Rotel cd player

[rbroer]

Most of the time the same discussion applies to TDA1541A and TDA1541A-S1. Some hear a difference while others claim to hear no difference at all. I was surprised by Peter Daniels report on the difference a S2 version makes.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=20260&highlight=tda1541

I'm very surprised too...would think A to A-S1 would be a bigger improvement than A-S1 to A-S2.
Anybody bought one of those S2's from Elib and would let me borrow and test-drive one ? Got a socket for the TDA1541, so it would be plug and play.

Maybe Thijs ?

 

[dom letor]

PCM-63-K piggyback?

hi,
just wondering what exactly does "piggyback" mean, and why would you want to do it to a DAC chip? is it any good?
dan

 

[jean-paul]

Piggybacking is soldering 2 of the same chiptype on top of eachother. Some say it sounds somewhat better, I think it is a waste of money, materials and energy.

 

[Fin]

My experience with replacing PCM63P or J is slightly different. K version is an improvement ( not too big but remarkable ).

Last time I bought K versions they were so cheap that I replaced the old ones for them anyhow.

Hi Jean-Paul

Where did you buy the PCM63P-K at a good price?

I assume these would be a good match with SM5842APT?

 

[kolwrath]

Some mod ideas

Hey,

I have an old Rotel 965BX that I moded. Here's what I did (may give you some ideas)

1. Replaced the OpAmps (OPA627)
2. New clock: trichord clock2's (its only about ~$44 pounds, way cheaper than any aftermarket clock I have seen)
3. New insulating feet
4. Removed the mutting transistors (cheep $0, really easy, and effective)
5. soon to be done: new female rca jacks and silver hookup wire.
6. soon to be done: new EMI filter IEC power plug, and a decent power cord

All pretty simple ones. Only the new clock was reall expensive.

Advanced ideas:
1. Replace capacitors (blackgates)
2. replace powersupply
3. replace rectifiers
4. insulate chasis with dampeners, and or lead/copper shielding

Good luck.

 

[buchignani]

971 mods

I fiddled quite a lot with one of these, and eventually I liked the sound as much as my Meriidian 508-24 (although it sounds very different).

replaced the main std rectifier diodes with 100V Schottkys, 8TQ100, Internation Recifier

replaced the audio output OpAmps with LM6172 (two of them)
installed an LC Audio replacement clock

added about 300uF extra low Z capacitance to the +- OpAmp lines
replaced the 100uF output caps with 15uF poly Auricaps.

bypassed most (about 12) power supply caps with ceramic 1uF
added 1uF ceramic bypass to the +-V supplies to the output OpAmps (which were already bypassed by .1uF film and 10nF film).

added a 10pF feedback cap to the LM6172s as per the spec. sheet

added a snubber network across each side of the transformer
secondary: a 100 ohm resistor and a 0.47 uf film cap

replaced main digital power supply cap with 8,800uF low Z cap

 

[dom letor]

advice for modding

replaced the main std rectifier diodes with 100V Schottkys, 8TQ100, Internation Recifier

i've been thinking about doing that mod. i've been successful with swapping out the op-amps with AD825s and installed a LCAudio X02 clock with separate power supply. my CD player is the Rotel RCD-971.

i'm still a newbie modder though, cuz i still have to ask: where do i find the diodes on my board? are they sticking out or are they the tiny round flat ones closer to the transformer? (how would i know if i had Schottkys already?) also, how do i tell which size and rating to get in order to prevent burning out the other components? if i know how to change the diodes then i'll be able to mod other stuff that i own.

another quick question... is there any benefit in changing the voltage regulators in audio equipment, or is it just not worth it?

thanks,
dan




100V Schottkys, 8TQ100, Internation Recifier

 

[Iliya]

My experience with replacing PCM63P or J is slightly different. K version is an improvement ( not too big but remarkable ) but if there are adjustment pots on the PCB it is better to remove them if you haven't the equipment to adjust them for least distortion. Leaving them as they are will degrade performance of K or whatever version more than no pot at all. My experience with these chips was not when used in this particular Rotel cdplayer but in some Pioneer models and separate DAC's.

In my Rotel RCD-971 those pins for adjustment are not connected to anything. But the PCM63 datasheet recommends connecting the pins 23 and 24 to the ground via 0.1uF caps. I am planning to solder two Black Gate NX Hi-Q 0.1uf/50V for each DAC on the bottom of PCB as shown on the picture. Is that a good idea, any thoughts?