Suggestions for Sheng Ya CDP Upgrades - diyAudio
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Old 21st November 2006, 06:32 AM   #1
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Default Suggestions for Sheng Ya CDP Upgrades

Greetings!

I picked up a Sheng Ya CD-S10 several months ago from a friend. This Chinese built CDP has a very decent sound. Many owners of the Sheng Ya CD-S10 have lauded their positive impressions of this player on a number of Forums reviews. This player has two tubes one 6DJ8 in the output stage and a 12AU7 in the power supply for voltage regulation. I have also heard that the 12AU7 is nothing more than a ďshow and glowĒ inside the circular window in the front of the player. Iíve rolled a number of tubes through this playerís with some improvements and some affect on the overall sound quality. Anyways, Iím considering performing some mods and upgrades to this unit. I did some research on this Forum and found very little on this specific player. Iíd like to reduce the noise floor of this player for a blacker, quieter sound. Iím also looking to get more detail and clarity but without any harshness. The sound of the player is a little laid back. I would like to bring the sound a little more forward while expanding the soundstage. Iím looking for some ideas and opinions.

I have tried unsuccessfully to get a schematic of this unit. This gray market product has no distributor in the USA so support is all but non-existent. My initial plans are to replace the Raltron clock (Model CO-72E-T, 16.9344 MHz) with a better clock with a separate PS for the new clock. A picture of the board with the clock is shown in the first photo.

Additionally, I would like to change out some of the opamps. The second photo has numerical designations of the playerís opamps. Opamps labeled 1 & 2 are BB OPA2604ís. Opamps 3 & 4 are NE5532ís, and opamp 5 is a BB OPA2134. Iím not sure what function all of these opamps provide? I donít want to needlessly replace any opamp that wonít serve my overall objective

Last of all I was considering replacing some capacitors in the output signal path and potentially in the power supply. The 3rd and 4th photos show the PC board for signal processing and the power transformer. The picture of the entire board shows most of the playerís functions HDCD and line stage pre-amplification ability.

Your perspective and ideas are very much appreciated.
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File Type: jpg shengya clock small.jpg (42.4 KB, 436 views)
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Old 21st November 2006, 07:27 AM   #2
zanash is offline zanash  United Kingdom
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If you can take a pic of the opamps and output section this could help......

reclocking is good but do that last ! squeeze what you can out of the existing parts and then be blown away with the reclocking ....!

first find the dc blocking cap in the output...this will be the last cap normally an electrolytic following the last opamp......replace with stacked [parallelled] film caps ....say 10 x 1uf wimas 63v per channel.

Alternatively fit using flying leads a big paper in oil caps say 10uf 200v you can pick these up of ebay .. most are ex soviet military ...the ones I've got sound sublime liquid, fast, clean makes you realise how much the fitted caps are actually destroying the sound.

if you fit good sockets at the same time these caps can be wired straight to the output ...but you will need a resistor from signal to earth for each chanel ....try a dale vishay rn55 50 k- 100k a lot depends on what the preamp wants to see ...so you have plenty of wiggle room.
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Old 21st November 2006, 03:34 PM   #3
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I was having trouble posting multiple pic's. Here's a pic of the opamps:

Opamps labeled 1 & 2 are BB OPA2604ís. Opamps 3 & 4 are NE5532ís, and opamp 5 is a BB OPA2134. Iím not sure what function all of these opamps provide?
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File Type: jpg shengya opamps.jpg (28.4 KB, 393 views)
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Old 21st November 2006, 03:34 PM   #4
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The picture of the entire board shows most of the playerís functions HDCD and line stage pre-amplification ability.
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File Type: jpg boardbigview.jpg (73.9 KB, 373 views)
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Old 22nd November 2006, 05:33 AM   #5
zanash is offline zanash  United Kingdom
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One of the top right hand corner would be useful too


As far as is possible from the pic .....

it appears that its relay muted which is good ...the single valve is in the last thing in the output.

there are sets of opamps ..but its impossible to see types

the front valve ......is it like my headphone amp in that its just for decoration ?
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Old 23rd November 2006, 03:23 AM   #6
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Thanks for your reply Zanash! Attached is a photo of the board with the opamps numbered. This photo offers the best picture of the output stage and shows the entire top right hand side of the board. Opamps labeled 1 & 2 are BB OPA2604ís. Opamps 3 & 4 are NE5532ís, and opamp 5 is a BB OPA2134. Iím not sure what function all of these opamps provide? The 2604's appear to be the last opamps in line prior to the output caps and tube. Note that the output caps are film type caps. They are labeled 4/7 uF, but the designated value on the PCB shows them as 5.1 uF.

