The overall view.Note that compare to earlier production,this one use a
"two-part" ATAPI drive as opposite to South Korea's DVS drive.
"two-part" ATAPI drive as opposite to South Korea's DVS drive.
An externally hosted image should be here but it was not working when we last tested it.
The R-core transformer with 3 separate windings:2 for analog stages and 1 for the others.
An externally hosted image should be here but it was not working when we last tested it.
Sanyo's SF-HD65 laser pick-up unit,which can be found inside many cheap DVD players.
An externally hosted image should be here but it was not working when we last tested it.
The ATAPI board,which almost equivalent to a normal DVDROM without:
-Master/Slave/Cable Select jumper setting,
-Analog Audio Output,
-Digital Audio Output.
This one use a VOS chipset rather than the popular MTK chipset.
-Master/Slave/Cable Select jumper setting,
-Analog Audio Output,
-Digital Audio Output.
This one use a VOS chipset rather than the popular MTK chipset.
An externally hosted image should be here but it was not working when we last tested it.
The 'heart' of the machine:Analog Devices' Blackfin audio DSP.Note that
the adjacent Xilinx's FPGA.
the adjacent Xilinx's FPGA.
An externally hosted image should be here but it was not working when we last tested it.
The SPDIF IN/OUT and DAC section.This CDP comes with digital inputs and putputs both on coaxial and optical,with AKM's AK4117 serves as input receiver and a AKM4103 as transmitter.
The DAC section employs a AD1955.
The DAC section employs a AD1955.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
The analog stages:OP275s as I/V converters and OPA2134s as low-pass filter/DC servo.Diamond buffers are also found at the final output stages.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Power supply section:Standard adjustable linear regulators for the analog stages,low-dropout for the digital circuits and switching regulators for the ATAPI drive.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
I've posted the I/V and discrete output stages here.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=77193
Cheers George
http://www.diyaudio.com/forums/showthread.php?s=&threadid=77193
Cheers George
Here is what Lars Viborg of LC AUDIO did to one, below is the pic, and he said it sounds stunning, even dacs at three times the RRP don't come close.
He instaled a LC Zapfilter MkII for the I/V and Output stage board with a Schoktty Shunt Regulated Powersupply board and Toroidal transformer.
And if you want to use it's own transport he put in a XO3 reclocking module and it's own XO Powersupply as well. Major surgery on this one.
I think just the output stage mods are enough and use it as a DAC only with a good transpot like Teac VRDS or alike. But then again a clocked internal transport like this could better the external clocked Teac VRDS?
Cheers George
He instaled a LC Zapfilter MkII for the I/V and Output stage board with a Schoktty Shunt Regulated Powersupply board and Toroidal transformer.
And if you want to use it's own transport he put in a XO3 reclocking module and it's own XO Powersupply as well. Major surgery on this one.
I think just the output stage mods are enough and use it as a DAC only with a good transpot like Teac VRDS or alike. But then again a clocked internal transport like this could better the external clocked Teac VRDS?
Cheers George
Attachments
Just a suggestion,
The original analog stage uses simple bias solution to avoid a use of sound coupling / DC blocking capacitors. I personally never liked the sound of ZAP filter (too cold, washed-out / sterile). The original IC's are surface mount duals - perfect opportunity to try fast IC's from AD stable, or mellow sounding ones from BB. This will (again, from my experience) most definitely give better results than ZAP filter, for much less money!
Boky
The original analog stage uses simple bias solution to avoid a use of sound coupling / DC blocking capacitors. I personally never liked the sound of ZAP filter (too cold, washed-out / sterile). The original IC's are surface mount duals - perfect opportunity to try fast IC's from AD stable, or mellow sounding ones from BB. This will (again, from my experience) most definitely give better results than ZAP filter, for much less money!
Boky
Leolabs said:
Has to be kept as fet input on both opamps, (as this is a direct coupled circuit from dac output to rca outputs), as bipolar input opamps in general tend to have more dc offset at their outputs an can cause the dc servo circuit to go out of it's nulling range and not null out the dc.
If I were going to do opamp subbing, I would dearly love to use the AD825 smd, but it's a single and I don't know if there is such a thing as a 2 x single smd opamp to dual smd opamp convertor board? Maybe Browndog?
In my experience the AD825 is the gun opamp the OPA627 is good also but doesn't have the slam of the AD825, and then I found that the Zapfilter II has even more slam but can on bad cd's sound a bit cold, but really makes up for it with good recorded material, but it's also more expensive way to go.
Cheers George
Your in luck Browndog have them @ $6.95 each, you need 4 of them and 8 AD825 's
http://www.cimarrontechnology.com/index.asp?PageAction=VIEWPROD&ProdID=19
Cheers George
http://www.cimarrontechnology.com/index.asp?PageAction=VIEWPROD&ProdID=19
Cheers George
Leolabs said:
Supply voltage is 24V - so AD8066 (my favourite) should work nicely. This IC requires very clean noise-free supply with proper PCB ground topology.
The second IC is half "DC servo", half diff-to-single-end gain stage (for discreet output) - I would try AD826 here. Alternative: LM4562 (different sound, also quite nice...)
Boky
No need(IMO..) for any upgrade.
Measurements for HD970 "as is". Jitter bellow 10ps!!
http://www.diyaudio.com/forums/showthread.php?postid=1186279#post1186279
Measurements for HD970 "as is". Jitter bellow 10ps!!
http://www.diyaudio.com/forums/showthread.php?postid=1186279#post1186279
BV said:
Yes it does, the sound standard is a little warm (OP275) and also lacks a dynamics, it also needs more bass slam, this is compared to two other very good dacs. But it can be heard that it's very extended smooth/clean and distortionless, and low in "jitter" if I can identify what jitter sounds like.
Saying this I believe it can be achieved, with subbing the OP275 (known to be softish) and the OPA2134 for either better opamps, like my personal favorite the AD825, or to do the radical transplant of a Zapfilter MkII. The latter is extremly dynamic (unbelieveably so) and can sound cold on some sterile recordings, but I belive it's just staying true to the source.
Cheers George
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.