Recent content by dr_mick51

I think your amplifier is in BP (bypass mode). In this mode the remote functions stop working. I think you can change it to the regular mode by pressing left or right on the controller. This also works for the other functions as soon as you get out of BP mode.

You need 28.28V output swings. This means your input signal multiplied by total amplifier gain. TPA3255 with PFFB has around (not sure if D1 has been measured) 20dB or 10x gain. This requires an input signal of 2.828V to produce 100w at 8ohms. Therefore you will need a preamp. Also, note that...

On my experience removing knobs, it's always easier if you use latex or rubber gloves to pull them with your hand instead of using any other "tool". It works for me and my sweaty hands. And the knobs come out easily because you had a much better grip.

Well, you can't. First, in mono mode the amplifier will use both positive terminals from both channels Why? Because it is using both channels as a one. Do you want both channels outputing the same signal(left or right) to a 2 different speakers?. Are these speakers identical or with same...

You are absolutely right. Clean power is more important than raw power. Why do you need a noisy SMPS with 48V at 10A if most (if not all) my music is heard at 0.1 to 1W, lets give it some headroom, let's say 10W/ch max. Also people seem to forget how output power works on audio amplifier. The...

And I don't disagree with you. I'm with you on this. Maybe the problem is I don't think as a regular consumer, I'm a hardcore modder. You are right, regula consumers should be informed and probably don't buy this amplifier under certain conditions. The Loxjie A30 is a good MA12070 based...

I assume you mean as the Wiim Streamers? Where they take that RCA signal and then use an ADC to convert to digital so it can be passed via Optucal or Coaxial to another DAC?. I really dont think so. The RCA inputs on the TPA3255 amps pass through the attenuators (Digital or Analog) and then feed...

Ok, sure. Whatever you say. You already made your mind up. I wonder if have not fully read the Infineon documentation: And saw all the tests (sections 10 to 15) are done with a filter and a 22uH inductor as part of the load: Also, there are tests on this website where 22uH inductors are...

Not really. TPA3255/51 are completely differential amplifiers. In fact the RCA inputs are converted to differential by the second stage on each opamp. You could feed differential inputs directly into the amp and completely bypass the opamps. These Opamps are there to generate a slight gain on...

Hello. It is my understanding you tested this with 4 and 8 ohm resistors only. Right?. This amplifier requires a 20uH inductance at the output which is normally produced by the speaker coil itself. Try adding those inductors and re-measure to make sure all that HF interference is reduced.

Nice, so basically you fixed the extra gain on the inverting stage by replacing the 10k resistors from the bottom left on each opamp, and also increased the overal gain on the first stage by increasing from 15k to 24k or 27k. And you just reused those 15k resistors you removed and solder them...

Thank you, that was very informative but a little hard to digest. I only have one observation: On the last graph you picked 10k and 50k, not 15k. 15k is between the 10k and the next 20k line. But your conclusion still apply. Thanks. I'll try those opamps

Good evening. This is a picture of my amp As you can see it has 10k and 15k on both input and feedback resistor for both opamp stages on each opamp. It is my understanding that the first opamp stage(left side of each opamp) is used for the unity gain inversion and you can see it is fed from the...

Hi, I'm confused with the resistor values. The schematics values don't match the values shown on the pcb. My understanding is, if you want to apply any type of gain(increase or decrease the input signal) that would be in the first opamp stage (Left of each opamp). The second stage(which is fed...

Thank you very much. I really appreciate it. But you left me thinking because I'm using OPA1612 with this amp, and the A07 Max and any other TPA3255/51 based amp. You are saying I should not use Bipolar opamp on this amp? Is it because of the NJW194 which is only used on the D1 and D3? I have...