Help for Kenwood dp-7050 mod

[Mooly]

I'd go along with substituting the opamps too but you need to exercise care, particularly if you need to make up adapter.

Don't take it for granted that it will be stable without at least some basic tests,
Swapping Op-Amps... you have checked to see it's stable haven't you ?

I would perhaps suggest trying OPA2134 or OPA2604

[SoNic_real_one]

For old SIL components I would use Brown Dog adaptors. Easier than making your own.
OPA 2134, LM4562, AD8599 are a few dual opamp options.

[UV101]

these are also available. 2pcs Single or Dual opamp SMD DIP8 to DIN8 Adapter | eBay

My personal fav's are LM4562,LME49720 & LME49860 which in fact are believed to all be the same opamp (check the datasheets!!!)

Anyone found a manual???

[UV101]

1 & 2 post regulator caps (probably on +/- 12v)Black gate, Rubycon ZA or ZLH
3 & 4 Smoothers for the regs on the heatsinks - will be for analogue rails mentioned above) Mundorf SI ot other high capacitance low ESR
5 & 6 DAC analogue Black gate, Rubycon ZA or ZLH
7 & 8 DAC digital Solid polymer ultra low ESR Oscon SEPC or Nichicon LE
9,10,11 & 12 analogue filter Black gate, Rubycon ZA or ZLH

OPamps all swapped for LM4563 or similar (assuming duals which I've not looked up so please check)

There is also another opamp in between the regs. This is probably a buffer and therefore in the audio path. this could also be swapped and the local decoupling swapped to Black gate, Rubycon ZA or ZLH

There are a host of other caps in the digital domain that could do with being swapped for Solid polymer ultra low ESR Oscon SEPC or Nichicon LE
Most of the remianin caps left of the DAC will be digital.

General rukw of thumb is to sue std electrolytics on any analogue rails and solid polymer electrolytics on digital.
I normally use anywhere between 220uF and 470uF for local decoupling.

Use the datasheet for all chips to establish which pins are which.

Please remember this is just guess work based on experience. The only way I can tell for sure is with the service manual.

Not a bad looking layout either (other than the big PSU near the output satges which has arguments both for and against!)

[ngovanhinh]

Dear UV101
NJM 4565L is dual opamp. According to the opamp datasheet and the CDP's board layout, the audio path from the njm4565L opamps seem to be as follows:

Therefore, the opamp you mentioned may have nothing to do with the audio path. I think this opamp and the pair of large 3300uF elna capacitors are related with power supply section for the digital and analog stages.

Unfortunately I don't have the player service manual of the player. I have found a service manual of Kenwood dp-7060 which uses the same DAC with my player. The major difference of these players i notice is that my player has different boards for audio and servo-drive parts. I attach the 7060 schematics herein for your refence



Link for DP-7060 service manual:
http://www.hifi-manuals.com/Download...service-manual

[ngovanhinh]

I also prefer LME49720 but I don't have any in hand, so I use OPA2134 to swap the old opamps and find that the sound is better and clearer, a bit more detailed, more bass.
3 and 4 are "elna for audio" capacitors, so i decide to leave them alone.
4,6,7,8 I will replace with Sanyo oscon and 9,10,11,12 with Rubycon

[ngovanhinh]

Link for Kenwood dp-7060 service manual
Download the Kenwood DP-7060 service manual for free - Hifi Manuals

[UV101]

I found that manual too but as you say, the layout is different.

Definatley check that the caps I have identified are PSU decoupling. Trace them to the IC pin and use the datasheet to confirm. It is also important to replace the PSU decoupling on the filter and logic to solid polymer type as these are exceptionally low ESR.

Another general rule is to get the caps as close to the IC pin as possible. Often there will be a bypass cap of approx 100nF shunting trace noise to groundvery close. I ofter remove these caps and use the holes left for the new elco's then use smt 100nF across the pins of the new cap under the pcb.
With certain caps types, Black Gate for example, some have reported further improvments removing these 100nF caps. I guess its worth trying with and without.

Just thought of something else, there are 11 PSU rails to the tda1547 ( datasheet here ). Some of the rails will share single elco's but have multiple 100nF caps close to the pin. Personally I'd replace the 100nF with multiple elco's

[ngovanhinh]

I am not so good at English, please tell me what "elco's" means?

[Mooly]

Originally Posted by ngovanhinh

I am not so good at English, please tell me what "elco's" means?

Electroylitic capacitor.