MBK I got my CDM-4-19 from Amron in Sim Lim Shopping Centre sometime back about 1 year ago. Opened up the CDP again last night and reassembled everything - the occational skip seems to have gone away. Will listen to it carefully over the next week or so. If the skipping does not occure again then I'll probably drip in some os-cons in place of the back gates, change the over caps to silver mica types and get a new clock. And of course change the ip-amps. Unfortunately the display died - 6r there's a cold joint somewhere.
IMO these old cdps are good practise for the real thing. As much as I like the CDM 4-19 mech/lens unit I have to move with the times and my real agenda is modding the Rotel RCD-971 ( a superb unit IMO) and better than the RCD-961 or the RCD-1070 that followed it. I havent heard the latest RCD-1072 though.
I think the 955 (1991) is an almost identical circuit as it was the replacement for the 855 however I am not sure about this. There's a sg based online shop that sells this part as well - this is the part I replaced: http://www.agencies.com.sg/cdpickup\CDM 4.19.htm
Check them out as they have several other mech/lazer unit.
IMO these old cdps are good practise for the real thing. As much as I like the CDM 4-19 mech/lens unit I have to move with the times and my real agenda is modding the Rotel RCD-971 ( a superb unit IMO) and better than the RCD-961 or the RCD-1070 that followed it. I havent heard the latest RCD-1072 though.
I think the 955 (1991) is an almost identical circuit as it was the replacement for the 855 however I am not sure about this. There's a sg based online shop that sells this part as well - this is the part I replaced: http://www.agencies.com.sg/cdpickup\CDM 4.19.htm
Check them out as they have several other mech/lazer unit.
MBK,
The Rotel RCD-855 uses these parts (does the RCD-955AX uses the same?)
Laser Mech/lens unit: Philips CDM 4-19
DAC: TDA1541A
Digital Filter: SAA 7220P/B
Gate: PC74HCT08P
Op-AMP: NE5532 AN x 2
According to a good friend of mine: dropping in the gate part PC74VHC OBN might be a good idea as well.
The Rotel RCD-855 uses these parts (does the RCD-955AX uses the same?)
Laser Mech/lens unit: Philips CDM 4-19
DAC: TDA1541A
Digital Filter: SAA 7220P/B
Gate: PC74HCT08P
Op-AMP: NE5532 AN x 2
According to a good friend of mine: dropping in the gate part PC74VHC OBN might be a good idea as well.
Rameish,
definitely these Rotels are solid units. I bought mine in France, shipped to Hawai'i, operated over a transformer from 110V, then to Singapore, second house, converted to NOS, different I/V, never serviced anything else, and it still works. But now a button fell off, the tray is lazy in coming out, and there is more and more CDs that it has problems with. So it needs a complete overhaul. Maybe I even fiddle with the I/V again, IF I manage to change the laser unit successfully.
I considered a new CD player also, but for small money I only found the lower end Marantz and Cambridge units that look promising. But: compared to my new Philips cheapo DVD-CD the NOS Rotel still has so much more life, so I don't feel like taking the plunge only to realize the old Rotel was better ;-)
Only drawback is the chassis with so many screws before you get to service the parts...
On a sideline - you wouldn't know a source for 2SK389's in SG?
definitely these Rotels are solid units. I bought mine in France, shipped to Hawai'i, operated over a transformer from 110V, then to Singapore, second house, converted to NOS, different I/V, never serviced anything else, and it still works. But now a button fell off, the tray is lazy in coming out, and there is more and more CDs that it has problems with. So it needs a complete overhaul. Maybe I even fiddle with the I/V again, IF I manage to change the laser unit successfully.
I considered a new CD player also, but for small money I only found the lower end Marantz and Cambridge units that look promising. But: compared to my new Philips cheapo DVD-CD the NOS Rotel still has so much more life, so I don't feel like taking the plunge only to realize the old Rotel was better ;-)
Only drawback is the chassis with so many screws before you get to service the parts...
