DIY DAC Kits and Easy Mods

Russellc · « **Reply #140 on:** 29 Sep 2010, 01:22 pm »

Quote from: wushuliu on 13 Aug 2010, 11:08 pm

Another option that I wish existed before I bought my dac is this:

http://quanghao.com/product.php?id_product=9

It's an AD1865 board incorporating the Salas (of diyaudio) shunt-reglated power supply. The DAC circuit should be similar to the rainbow as they are both based on Andrea Ciuffoli's design. The Salas PS gets kudos and is guaranteed to be far far better than the rainbow design. And you dictate the parts quality, so end result will be in your hands.

For the IV stage, a tube-based design is also offered on that site - but another option to go easier on the wallet is rainbow's tube IV stage:

http://cgi.ebay.com/DAC-I-V-conversion-module-SRPP-tube-module-/320572208796?pt=LH_DefaultDomain_0

I'm trying to not to give in to temptation with trying this out but the chance to control all the parts myself and use Salas' PS is almost too much...

How about the new I/V converter on the Pass DIY site?

russellc

wushuliu · « **Reply #141 on:** 29 Sep 2010, 07:48 pm »

I'm keeping my eye out for PCBs to get made for it for sure...

wushuliu · « **Reply #142 on:** 6 Oct 2010, 09:57 pm »

Quick update on the raindrop AD1865 DAC: I was taking a look under the hood earlier this week, thinking I should add some more Oscons to the PS regulator area (which is recommended in Andrea's original design) and thought while I'm poking around, maybe I ought to just bypass the jfet output stage and just use 2 resistors by passed with a small value cap (.0068uf) for a passive I/V. Andrea (Ciuffoli) mentioned that this method gave the best sound but the voltage was too low to drive an amp, so I never gave it a shot. But after a ridiculous amount of googling and reading the Analog Devices pdf it turns out that you can go use values as high as 1.5k for the resistors and several people were using just passive i/v with success. So with a fresh stock of Cardas quad and more curiosity than smarts, I used 220 ohms for the i/v (note, the outputs go to my DCB1 buffer, and then to my amp); the nice thing about the raindrop board is that there are outputs next to the dac for just this purpose.

I was pleasantly surprised to find that I could drive my amp loud enough for my preferred low to moderate listening volume. Not only that, but it sounds good, I mean real good. I think I'm really hearing the true signature of the AD1865. Not quite syrupy warm and not quite the crystalline cs4398/gigawork, etc. Real neutral. With the jfet output stage out of the way, there's more of everything. I'll spare the adjectives - it just sounds better, much better. toe-tapping better. Down side is at 220 ohms you can't crank the music. Even with 1k, although I get more than enough volume for my needs - possibly at the expense of increased, but not necessarily audible distortion. But then I have the DCB1 which has zero gain, so this is to be expected. I'm sure a tube stage after the passive I/V would sound great, but for right now I am more than satisfied.

wushuliu · « **Reply #143 on:** 14 Oct 2010, 03:54 am »

Well I broke down and got one of these guys today. It's a new offering from Raindrop and is exactly what I've been looking for in the TDA series to try out (I'm currently listening to the little Muse, which I've written about in Cheap and Cheerful): 1541, NOS, passive output, decent PS, and no frills. Straight, no chaser. I'll for sure put in new bypass caps by the chip. It takes USB, BNC, optical and I2S.

All these DAC flirtations may seem impulsive, but I think this is a 'golden age' of sorts for diy audio and these kinds of kits/boards don't have that long of a shelf life. For a fraction of what I would pay retail I can decide for myself what DAC 'sound' appeals most: upsampling/OS like the gigawork, straight OS like the TDA, or something in between like the AD1865?.. And you can't beat the price ($110 shipped). My only worry is that the TDA chip may be fake. Should only take minutes to set up, aside from the usual enclosure headaches.

JohnR · « **Reply #144 on:** 14 Oct 2010, 05:06 am »

Wow, you're really going for it

The price on that one has come down, if I remember. I think I saw it a while ago, don't remember it being that cheap.

parodielin · « **Reply #145 on:** 14 Oct 2010, 05:03 pm »

So my AD1865 hasn't arrived yet and you have a new toy, oh, no, two new toys.

parodielin · « **Reply #146 on:** 18 Oct 2010, 09:38 pm »

My AD1865K arrived today. I don't have wire instructions on the Transformer. For the 115V x 2, I have four red wires and one yellow wire. How should I wire them? Which one is ground (yellow?) US uses 110V, so I don't need to tap any wires together, correct?

The other side of transformer has four sets of wires marked as 2 18Vs and 2 9Vs. For example, brown-brown 9v, I should connect two browns to one of the power at the board, doesn't matter which brown to + or -, correct?

