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Rotel 965BX CD Player tweaks

W

WJJ

pfm Member
Hello. Does anyone have any experience or advice on modding a Rotel 965BX CD? I've picked one up for a 5 quid from a local car boot.

It works perfectly and was wondering if I could tweak it to improve it's performance. I seem to recall reading something about this a while ago.

As it didn't cost me alot I've got nothing to lose really.
Any input would be greatfully received as I've not attempted modifying equipment before so i am new to this.....Cheers Wayne
 
Hi, I have no experience with tinkering on the inside of the Rotel, but as I own one I can tell you that it benefits alot from proper isolation against vibration. Using sorbothane feet takes it into a different league. It is also very sensitive to the quality of mains power.
 
Yep.

Op amps would be your first experiment. Whip out the 5532's and solder in some sockets.

OP627's and OPA2604's are worth a try. The former more lively, the latter smoother.

Then there's output caps, and some decent panel-mount sockets.

The RCD 965 is a pretty decent sounding player as it is, so doesn't need massive tweaking.

You could also go for a clock if you're generally happy with what it's doing.
 
Thanks for the replies so far. I intend to use it as an alternative to a Marantz SA7001KI which, to my ears anyway, is quite smooth and easy to listen to. My preference would be to liven things up a bit with the 965 and would go down this route.

As I said in the OP I'm new to this, where would I go to buy components if I wanted to attempt these mods?
 
Places like RS and Farnell, and to a lesser extent Maplin, will sell basic components. You'll get good results from things like voltage regulators, thgese cost loose change if you can solder, you can get the bits from the shops/online above, and there is loads of advice on the DIY section here. As has been pointed out, you are actually in DIY classifieds here where people don't actually talk DIY, they just offload their unwanted tat, sorry, craftsman made precision hifi circuits and incredibly desirable components, to others.
 
Hi, WJJ

First thing is a new clock, that will really improve it, then Opamps I think I used LM6171s.
You can also add separate supplies for all parts of the DAC and by pass the muting, you end up with a nice sounding player. I was going to mod the Opamp supplies then I bought a Densen
I have the service manual I can Email you.

Pete
 
5532/4 op amps are very good - better than many modern ICs for audio use.
Leave them in place.

Playing around with sockets will make no difference whatsoever.

If you want to tinker, look at the clock and PSU where you might be able to make some (tiny) gains.
 
Congratulations on your purchase - I bought mine in 1992 and it's still in full working order. It can sound slightly 'fuzzy' or vague in comparison to more modern designs, but really it's a very enjoyable sounding machine even now/stock. It also makes a superb transport - those CDM4/19 mechs were really very good.

Agree with Robert in that those 5532/4 op-amps sound very nice - if one only looks at specs then yes they do look dated perhaps, but where sound is concerned they are very nice devices.

One very effective (and free!) mod is to remove the output muting transistors - just clip 'em off. Very nice upgrade.

I'd attend to the PSU first (the heart and soul of ANY player) then look to experiement with a new clock. Net Audio's is meant to be rather nice:

http://www.net-audio.co.uk/965discrete.html

If I hadn't built a Shigaclone I'd probably do the above myself on my Rotel.

This might also be of use:

http://www.diyaudio.com/forums/digital-source/130516-rotel-rcd-965-bx-2.html

- John
 
I have decided to try the Net audio Micro clock and PSU for starters to see what improvements this brings. This seems quite a straight forward mod to do, as I'm relatively inexperienced in this I want to take it one step at a time. And from the feedback i've had from yourselves this is a good way to start. Thank you for the advice thus far, I will most likely need some more once I get the lid off.......Wayne
 
RustyB said:
Bad advice from someone who cannot, for whatever reason, hear the obvious, or bother with the experiment.
Click to expand...

Why is it bad advice?! Robert knows what he's talking about. I tried OPA627s in my Rotel and, whilst very impressive initially I found them tiring to listen to after a while - too 'showy' - and went back to the 5532/4s which sounded far more analogue-like/natural to me. Lest we forget 300Bs are VERY old technology and plenty of people love how those sound, so I don't buy this it's old therefore it sucks ideal... :rolleyes:

At any rate it's easy to install sockets and try various kinds and find what works for one's own musical taste.
 
Major retread of previous posts of mine, but casual opamp swaps are a minefield.