On a sideline - you wouldn't know a source for 2SK389's in SG?
Rameish,
just checked, the 955 uses identical parts. I just unmounted the laser, it was easier than I thought, I didn't even have to remove the PCB. Funny, the suspension is spring loaded, but not damped (it wobbles quite a long time when tapped).
Wonder if it's worth changing the PC74HCT08P, desoldering multi pin IC's is quite a risk... I might try adding some smd bypass caps to the TDA1541 though.
Thanks for all the info BTW 😉
just checked, the 955 uses identical parts. I just unmounted the laser, it was easier than I thought, I didn't even have to remove the PCB. Funny, the suspension is spring loaded, but not damped (it wobbles quite a long time when tapped).
Wonder if it's worth changing the PC74HCT08P, desoldering multi pin IC's is quite a risk... I might try adding some smd bypass caps to the TDA1541 though.
Thanks for all the info BTW 😉
MBK,
As you know sg isnt a wonderful place for diyers. Yes you can get some parts but on the whole you need to import.
Yes the screws are a pita - the RCD-971 has even more screws! Just to remove the cover, you need to unscrew 8 LOL.
The RCD-971 can be had for about S$400 - S$450 second hand (that's a bargain when you consider the toriod trans, the 30 or so Black Gate caps, the PCM63 dac (not K grade unfortunately). Personally I dont like the liner tracking transports that the 971 has but the old swing arm Philips are alas a thing of the past.
Let me know the mech part number - I'm going doen to Sim Lim Tower to look for a new quartz oscillator. If I do see it I'll let you know.
If you;re modding it further try os-cons - my bussy has tried them in his Pioneer 904 and it's an improvement over the silmics.
As you know sg isnt a wonderful place for diyers. Yes you can get some parts but on the whole you need to import.
Yes the screws are a pita - the RCD-971 has even more screws! Just to remove the cover, you need to unscrew 8 LOL.
The RCD-971 can be had for about S$400 - S$450 second hand (that's a bargain when you consider the toriod trans, the 30 or so Black Gate caps, the PCM63 dac (not K grade unfortunately). Personally I dont like the liner tracking transports that the 971 has but the old swing arm Philips are alas a thing of the past.
Let me know the mech part number - I'm going doen to Sim Lim Tower to look for a new quartz oscillator. If I do see it I'll let you know.
If you;re modding it further try os-cons - my bussy has tried them in his Pioneer 904 and it's an improvement over the silmics.
Rameish,
my transport is labelled CDM4 19E-43611 19
Thanks, I appreciate!
Checked RS, they have Oscons though not the 15uF SC series that I have seen recommended. No PC74VHC OBN. I guess I start out with replacing the electrolytics with standard parts first and throw in the Oscons later... and a separate PSU for the analog out will also fit.
Rotel 971: if that one uses PCM 63 it would be a prime candidate for a Pass D1 I/V... I thought of adapting it to the TDA1541 anyway... though it might be interesting to compare a tweaked PCM63/D1 with oversampling ("proper engineering") vs. NOS 1541 ("bleeding heart audiophile" (tm)) 😉 😉 ;0
Markus
my transport is labelled CDM4 19E-43611 19
Thanks, I appreciate!
Checked RS, they have Oscons though not the 15uF SC series that I have seen recommended. No PC74VHC OBN. I guess I start out with replacing the electrolytics with standard parts first and throw in the Oscons later... and a separate PSU for the analog out will also fit.
Rotel 971: if that one uses PCM 63 it would be a prime candidate for a Pass D1 I/V... I thought of adapting it to the TDA1541 anyway... though it might be interesting to compare a tweaked PCM63/D1 with oversampling ("proper engineering") vs. NOS 1541 ("bleeding heart audiophile" (tm)) 😉 😉 ;0
Markus
I happen to like both the PCM 63 and the TDA 1541A!
Anyways yes confirm you have a CDM 4-19 lens/mech unit. Treat the rest of the mech (the plastic drawer and cog wheels) with care as I dont know what the model no is for that. It's obviously Philips but which and where to get it is unknown to me.
