Hello Vincent Thank you very much for this great video. It is incredibly informative. Top job! I thought I knew that the ratio of the output impedance to the input impedance should be 1:10. I will connect my DAC to my audio amplifier via the line-in connection. Is this the difference to your application? Or what am I misunderstanding? Best regards Matthias
Thanks for watching. Ideally the output impedance is 0 ohm and the input impedance is infinitely large. But in the real world nothing is perfect, so in reality it's preferable that the output impedance is not larger than 1/10 of the input impedance. In this video I mainly talked about the bass cut off frequency but not frequency matching. This DAC should have low enough output impedance to drive both the solid state and tube amplifiers. Hope it helps.
@@vincentfong4154Thank you for your answer. I had misunderstood something. Now I think I understand. So you are taking into account the imput impedance to determine the components of the high pass filter. And the output impedance remains unchanged.
Thanks. I had actually purchased several voltmeters and ammeters but they didn't fit the case. I do have them in my balanced isolation transformer. photos.app.goo.gl/htuX9csyiih4L8TG6
Nice video. I've been playing with the TDA for a long time. If I may , change regs to shunt type you'll be surprise of the improvement. I/V resistor type used paramount importance. You just have to experiment with it. For me shinkoh works best, tried many brands
@@vincentfong4154 There's lots of things you can do around the Tda to improve sound. Yes I/V resisitors is very important. I see that your going passive with step up transformer but the set back is dynamics wont be good. You need to increase current flow & lower ouput impedance.
The I/V resistor of 500R will result in clipping with a 0dB signal (or perhaps even less) with the TDA1387 at 5 VDC. It should be no larger than 430R. See the chart under section 3.2 of the Builder Guide at Moode Audio.
Hi Mark, thanks for the comment. Actually I had read the instruction. At first I was using an 400R resistor but later I struggled between the 400R and 500R as I need a higher Vout for the TDA1543 too (I'm not using a pre-amp). So it's a compromise.
hello, is it possible to buy a ready software configuration only for player somewhere? I have a player at home based on Rpi5 with waveshare display and picore player. LMS is running on a dedicated server. Is it possible to buy a ready-made sw configuration? thank you ;)
Hi, what is the model of your Waveshare display? I don't think Picoreplayer supports widescreens. Just of out curiosity, does the current version 8.2.0 support Pi 5? I don't sell software but I can share with you a link to download the pre-configured image for Pi 4, and you can donate to the developer if you're satisfied with the work.
Hi Vincent, thanx for this video and for the work you share with us. I'd be really interested in a Finished good (TDA1387 included) but, living in Italy, cannot use Carousell to contact you (don't know why, but seems to work only for asian countries). Is there a way to get in contact with you and manage a deal for a finished TDA1387 Hat Dac? Thanks again. Stefano
Thanks for your interest. Probably Carousell does not accept non-Asian country phone numbers.. Anyway, I can be reached at facebook.com/SMPGadgets Please drop me a message so that I can provide a quote to you.
I'm not a native English speaker. If I speak Cantonese, some of the audience understands. But if I speak English, nobody understands. Please refer to the subtitles.
It depends on music types and personal preference. For myself I usually listen to vocal (mostly female) so I'd rate like this: TDA1387 > Allo Boss 2 > i-Sabre > Monalisa > IQaudio. Again, please note that this is very personal. Others may not have the same thought. If you'd like to listen to classicals or rock music, I think IQaudion would be the best option though.
Interesting video. Nice design. I chose a higher value coupling capacitor so that phase shift of the high pass filter is well outside the audio range. It is designed for solid state components in the following stage, approximately 10k impedence. You could omit the coupling cap if there is a DC blocking cap on the input of the next stage. Don't forget to do polarity inversion. The easiest is with software (Moode or PiCorePLayer/LMS) or reverse both +/- speaker leads. Yes, metal foil I/V resistors are much better than metal film, and well worth the extra cost. TDA1387 is not an R2R DAC. "11 bit binary current divider consisting of 2048 transistors" according to data sheet page 5. Philips multibit DACs are called dynamic element matching (DEM) DACs.
Hi Mark, thanks for your comments and suggestions. Just one question: what is the effect if the polarity is not inversed? For some tube amps the polarity is actually reversed at the output.
I think absolute polarity is important. Some recordings might be inverting polarity, because a piece of equipment in the chain is inverting. It does change the sound quality. It depends on the type of music. Acoustic music in a hall with reflections can sound very odd. Almost disorienting. In the end, in most cases, I think it will sound better with correct polarity. The nice thing about software polarity inversion, is that it is very easy to do. Also, if a track just doesn't sound right, try inverting the polarity.
It's not available on Facebook due to the regional restrictions but it's available in Carousell. More details can be found here: carousell.com/p/1282663425