Fitting an IC socket and swapping opamps appears a nice easy usually fairly benign way to play. BUT I think most of the time what you are playing with isn't the difference between opamps, but the difference between opamp susceptibilities in the circuit you are experimenting within, which get folded into the audio as audible, if subtle, differences. These are very real, and may make for audible diferences where on paper there should be none.

For example - an opamp that has high bandwidth or very high open-loop output impedance or restricted output drive current could be poor choices in a filter circuit, or wherever the load is capacitative. A circuit with a noisy raw supply could easily sound better with a 'worse' (slow, low-bandwidth) opamp with great PSRR than a 'better' opamp with poor PSRR.. and so on and so on. Remember every pin on an opamp is effectively an input!

The OP627 has a very large GBw. As such it is inordinately sensitive to decoupling arrangements and similar precise implementation details. As a result even using it in IC sockets is a a 'NO' for halfway-good results.. . likewise the Ad8065, the LM6172 and similar 'must haves'. 10-Mhz+ GBW opamps in sockets is just asking for trouble; that 'great treble' is probably the result of major HF unhappiness.

Conversely, the 5532/34 measures well, but it is also very tolerant of less-than-perfect implementation.Reliable, if not the last-2% word. But very reliable. So which would you rather have?



This is why I don't recommend any generic swaps anymore - leave the opamp be, get the circuit working as well as you can via attention to PSU and layout and maybe passive parts replacement, and then - only if you must - try rolling opamps. And then be prepared to work at it. Either way you may be surprised how little there is to be gained when other problems are 'fixed'!
 


At any rate it's easy to install sockets and try various kinds and find what works for one's own musical taste.[/QUOTE]

Exactly, so in your case the OPA2604 would have been a better choice.

Age has nothing to with it, the OP27, my preferred choice for single channel op-amps, has been around forever. You'll find them in the IV stage of the AA5.
 


Conversely, the 5532/34 measures well, but it is also very tolerant of less-than-perfect implementation.Reliable, if not the last-2% word. But very reliable. So which would you rather have?

I'll have the better sounding option, thanks, and despite your learned discourse, that's never a 5532/4 IME.

Further thoughts:

1. You'll never find one of those inside a Naim CDP.

2. If a 5532/4 was as good as needed, Silicon Valley wouldn't have a market for all the superior product available.

3. You can see the logic inside some products. Look inside a Creek Evo integrated and you'll see a pair of OPA 2604's for the linestage, plus a 5532 for the tape out buffer. Fair enough, and all are socketed, a tacit invitation to do some substitution.
 
RustyB said:


... that's never a 5532/4 IME.

Further thoughts:

1. You'll never find one of those inside a Naim CDP.

2. If a 5532/4 was as good as needed, Silicon Valley wouldn't have a market for all the superior product available.
Click to expand...


1. So what? Naim CDPs are deliberately made to sound "analogue" or even "Sondeky"

2. NE5532/4 has poor offset specs, however its audio performance is good. Does Silicon Valley really nead all the 1000's of opamps that are available?

FWIW, I don't like the OPA627, I prefer the 5534 and 2604. I agree that the OP27 works well in I/V. These opinions are mostly irrelevant though, because every op-amp I have tried is remarkably transparent to its PS and decoupling - i.e. exactly what Martin said.
 
http://www.tnt-audio.com/accessories/rockclock3_e.html

i have two of these player best CD player i ever owned sounds better with out the DAC magic

Bit of trouble I'm having

After i make compilations CD's in Roxo . I put the disc in the Rotel. It sees the TOC the contents are displayed But it will not play it.

it will play CDs i copy via roxo. So whats the difference do you think.. why wont it play the drag and drop compilations

My Sony CDP-XE310 plays anything .
 
Take Pete's advice, fit LM6171's. Take Martin's advice, solder them directly to the board. You won't want to remove them anyway. The sound will be more detailed and faster, very similar to the 965 Discrete.

Replacing the DAC 7805 regulator with a miniature super regulator is a very good upgrade. Audiocom sell them, they are a drop in replacement.

The clock is worth doing, but I found the improvement to be subtle.

Glue a sorbothane pad on the opposite side of the PCB to the DAC. The DAC is underneath so it's glued to the top.

You could upgrade the capacitors to special edition spec. I'll post some pictures showing the SE capacitors.
 
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