Yes, and how about some pics of the PCB and layout.Any thump, pop or crack at startup, shutdown, or loss of power?
Yes, and how about some pics of the PCB and layout.Any thump, pop or crack at startup, shutdown, or loss of power?
3.5W 16ohm dual channel driven.Wow, nice!
Can it handle 16 ohm load? How much power at 16 Ohm?
Any thump, pop or crack at startup, shutdown, or loss of power?
Simply.I remember people criticized nwavguy's design for using half-wave rectification saying it creates more ripple
Well... what ripple?
L30 doesn't show that behaviour.Chapeau bas! Stunning performance in affordable package.
I had somewhat similar idea with my composite headphone amplifier. TPA6120A2 nested inside feedback loop and half wave PSU.
I wish I could own APx555B and be able to optimize my amplifier to such high SINAD levels.
Do you also observed increased distortion from thermal feedback effect at TPA6120A2? It happens with heavy loads like 16-50Ω at low frequencies.
johnc from Texas Instruments introduced me to this distortion mechanism here.
Is L30 DC-coupled? I see some relays, only power-on delay or maybe there is DC protection too?
. Congrats John, this is one great ampLow frequency distortion is still under 0.00003% (4 zeros after decimal point).
2.5k for mid and high gain setting. 7.5k for low gain setting.Thanks for the review @amirm!
Did you have time to look at the input impedance?
Oh I was asking about input voltage.9V for mid gain, 3V for high gain. Internal works at 15V.
That's very low. Why?2.5k for mid and high gain setting. 7.5k for low gain setting.
Yes, those are input voltages required for max power outputs. 9V for mid gain, 3V for high gain.Oh I was asking about input voltage.
Rejection to interference. And I directly use pot at the input. Pot value has to be small in order to get low noise at all volume position (50% position).That's very low. Why?
Even today one could spend 4 figures to meet it or beat it!OUTSTANDING !! I can’t believe one can get such reference performance at $130. It feels like yesterday when you needed to spend 4 figures and no objetive data...
Thermal noise depends the way the input is implemented. You can have high impedance low noise input.To keep thermal noise down.
Thermal nosie of 10kΩ resistor in 20°C with 20kHz BW is already 1.8µV.
IMHO any DAC with comparable performance to this amplifier would drive 2k5 without any problems. If we want compatibility with worse gear 10k or more would be preferable.
EDIT
John was a bit faster
M400 RCA output supposedly have buffer but they fked up the LPF. It pairs with E30 and D10s so no issue from my point of view. 2.5K is low in your book. But higher than 600ohm means high to me.Thermal noise depends the way the input is implemented. You can have high impedance low noise input.
I would be curious to see M400 RCA -> L30 bode plot...
More generally, I don't think that consumers should pay attention to such details. An input stage should work well with whatever it's fed (the same for a line output BTW). Else the door is open to whatever BS like "synergies" between gear.
Nice!3.5W 16ohm dual channel driven.
No pop on startup and shutdown.
The indicator LED is gentle and warm white color that's visible at all angles.