Power transformers and R-core
Thanks for the info. I don't have good luck with torroids, they have huge interwinding capacitance (primary to secondary) which brings in all the powerline hash into the amp or DAC. Adding EMI/RFI filters can make it worse or better depending on how you've grounded your system. The EI split bobbin transformers I have best results with, for preamps and DACs.
Anyone know of good mixed secondary (9V and 14V or so) transformers?
Thanks for the info. I don't have good luck with torroids, they have huge interwinding capacitance (primary to secondary) which brings in all the powerline hash into the amp or DAC. Adding EMI/RFI filters can make it worse or better depending on how you've grounded your system. The EI split bobbin transformers I have best results with, for preamps and DACs.
Anyone know of good mixed secondary (9V and 14V or so) transformers?
Gigawork DAC and Tube buffer
Hi, inspired by this tread
, I have been using the Gigaworks Dac with the opa627 op amp and have been quite happy (understatement, i have been very impressed ) with the sound using Lowther horns, pse 2a3 and old quicksilver amps, and iTunes and spotify on a MacPookPro as digital source.
I then invested in the Gigaw. Tube Buffer, tried it after the dac and found the sound involving and dynamic but slightly forced or overexposed, it was however quite good as buffer after my analogue source, Linn LP12, Moerk UP4, Ortofon MM and Audio Alchemy riia.
I wanted to try bypassing the opamps altogether and because i managed to destroy the upper layer on the print around the 4 capacitors Im connecting directly from the Dac chip print (legs 19, 20, 23, 24 - R-, R+, L+, R- respectively) into the tube buffer.
If i run directly from the buffer to my pse 2a3 amp, i get a lot of hiss (white noise) with the music, but if i go through the Noble pot in my passive pre i get detailed, clear and clean sound that is however quite flat, un-engaging and lacking in dynamics.
Is my problem that i dont have enought gain, or is there a poor fit between the dac and the buffer or the buffer and amp? Do I need some coupling caps between dac chip and buffer? Or
Regards
Kjartan
Hi, inspired by this tread
, I have been using the Gigaworks Dac with the opa627 op amp and have been quite happy (understatement, i have been very impressed ) with the sound using Lowther horns, pse 2a3 and old quicksilver amps, and iTunes and spotify on a MacPookPro as digital source.I then invested in the Gigaw. Tube Buffer, tried it after the dac and found the sound involving and dynamic but slightly forced or overexposed, it was however quite good as buffer after my analogue source, Linn LP12, Moerk UP4, Ortofon MM and Audio Alchemy riia.
I wanted to try bypassing the opamps altogether and because i managed to destroy the upper layer on the print around the 4 capacitors Im connecting directly from the Dac chip print (legs 19, 20, 23, 24 - R-, R+, L+, R- respectively) into the tube buffer.
If i run directly from the buffer to my pse 2a3 amp, i get a lot of hiss (white noise) with the music, but if i go through the Noble pot in my passive pre i get detailed, clear and clean sound that is however quite flat, un-engaging and lacking in dynamics.
Is my problem that i dont have enought gain, or is there a poor fit between the dac and the buffer or the buffer and amp? Do I need some coupling caps between dac chip and buffer? Or
Regards
Kjartan
Thanks data I will try that, and yes I have thought about getting some trafos, but just wanted to see if i could do without as my system is very sensitive to any component changes. I would probably go for the Lundahls as Im planning to get MC step-up trafos from them as well.
mvh
Kjartan
Hi data, I soldered in som 1.1k resistors I had at hand and it did not change the hiss when connecting directly to the amp, so some mismatch is still there.
Through my passive pre (pot) i dont get the hiss. I get a lot of resolution but somehow everything is tilted to the light side, ultra smooth and liquid. Maybe Im losing some colourations but I still think its too kind and unengaging to be intresting.
regards
Kjartan
Through my passive pre (pot) i dont get the hiss. I get a lot of resolution but somehow everything is tilted to the light side, ultra smooth and liquid. Maybe Im losing some colourations but I still think its too kind and unengaging to be intresting.
regards
Kjartan
If you're going to go the PCM1798 route wouldn't it be almost as cheap and much simpler to get something like this(you can click the Google translate button for English version): http://www.audiophonics.fr/audiophonics-dac1798-dac-24bit-192khz-cs8416-pcm1798-p-4993.html
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From what I gather your best bet would probably be the XSM10K/10K or the XSM600/600 if you insist on 600ohms
I have been researching excessively and I'm circling back here.
List of DACs Under $450 - AudioKarma.org Home Audio Stereo Discussion Forums
Has anyone used this transformer? Hammond Mfg. - Power Transformer - (229 Series)
I am getting on for another project, wondering if it's a good one for this too.
Also, is there a list of recommended mods to this DAC somewhere compiled in one spot? I'm putting in an order of BlackGates and want to know if it would make sense to get some for this project.
List of DACs Under $450 - AudioKarma.org Home Audio Stereo Discussion Forums
Has anyone used this transformer? Hammond Mfg. - Power Transformer - (229 Series)
I am getting on for another project, wondering if it's a good one for this too.
Also, is there a list of recommended mods to this DAC somewhere compiled in one spot? I'm putting in an order of BlackGates and want to know if it would make sense to get some for this project.
McK, I was hoping to use you pic here as a guide to doing the opamp bypass, but it looks like my layout is slightly different (why are they always changing the components?).
1) In the background you pulled off the 4 caps in front of the cs4398. Did you jumper them? Doesn't appear so in the pic.
2) Is the L/R out w/ the bypass from the 2.2ufs? (see my pic).
3) I can just use those L/R uouts straight to rca jacks, correct? Or do I have to solder them to that resistor like in your pic?
Man, we really need that wiki going. I think the actual pertinent and useful mod info takes up all of a couple pages to have to weed through this beast!
Attachments
1) Yes they are jumpered underneath the board.
BTW the board was a basic(non-ups) CS4397.
I can't quite remember what else I did under the two twisted resistors as this was quite a while back and I no longer have the DAC. I do remember that I replaced original in/out RCAs but hooked the new ones up in the same spot.
I'll see if I can dig up some pics somewhere.