Has anyone tried the Altmann Jitter 'filter' with a different NOS DAC to see if it's really the Altmann or the Jitter or the combination that everyone seems to find magical? I didn't want to crash the other thread. I'm just really curious. For instance MHDT says specifically that they do not do any clock matching because in their opinion, it should be done by the source and there should be only one clock. I'm just curious how something like the SN or the MHDT would sound with the Altmann DeJitter with it?
George? Carl? Anyone?
Bryan
Hi Bryan
I didn't notice any difference flipping the jisco switch on the DAC, but source was Oracle CD1000, (didn't see what cable was used) so Jitter may have been low already. Couldn't tell with SB as source due to my poor setup but it could be helping there and I just don't know it. The character of the ALtmann DAC doesn't seem to change much with Jisco enabled or disabled. Would be interesting to hear jisco by itself.
Rich
Same here...
I should of tried a cheap transport to check it out.
Was just curious as pretty much everyone that I hear recommending the Altmann seems to include the JISCO as part of what should be purchased.
Bryan
I did my night of listening with the jitter feature switched off and was so enamored I didn't want to touch anything for fear I'd mess it up. I didn't do much experimentation because it sounded good 'out of the box'. ;)
I didn't want to like and still don't... but can't deny there is more to it than anything I've ever heard.
-C
I don't know the nuts and bolts of it. I'm not sure it's a clock-matching circuit. One of the stops on the Tour (mgalusha's) using a heavily modded SB as source said they could hear the difference with a cheap digital IC but not with a better one.
It's a proprietary thing, the different manufacturers all seem to have a different spin on spinning the bits. I just bought all the options to make sure I didn't leave anything necessary out. Based on what I've read from the Tour stops, most folks couldn't hear the difference and I wouldn't consider it necessary to enjoyment.
Chalres Altmann describes the JISCO operation on his website (http://www.jitter.de/english/jisco.html):
Main page here (http://www.jitter.de/english/jisco.html).
Hi,
I got a chance to listen to quite a few NOS DACs and upsampling and.or oversampling (I have own them before). I think the Attraction DAC with a simple circuit and JISCO system is a winner IMO. I still love the sound of Attraction DAC after heavily modifying and tweaking the Promitheus DAC (still in the process of doing that further). :D/
Altmann uses a Xylinks chip to reconstruct and reclock the digital input, erasing almost all jitter. He calls it UPCI, it is standard on every DAC. JISCO is intended to filter out jitter when onboard clock is not available, but he added it onto the DAC anyway.
From his website: "The digital input signals are recovered with extremely low jitter as they are generated by custom made voltage-controlled crystal-oscillators (VCXOs) and employ the UPCI (Ultra Precision Clock Injection) technology."
yummy!
Quote from: tanchiro58 on February 03, 2008, 07:18:37 AM
Hi,
I got a chance to listen to quite a few NOS DACs and upsampling and.or oversampling (I have own them before). I think the Attraction DAC with a simple circuit and JISCO system is a winner IMO. I still love the sound of Attraction DAC after heavily modifying and tweaking the Promitheus DAC (still in the process of doing that further). :D/
I tried to improve the Promitheus DAC as well. Working on outboard power supply [ 100W ]. Changed RCAs to Vampire Copper/gold. All signal wiring to copper and power wiring Silver. Now looking at Some cap changes to V-cap Teflon. Shielded enclosure, changed cover plates to copper. Now its beginning to sound much better but still nedds some help.
rollo
Hi Charles,
I have tried to modify the Promitheus DAC to the max but it could not beat the Attraction DAC in all aspects. Maybe it depends on the design. My next step to try is put the ebony wood underneath the trannies. I tried a small pinewood platform under pcb dac. It sounded little better until I swapped the stock opamps with Burson Discrete opamps. The DAC sounds way better but the thing is Nicholas told me that he set opamp voltage at 12VDC whereas Burson works at 25VDC (I measured 22.65 to 23.45 VDC at pin4 and pin7 where the bypass cap of 0.01uF soldered. He also told me to retune down to 12VDC but how? Do you know if I can replace resistors or high value caps around Burson opamps? Thanks in advance.
Regards,
Tan
I sent my DAC to rollo and now I am getting to know the SB3 stock analog output all over again. Look to my early AN posts to see all the problems I was having with shouting, harshness etc. and blaming amps and speakers, speaker wires. It's all back. Listening to some opera tracks (yuk) on Gramophone sampler were unbearably harsh when they really let loose, and the harshness peaks with the output level. Same as before. Kinda funny. Before I bought it I had hoped the DAC would solve the harshness, but I never really did A/B tests, since I already owned it I figured whatever, just use it. It definitely helped. I would imagine it would be the same with any quality DAC, and my point is that a good DAC or other source makes all the difference in the world.
It is very easy to grow accustomed to good audio gear. What is the "sound" of low distortion? You don't appreciate it until it goes away. Eye opener for me.
Rich
Maybe any quality DAC would help that problem but that DAC does a lot more. What a nice guy, sending your stuff around. I think I have something of yours laying around here, now if I can just find it. :D
Rich,
So...are you saying that most of the 'ills' you were fighting, at one time, were ameliorated with the Altman DAC...at least in retrospect?
Yeah Steve, that was the big surprise. I think the DAC has made more of a difference than I was aware of until I plucked it out again and heard the sudden change in reverse direction. Maybe it is easier to hear degradation than improvement? It is not terrible or unlistenable, but on the louder stuff where I was having problems before, I blamed everything except SB, and now it suddenly returns when DAC goes out for canolies! All the other upgrades this past year (everything but the speakers) certainly improved the sound, but I was really frustrated when a week after doing an upgrade I would still hear vestiges of the same problem that I tried to cure. No regrets in hindsight, the system is light years beyond what it was a year ago, but I wonder if I got the DAC first, how itchy I would have been to upgrade everything else. Probably just as itchy... :D I'm glad I took the route I did. I kept saying I wanted to go from the speakers back to the source, which is what I did and it worked.
Well the DAC is in the house. Thanks Richadoo. Tonight, tonight The batery arrives and we will give it a go. Will compare to Oritek, Promitheusand Lector CDP.
Great. Check the batt voltage and have fun! I look forward to another classic "rollo" review. Have fun!
Rich