Hello McGyver,
Other than learning Polish do you know where/how I could order one of these?
But I did it. I got rid of opamps, I desoldered them and connected transformers right to the chip's legs. And grounded center taps.
Frequency Response with Lundahl 1674
I am listening to my DAC with Lundahl LL 1674 for some weeks now.
I attach a picture with how I connected the Lundahls. I use two 1K resistors for R1 and R2 and no resistor for R3.
I also have a 1nF MKP cap connected between the output sides of R1 and R2 as a very light filter for high frequencies at the input side of the Lundahls.
Today I measured the output of this configuration, and I wasn't pleased to see the frequency response. As you can see on the picture, already at 20 kHz the level is down by some -6 dB
These Lundahls should be quite flat up to 20 kHz, so apparently my connection is not optimal.
Can anyone give me a clue as to get better results?
I am listening to my DAC with Lundahl LL 1674 for some weeks now.
I attach a picture with how I connected the Lundahls. I use two 1K resistors for R1 and R2 and no resistor for R3.
I also have a 1nF MKP cap connected between the output sides of R1 and R2 as a very light filter for high frequencies at the input side of the Lundahls.
Today I measured the output of this configuration, and I wasn't pleased to see the frequency response. As you can see on the picture, already at 20 kHz the level is down by some -6 dB
These Lundahls should be quite flat up to 20 kHz, so apparently my connection is not optimal.
Can anyone give me a clue as to get better results?
Attachments
Thanks, Havoc08, for directing me to this thread. It's taken me about three days to read and although I cannot pretend to understand everything, I am convinced already go the transformer route. Which transformers is a decison yet to be made.
It still looks to me, however, that the DAC you suggested is a baby brother to the ones talked about here.
I don't see any obvious reason they shouldn't, but can someone please confirm that these mods also apply to this DAC.
My aim is to place this DAC between a Shigaclone (still to be built) and a MyRef amp via a Lightspeed attenuator and finally going into 98db full range speakers.
I also have a T-Amp which I like to use during trials. Are we saying here that the T Amp needs a special arrangement and so we cannot just swop amps around ?
It still looks to me, however, that the DAC you suggested is a baby brother to the ones talked about here.
I don't see any obvious reason they shouldn't, but can someone please confirm that these mods also apply to this DAC.
My aim is to place this DAC between a Shigaclone (still to be built) and a MyRef amp via a Lightspeed attenuator and finally going into 98db full range speakers.
I also have a T-Amp which I like to use during trials. Are we saying here that the T Amp needs a special arrangement and so we cannot just swop amps around ?
Although I have the DAC mentioned in the previous post on order, I had been looking at this one which is locally available. As it is PCM1798 based, I thought it might be of interest seen McKyver's recent comments. It even has a Chinese price and might have originated there for all I know.
SPDIF only!!
Anybody have any experience with this one?
SPDIF only!!
Anybody have any experience with this one?
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Looks good, nice layout and quality components. But Yoy should bear in mind that PCM1798 is not a voltage output DAC. It is a current output DAC, and requires completely different analogue stage than CS4397 or CS4398.
For PCM1798 I'm using Sowter transformers for I/V conversion, desymmetrization and analogue filtration followed by tube amplification stage.
1nf is too large, try around 200pf. That should give you an f3 around 150khz.
Been listening for 5minutes to my dac ,and I imidiately changed the opamps to LM4562 and bypassed the e-lyts.The highs are more laidback then on my Benchmark DAC1,well lets hope it "burns in with more listening(if it does...)
And hope i gets my hand on sóme outputrafos..
And PCM1798..
Maybe the LL1690 would fit for the laidback highs?..
And hope i gets my hand on sóme outputrafos..
And PCM1798..
Maybe the LL1690 would fit for the laidback highs?..
That's one I have, and I've been using the output transformers for a while.
There is some pretty good information here about that DAC
CD DAC Lampucera lampizator
Also try theartofsound forums
Sry Tony didn't see your post.
There is a small dac which has the psu on daughterboard which is the one preferred as it is easier to change components on it. You also do not need everything after the dac chip (opamps etc) so that i a waste of money.
If you want USB then you have to take the larger DAC and it can be used also. You just do the same to it by stealing the output after the chip and doing a new output section with the trannies.
As far as I understodd from other threads on this issue, Tamps are no problem with trannies. They can be hooked up as normal. Jkeny just speculated that you could make the 2,5v bias and bypass something on the amp (Have not quite understood the benefits as I'm probably not going to do it).
There is a small dac which has the psu on daughterboard which is the one preferred as it is easier to change components on it. You also do not need everything after the dac chip (opamps etc) so that i a waste of money.
If you want USB then you have to take the larger DAC and it can be used also. You just do the same to it by stealing the output after the chip and doing a new output section with the trannies.
As far as I understodd from other threads on this issue, Tamps are no problem with trannies. They can be hooked up as normal. Jkeny just speculated that you could make the 2,5v bias and bypass something on the amp (Have not quite understood the benefits as I'm probably not going to do it).
Yes Tripath amps can be used as normal with transformers. I just wired up the transformer so as to avoid a cap on the input of the Tripath amp - sounds great & no turn on thump either
So between my DAC and amp there is only a transformer, no caps.
Hello all,
New on this thread, I had many hours of reading and must say this subject is fantastic. I just ordered the DAC you are talking of, and I wish to switch the analog output stage to transformers.
I found these which are localy available :
Oxford Electrical Products | Transformateurs | Transformateurs | Transformateurs audio | Montage sur CI et châssis |A262A6E
Do you think they could do the job ? And also what is the value of resistors and caps needed ?
Btw has anyone noticed some sellers offer CS 43122 dac chip on a daughter board for this DAC ?
New on this thread, I had many hours of reading and must say this subject is fantastic. I just ordered the DAC you are talking of, and I wish to switch the analog output stage to transformers.
I found these which are localy available :
Oxford Electrical Products | Transformateurs | Transformateurs | Transformateurs audio | Montage sur CI et châssis |A262A6E
Do you think they could do the job ? And also what is the value of resistors and caps needed ?
Btw has anyone noticed some sellers offer CS 43122 dac chip on a daughter board for this DAC ?