Quote from: parodielin on 14 Oct 2010, 05:03 pm

So my AD1865 hasn't arrived yet and you have a new toy, oh, no, two new toys.

wushuliu · « **Reply #147 on:** 18 Oct 2010, 09:47 pm »

Quote from: parodielin on 18 Oct 2010, 09:38 pm

My AD1865K arrived today. I don't have wire instructions on the Transformer. For the 115V x 2, I have four red wires and one yellow wire. How should I wire them? Which one is ground (yellow?) US uses 110V, so I don't need to tap any wires together, correct?

The other side of transformer has four sets of wires marked as 2 18Vs and 2 9Vs. For example, brown-brown 9v, I should connect two browns to one of the power at the board, doesn't matter which brown to + or -, correct?

4 red wires? A picture or a drawing would be helpful.

parodielin · « **Reply #148 on:** 18 Oct 2010, 10:21 pm »

There you go... There are four red wires and one yellow wire on the Primary 115V x 2, red, red. My guess is to make 115v, the first and the third wires will go together and the second and fourth wires will go together, but this is just my guess. Which one will be hot and which one will be neutral? The yellow wire should be the ground.

wushuliu · « **Reply #149 on:** 18 Oct 2010, 10:39 pm »

Quote from: parodielin on 18 Oct 2010, 10:21 pm

There you go... There are four red wires and one yellow wire on the Primary 115V x 2, red, red. My guess is to make 115v, the first and the third wires will go together and the second and fourth wires will go together, but this is just my guess. Which one will be hot and which one will be neutral? The yellow wire should be the ground.

I'm not sure it matters which side is hot or neutral, but you should contact Raindrop re: wiring to be on the safe side. I wouldn't take chances. He should have at least provided a diagram.

parodielin · « **Reply #150 on:** 18 Oct 2010, 10:49 pm »

Quote from: wushuliu on 18 Oct 2010, 10:39 pm

I'm not sure it matters which side is hot or neutral, but you should contact Raindrop re: wiring to be on the safe side. I wouldn't take chances. He should have at least provided a diagram.

Yes, I sent an email. I don't want to take chance either. Also, a regular RCA jack will do for the coaxial input, right?

wushuliu · « **Reply #151 on:** 18 Oct 2010, 10:59 pm »

Quote from: parodielin on 18 Oct 2010, 10:49 pm

Yes, I sent an email. I don't want to take chance either. Also, a regular RCA jack will do for the coaxial input, right?

Yes, a regular jack will do.

parodielin · « **Reply #152 on:** 18 Oct 2010, 11:07 pm »

Quote from: wushuliu on 18 Oct 2010, 10:59 pm

Yes, a regular jack will do.

The six capacitors on the Dac board says 22uf/16v. There are "seven" similar caps instead of six.

1. Should I replace seven of them?

2. Using 47uf/16v instead of 22uf/16v?

Thx!

wushuliu · « **Reply #153 on:** 18 Oct 2010, 11:42 pm »

parodielin · « **Reply #154 on:** 27 Oct 2010, 02:38 am »

So I am in love with the AD1865. I haven't done anything yet but it is good. Thanks wushuliu ...

Quote from: wushuliu on 18 Oct 2010, 11:42 pm

Yes

Nickel · « **Reply #155 on:** 4 Nov 2010, 08:32 am »

Hi Wushuliu

When you did the Lampo mod on the 1865 , what was the analogue output in mw?
Mine's around 6, which is too high - any idea what's wrong?

Cheers

Nick

parodielin · « **Reply #156 on:** 4 Nov 2010, 09:19 pm »

I received seven 47uf/35V Elna Cerafine today. These are polared. How do I know which side is positive and which side is negative?

Duh... I guess when I removed the cap, I'll know.... hate to answer my own questions.

I will report back on these caps. The sound is very good stock and was wondering what can be improved...

Quote from: parodielin on 18 Oct 2010, 11:07 pm

The six capacitors on the Dac board says 22uf/16v. There are "seven" similar caps instead of six.

1. Should I replace seven of them?

2. Using 47uf/16v instead of 22uf/16v?

Thx!

parodielin · « **Reply #157 on:** 10 Nov 2010, 02:57 am »

I finally concurred the soldering/desoldering w/ lots of help from wushuliu. I upgraded seven oscons and four 10000uf PS caps. It is really really good. I re-listened most of my music in a two sets of my DIY speakers. It is so smooth and transparent.

I did not do the digital bypass yet. That takes some courage...

Russellc · « **Reply #158 on:** 14 Nov 2010, 03:58 pm »

Where are you guys finding this DAC? The older link aren't bringing it up on ebay.

Russellc

wushuliu · « **Reply #159 on:** 14 Nov 2010, 05:47 pm »

Quote from: Russellc on 14 Nov 2010, 03:58 pm

Where are you guys finding this DAC? The older link aren't bringing it up on ebay.

Russellc

It will come up under a search for AD1865 on ebay

http://cgi.ebay.com/DAC-AD1865-AD1865N-K-NOS-1-0-NOS-/320616005653?pt=LH_DefaultDomain_0&hash=item4aa6340015#ht_2469wt_1135