Thanks, I know.
Will try first with the ultra for volume control.
As the passive preamp is diy I have the option to add am extra volume channel for the sub later.
The European wait for the WiiM Ultra
- Thread starter Steve Woodhouse
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Will try first with the ultra for volume control.
As the passive preamp is diy I have the option to add am extra volume channel for the sub later.
Why stay away from the ZA3?
If you go for a dedicated power amp based on TI's TPA325x chip amps you will want to make sure it features Post Filter Feedback. The ZA3 does not.
the pffb is an attempt at compensation...but remains rather relative...
(the idea, respectable, which irrigates the approaches is the unsaid of ""cheap watts"")
What do you recommend
Feedback is generally considered the number one tool of choice for designing good power amplifiers.
What do you recommend regarding the choice of ZA3 vs V3 Mono?
Feedback is generally considered the number one tool of choice for designing good power amplifiers.
I heard the same. Also the V3 mono run real, real, real hot and i've also heard they may not match very well with systems that are on the "bright" side (bright sounding speakers like for instance B&W etc.).
pffb is welcome...but does not completely resolve the particularities-limitations of these chips
you just have to be aware of it...
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Yes, the effectiveness of the feedback loop is lower than say used with an op-amp, simply because the gain of the original chip is much lower. Following the design considerations in TI's white paper from 2017 the best compromise is to sacrifice ~6-7 dB of gain for improving distortion and load dependency by roughly the same factor.
Even with the best possible output filters used (costing more than the amplifier chip) PFFB will still improve the performance.
WiiM claimed that they didn't implement PFFB on the Amp because they observed additional pop and click noise with there original design, so they decided to stick with the conventional design at that point. They already confirmed that the Amp Pro will come with PFFB. It is very obvious that this wil reduce load dependency to absolutely inaudible levels, even if it cannot turn a TPA3255 into a Purify Eigentakt module.
I cannot confirm that. If you are interested into sounding those amps differently you can still replace one or two of the op-amps e.g. with SparkoS Labs Muse02.
Replaceable BT20A PRO V3 Op-Amp Chips - SS3602, MUSES02, OPA
Upgrade your music experience with SparkoS Labs SS3602, MUSES02, OPA2604AP, OPA2134PA - high-quality amplifier chips for BT20A PRO and V3.
fosiaudio.com
Every TPA3255 based amplifier lacking PFFB will potentially sound brighter into speakers with impedance rising above 4 ohms in the treble region.
no ..
inverse..
increases as soon as it exceeds 6ohm etc. it is even more difficult to describe and often politely observed just at 8ohm..but can we come across situations at well as 8...
(small example
Post in thread 'WiiM Amp Streaming Amplifier Review'
the pointed measurement is oversimplified conditions...
in real life, the effective load is much more complex on the tweeter side...
too bad it's not lower, would be much less annoying ;-)
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Level increases with rising impedance. That's not the inverse of what I said. The exact (resistive) impedance at which the rise starts depends not just on the chip alone, but also on the output filter
That links doesn't work.
Yes, it's absolutely trivial that a real speaker presents a complex load (which has nothing to do with "complicated", it just means that the phase and magnitude are described using complex numbers, it's just mathematics). Using one or two (as Erin does). exemplary "dummy loads" doesn't provide the real picture, either. These remain special cases, just examples. There's not.muchbtypical about them.
What's really important here is that PFFB reduces all these unwanted effects! Not just the rise of the transfer function into higher resistive loads.
castalla
Major Contributor
????
slartibartfast
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Why the ????
Which of those question marks do you want me to resolve?
read too quickly...
just that between this strange behavior in "load" certainly always apprehendable mathematically, and the complexity-variability of the music "in real time" .... things-impacts become really hard to grasp finely.. remains what emerges very often, an excessive brilliance, tiring in many cases
hoping to be understood ;-)
(the irony is that the pffb will impact the cost of these small amps....while what created the excitement around this was their cost/amp... the cost will approach the cost of other more classic solutions)
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castalla
Major Contributor
I have no idea how any of this discussion relates to the availability of the Ultra on the European market.Which of those question marks do you want me to resolve?
no relation indeed...
castalla
Major Contributor
See my reply above
one,now , of the big European players for this type of Chinese products.....
seems to be waiting for new batches...
seems to be waiting for new batches...
slartibartfast
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It doesn't say they are out of stock so why do you think they are waiting for new batches?one,now , of the big European players for this type of Chinese products.....
seems to be waiting for new batches...
"incoming new stock"
???
(but I don't know if they sold so many in Europe, outside the UK, of the series that circulated this summer)
