a voltage reference. It is fed by a Constant Current Source attached to the output of the regulator which dramatically minimise the noise and ripple through the Zener (and hence at the input of error amplifier). The High-frequency Zener noise is additionally filtered by a Low-pass filter between Zener diode and error amplifier.

The output stage consists of two power-Darlington bipolar transistors working in Common-Emitter mode. This allows the regulator to work as a LDO (Low-DropOut) with smaller difference between Input and output voltages which diminishes the thermal dissipation over the regulation transistors.

At the input of the regulation transistors is placed trigger-type overcurrent protection network which engages at a given output current and turns-off them. Once the protection is engaged, it can stay in this mode for an unlimited period of time which prevents the system from doing any harm even in a human absence. In order to returns to normal operational mode the regulator must be turned OFF for a while (to discharce the electrolytic capacitors) and then turned ON again.

And since SAFETY is a thing we care about a lot, a thermal switch is added in parallel with the overcurrent protection. This way even if the current protection is not engaged (which is almost impossible) the output regulation transistors will be turned OFF when their heatsink’s temperature reach 85°C.

Quote
Specifications

– Input voltage: AC 115V or AC230V (according to the destination country or user request)
– Output voltage: DC 12V/19V/24V (user-defined values are also available upon request)
– User selectable option for 8mm. aluminum front panel (black anodized)
– Dimensions: 220x220x75 mm.
– Transformer Power: 100VA
– Weight: about 4.5kg
– Output DC cable with barrel jack 5.5/2/5 mm. (OD/ID)
– Possibility for different output connectors upon customer’s request
– Built-in trigger-type overcurrent protection (in case of protection’s engagement the unit must be turned off for a while in order to recover its normal work)
– Built-in trigger-type overheating protection preventing the unit from burning in case of serious malfunction
– Common mode AC filter on the input of the AC supply voltage
– Front panel LED

Quote
Schematic description

The regulator has all-discrete topology. No Operational Amplifiers are used. This allows complete design control over all operating points and parameters for superior performance. Low noise, high PSRR.

There is a bridge rectifier block on the input which is filtered with a massive electrolytic capacitor on the output. This greatly reduce the ripple charge voltage and hence helps for better output filtering...

Quote
Measurements

Measurements of DC and AC voltages were taken with Keithley 2015 Multimeter while the spectrum plots were drawn using RTX 6001 Audio Analyser. The obtained results are as follows:

– Line regulation (AC input voltage between 216 – 235 V): 0.05%
– Load regulation (DC output current between 0 – 4.5 A): 0.06%
– Output AC ripple voltage when loaded with real load (Lenovo ThinkStation M92p): 4.2 mV RMS
– Measured Power Supply Rejection Ratio (PSRR): -120 dBV for fundamental harmonic (100 Hz)

And ALL the components from well-known shops like Digikey, Mouser and others trusted stores for professionals. ORIGINALS.

maty

Re: < or = $700 Linear Power Supply Comparisons
« Reply #58 on: 22 Dec 2018, 03:08 pm »
To compare, a cheap chinese of 100VA too.

Finished 100VA 12V 6A Low Noise LPS Linear Power Supply with toroid transformer US $127 + shipping from China

https://www.ebay.com/itm/Finished-100VA-12V-6A-Low-Noise-LPS-Linear-Power-Supply-with-toroid-transformer/122728397679?hash=item1c932ebb6f:g:9uoAAOSw8aVZzGwR:rk:41:pf:0

[Big IMG] https://i.ebayimg.com/images/g/0WMAAOSwS1VZzGy1/s-l1600.jpg

Quote
Technical highlights

All-discrete topology.

Single-pass, series regulator design.

No IC (integrated circuits) are used. This allows complete design control over all operating points and parameters for superior performance.
Low noise, high PSRR

A constant-current source feeds a zener diode as a stable voltage reference. A low-pass filter (with a corner frequency of 1.6Hz) prevents zener noise from being introduced into the error amplifier. This is an effective yet lower-cost alternative to expensive voltage reference ICs. The low-pass filter also provides a soft-start characteristic.

The output noise (unloaded) is less than 13µV at 24VDC output (measured using a Tangent LNMP (low-noise measurement preamplifier) and a Fluke 187 50000-count DMM in ACmV mode). The output noise is even less when the output voltage is lower. This is much better than the noise of an IC regulator based PSU tested under identical conditions.

The error amplifier is a discrete implementation of an opamp with a high open-loop gain of 102.5dB. The voltage supply to the error amplifier is isolated with capacitance multipliers to boost its PSRR (power supply rejection ratio). This greatly improves the line regulation performance of the PSU.

A long-tailed pair differential amplifier with current mirror and constant current source forms the first stage of the error amplifier. The second stage is the voltage amplification stage (VAS), also with constant current source load. The 3rd stage is comprised of the power MOSFET output devices configured as a source follower.

High-current MOSFET pass transistors

Two paralleled high-current, highly reliable MOSFETs (rated at 18A each) serve as the "pass" transistor.

The high current rating provides a very high safety headroom against overcurrent damage.
The use of paralleled MOSFETs divides the heat dissipation, simplifying thermal management. Onboard heatsinks can be used which would allow the this PSU to supply up to 1A continuous (with much higher peak currents). More sustained currents are possible by using larger, offboard heatsinks.

The negative temperature coefficient of MOSFETs prevents damaging thermal-runaway conditions that may plague conventional BJT devices.

No current-limiting.

Btw, I can not view the opamp.

Quote
The error amplifier is a discrete implementation of an opamp with a high open-loop gain of 102.5dB...