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+--- Thread: ProtoDAC TDA1387 X8 project (/showthread.php?tid=5531)
RE: ProtoDAC TDA1387 X8 project - eDad2003 - 04-05-2024
(04-04-2024, 10:46 PM)Tim Curtis Wrote: Mentioned earlier but the test to determine whether there is some sort of attenuation in the Camila pipeline when there is no -gain anywhere in the pipeline, or whether its just diffs in volume curves is to set moode to output 0dB/100% volume with and w/o camilla on.
There "should" be no difference in SPL at the ear. If there is then maybe someone could post to the camilla thread at diyAudio and ask if there is some sort of built in attenuation.
Tim, I should have mentioned that - I agree this would work. In my case, I am going rPi>ProtoDAC>Power amp, so I'd either damage equipment or my eardrums, so I cannot test this way.
RE: ProtoDAC TDA1387 X8 project - Tim Curtis - 04-05-2024
Refer to the diyAudio post made today by @varunach. Based on the responses so far it looks like some attenuation is inherent in the filtering process itself.
https://www.diyaudio.com/community/threads/camilladsp-cross-platform-iir-and-fir-engine-for-crossovers-room-correction-etc.349818/page-239#post-7649476
RE: ProtoDAC TDA1387 X8 project - DRONE7 - 04-07-2024
Seems Henrik has found the problem . :-)
https://www.diyaudio.com/community/threads/camilladsp-cross-platform-iir-and-fir-engine-for-crossovers-room-correction-etc.349818/post-7651407
Look forward to a MoOde update.
RE: ProtoDAC TDA1387 X8 project - Skip Pack - 04-13-2024
Over the last few weeks I've assembled two more ProtoDACs (now 4 total). I got four of the Soviet K77-1 0.68 polycarbonate caps previously discussed to use for I/V output. I had used K75 hybrid caps very successfully in passive crossovers, so was positively inclined. I used the Panasonic EEU-FR1A102LB electrolytics on both dacs. The sole difference is vishay bulk Z-foils (purchased from @hifinet early in this adventure) and vishay dale rn55d mil-spec 1/8 watt resistors in the I/V positions. I was curious to hear a compariaon.
The second ProtoDAC I built is essentially a copy of the 'poster' dac with the PCP polycarb caps and bulk Z-foils. Comparing that dac (#2) with the bulk Z-foil K77-1 led me to slightly prefer the K77-1. All three dacs were burned in for 100 hrs+. In this first comparison, with identical resistors, the K77-1 version was a tiny bit more musical/richer.
Comparing the other rn55d K77-1 with the Z-foil K77-1 was a bit of a surprise. I heard more air/transparency perhaps 2.5 khz up with the Z-foils, but a richer, better integrated sound from 1.5 khz or so downward. I'm 77 and have very mild tinnitus, so I'm sensitive to bad recordings with too much HF or HF distortion. I'm sure this plays into this result through my ears. I am not saying one is better than the other. The difference is small, and the majority of listeners are likely to prefer the Z-foil in the build configuration. The resistor comparison seems consistent comparing either of the Z-foil dacs to the rn55d one.
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On another subject, I have and have been using an Allo Shanti power supply for several months now (purchased in 2021). It has two separate linear supplies, a higher current one for the RPi, and a 1 amp or so for the hat if the hat GPIO power connection can be cut one way or another. I've only used the single high current section connected to the RPi 4B thus far, but will be using a pin extender with pins 1, 2, and four cut to use both sections of the Shanti.
In other discussions wrt RPi's and hats, and also usb situations. People have mentioned noise on the RPi grounds. Is there a simple way minimize this (potential) problem?
ProtoDAC TDA1387 X8 project - thomaschan - 04-14-2024
I recently built one with universal PCB, point to point soldering. Connects to Pi 4B via 40 pin GPIO connector. Philips resistors and Bennic FPP output capacitors. Linear power supply.
Sound quality is surprisingly good. Warm and musical.
Total component cost to me is about US$15 (without chassis and display). Cost varies a lot with the output capacitors.
https://www.youtube.com/watch?v=whaTogwxXfA&t=11s
RE: ProtoDAC TDA1387 X8 project - bobdcarr - 04-17-2024
I finally got all the parts to assemble my stand alone ProtoDAC. I have it connected to my Digi Allo-one output via coax cable. It sounds great.
I used this for the enclosure: https://www.amazon.ca/dp/B098P7M5R2?psc=1&ref=ppx_yo2ov_dt_b_product_details
I am currently using an external 5V SMPS, it measures fairly low noise, I have been ising these for most of my Pi builds:
https://www.amazon.ca/gp/product/B00DECXUD0/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Check out my review here:
https://www.amazon.ca/gp/customer-reviews/R2U6VSS03D16KU/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=B00DECXUD0
I am planning on using a 7.4V LiFEpo battery with the 5V linear regulator for the external power soon, awaiting parts from ebay.
I have attached pics for reference. Might put an LED on front plate that turns on when DAC is active. Enjoy! Bob.
[attachment=3728]
[attachment=3729]
[attachment=3730]
RE: ProtoDAC TDA1387 X8 project - oeyhamre - 04-24-2024
Hello, I am new to the forum. Intrigued by Gabsters review I got a kit from hifiamps on ebay. Finished it a couple of weeks ago and put it on a Raspberry Pi 3B running roopie. WOW, this little DAC is seriously impressive! Compared with my old Auralic Vega (got a great used deal on that 6 years ago), the ProtoDAC is different, more natural, with a deeper soundstage, softer and more mellow, it can not match the Auralic in neutrality and sheer detail, with the music emerging from this totally black background. I would not call the ProtoDAC significantly worse, it is just different and i like it a lot! I have order a second kit to experiment with, and have som old russian caps inbound from Bulgaria to test out. Considering getting some Ian Canada stuff as well. Considering the DAC already performs great, I am curious how much better it can get. How much of a difference will a reclocker make? Considering a stack with Ian Canada UCPI, (Rpi3B), IsolatorPi III, FifoPiMA, ProtoDAC.
RE: ProtoDAC TDA1387 X8 project - hifinet - 04-24-2024
People in posts here on this thread and elsewhere have reported a significant, even a huge improvement, with the addition of a reclocker/isolator. Reducing noise will result in a blacker background and increased detail. Better coupling caps will also help detail (lower losses/greater transparency). Reducing jitter also helps as well.
RE: ProtoDAC TDA1387 X8 project - Skip Pack - 04-24-2024
As mentioned above, I have been running my ProtoDAC setup with the extended GPIO pins (1,2, and 4 cut) for the past week or more, and the clean isolated (Allo Shanti) power to the ProtoDAC made for a nice improvement -- same tonal balance but 'calmer'. WRT @oeyhamre's comment, this is part of the gains promised by the iancanada stack. At this point, I can't afford to go for that group of components, but would like to here the effects of a good quality reclocking addition to my setup.
RE: ProtoDAC TDA1387 X8 project - thomaschan - 04-25-2024
Clean power will definitely help.
Recently I had used a power bank (the ones to charge up mobile phones) to power up my Pi4B and ProtoDAC TDA1387 x 8 and compared it against ordinary 5V power adaptor (the cheap ones which comes with Pi). Music source is FLAC file stored on USB thumb drive. I used an open back headphone driven by a headphone amp.
The difference was day and night. With a power bank, the sound quality was hugely improved across the entire spectrum.