But it didn't stop you from commenting and sharing your immense knowledge - great! ;-D
//
Today test
full signal in (4.3Vrms) from a modified Katana XLR at 0.00037 THD+N (from DAC)
Output on AMP side (121W) at 0.00034
Why the better output ? CMRR. We have 75db minimum
I am wondering if I feed a 0.0001 signal what will be the output, my generators are not good enough. I guess-estimate 0.0002
full signal in (4.3Vrms) from a modified Katana XLR at 0.00037 THD+N (from DAC)
Output on AMP side (121W) at 0.00034
Why the better output ? CMRR. We have 75db minimum
I am wondering if I feed a 0.0001 signal what will be the output, my generators are not good enough. I guess-estimate 0.0002
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No need for sarcasm TNT.
The other poster was implying that Benchmark-like measurements were achievable without the use of FF EC or Feedback. IME this just isn't the case.
I clearly stated, you can achieve (and I have) very low measured distortion in an amp front end. We achieved around 0.0006% at 25V OP, 26dB of gain,
very flat out to 20kHz for an amp voltage stage with pre OP stage buffer using only degeneration, measured on AP1.
It's impossible to get even close to these numbers with an open loop OP
stage driving 4 ohms at decent power levels.
TCD
Ok Terry , I am stopping the development of the amp based on your feedback.
Haha... OK go ahead
I jumped into this discussion not knowing it was a class D amp module, sorry for barnstorming your party! I've had a look at the data sheet, it's an interesting chip, certainly capable
of a nice amount of power in PBTL mode. This chip would be great for some
PA applications.
What I don't understand is how you can actually know how much feedback is
used. They do not provide much specific info on the internal workings.
WRT distortion, I think testing with 4 ohms, 10kHz and at least 100W will
show more clearly how it stacks up to something like the ABH2.
This where objectively, Bruno's amps are very good.
Cheers
TCD
Will this amplifier be suitable for quiet night listening? You know what I mean?
FWIW, cdsgames has claimed that by ignoring the reference implementation and building the amp and power supply "from scratch" around the TPA3255, Allo has managed to eliminate the rising distortion at higher frequencies that seems to afflict the other TPA3255 implementations. I think he said on 8/9 that his testing shows THD+N of 0.00034 at 121W. Not actually better than Benchmark, but up there with the Purifi amps.
It will be interesting to see if 3rd parties can reproduce those numbers, and also see if anyone can hear a difference between the new Allo amp and the NCore type amps that seem to be in the same price range.
I have not eliminated the 6.67Khz distortion but I reduced it quite a bit .
Yes I got 0.00034 at 120W with a DAC input signal measured at around 0.0004.
The DAC signal has CMRR noise and my from end design has good CMRR (theoretically 80db). Benchmark is 0.00016. (and I assume the input signal is 0.0001)
Our amp will be measured independently .
This new amp was designed for sound quality . That was and stays the main goal .
Yes I got 0.00034 at 120W with a DAC input signal measured at around 0.0004.
The DAC signal has CMRR noise and my from end design has good CMRR (theoretically 80db). Benchmark is 0.00016. (and I assume the input signal is 0.0001)
Our amp will be measured independently .
This new amp was designed for sound quality . That was and stays the main goal .
PSU shuts down randomly . We are debugging .
AMP and buffers perform very good. We were able to improve further, on test data. We have identified and fixed a small heating issue. RCA test data was fixed (it performed worst than XLR) but now it performs on par .
We are expecting shortly the casing .
AMP and buffers perform very good. We were able to improve further, on test data. We have identified and fixed a small heating issue. RCA test data was fixed (it performed worst than XLR) but now it performs on par .
We are expecting shortly the casing .
Out of curiousity, is that number with PFFB enabled? Some people claim that using feedback effects sound quality (yet many others don't complain).
Hello,
I recently discovered that it was possible to use a CM4 Raspberry module on the USBbridge signature with a CM3/CM4 adapter.
Is there any comments about this possibility? I saw that someone already tried it but I am not sure that it would work properly...
Thank you in advance for your support!
I recently discovered that it was possible to use a CM4 Raspberry module on the USBbridge signature with a CM3/CM4 adapter.
Is there any comments about this possibility? I saw that someone already tried it but I am not sure that it would work properly...
Thank you in advance for your support!