The suspension springs wobbeling is normal. Dont try to take them apart (unless there;s a prob with it).
I belive this lens/mech should last you another 10 years or if somthing else gives way.
I am wondering, other than the facia, what's the differnece betwen the 955AX and the 855?
Anyways yes confirm you have a CDM 4-19 lens/mech unit. Treat the rest of the mech (the plastic drawer and cog wheels) with care as I dont know what the model no is for that. It's obviously Philips but which and where to get it is unknown to me.
The suspension springs wobbeling is normal. Dont try to take them apart (unless there;s a prob with it).
I belive this lens/mech should last you another 10 years or if somthing else gives way.
I am wondering, other than the facia, what's the differnece betwen the 955AX and the 855?
Could be that the 855 and 955 are simply the same machine with different names depending on the country. That often happens...
My 955 AX has a remote, and standard shuffle, program, scan and repeat functions. I don't know if it supports HDCD. Internally it almost looks like a transformer with separate various secondaries (as opposed to multi tapped). A lot of Black Gates in the output region, and coaxial digital out. The PCB has room for various parts which are not fitted this model. TDA1541 bypassed with what looks like PP caps.
The tray mechanics are quite flimsy actually, I have been concerned about that but so far it works. I had to epoxy a plastic switch already, no need for more of that 😉
My 955 AX has a remote, and standard shuffle, program, scan and repeat functions. I don't know if it supports HDCD. Internally it almost looks like a transformer with separate various secondaries (as opposed to multi tapped). A lot of Black Gates in the output region, and coaxial digital out. The PCB has room for various parts which are not fitted this model. TDA1541 bypassed with what looks like PP caps.
The tray mechanics are quite flimsy actually, I have been concerned about that but so far it works. I had to epoxy a plastic switch already, no need for more of that 😉
Yeah I think they are identical in most aspects. I wonder what improvements - if any - were made? In sg we had both models - the 855 was around until 1991 and the 955 was introduced in 1992 . I remember this because shortly after buying the 855 I went back to the shop to let a friend of mine demo the same model against the 865 - he prefered the 865 (a bitstream model as he felt the 855 was too bright. But I saw the 955 as well and went damn! "just when I buy it a new model comes out" Try as I might to explain to him the brighness will be reduced as burn-in took place he didnt believe me.
I belive my friend still has the 865 but he lives in KL (Msia). Somday I'll get a chance to compare the 2 again with 14 years of burn in LOL.
I belive my friend still has the 865 but he lives in KL (Msia). Somday I'll get a chance to compare the 2 again with 14 years of burn in LOL.
Hi all,
I agree that OPA2604 is a bit harsh/sharp.
OPA2134 is much2 better and cheaper in Farnell. I recommend you use OPA627 if you can find. It has a valve sound to it..🙂 .
I would like to try Analog devices AD825. People say its a very clean and open sound. Can't find them.
Ever think about Elna Cerafines cap. expensive but worth the money. And if you want big improvement go for the black gates cap.
Cheers.
JFD
I agree that OPA2604 is a bit harsh/sharp.
OPA2134 is much2 better and cheaper in Farnell. I recommend you use OPA627 if you can find. It has a valve sound to it..🙂 .
I would like to try Analog devices AD825. People say its a very clean and open sound. Can't find them.
Ever think about Elna Cerafines cap. expensive but worth the money. And if you want big improvement go for the black gates cap.
Cheers.
JFD
jfd,
The rotels stock come with Black Gates (unless you're refering to the really premium Black Gates). I do have the LC Audio AD-825 op-amp modules. They are nice but a bit too smooth for me. I like the legato but still need the seperation. I used the in one of my RCD-971 (the other 971 I have I'm gonna leave it as stock as reference). I do this because all too often we change somthing and have no reference and paychoacoustically we feel it's better when all it really is slightly different.
In some applications I actually prefer cerafine over black gates (standard grades).
