Re: Re: LL1690 diagram and capacitor
I have been doing some listening with different filters on my Tamuras.
On the primary, I have tried;
A - 270 Ohm resistors from each DAC output (+ & -) with 2000pF cap in between primary inputs (= 147kHz cutoff, like Jensen circuit, louder)
B - 2 x 1K resistors from each DAC output (+ & -) with 470pF cap in between primary inputs (= 169kHz cutoff, legarem's original recommendation, quieter)
On the secondary I have tried;
C - 1K resistor in series with 1200pF cap, between the secondary outputs (+ & -) (as close as I could get to Jensen circuit, which is ~50KHz cutoff filter)
D - 680 Ohm resistor only, between the secondary outputs (+ & -)
I like B and C together - it's the most organic combo in my setup so far.
I can't help feeling there is more to squeeze out of this DAC - any more ideas welcome!
legarem said:
I have been doing some listening with different filters on my Tamuras.
On the primary, I have tried;
A - 270 Ohm resistors from each DAC output (+ & -) with 2000pF cap in between primary inputs (= 147kHz cutoff, like Jensen circuit, louder)
B - 2 x 1K resistors from each DAC output (+ & -) with 470pF cap in between primary inputs (= 169kHz cutoff, legarem's original recommendation, quieter)
On the secondary I have tried;
C - 1K resistor in series with 1200pF cap, between the secondary outputs (+ & -) (as close as I could get to Jensen circuit, which is ~50KHz cutoff filter)
D - 680 Ohm resistor only, between the secondary outputs (+ & -)
I like B and C together - it's the most organic combo in my setup so far.
I can't help feeling there is more to squeeze out of this DAC - any more ideas welcome!
Does this DAC have a provision for switching between digital inputs?
If not, how difficult would it be to install one that switches between optical and
coaxial?
If not, how difficult would it be to install one that switches between optical and
coaxial?
I never thought using the USB input of this dac
Yesterday, I bought a Mac mini and tried many encodings for ripping cds
I will probably become an addict of music server soon. My CEC TL51X transport is 'perhaps' outclassed by the Mac mini.
I'm still amazed because before yesterday, I had great doubts about this technology.
Yesterday, I bought a Mac mini and tried many encodings for ripping cds
I will probably become an addict of music server soon. My CEC TL51X transport is 'perhaps' outclassed by the Mac mini.
I'm still amazed because before yesterday, I had great doubts about this technology.
Using the Tamuras, I am currently using 680ohm resistors on each of the DAC inputs with a 2200pf cap across them - F = 51Khz, and a 680ohm across the secondaries.
I really like this configuration. I had previously used the 1Kohm resistor with a 4700pf cap, but I was getting lots of dropouts.
Now I have no dropouts, and I discovered more detail in my music.
🙂
BTW - I am using the SMD version of this board with the CS4397
I might try a few different brand resistors. I am currently using Allen Bradley 1/2 watt. I'd like to try the Mills and also some Kiwames.
Thanks to all who have contributed here I have a very nice little DAC.
I really like this configuration. I had previously used the 1Kohm resistor with a 4700pf cap, but I was getting lots of dropouts.
Now I have no dropouts, and I discovered more detail in my music.
🙂
BTW - I am using the SMD version of this board with the CS4397
I might try a few different brand resistors. I am currently using Allen Bradley 1/2 watt. I'd like to try the Mills and also some Kiwames.
Thanks to all who have contributed here I have a very nice little DAC.
Are you asking for a Windows application?
Any player can use USB, as soon as you connected a USB audio device and the drivers are installed.
I am using Foobar2000 with the Kernel Streaming Plugin (better audio quality than WMD, less CPU consumption than ASIO4all).
http://www.foobar2000.org/?page=Download
Franz
fordgtlover said:
fordgtlover, 2 questions!
1 - What are dropouts?
2 - What is purpose of the 680 Ohm resistor on the secondaries? I tried it but wasn't sure why I was doing it!
Thanks
hoverdonkey said:
1 - The dropouts are when the music would dropout briefly - usually only for less than maybe half a second, but it was annoying. I'm not sure what caused it, but it has now stopped. The only thing I changed were the resistors and the cap on the primary.
