Finally, an affordable CD Transport: the Shigaclone story

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uncle_leon

uncle_leon

Member
Joined 2007
studiozey.com/
Following a suggestion from spartan, I am planning to investigate the hypothesis that Fran's attenuator sounds better than an L-pad made with standard resistors because the Pi-pad configuration is inherently better than an L-pad.

So I need a Pi-pad that has the same parameters as the 300/100 L-pad, and this is where things get a little tricky with my limited understanding of impedances...

I am guessing I should go for a Pi-pad calculated for 75Ohm input, 75Ohm output and 12dB attenuation (2V/0.5V=4 ->12.04dB) - is this right? That would mean two 125R shunt resistors (R1 and R3) and a 141R series resistor (R2) - could someone please confirm?

300px-Attenuator%2C_Pi-section.svg.png
 
W

woodturner-fran

Member
Joined 2006
I recently tried out some resistors made by Uncle_Leon in my shigaclone, specifically testing them against the RF attenuators that I have been banging on about here for the past year or so. Well, against all my expectations, the resistors I think have the edge on sound quality.

Before this I had tried a good number fo different types of resistors on the shiga output and the RF attenuator easily beat them all. Now Uncle_Leon comes along and upsets the world order.......

So what differences do I hear? Well, for one, the midrange is a bit more smooth. Things like voices are more rounded and real, cello you get more of the tone and wood of the instrument. Putting back in the RF attenuator, you can hear a slight thinness by comparison. Bear in mind that the RF attenuator beat all other resistor types up to now. As I mentioned, I was not expecting them to come anywhere close.....



Fran
 
iTiberius

iTiberius

Member
Joined 2005
In the last days we have tested and compared new shigaclone board in different configurations.
The new board is performing excellent and I'm really excited by the results. Hope many of you will rediscover this fantastic transport. :)

Finally, we have performed some more modifications and removed others.
AD151 2,5 ultra low noise regulator will be removed and instead we will use an extra resistor divider, bypassed with silver-mica, at LA9242 pin57. This will greatly reduce noise level at LA9242 pin58. The sound if far better this way.
AD151 will be removed from order list. However, if you like to experiment further with this regulator we can provide you this component.
All 5V LT1763 regulators will be optional and moved to power supply board.
These trend to have a low residual oscillation, 2-3mV at very high frequency and need to be decoupled with at least 100nF ceramic and 1nF silver-mica. As you may know, the downside is that 100nF ceramic can be found in X7R or Z5U, both have big piezoelectric effect. So, in final, you have a low-noise regulator very susceptible to vibrations. :-~ Will be up to you to use them or bypass them. The board already allow this.
LA6541 have pin1 and pin24 internally connected. There is no sense to have two separate 8V power supply for this chip.

Please also note that the list will be closed on 15.July.2012.
Only people who are registered on this list will get the components at the listed price.

Best Regards,
Tibi
 
Last edited by a moderator:
iTiberius

iTiberius

Member
Joined 2005
massimo said:
Sorry Tibi, where can I find pcb & components prices?
Click to expand...

Massimo,

In my synature you have the "Shigaclone pcb interest" list.
If you move your mouse ower raw 2, you'll se some comments who include the price as well.
For your convenience:
- 3 IC chipset LA9242M; LC78601RE; LA6541 is 7,7euro
- mechanic SFP101N-16P is 7euro
- transistor set 2SA608NF; 2SB764E; 2SA1342 is 1,75euro
- optional ADP151AUJZ-2.5-R7 is 0,76euro
- custom multiplexed LCD is 6euro
- price for PCB set board will be announced by the end of this week

Please note that all above components are with 0%-5% profit margin and is our thank for this community.

Those who want full components Kit or ready made Kit, this will be sold via Vicol-Audio webshop starting with 1st August.

Regards,
Tibi
 
Last edited by a moderator:
S

syklab

Member
Joined 2009
tvicol said:
In the last days we have tested and compared new shigaclone board in different configurations.
The new board is performing excellent and I'm really excited by the results. Hope many of you will rediscover this fantastic transport. :)

Finally, we have performed some more modifications and removed others.
AD151 2,5 ultra low noise regulator will be removed and instead we will use an extra resistor divider, bypassed with silver-mica, at LA9242 pin57. This will greatly reduce noise level at LA9242 pin58. The sound if far better this way.
AD151 will be removed from order list. However, if you like to experiment further with this regulator we can provide you this component.
All 5V LT1763 regulators will be optional and moved to power supply board.
These trend to have a low residual oscillation, 2-3mV at very high frequency and need to be decoupled with at least 100nF ceramic and 1nF silver-mica. As you may know, the downside is that 100nF ceramic can be found in X7R or Z5U, both have big piezoelectric effect. So, in final, you have a low-noise regulator very susceptible to vibrations. :-~ Will be up to you to use them or bypass them. The board already allow this.
LA6541 have pin1 and pin24 internally connected. There is no sense to have two separate 8V power supply for this chip.

Please also note that the list will be closed on 15.July.2012.
Only people who are registered on this list will get the components at the listed price.

Best Regards,
Tibi
Click to expand...
Hi Tibi,
Will decoupling the AD151 with 100nF ceramic and 1nF silver-mica cure the oscillation? I will be building a DAC and going to use the same LDO regulator and wonder if the same oscillation will ocur.

Thanks
 
iTiberius

iTiberius

Member
Joined 2005
syklab said:
Hi Tibi,
Will decoupling the AD151 with 100nF ceramic and 1nF silver-mica cure the oscillation? I will be building a DAC and going to use the same LDO regulator and wonder if the same oscillation will ocur.

Thanks
Click to expand...

My oscillation comments are related only to LT1763.
AD151 is another story. He is doing a great job and is stable, but shiga will sound far better with resistor divider at LA9242 pin 57.

Regards,
Tibi
 
lehmanhill

lehmanhill

Member
Joined 2008
Great Results!!!

Hi Tibi,

Fantastic news all around.

Could you overview the power supply situation as you now see it?

My memory is that we have +8V, higher current for the motor drive,
V1, V2, V3, and V4 are all +5V, low current and used for?
And you are suggesting using a resistor divider + cap for the 2.5 V reference voltage.

Do you have a sense of the value of separate regulation for V1 - V4? I was thinking about using a spare Salas regulator to supply V1 - V4 in parallel.

Output?

If I remember correctly, the output is SPDIF. There was some talk about members of this thread designing a small optional board to convert the SPDIF electrical signal to both AES/SBU balanced and Toslink or other optical output. Does anyone have any thoughts about doing the optional output board? I personally am interested in making AES/SBU possible because that is the only input left unused on my DAC. I might go with a simple transformer/passive conversion, but a true balanced output would be great.

Thanks,

Jac
 
T

tonyptony

Member
Joined 2006
tvicol said:
In the last days we have tested and compared new shigaclone board in different configurations.
The new board is performing excellent and I'm really excited by the results. Hope many of you will rediscover this fantastic transport. :)
Click to expand...

Awesome news Tibi. Have you been able to compare it to any of the well known mega transports (ML 31.5, CEC, Linn CD12)?

BTW, I should have asked this a while ago when I signed up, but in order to build 1 of these, do I ask for "1" of every line item on the list? :)
 
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