Best low noise regulator?

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#585
analog_sa said:
Spent the last week trying to find something which will power an opamp phono (627->637) and sound better than an ALW-Jung regulator.

In short: nothing came close.

What i tried:

1. 317/337 followed by a cap multiplier. Claim to fame: JC uses the topology in the Vendetta and BT. I was a bit worried about starving the four opamps for current and instead of parallel fets used a bipolar multiplier as Teddy Pardo.
Pleasant, "natural" sound but not much detail or particularly wide soundstage. Diffuse sounding pianos. Still, an obvious improvement upon a 317.

2. Simple 3 transistor regulator using a board from the UGS group buy. A differential amplifier and a pass mosfet (IRF9610). Obviously not so low noise. Similar sound to above.

3. Used a fast opamp (AD811 - 45mA max current) with a low noise voltage reference. Opamp output feeds the phono pre directly. 317/337 used to power opamp.
Interesting sound. Larger than life dynamics, extreme detail in high frequencies. Very impressive on some records but something is obviously not well. Slightly peaky midbass and generally nervous sound. Oscillations that i cannot see on a 60MHz scope? Tried the same using more ordinary opamps. Less nervousness but still not great.


These are not the first regulator experiments i've made. Looks like open loop designs don't attract me too much, at least when powering opamps. This is so uncool 🙁

Any ideas i've missed? Is the ALW really the best regulator to power an opamp circuit?

Previously i didn't like the sound of simple shunts (CCS feeding a TL431 with a bipolar shunt). Should i re-examine them? Any particular recommendations?

Not surprisingly the ALW is very sensitive to the opamp used. Its sound flavour is very similar to that of the opamp used as an amplifier. I have had best results with AD797 and OPA627 and less pleasant with the AD825.
Click to expand...
When I experimented with different series regulator topologies, my observations were that certain sound characteristics could always be heard - also depending on the type of OP-amp IC. This is simply because it was not possible to connect a really large total capacity (e. g. 100.000uF) between the regulator output and the voltage input of the op amp gain stage (between the positive and negative rail for the op amp.
This inevitably means that the intrinsic sound signature of the voltage regulator is always superimposed.
The main advantage of parallel regulators is that any regulator sound disappears due to a very (and arbitrarily) large total capacitance directly at the supply rails of the op-amp. This means that even very easy passive filter chains consisting of filter resistors and caps and a simple zener diode are superior in terms of sound to series regulators.
The first circuit in post #8 under
tiefbassuebertr

Thread 'Which differences between Mark Levinson's "JC-1" and "JC-1DC"'

Both versions are for operating without mains power supply - just two secondary D-cells are in use.
What is the difference ?

BTW - the mains supply version uses the additional term "AC"
The difference is the year of release - the suffix "DC" means a newer series (release 1976) than the older series without that suffix (release already 1974) go to
ハイファイ堂メールマガジン
Who know the difference between the gain stage circuits of this both versions ?

The schematic of the JC-1DC (potted version), which I have create some years ago, you will find in post #8 below.
Maybe there is also a schematic...
which works excellently as a replacement for battery operation, can easily be converted to the appropriate voltages that are common for op-amps.
Prerequisites are large capacitances at the voltage input of the OP amp and a current through the shunt that has approximately the same value as the current through all OP amps that are in use.
 
#587
What is the performance of this power supply?
What does the circled part on the diagram represent, what is the role of those capacitors?

Power_plus.SCH_page-0001.jpg
 
#591
Various electrolytic capacitors (capacitors dimensions) in PCB.
See attached file.
.
Solders follow capacitors.
.
C2, C2_11, C2_12, C2_13, C2_14
or
C2.2, C2_9, C2_10, C2_11, C2_12, C2_13, C2_14
or
C2_1, C2_2, C2_3, C2_4, C2_5, C2_6, C2_7, C2_8, C2_9, C2_10
.
 

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