2 - Perhaps there is someone here with far more knowledge that I have who can explain this.
hoverdonkey said:
As the transformer is a 600 to 600 ohm transformer, the 680 ohm resistor shunting the secondary is the optimal load for this transformer and you get near 600 ohm of impedance in the primary.
I never experienced the 'dropout' mentionned when I used 1K resistors. With 1K, resistors, the gain is a little on the low side.
The secondary load is supposed to eliminate ringing(resonance) but an RC filter does a much better job without loosing as much signal.
Read some of Jensen's white papers on their website, secondary loading is not beneficial to OP transformers.
Bill
Read some of Jensen's white papers on their website, secondary loading is not beneficial to OP transformers.
Bill
Bill Fuss said:
With the Tams, I tried many secondary loads with a scope and by ear.
Near 600 ohms I got the best results.
How to calculate a RC filter to correct the ringning ?
I search about this topic and it seems that this is not an easy task to design.
well, i have 680R across the outputs of the tamura, i have to admit that i am still not happy with the sound, althought all i have to compare it to is a lite audio dac 60 which used the burr brown 1704 and a tube output. however i have a tube preamp now and did not feel the need to go down the tube output route for this dac.
i will say that i have not connected the black ground lead from the tamuras, will this make a difference? i guess i should just try it, but i have read conflicting reports about the overall grounding of this dac, i currently have no ground from the mains connected to the dac, i read that mains earth could be connected to the center of the 15, 0 15 rails. And then where would i take the ground from the tamuras to? other than the signal ground?
and would the type of resistors used in the tamura output and input affect the sound massively?
i don't know what it is about this dac but it just seems a little weak the way i have it configured at the moment, i know i must have done somethng wrong as i keep hearing great things about this dac in this thread, and i trust you all!!
cheers stuart
i will say that i have not connected the black ground lead from the tamuras, will this make a difference? i guess i should just try it, but i have read conflicting reports about the overall grounding of this dac, i currently have no ground from the mains connected to the dac, i read that mains earth could be connected to the center of the 15, 0 15 rails. And then where would i take the ground from the tamuras to? other than the signal ground?
and would the type of resistors used in the tamura output and input affect the sound massively?
i don't know what it is about this dac but it just seems a little weak the way i have it configured at the moment, i know i must have done somethng wrong as i keep hearing great things about this dac in this thread, and i trust you all!!
cheers stuart
legarem:
i used your original circuit for the tamuras (without connecting the black wires from tamura), which i appreciate by the way.....
but am i to beleive you have changed the low pass filter now?
stuart
i used your original circuit for the tamuras (without connecting the black wires from tamura), which i appreciate by the way.....
but am i to beleive you have changed the low pass filter now?
stuart
Hey Stu,
Make sure to have the primary and secondary correctly identified. I do everything in rush and had them reversed by accident. When corrected it was great.
Make sure to have the primary and secondary correctly identified. I do everything in rush and had them reversed by accident. When corrected it was great.
no, they are definatley the right way round as colour coded by legarem in his drawing,
cheers though stu
cheers though stu
it seems of the mods are directed at using transformer "buffer".
Has anyone used an opa627 on these? I have read only 1 reply on my question.
thanks! 🙂
Has anyone used an opa627 on these? I have read only 1 reply on my question.
thanks! 🙂
New version
Seems there is a new version of this kit:
NEW Version 24bit/192Hz DAC DA CONVERTER W/ USB Kit,
it now looks identical to gigaworks module as far as I can see. and now has the Daughter Board design for the CS8421 and USB support but apart from that I can not see anything to justify the near $50 price hike over the plain NEW BIG 24bit/192Hz HI-FI DAC DIY KIT,ASSEMBLED MODULE. can anyone see any other differences, is the Daughter board the way to go, "i will be using it in up sampling mode".
Thanks
Seems there is a new version of this kit:
NEW Version 24bit/192Hz DAC DA CONVERTER W/ USB Kit,
it now looks identical to gigaworks module as far as I can see. and now has the Daughter Board design for the CS8421 and USB support but apart from that I can not see anything to justify the near $50 price hike over the plain NEW BIG 24bit/192Hz HI-FI DAC DIY KIT,ASSEMBLED MODULE. can anyone see any other differences, is the Daughter board the way to go, "i will be using it in up sampling mode".
Thanks