Anyone finished a Gigawork DAC?

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I have been trawling the threads for finished DACs, specifically the old style Gigawork DAC (Lampucera). Lots of posts about about what should and should not be done to modify the DAC, but never a definitive, 'It's all finished and sounding great' type comments, just meandering threads about the benefits of various mods.

Does anyone have a finished 'Lampucera' of any flavour, that has been tested against any commercial product?

I will soon have my bog standard, unmodified DAC and PSU board running and want to modify it for possible improvements, but only once! Too much time spent tinkering diminishes any financial gains to DIYing for me and if the finished product of any description only matches a commercial product of modest cost, then I may as well buy that instead.

Which brings me around to another question. Are there any DIY DACs out there that truly compete with mid range (or higher) commercial products?

Many thanks for your help and I'm looking forward to seeing some finished products. ;)
 
Lampucera(s)

Greetings, fastasulike. I have some Lampucera experience that may, or may not, be useful to you.

The Lampucera I built up is this one, with the 6n6p output stage: CD DAC Lampucera lampizator

The DAC board utilized therein, and by me is CS4397 chip based. The Gigawork "Lampucera" board is PCM1798 chip based. Look here:
Lampucera | eBay

The reason I point this out is that all the mod threads I've seen are for the CS4397 board.

I've recently acquired a Grant Fidelity TubeDAC 09 to compare my homebrew Lampucera to, and I must say it's hard to choose one over the other as far as SQ goes. I'd be glad to elaborate on my Lampucera build and general comparison observations if you wish, but I thought it advisable to make sure we're talking "apples to apples" first.
 
YES...

"Which brings me around to another question. Are there any DIY DACs out there that truly compete with mid range (or higher) commercial products?"

Yes, certainly. My TPA Audio Buffalo II/Legato 2 build with all shunt power supplies easily equals or betters some very fine commercial DACs costing a lot of money. I would expect that there are other DIY/kit options that offer very good performance as well, given a good build.
As long as there is a good well sorted circuit design, DIY adds the additional advantage of being able to hand select parts to bring additional sonic gains (resistors, caps, wire, IECs, etc) that manufacturers, of even quite expensive products, cannot afford to use.
 
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Thank you all for your replies. Please excuse my scepticism/cynicism, the main reason for these questions is to avoid either wasting a lot of money on a commercial DAC (Onkyo DAC1000, Benchmark DAC1 etc) or a lot of time building something that could be bettered by a DACmagic/Beresford Caiman. I don't even know if any of these products would benefit my system yet, hence the cheap DIY route first.

Any real experiences of DIY DAC comparisons would be great.

Mazzepa, I would very much like to hear what you have experienced with your DACs, I am looking for detail, clarity and soundstage for myself.
 
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The DIY Lampucera DAC (standard trim) all fired up, no smoke or anything and there seems to be a slight improvement over my OPPO 981. Early days yet, so I'll try different material first to give it a work out before thinking about tinkering.

Not being all that experience with mid range to high end audio, or any critical listening for that matter, what improvements should I be aiming for with this DAC?
Also what are the first noticeable performance step ups?

One thing I have noticed with this DAC is its highish output level, much louder than my OPPO or the Pc. Makes comparisons tricky.
 
Gigawork DAC

I have built 2 of their hi-end DAC's and am about to build another. I have a Rega Saturn CD player which is very good. When I use the Gigawork DAC on the Rega digital output, I cannot pick any difference between the Rega RCA audio out and the GW audio out. From this I deduce that the GW is very good (up to the Saturn DAC standard) or the Saturn transport is the limiting factor and the GW may have even more potential on a better transport. BTW, I have just upgraded to an Audio Aero Prestige CD/SACD player. It's performance is way beyond anything I have heard. When I build the next GW DAC I will connect it to the AA digital output and maybe get some idea of the GW's potential.
 
I have a finished one. I've compared it in sound and measures with various commercial and other DAC identical unmodified Lampucera.

In a Lampucera DAC is mandatory: short cut the 4056 as shown in the picture:

An externally hosted image should be here but it was not working when we last tested it.


It is simply put two drops of tin. Very ease and very important.

If you trying to compare with good commercial DAC or DIY DAC, is not the best in the world, has many defects: power supply, mass, much digital receiver jitter, than other commercial and DIY DAC.

DAC is not the final to all rest of life. DAC is very good for that price. DAC is ideal for fun, designing circuits, output valves, transformer, to learn, etc. If you screw up something you lose a little money.

It is better that the audio output of many current CD readers. Is less than Bechmark DAC1 and other good comercial DAC.

A definitive DIY DAC for all your life, to meet or exceed a very good commercial DAC, is the buffalo DAC. Much better than Bechmark DAC1, and other higher-priced commercial DAC this.

-------------------------------------------------------------
Only recommended changes, no mandatory (better but you will not exceed commercial Bechmark DAC1):

- Change OPA (I think those who come AD827 are not original, I have tried many different OPA. All good measure, some OPA better than others, but with little differences among them. Those AD827 who are worst measure quite different from the rest.

- 4 parallel 470 Oh. resistors R27, R28, R29, R30. Signal level drops to similar values ​​than commercial CDs. Low distortion on maximum output level of the DAC.

An externally hosted image should be here but it was not working when we last tested it.


No further change did been a major improvement for me: SPDIF input transformer, capacitor change, add condenser bid, up to 15 vol. modify SPDIF, etc.
 
