Beautiful implementation of the original JVC shiga! I especially like repurposing the leather box to cover the transformer and the pop up display.
The BOM for Vicol-audio shiga only requires 20VA transformer. I have wondered also about larger power transformer for shiga black as this was subject to significant discussion/experimentation for the JVC clone. Physical space, of course is a limiting factor - i would need to design around a bigger case for bigger trafo (unless you are having the trafo/psu separate).
Made a test today with the MKII Black... changed the transformer from a toroidal transformer to the Hammond laminated core transformer I had in my JVC transport. Both quality transformers, both 120VA sec 12-0-12.
The toroidal may be the openness king, but I much prefer the Hammond! More vivid, musical, 3D soundstage, better hitting bass, symbals are more sophisticated... just more emotional
I tried this once before, but the toroidal I had then may not have been a quality piece, so was not certain. Now I am: laminated core is better for this transport - or at least Hammond is.
And that's just a transformer...
Thanks for the compliments Tibi and sthcoaster!
The toroidal may be the openness king, but I much prefer the Hammond! More vivid, musical, 3D soundstage, better hitting bass, symbals are more sophisticated... just more emotional
I tried this once before, but the toroidal I had then may not have been a quality piece, so was not certain. Now I am: laminated core is better for this transport - or at least Hammond is.
And that's just a transformer...
Thanks for the compliments Tibi and sthcoaster!
Interesting. I've read elsewhere various people preferring EI core trafo over toroid for digital.
Part numbers on the BOM go to a 20VA EI core trafo.
I'm currently using 30VA 9v toroidal but have a 100VA 12-0-12v EI from the JVC Shiga which I will try. I have read in earlier posts Tibi cautions using 12v trafo as the v drop through the regulator produces a lot of heat. Will test with the 12v trafo and if I like it I may spring for a high VA 9v EI. However, bigger trafo physical size means I will have to rethink my plans for casing this project - may revisit 2 box idea.
We have updated Shiga MKII wiring draw.
Regards,
Tibi
Regards,
Tibi
An externally hosted image should be here but it was not working when we last tested it.
Hi all,
I assembled my kit yesterday. Initially I connected the cd transport to Chord Mojo via co-axial and listened to it for about an hour on headphones and it sounded good.
When I connected the Mojo to integrated amp the audio was cutting out, I hear audio for 2 - 3 seconds max and it cuts out for 5-6 seconds and plays again for couple of seconds before it cuts out again with occasional clicks and pops. Then when I connect back headphones it was playing fine.
Today it was not playing from headphones and hi-fi too and had the same problem as yesterday. Any idea what could be wrong?
BTW the voltage from the regulator board is 7.95 volts. The disc gets initialised properly and all the functions work.
I've two kits (one is mine and other belongs to a friend). The problem is consistent and can be reproduced with swapping the cd mechanism, main board and cables. The only thing I didn't swap are the transformer and regulator board which I don't think will make a difference. I use a co-axial cable with rca to 3.5mm adapter to connect to mojo.
Any help would be appreciated. I'll borrow another dac tomorrow from a friend to see if Mojo is failing to lock on the co-axial signal or any problem with the adaptor cable.
I assembled my kit yesterday. Initially I connected the cd transport to Chord Mojo via co-axial and listened to it for about an hour on headphones and it sounded good.
When I connected the Mojo to integrated amp the audio was cutting out, I hear audio for 2 - 3 seconds max and it cuts out for 5-6 seconds and plays again for couple of seconds before it cuts out again with occasional clicks and pops. Then when I connect back headphones it was playing fine.
Today it was not playing from headphones and hi-fi too and had the same problem as yesterday. Any idea what could be wrong?
BTW the voltage from the regulator board is 7.95 volts. The disc gets initialised properly and all the functions work.
I've two kits (one is mine and other belongs to a friend). The problem is consistent and can be reproduced with swapping the cd mechanism, main board and cables. The only thing I didn't swap are the transformer and regulator board which I don't think will make a difference. I use a co-axial cable with rca to 3.5mm adapter to connect to mojo.
Any help would be appreciated. I'll borrow another dac tomorrow from a friend to see if Mojo is failing to lock on the co-axial signal or any problem with the adaptor cable.
Attachments
Could you please reverse DOUT output as per my above drawing post 1485.
This is also happen when your amplifier have a noisy power supply or is self oscillating. Shiga MKII do not have a galvanic isolated output. The downside of this is that your entire audio chain must be very low noise.
To clear such issues, you must use a s/pdif trafo. Scientific-conversion make some very good ones. I have used murata da101c with good performance as well. However, I recommend you to use Shiga MKII as it is, with direct output from resistor divider.
Regards,
Tibi
This is also happen when your amplifier have a noisy power supply or is self oscillating. Shiga MKII do not have a galvanic isolated output. The downside of this is that your entire audio chain must be very low noise.
To clear such issues, you must use a s/pdif trafo. Scientific-conversion make some very good ones. I have used murata da101c with good performance as well. However, I recommend you to use Shiga MKII as it is, with direct output from resistor divider.
Regards,
Tibi
Last edited by a moderator:
Its working now!
I've replaced the ribbon cable and the unit works! Only now my display is not working properly. Can the LCD display unit be replaced?
tom
I've replaced the ribbon cable and the unit works! Only now my display is not working properly. Can the LCD display unit be replaced?
tom
Thanks Tibi. Reversing the DOUT polarity as per the new connection diagram worked for me. It sounds very good as per my initial listening impressions.
I've replaced the ribbon cable and the unit works! Only now my display is not working properly. Can the LCD display unit be replaced?
tom
Can you describe what is the problem ? Backlight or digit missing ?
Regards,
Tibi
Backlight works fine. You can say the digit is missing or to be more correct not formed correctly. Again many thanks for your replies and great support!
tom
This is caused by ribbon cable who do not make contact with connector. Display is ok.
Regards,
Tibi
Hi Tibi
Just getting back to this now.
Do you mean C57 + C58?
they are side by side on board and marked for use by X01
I could not find C67
Thanks
Thanks
In my haste
it looks like I may have lifted the small central pad for the hot from XO3. Is it possible to add to the hot of any of the other XO positions?Need to take closer look when I have time
Best
Clayton
Trouble in paradise
Thanks Tibi
I had worked that out for myself from the schematic for XO options on the assembly manual. I believe I have fitted neutron clock correctly but..
But for now shiga is kaputt.
- mechanism does not spin on startup
- display is backlit but no info displayed
Do these symptoms suggest the clock is not installed correctly or is something else at fault? If Shiga is not receiving clock signal are these expected?
Will go back to check all is as it should be again.
Thanks in advance for your help
Thanks Tibi
I had worked that out for myself from the schematic for XO options on the assembly manual. I believe I have fitted neutron clock correctly but..
But for now shiga is kaputt.
- mechanism does not spin on startup
- display is backlit but no info displayed
Do these symptoms suggest the clock is not installed correctly or is something else at fault? If Shiga is not receiving clock signal are these expected?
Will go back to check all is as it should be again.
Thanks in advance for your help