IVX

try to increase the ADC input level up to .1-.5db to find the lost 3db ;)

right, 200k 25C thermal noise -116db(A) + OPA1612 about 2pa/Hz^.5 of input current noise. Exactly -104db(A)

Thank you for this great piece of software! By making it free to use you make it available even to people who don't have much to spend...

yes, the direct email works, thank you.

yeah, me too: 此国家或地区不支持捐赠给此收款人 I think it is a web form issue, I wanna try PayPal directly to the email but how to get that?

pavlo_y0l0s, set the sampling freq higher, 96k or 192k, 768k. BTW, please don't crop the REW window, let us see all FFT parameters.

just an idea, I don't need R2R too. However, I don't believe if my idea doesn't work ;)

l think if the FFT of Apex 456 tape's noise played with two different R2R is identical, then these 2 R2Rs have the same frequency...

the idea: I think the spectrum of demagnetized tape(no bias) on the calibrated R2R(with special test tape), may be used as a reference...

the model is simplified, THD simulation shows -200db+ ;) MC12 model OPA1632 has a reasonable H3 -124db.

Oh, like a netlist for Pspice.. I see, nice!

yes, it works, how did you make it work?

right, the power rail is regulated and smoothed with 3pcs Low-ESR solid polymer caps 1500uF/6.3V.

Ah, it was early morning on my side, my bad, 550mA is calculated current, 650mA is actual. It was16ohm. Not everyone's phone may handle...

around 150/650mA. Interesting that I roughly calculated the max power current first, and got 5V/((.7W+.7W)/.7) = 400mA(typical class AB...