FB-Ultra layout (4 layer board):
Capacitor style plate layout for the opamps like on THS4222EVM.
Also avoided putting ground planes on inverting pins of the opamp / amp.
Input ground references opamp supply ground (in my BTL o/p design).
Attached docs for guidelines that I've used in designing the layout.
Capacitor style plate layout for the opamps like on THS4222EVM.
Also avoided putting ground planes on inverting pins of the opamp / amp.
Input ground references opamp supply ground (in my BTL o/p design).
Attached docs for guidelines that I've used in designing the layout.
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Has anyone ever added VU meters to one of your amps? Is there a kit that would be easy to integrate?
Kind Regards,
Mark
Kind Regards,
Mark
Hmm no idea if anyone added a VU meter before.
It needs 7.3Vrms balanced input. Gain is 10dB or 3.16V/V. Max output is 23Vrms
FB100 and FB360 requires 4Vrms balanced input.
Latest budget DACs like DL200 have 5Vrms outputs already.
Though we will release a budget SE to Differential preamp module to complement the FB series.
FB-Ultra prototype after all the testing lol. Sings beautifully, no click/pop on power on/off.
Needs multiple rounds of PCB prototyping for layout and parts optimization. ETA 6 months.
Needs multiple rounds of PCB prototyping for layout and parts optimization. ETA 6 months.
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Sami,
I'm probably going to order your FB100 but wondering when you expect to have the SE to diff preamp modules available?
I'm probably going to order your FB100 but wondering when you expect to have the SE to diff preamp modules available?
around 3-6months, fixed 12dB gain, can have a volume potentiometer on its input to adjust gain.
haven’t tried to listen to them side by side. I think clarity-wise not much difference.
-Lester
How does the FB100 do with loads down to ~2.5 ohms?
Also, is there any possibility to order the FB100 with non-standard gain? I'm interested in possibility of setting up an FB100-based amp but with gain matching my Buckeye NC252MP which has 26 dB voltage gain (balanced input only).
Also, is there any possibility to order the FB100 with non-standard gain? I'm interested in possibility of setting up an FB100-based amp but with gain matching my Buckeye NC252MP which has 26 dB voltage gain (balanced input only).
It can handle it but only for a certain volume level / output power.
I think no because we have to replace a lot of 0603 SMT caps to do it.
I re-voiced the FB100, it now comes with Black Elna Silmic II input caps.
Also replacing the VDD chip inductor with 0 ohm resistor greatly improved the highs. (Only applicable to FB100 and FB360)
Also replacing the VDD chip inductor with 0 ohm resistor greatly improved the highs. (Only applicable to FB100 and FB360)
I checked the LTSpice sim, maybe 20dB gain can be done with four SMT resistor changes with slight roll-off at 20kHz.
Already checked, FB360 has "finer" highs.
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I've put it back since the module's sound became sensitive with lower quality SMPS. Means the highs became worse if the supply that's being used is not good.
Latest 5W, 4 ohm measurements for a "random" FB100 module.
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The FB100 page now reads:
Update: Feb. 2025
Changed input caps, all OPA1612 preamp
An FB100 board shipped middle of January would still be the old version, whereas ordering now would get the new version?
Update: Feb. 2025
Changed input caps, all OPA1612 preamp
An FB100 board shipped middle of January would still be the old version, whereas ordering now would get the new version?
We only sent the boards with all OPA1612 in the last week of January.
Before that, it was OPA1612 + OPA1602.
SE800 PFFB is already available!
Here's the 5W 4Ω FFT with the highest rail supply (+/-85V) and 26dB gain.
We'll get better THD+N if we lower the gain to 22dB (through resistor change).
5W 4ohm SINAD already better than a non-PFFB TPA3255.
Sound is bass heavy, and the highs are good. Really a step up from High-density Pro-Amps
Here's the 5W 4Ω FFT with the highest rail supply (+/-85V) and 26dB gain.
We'll get better THD+N if we lower the gain to 22dB (through resistor change).
5W 4ohm SINAD already better than a non-PFFB TPA3255.
Sound is bass heavy, and the highs are good. Really a step up from High-density Pro-Amps
