Hi and welcome to TAS - I moved your post from the Show us Your CD Players thread to create a new thread of its own. This way it will get people's undivided attention!!

Cheers

The modifications were done professionally but unfortunately my technical knowledge is somewhat limited to say the least . My understanding is that the power supply was upgraded including new regulators and a large transformer , new clock fitted and large number of capacitors replaced . The various modifications done over a couple of stages have shown a definite improvement but I am now looking for the next step as I believe a more transparent sound is available I just cannot afford to spend what I assume would be £1500 + to show an appreciable difference , I have compared my player with a standard Audiolab 8200 and believe it shades this player.
Just wonered if any members had any positive results using the Dac with mid priced or higher cd players before I commit ?

I'm not sure whereabouts you are located but I'd recommend trying to get a listen to a Beresford near you. you might find someone on this or another forum who can let you hear theirs

Yes Andrew suggestion is the best way forward with this

Stan's a good man and will help I'm sure.

Apologies for saying this, but the base Marantz unit is a jitter prone model from times when this aspect wasn't as fully understood. 'KI' just slapped some copper screws here and there and authorised some other not-really-necessary tweaks to an originally smooth and inoffensive sounding base player and what we ended up with is a harsh toned screamer that doesn't 'do' bass and with an output stage that fell flat if asked to work too hard - in my personal experience.

Good upgrades at the time came courtesy of Musical Fidelity (spit! - for the way they treated their independent dealers), with the X-10D line buffer if the original output was used and the X series DAC was a big upgrade in musical terms.

So, what do we do today, nearly twenty years after the 63-KI Sig was first inflicted on us? Adding a Caiman II would be a similar kind of upgrade as the MF X-DAC was, but you still have the base player there, which ought to be replaced at some point I think, internal tweaks or not.

Another choice - and I have a sneaky feeling it would sound better in a big-player-on-the-cheap kind of way, is to see if you can loan a Denon 520 CD player - www.superfi.co.uk/p-10435-denon-dcd520ae-cd-player.aspx?VariantHid=21899&gclid=CPjQ0pa-28oCFUKeGwodLZMHyg . Very cheap to buy (far eastern construction costs are minimal today and Denon don't seem to have big ego's to pay). I think that if you compared one behind a curtain to any other audiophool confection, I wonder if you'd hear any difference at all, let alone how big... Rega players and DACs remain a favourite of mine, but again, warmth comes before true accuracy - jolly nice though with sparkly sounding cheaper systems...

Do please forgive me if I don't pay lip service to domestic audio 'Gurus' like KI or that Westlake chappie, but time after time in my career in the dem room, they've let me down in only delivering promises, not actuality. That Denon has thirty years of damned good popular players behind it and I've seen and heard the progression with my own DCD 1520 battleship player (used now as transport) and the later, lighter but no less good sounding 1015, which I have as a spare - the mid noughties 820 series was excellent too and could embarrass an Arcam at nearly three times the price.

The Caiman-II has nothing in common with the original Caiman and is in a different class sound-wise.

Dave dsjr has his own experiences and views -- and they generally differ from mine!

In my view Stan Beresford has always made good sounding DACs that excelled at their price point at the time. I've never heard one sounding thin, but I haven't heard them all, but I have heard quite a few.

And the Marantz 63 series may or may not have more jitter than most, but to my ear they put in a convincing musical performance and I am not surprised that you have enjoyed yours.

Like other folk here say, it's impossible to know what your modified Marantz sounds like so cannot advise on what would be an improvement.
Try it and see!

If you were reasonably local to me (Glos) I'd be happy to pop round with a couple of interesting DACs to see if you think that route may be worthwhile.

I haven't heard the 63KI, but I do own a 63. It's used as a transport with a Caiman MKII. It's not a fair indication for a comparison between a 63KI and a 63, but with the Caiman used as the audio output path the sound if far more entertaining. If detail is a high priority on your list, then the Caiman is certainly far more detailed than the 63. But we have been here before. I remember the time when many Naim CDP owners were bolting one of my TC-7510 to the digital output of their £5K machine.