LL1674 I/V
Hi Ian. I'm using LL1684's for i/v (as Andrea uses in his dac (http://www.diyaudio.com/forums/quan...018-full-assembled-board-174.html#post3649270 , the resistor is 10k). How do you compare the sound of AR's active i/v with the sound of the transformer i/v? Thanks.
Hi Ian. I'm using LL1684's for i/v (as Andrea uses in his dac (http://www.diyaudio.com/forums/quan...018-full-assembled-board-174.html#post3649270 , the resistor is 10k). How do you compare the sound of AR's active i/v with the sound of the transformer i/v? Thanks.
Hi Ian
I ordered a UFL to UFL RG178 here MMCX Male to U FL IPX Cable for Mini PCI Components | eBay the seller makes custom cables and connector,I must soon receive and give you my impressions against UFL 1,37.
I have almost the same case - in my dual mono BIIIse in synchronous mode powered (directly with jumper on Vin and Vout for ext.reg.) with isolator from A123 LiFePO4 (3.4V) there is no lock in 1 channel .The second channel - few seconds later loosing "lock" and sound too. What is funny - when I put the minireg in place of jumper everything is OK ! On 1 3.4V cell ! I don`t think it is related with u.fl cables ... my cables have the same length ...
@clsidxxl, Universal I2S/DSD isolator PCB
This board was designed a year ago. I didn't list it on GB. I might still have some prototype PCBs.
The attache are schematics and BOM. Please let me know if you have question.
Sorry for my late reply.
Ian
This board was designed a year ago. I didn't list it on GB. I might still have some prototype PCBs.
The attache are schematics and BOM. Please let me know if you have question.
Sorry for my late reply.
Ian
Attachments
Actually it is all one. The active board is balanced jFet buffer board not an I/V board. The idea is different from the concept where mic transformers are used with resistors. In that scenario, the signal is attenuated by resistors to a minimum and than voltage is increased through transformer. I did not like that approach, but it is impossible to properly direct connect a line transformers that are 1:1 or 1:2 to a DAC. For that the best way is to connect buffer to DAC and than Lundahls to buffer. These jFet buffers designed by my friend Zen Mod are balanced without any capacitor in the line of signal and are leaving no signature to the sound. Than Lundahls are perfect match for the role of blocking of DC and safely transferring sound to the amp. The rest you now, you are listening to transformer sound as well. Unmatched detail and superb natural top end.
I was following Rasmundsen tread on transformers with great interest. I have been using Lundahls for many years, previously with AK4396 DACs, so I am very familiar with their sound and problematic involved. I am little bit suspicious to Joe's approach where signal is so much attenuated, and than amplified, so I decided to go this rout.
These Ludahls are 1+1:4+4, but in my configuration I am using them as 1+1:2+2. One way to use them without buffer is to have them reversed in configuration 4+4:1+1. That way they provide a proper loading to the DAC. With that signal is attenuated. My preference is still to use buffer in configuration I described.
Sound of transformers used after DACs is such a unbelievable transformation and improvement. I wanted to share it with Ian, who is pushing boundaries with improvements in digital domain. The difference compared to regular I/V is hard to explain or believe if not experienced.
We have this published previously. This buffer works beautifully. It is very simple circuit, yet outstanding.
Enjoy
AR2
I should have said 'side'
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Femto Clock?
Ian: Have you checked a Femto Clock against OCXO that you positively mentioned earlier? Can that OCXO be categorized as femto clock? Why suddenly all the companies have started putting "femto clock" in their DACs?
Ian: Have you checked a Femto Clock against OCXO that you positively mentioned earlier? Can that OCXO be categorized as femto clock? Why suddenly all the companies have started putting "femto clock" in their DACs?
Femto Clock is a serious misnomer targeted at insecure audiophiles. It all depends on how you measure them. The oscillators that can meet those numbers are not really available for commercial products. When I tried to get them I was told that they were a controlled commodity and I could only sell them inside the US. Typical SOTA commercial performance at 22 MHz works out to about 1.6 pS RMS jitter 10 Hz to 100 KHz. Getting it below that requires very low close in phase noise- -100 dB or less at 10 Hz. Getting that low close in phase noise is very hard and expensive. However phase noise at low frequencies has far less impact on audio. The DAC's internal processes actually limit the performance such that past a pretty accessible level (NDK, Crystek) you won't get improved performance. However good execution will trump even the best conceivable clock used badly. Ian's efforts here are among the best you will find in audio.