ProtoDAC TDA1387 X8 project

[speedy210]

[hifinet]

@abraxalito at diyA is the TDA1387 expert. He probably has massive quantities of TDA1387.

I have seen TDA1387 labeled with the NXP brand, which was a spinoff from Philips in 2006.

[Ludomaniac]

I swapped from Wima MKP to Jantzen Superior Z-cap today, and the soundstage opens up even more, clarity and definition in the whole area. They are not that expensive either, £45,- for a pair at Hificollective. I also use the AudioNote Kaisei 2200uF on the powerside which also is a cheap upgrade. I'm really amazed by what this design can do - thank you so much!!

Hello Ludomaniac, I would also like to install the Jantzen Superior Z-cap. Do these fit on the board at all? Or how did you install them? Thank you and best regards

Hi,

I haven't attached them to the PCB yet and I probably wont since I've connected a Miflex KPCU-03 Copper Foil Paper capacitors in parallell with Jantzen - and it takes up some space as they are almost the same size. I'll probably use cable ties to the bottom of the chassis when the unit is out of lab-mode

[hifinet]

Update on the tantalum I/V resistors. They always had a hard edge to them, even after 60+ hours of burn in, and it was not improving. Excellent soundstage, but fatiguing. Relieved to be back to the TX2575.

I will try a single 100 ohm tant with a preamp. Also, 100 ohm TX2575 and Rhopoint.

1. TX2575
2. Caddock TF020
3. Tant SMD 4 x 100 ohm

[thomaschan]

Update on the tantalum I/V resistors. They always had a hard edge to them, even after 60+ hours of burn in, and it was not improving. Excellent soundstage, but fatiguing. Relieved to be back to the TX2575.

I will try a single 100 ohm tant with a preamp. Also, 100 ohm TX2575 and Rhopoint.

1. TX2575
2. Caddock TF020
3. Tant SMD 4 x 100 ohm

I am using AMRS resistors for I/V and they are very musical and cost effective. If cost is not a concern, I will use AMRG. Takman is another excellent choice used by Audio Note in Japan (not UK).

[hifinet]

Amtrans resistors are difficult to get here in the US. Would need to order from PartsConnexion in Canada or HiFiCollective in the UK. Occasionally, they show up on eBay.

[hifinet]

Using 100 ohm I/V resistors (TX2575) and a NE5532 based preamp with 15dB gain. The same C3/C4 caps and output caps. This sounds very nice. I think the sound quality is better than 420 ohm I/V resistors without the preamp. Bass is better. I am not familiar with the sound of this particular preamp. If a preamp is added, it will determine much of the sound character.

Measured output with the 100R I/V resistor playing a 0dB 50Hz sine wave is 0.235VAC rms. That works out to -14.3dB compared to the 420R I/V resistor and about -18dB from 0dBFS.

If you have 15dB of gain to spare, I can recommend using 100 ohm (or possibly even lower, if you have the gain). I/V resistors in ProtoDAC.

I think a tube preamp will probably have a better impedence match with the 420R I/V. For solid state, the 100R would probably match better.

[smokey_mountain]

   
Thank you @hifinet  for suggesting K77-1. I gave it a good listen with Soviet K77-1 caps. K77-1s only have 8 hours on them, and some say that polycarbonate caps need 60+ hours, I am not sure if true but will keep listening to them. I did not know that eBay seller sells pairs, so I bought two. Three of them measured 7.08, so as close as I can get to matching. My multi-meter is not the most sophisticated so that could be culprit too.

Strangely, I miss the sound of those inexpensive kit Audiophiler caps that @hifinet included, they sound mighty fine after 20 hours. Will give K77-1 20+ hours and compare again. I have an intial impression that lows are not as tight with K77-1, highs might be a bit clearer but certainly difference is not immediately obvious. I will order a second kit from @hifinet and will do blind testing of caps.

[smokey_mountain]

I swapped from Wima MKP to Jantzen Superior Z-cap today, and the soundstage opens up even more, clarity and definition in the whole area. They are not that expensive either, £45,- for a pair at Hificollective. I also use the AudioNote Kaisei 2200uF on the powerside which also is a cheap upgrade. I'm really amazed by what this design can do - thank you so much!!

Hello Ludomaniac, I would also like to install the Jantzen Superior Z-cap. Do these fit on the board at all? Or how did you install them? Thank you and best regards

Hi,

I haven't attached them to the PCB yet and I probably wont since I've connected a Miflex KPCU-03 Copper Foil Paper capacitors in parallell with Jantzen - and it takes up some space as they are almost the same size. I'll probably use cable ties to the bottom of the chassis when the unit is out of lab-mode

@Ludomaniac, @hifinet  had confirmed that Jantzen Superior Z-cap do sound better than most caps but was wondering if Audionote Kaisei 2200 had any audible impact, also which connection points did you connect Kaisei 2200 to on the board? Thanks.

[hifinet]

The consistency of the Audiophiler MKP caps is much better now. They are more consistent is size and value. I think they sound very nice. I like the K77-1 also. I think the polycarbonates are clearer in the highs, compared to the MKP in general. The Jantzen Superior-Z is on another level soundwise and costwise.