I have the D802 and the Popu D2P. IMO, those 2 pure digital amp still missing the last bit of music texture or organic feel from a really good dac + system. But I would agree those digital amp represents one of the best values in hifi after a bit of tweaking.
What mods have you done to the Popu? I'm about to start some mods to an STA326 amp, not sure of its model number.
Popu D2P does not have STA326. I have tried a few amplifiers with STA chips and it seems STA326/328 equipped ones are the best bang for the buck. Still the dreaded equaliser settings are often implemented in a way that it only hampers performance. Alientek D8 looks like an appealing FDA with useful features and even choice which USB input one wants.
I am waiting for a STA326/328 FDA with built in PSU, 2 x SPDIF and 2 x optical input and speaker protection but that one is not made yet 🙂 Till that time I go on with Wadia PowerDAC 151 which is also a vey good FDA.
I am waiting for a STA326/328 FDA with built in PSU, 2 x SPDIF and 2 x optical input and speaker protection but that one is not made yet 🙂 Till that time I go on with Wadia PowerDAC 151 which is also a vey good FDA.
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Right, its using D2-41051. Incidentally there's a new Popu which I've recently gotten my hands on : 'Mercury', it has fixed the problem of the too-low valued FET driving caps. It also has no analog or USB input in its most basic incarnation - https://item.taobao.com/item.htm?spm=a230r.1.14.57.HThuTt&id=19260362926&ns=1&abbucket=18#detail. Does come with remote control though.
https://item.taobao.com/item.htm?spm=a230r.1.14.57.HThuTt&id=19260362926&ns=1&abbucket=18#detail
https://item.taobao.com/item.htm?spm=a230r.1.14.57.HThuTt&id=19260362926&ns=1&abbucket=18#detail
Just to add one info to my #159 post above I used several good DACs to make the comparison, the last one of the series I own since a couple of months is the NAD M51.
Though this is a very nice sounding unit using a similar tech of the PowerDACs I used for my tests, the difference of price is obviously in favor of the latter units.
I'm waiting for a unit using the TDA7498E from ST microelectronics, which is a more powerful unit.
I'll report here the results of my test asap.
Though this is a very nice sounding unit using a similar tech of the PowerDACs I used for my tests, the difference of price is obviously in favor of the latter units.
I'm waiting for a unit using the TDA7498E from ST microelectronics, which is a more powerful unit.
I'll report here the results of my test asap.
For those who are interested in modifying a cheap board, the one mentioned by Abraxalito on eBay with a STA333BW chip is now also available on Aliexpress at a comparable price :
https://www.aliexpress.com/item/STA...lt&btsid=937a3732-7241-432b-bf22-616ff60e8420
https://www.aliexpress.com/item/STA...lt&btsid=937a3732-7241-432b-bf22-616ff60e8420
I've modded my first STA326 enough to listen to now - replaced the 22uH inductors with pairs of 150uH to increase the working impedance (and hence reduce the output current). 2:1 step down toroidal transformers on the outputs. Sounding very promising even before I do the next round of mods to install a local PSU regulator.
This is the unit on Aliexpress - https://www.aliexpress.com/item/STA...lt&btsid=84435f91-ea04-42cd-9fd6-b7625e0d0b33
This is the unit on Aliexpress - https://www.aliexpress.com/item/STA...lt&btsid=84435f91-ea04-42cd-9fd6-b7625e0d0b33
Been there - tried the STA333BW boards (which have less power due to their lower max voltage) and found they still needed an output transformer to deliver the sonic goods. Which reduced the output power too far. Hence why I'm now working with chips that go well above 20V operation.
<edit> Internal pic attached.
<edit> Internal pic attached.
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Depends on what the purpose of the transformer is. Is it only to lower output voltage or is it to filter out nasties ? Or both ?
Neither - its to reduce the signal-induced sag on the power supply. Digital amps don't have any PSRR to speak of so modulations of the supply rail get passed through to the output.
Was just looking up previous posts of you but you answered faster than I could find it. I see what you mean. A 1:1 won't help out much in that case I guess. PSRR is indeed bad with most boards.
Won't hurt to try out 1:1 transformers though as I have a few of those. Anyway I messed up the STA333BW board and have to wait till a friend with pro tools can fix it. I flowed solder on the pins but can't get it away from between the pins 🙂
Won't hurt to try out 1:1 transformers though as I have a few of those. Anyway I messed up the STA333BW board and have to wait till a friend with pro tools can fix it. I flowed solder on the pins but can't get it away from between the pins 🙂
I'm a dynamics freak, particularly in the bass and capacitor-based power supplies don't have particularly low impedance in the bass, leading to sogginess (subjectively). Nige2000 has a chipamp where he's using LiFePO4 batteries in series for the supply (very low impedance), I heard his amp a few months ago and the bass dynamics are tremendous. Even with that kick-*** PSU he's found benefit with output transformers.
If you do get to try out your 1:1 trafos, I shall be interested in the listening results 🙂
If you do get to try out your 1:1 trafos, I shall be interested in the listening results 🙂
I don't get it. Why use a high efficient class d amplifier,and then reduce the output power. Does the STA326 so much better than a LM3886 or similar type of class AB chip?
The shorter chain is appealing with FDA. Otherwise a DAC is needed plus high quality source switch and volume control etc.
If I was aiming for maximum efficiency then it would be silly, I agree. But I'm not, I'm aiming for maximum satisfaction in the sound.
Its not an apples-apples comparison. But assuming we took a fairly decent multibit DAC like an optimized TDA1387 design and fed that to an LM3886, yes the STA326 easily beats that. primarily in HF purity. Secondarily, in bass slam.
To Jean-Paul
But output transformers add to the signal chain, and they are not free. I don't know the cost, or if it's similar to a decent DAC.
But output transformers add to the signal chain, and they are not free. I don't know the cost, or if it's similar to a decent DAC.
Trafos aren't free, agreed. The ones I'm using cost about $7 each. But I'm in China, shipping costs would easily double that if you're sending them to Europe.
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