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Desktop amplifier.
I have a Dayton class D amplifier that I have been using for desktop duty for a long time. I recently took my desktop speakers to a friend's house and it quickly revealed that my desktop amplifier is a weak point in my system.
There have been a flood of TPA3255PFFB amplifiers that have come out recently. Please post your experience with PFFB amplifiers or a reason to consider one model over another or any other model of amplifier that you have enjoyed for desktop use.
Any other recomendations on how to maximize desktop listening would be greatly appreciated. I have my speakers raised off the desk as much as possible and I am using an audio interface as a DAC streaming Amazon HD. It's not bad but I know it could be better.
Thanks.
Comments
Well... What Dayton amp?
https://www.parts-express.com/Dayton-Audio-DTA3116HP-Class-D-Mini-Amplifier-with-Headphone-300-3810?quantity=1&srsltid=AfmBOoo-5HNKIq_XSSGUkhBv6r9LPCqBo4iSe5rEseY-zqxITQnEPQ6j
Ken,
I built this shelf for the electric table top and it works well:
Amp is this one with an 8" Sealed sub near corner of the room:
https://www.parts-express.com/Dayton-Audio-DTA-2.1BT2-100W-2.1-Class-D-Bluetooth-Amplifier-with-Sub-Frequency-Adjustment-300-3831
Thank you.
Ken,
I have one of the relatively new Fosi V3 monoblock TPA3255 amps with PFFB. It measures really good at ASR (HERE). I got it to be my measurement amp (thus the reason for only having ONE monoblock) but have not taken it out of the box yet. If you want to borrow it and check it out you can.
There seem to have been several TPA3255 amps with PFFB released recently that are fairly cheap. Pick the features/asthetic that best suits you.
David, I might take you up on that. The Fosi seems to get a lot of love.
I get very skeptical when the reviewers seem to shift gears as soon as there is a new product.
The Douk A5 seems to split the road between the Fosi ZA3 and the Aiyima A07 Max.
On my bench, I'm still operating in the dark ages with a Lepai 2020 that I picked up years and years ago. Had to google PFFB to find out what that meant. Concept seems to be a reduction in power supply switching noise by including an additional low pass filter inside the amp's feedback loop. Have not listened to amps using this concept, so I guess I am of no help in that department. My main problem with the Lepai 2020 has always been the lack of power. It came with a wall wart type 12Vdc 2 amp power supply and it distorts badly at very low volume levels. So, be sure to look for a PFFB amp with the biggest power supply you can find.
One of the first amps I tested when I acquired the Quantasylum audio analyzer was the Dayton DTA3116HP, which I received as a door prize from PE at InDIYana quite a few years ago. I am not surprised that you find that amp to be a limitation for your desktop system. Using 1 kHz data, distortion rises above 0.1% for anything above about 1W.
At higher frequencies, distortion gets worse.
Frequency response is load dependent at high frequencies. There is about a 1 dB of roll off at 20 kHz into 4 ohms or about 0.5 dB rise at 20 kHz for an 8 ohm load. If your speakers are low efficiency and padded with a big series resistor, this could be an even bigger problem.
I also tested one of the 2020 amps (a Lepy). It has a generally similar level of performance as the DTA3116HP, but less power and a little more ragged distortion curves.
My experience is that any of the decently implemented TPA3251 or TPA3255 amps - even the older Aiyima A07, will take your desktop system across the threshold of being "good enough". The PFFB amps do help eliminate the variable frequency response vs. impedance and further reduce distortion.
Here's the 1 kHz distortion vs. power curves for the A07.
Sehlin Sound Solutions
I'm running an ACIN hybrid tube amp. I'm running an M2 Pro Mac Mini mounted to the side of my desk, with the ACIN and old time Yamaha FM tuner in a stack beside the desk with my printer on top. The ACIN plays thru a pair of Piccolatas mounted on the wall flanking the desk.
I have a small Parasound ZAmp for my surrounds, pretty solid little amp
https://parasound.com/products/zc-zamp?srsltid=AfmBOoo9LrUkopWDyfnRtNBpZtAPJS6nz2nQt57MVraVNkBAUz3qDK-D
You've misunderstood the info you found on the internet. The concept is to include the output filter inside the feedback loop to maintain linear output response across the entire spectrum. I'm guessing you have experienced this first hand with a dual channel measurement jig. Simple measure with the reference probe placed before a filter (ie high pass capacitor), and measure again with the probe after the filter so it's include in the feedback loop. The filter is compensated for by including it in the feedback circuit.
The acronym is a bit unfortunate, post-filter feed-back and pre-filter feed-back both end up as PFFB, so which is it?
The filter is not additional, it's "the output low pass filter" that Class-D amps utilize to reconstruct audio for a high frequency PWM signal.
All Hypex amps utilize post-filter feedback, I'm willing to bet you have heard one.
To the topic at hand, I use a Hypex UcD180 amp at my desktop, fed from a Topping DX3 Pro. It's a great combo that provides more output than I'll even need for nearfield listening. I utilize a system-wide EQ for fine tuning the response, compensating for the desk reflection mostly.
Amazon is having 10% brand promotion on wiim, the amp pro is under 350 with pffb. Without pffb the wiim amp is solid, yes the top end rises for 8 oym, but relatively doesn't make much difference in what you gear. If you want amp only the wiim vibe link is good with built in dac and pffb at 300, no streamer.
The Dayton DTA-PRO I picked up for my father finally died. It was an open box return that I got for stupid cheap so I wasn't too heartbroken. He finally got a TV in his living room, and his GF has started getting into LPs, so I picked up an Arylic B50 since it pretty much has ALL the inputs. HDMI ARC, Bluetooth, Optical, RCA, Phono, USB (data drive), USB-C (DAC). Even has a SW out. Though sofar we only listened to a few songs, and the speakers were moved in the room, so nowhere near settling in to understand the quality yet. Just something to potentially look into.
I did a quick search and wasn't able to easily find what amp chip it uses. The B50 SE has the same power rating, but fewer inputs and lists TPA3116D2. Not that that necessarily means anything though.
As an interesting side note. I see also saw the Arylic BP50. Which is a "preamp" that has all the same inputs fed to RCA, Coaxial and optical outputs (still has SW out).
The Fosi BT20A Pro looks pretty good for the money. Buy one from Amazon and have the option to return it if you don't like it.
For what it’s worth. I’m working on a speaker that is nominally 8 ohms and higher (lowest dip is 4.9-5) and I ran sweeps with a non-PFFB Fosi stereo v3, a Yamaha av385, and a Lepai and there is almost zero difference among the D amps and the A/B Yamaha. They were all consistent. The Fosi has the 48v brick and I like it, aside from the Lilliputian terminals. If it’s in the budget PFFB would be peace of mind switching between different speakers but if it’s not I wouldn’t sweat buying a 3255 without it.
Fosi V3 stereo non PFFB vs Fosi V3 mono PFFB. 0.5db difference for 8 ohm load at 20khz, 4 ohm is in the negligible category.