The rotels stock come with Black Gates (unless you're refering to the really premium Black Gates). I do have the LC Audio AD-825 op-amp modules. They are nice but a bit too smooth for me. I like the legato but still need the seperation. I used the in one of my RCD-971 (the other 971 I have I'm gonna leave it as stock as reference). I do this because all too often we change somthing and have no reference and paychoacoustically we feel it's better when all it really is slightly different.
In some applications I actually prefer cerafine over black gates (standard grades).
Hai rameish,
So youre' from Singapore. I am from Malaysia. Now working in UK. I design hi-fi AV receiver and amp. I have a rotel 976, a roksan CD player and some mission freedom speakers. Its old and tatty but it sounds like an angel. I did some audition on some newer amp but nothing come close unless youre talking about £1000 plus.
Basically in my rotel, I changed all the opamp to OPA2134, some resistors to tentalum, some wires to pure silver and silver plating, mains wire, most caps are either black gates/elna and some ground change. what a change in sound especially when bridged.
Roksan still under warranty so won't touch it yet! Good enough for now.
I build my own line conditioner. Luckily I am close to a transformer supplier so I can ask for an isolation transformer.😉.
So youre' from Singapore. I am from Malaysia. Now working in UK. I design hi-fi AV receiver and amp. I have a rotel 976, a roksan CD player and some mission freedom speakers. Its old and tatty but it sounds like an angel. I did some audition on some newer amp but nothing come close unless youre talking about £1000 plus.
Basically in my rotel, I changed all the opamp to OPA2134, some resistors to tentalum, some wires to pure silver and silver plating, mains wire, most caps are either black gates/elna and some ground change. what a change in sound especially when bridged.
Roksan still under warranty so won't touch it yet! Good enough for now.
I build my own line conditioner. Luckily I am close to a transformer supplier so I can ask for an isolation transformer.😉.
Hi JFD,
What about a comparison between OPA27 and OPA2134? My Arcam Alpha 5+ has the former, am thinking of changing it to the latter of course 🙂
What about a comparison between OPA27 and OPA2134? My Arcam Alpha 5+ has the former, am thinking of changing it to the latter of course 🙂
Update on CDM 4-19 in SG: I found that dealer in SLT, he was well aware of the drive and said he has a few orders already... but no stock and unknown lead time. I guess I will just lube my old one for the time being...
Hi dewdrop,
Why change? basically the OPA 627 ( in my humble opinion) has a warmer, lustier sound to it. Its near to the valve sound. Some might not like it especially if youre into dance music. But if your into Norah Jones, katie melua and sarah mclachan tyope of music then i don't recommend you change.
Not as detail as the OPA2134. Most amp designer go for later ones because its a save bet generally. Its built for audio and does its job wonderfully well.
why don't you try it. It won't put a huge hole in your pocket.
Cheers.
JFD
Why change? basically the OPA 627 ( in my humble opinion) has a warmer, lustier sound to it. Its near to the valve sound. Some might not like it especially if youre into dance music. But if your into Norah Jones, katie melua and sarah mclachan tyope of music then i don't recommend you change.
Not as detail as the OPA2134. Most amp designer go for later ones because its a save bet generally. Its built for audio and does its job wonderfully well.
why don't you try it. It won't put a huge hole in your pocket.
Cheers.
JFD
Rotel 855 circuit diagram.
Hi Psonic,
Could you send me a copy of the PDF file of the Rotel 855 circuit diagram ?
Thanks.
Ashok.
ashokm(at)sify.com
Hi Psonic,
Could you send me a copy of the PDF file of the Rotel 855 circuit diagram ?
Thanks.
Ashok.
ashokm(at)sify.com
Are you referring to OPA27 or OPA627?
Hi JFD,
Is your comparison for the OPA27 or OPA627? The Arcam has the OPA27 not OPA627.
Hi JFD,
Is your comparison for the OPA27 or OPA627? The Arcam has the OPA27 not OPA627.
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