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My level of experience in this area is rather limited. I've done some mild mod.s to mid level, older cd players such as a Magnavox CDB582 and Onkyo DX2500. My next step was to a CS4397 Lampucera w/the 6n6p output stage. This was a significant improvement over the cd players I mentioned, and I'm quite satisfied with how my system sounds at this level. This is consistent with oneoclock's comment, that the Lampucera is a step up from most cd readers. I can't speak any further upscale as I've never heard, or even seen any of the highly touted standalone DACs that are available.

I recently became interested in using a PC w/FLAC music files as my primary source. So I researched the ways & means to go about it, and decided to go w/a separate DAC through a USB adapter and the PC. I decided on a Grant Fidelity TubeDAC09 as it has the USB adapter and a tube output stage. This item is considered sonically good, but not great by the internet audio community at large, but I think the sound is excellent. Very comparable to, maybe a bit better than my Lampucera. It is similar to my Lampucera in that it has both tube and opamp output stages available, and the chip is a Cirrus Logic, output tube is a double triode as well.

The TubeDAC costs $215, and I've probably got close to that in my Lampucera (to which I also added passive volume/balance control) and it's not even in a proper enclosure yet. So $ costs are comparable, time investment is higher for the Lampucera, of course. As they are comparable sonically (IMHO) it seems to come down to 3 things to make a choice in the context of this thread.

1. Would you enjoy doing the mod.s to bring the Lampucera up to it's potential?
2. The TubeDAC, or another off the shelf component of similar cost/performance would be easier to sell than a homemade item if you decide to move up.
3. Forget the Lampucera/TubeDAC level and go on up to a higher end DAC.
 
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Thank you once again for the replies, all very helpful.

The reasons for my questions are that I want to better understand audio electronics and how to possibly improve or modify my existing equipment. I will also be better placed to make an informed decision when buying new kit and be able to cut through a lot of marketing BS, plus I also like tinkering.:)
 
I think it's horses for courses in some ways.

Some prefer the Lampuchera route, others add an output transformer. I'm actually happy with the sound using an Op Amp output stage.

I have been running a Gigawork "Big" DAC for 2 years now. I corrected the calculation of the filter components around the first Op Amp stage, removed the second Op Amp stage, upgraded the Op Amps and that's pretty much it. Info on what I did is there early on in the mammouth thread - Here, for example:

http://www.diyaudio.com/forums/digital-line-level/137976-experience-diy-dac-14.html#post1774907

I recently got the chance to try it against a Lampuchera my cousin built and it left us both firmly of the opinion that my DAC with an Op Amp output stage sounded the better of the two. The Lampuchera was warmer but detail was lost. It was a little muddied in comparison. I have yet to hear one with a transformer output.

What I can say is the minimum these boards need, if you want a "build and forget" DAC, is for the filter components around the Op Amp stage to be corrected. Both "big" and small Gigawork DAC boards seem to have these components sprinkled over them and soldered in where they land.;)

It does make me wonder whether there would be such popularity in modifying them if the Op Amp output stage was performing Ok out of the box.;)

They do offer the possibility to experiment beyond that but there's no clear consensus as to what's best, although, in my experience, the lampuchera route doesn't offer as good results as a properly sorted Op Amp output stage.

You can certainly get a great DAC for the money even if you don't delve into lots of experimentation.

I have recently bought one of the PCM1798 based "small" DACs but haven't yet done any listening beyond confirming that it makes a noise (and that the filter components are all wrong).:rolleyes:

Kevin
 
Nice to hear from you, I was an original lurker with the still running thread. I'm in the minimalist camp so I didn't even power up the opamps when I got mine, went straight to the trafos. In all honesty, I haven't had the slightest notion of trying the opamp circuitry although I'm sure if done right it would be just fine.

Best, Bill
 
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Excellent info, thank you. How does one go about working out what the correct filter circuit should be and also if there is a problem with the existing one?

The more I look into these mods, the more it becomes apparent to me that the quality of a DAC is much more about circuit design and integration of components, rather than the quality of the components themselves.
 
What is the purpose of this mod please and how does it work?
Apologies. I'm wrong seeing the photo. The chip is HEF4053BT. It is an analog switch that performs CS8416 mute. It mute OPA output to RCA connector. But you can see is not linear.
http://www.nxp.com/documents/data_sheet/HEF4053B.pdf

In these pictures you can see the difference in short-circuit, the photo 4 only has short circuit, the most important modification.

In other've changed the resistance and the OPA.

The digital input signal is 0 dB 1 kHz. sinewave.

An externally hosted image should be here but it was not working when we last tested it.
 
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I have been trawling the threads for finished DACs, specifically the old style Gigawork DAC (Lampucera). ......

Does anyone have a finished 'Lampucera' of any flavour, that has been tested against any commercial product?

Many thanks for your help and I'm looking forward to seeing some finished products. ;)

I have! First I 'lampizised' the small dac with great result:


An externally hosted image should be here but it was not working when we last tested it.



Then I tried the large version, also 'lampizised':


An externally hosted image should be here but it was not working when we last tested it.



Both these versions are great! I have compared them to an old Pioneer PD-SO6 and a new Cambridge Azur 650BD. No competitions at all. The Gigawork Dacs sound sounded more real and natural.

I demonstrated the dac's to a record producer. He commented on the sound of the dac as if you have removed almost all the compression used on the recording.

Let me add that I used the anode follower. In the large version I also had to dc heat the tubes, but not in the small dac. Here I could use ac heat (and I think this sounds the best...)

Best wishes
Jan Ove
 
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