I've been told the tube in the front of the player is used for voltage regulation. I could very well be just for "show and glow". I have not removed the PC board to try and trace it's function.

This player is supposed to be identical to Kavent CD-731 and the Vincent CD-6 (I think??). All of the players are manufactured by Sheng Ya in China. Thanks again for your suggestions.
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Old 23rd November 2006, 04:10 AM   #7
zanash is offline zanash  United Kingdom
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the opamps will buffer filter and add gain/buffer

for me the obvious possition to change would be the last opamp before the valve stage.

fit good sockets so its easy to swap them in the future.

As to what to swap to thats difficult ....I've just fitted some opa2227 that are making interesting noises and may go well feeding the valve

what are the two transistors doing next to the valve ? is one leg attached to the signal and the other to ground ?

you'll need a dmm to test ....

all the resistors look like cheap metal films ......those that arearound the opamps could be swapped for dale vishays for a worthwile improvment.

Are the two 4.7uf in the signal path ? [they ought to be ]

these are good but theres no harm swapping thes for more exotic types
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Old 23rd November 2006, 06:15 AM   #8
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Hi,

I am also a pround of a China made tube CDP ( ref consonance 2.2 ). I've done some parts upgrades too. The biggest improvement that i've got was the replacement of the film cap at the tube stage. I replaced it with Mundorf Supreme cap .. i've got friends used Mundorf Silver in Oil with outstanding results. The 5.1uf and 4.7uf should not be a issue not unless you replace it double the value for any audible difference. Basically, the higher the value .. the bigger/bolder would be your bass but it would be a bit slower.
Click the image to open in full size.

Replace the OPA2604 by LM4562 .. it is from National semiconductor and they have sample program . See this
LM4562 thread . I've also replace the opamp bypass caps with 0.1uf BlackGate NX HQ. Aslso replaced the caps around the opamp with Silvered Mica and the resistors with Riken resistors.

Replace the clock with a better one with external PSU ... the
Flea is a very good and cheap alternative.

Replace the PSU filter caps with low ESRs like Rubycon ZLs/ZA or Panasonic FCs. The rectifier diodes with 11DQ10 schottky . These upgrades will lower down the noise floor and you will hear better details and clarilty. The cheap Voltage regs were replaced with LT317/337 and LT323 . You can also use this Voltage Reg Module

I also replaced the caps at the transport with OSCON SP series and the IC bypass caps with BG NX HQ.
Click the image to open in full size.

By the way .. you can use Photobucket.com to upload your pictures for bigger/higher resolution pictures.

Good luck
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Old 23rd November 2006, 07:08 AM   #9
zanash is offline zanash  United Kingdom
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Nice player .....

did you listen to the nos version ?

Yes I've been attacking the output caps in my cdp and preamp .with odd results ...

As you say more uf should add bass etc..... but on one unit swapping out 100uf bipolars with 10uf 160v pio's as given loads more bass a clean fast top and a liquidity to the music to die for.

Have you thought about decoupling the supply rails with 10uf tants ...as well as the normal decoupling [its not my idea] this seems to work well on a couple of cdp I've tried it on.

Of cpourse getting good sounding valves will work to ...if not already fitted ..I've not been overly impressed with chinese stock units.
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Old 24th November 2006, 01:15 AM   #10
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Thanks for the info and recommendations Audioboy69! I do have some LM4562 samples on the way to me. Based on what I've learned from research on this Forum, the last opamps in my signal path are the OPA2604's. See pic:

Click the image to open in full size.

Based on your reply, you are also recommending changing the resistors next to these opamps?

Thanks for your recommendation on the Mundorf silver/oil caps. These are VERY pricey!! I was considering Soncap capacitors as they are used in a lot of audio preamp applications.

I still not sure which PS caps to replace. Here's a bigger pic of my board:

Click the image to open in full size.

Thanks for the recommendation on photobucket!
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