Yes, basically an IRS chip + IRFB4227 with added post-filter feedback.
The sound quality is comparable to amps with 90dB SINAD at 5W 4Ω, but with way more power.
Attached is the FFT with OPA1612 as the control stage. Harmonics are under -100dB. Non-harmonic artifacts come from the switching supply.
Attachments
so it's perfect for subwoofer aplication.
can you show measurement with 100hz carrier?
also - how can you rate sensivity for differential input / 2Ohm load / full output power / +-55-60V PSU voltage
can you show measurement with 100hz carrier?
also - how can you rate sensivity for differential input / 2Ohm load / full output power / +-55-60V PSU voltage
It only requires 2Vrms input sensistivity to achieve 800W output into 2Ohm load.
4Ohm 5W
2Ohm ~5W (3.17Vrms out) (using +/-85V rail)
Yes, much better since it will lower the noise floor. Just a single resistor change to reduce the sensitivity.
94dB SINAD at 5W 4Ω is possible with 22dB gain.
Using lower supply rails will also reduce the noise floor.
I'll test later with lower power supply rails and lower gain.
ok. great! probably will be interested
... as a car-aurdio-subwoofer-amp 🙂
powered with something like this: https://pl.aliexpress.com/item/1005003166451225.html
... as a car-aurdio-subwoofer-amp 🙂
powered with something like this: https://pl.aliexpress.com/item/1005003166451225.html
The full range sound quality is actually pretty solid, even sharp ears would approve. 🙂
Impressive. IRS2092(S) or something newer? I don't think I ever heard about PFFB with IRS2092. What kind of
Impressive. IRS2092(S) or something newer? I don't think I ever heard about PFFB with IRS2092. What kind of Op Amp did you use for the first post? I am surprised that OPA1612 resulted in that much of an improvement (HD2 from -96 to -104 dB).
Yes, IRS2092S so this is intended as a pro-amp/subwoofer amp replacement.
First post is OPA1656. There is a lot of gain in that stage, so the OPA1612 excels in it.
Here are the prototype measurements.
There is SystemD LiteAmp, but this one is implemented differently.
SE800 gain will be finalized at ~23dB, so there's not too much gain when bridged (~29dB).
Retested the 5W 4Ohm FFT with the reduced gain.
PFFB softened the sound, unlike the usual IRS2092. No hiss because of the low noise floor.
Retested the 5W 4Ohm FFT with the reduced gain.
PFFB softened the sound, unlike the usual IRS2092. No hiss because of the low noise floor.
Shipping will be ready by next week.
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SE800 PFFB High Power Amp
Looks like a 100dB SINAD at 5W/4Ω is achievable with a lower voltage power supply and reduced gain.
I’ve swapped the power supply for a ±70V DC SMPS.
The numbers are looking better—5W/4Ω is hitting 96dB, already in ASR’s "excellent" category.
Looks like a 100dB SINAD at 5W/4Ω is achievable with a lower voltage power supply and reduced gain.
I’ve swapped the power supply for a ±70V DC SMPS.
The numbers are looking better—5W/4Ω is hitting 96dB, already in ASR’s "excellent" category.
But why reduced gain? No one will buy it for max fidelity purposes. And to use the full power, your source would have to be... not doing the math right now but you should consider the variety of AV receivers, sub processors, etc. that this application might actually include.
Or do you think this will be for pro audio?
Or do you think this will be for pro audio?
For FB100 and FB360, removing the 22uF electro cap before the LM7812 reg going to TPA325x improves the sound. Verified 5W/4R FFT and 7812 output on scope and it's the same before and after. Same 22uF caps on ADJ of 317/337 regs can be removed without affecting the SINAD performance. Perfect warm neutral sound if those 3 caps were removed.
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Finally got the time and resources to proceed with the finalized Preamp / buffer.
All OPA1612 opamps.
Diff / SE inputs and outputs
All OPA1612 opamps.
Diff / SE inputs and outputs
You should make the product page more clear that this is a stereo board, not a mono board.
Is it possible to add a potentiometer for volume control?
Is it possible to add a potentiometer for volume control?
Thanks, we’ll change the product page to make it clear.
Yes, you can put a pot before it.