opa 627bp in MHZS cd33

Hi Guys,

I bought an MHZS CD33 a few days ago and came across this excellent thread when doing a Google search. I wasn't too happy with the sound of the unit in stock form finding it rather "hazy" and vague sounding. I have started modding it and so far have replaced all of the grotty 1N4007 diodes with ultrafast UF4007 types..... whilst I was under the bonnet I replaced some of the caps with Panasonic FC / FM types and will eventually get round to fitting Panasonic FM throughout the unit.

Popped in an OPA2107 and fired her up.... you know what? chalk and cheese, the improvement is VAST with the sound now being extremely open, spacious and with absolutely subterranean bass... astonishing improvement (not a difference but a marked improvement) I've got a feeling the stash of 1N4007 were adding a bit of grunge to the sound and the OPA2604 probably not the optimum chip for the job.

I can't wait to hear this puppy with half decent output valves, hardwired output connections, Ultrafast diodes in the PSU section, more capacitance, damping... etc. etc. etc. This is a true tweakers dream and @ £180 (or cheaper) an absolute bargain! What price can you buy a CD33 for in China?

One helluva CD player for the money though and one I know I'm going to have a lot of fun with, not only can you opamp roll to tailor the sound to your own ears you can also valve roll.... PCB's are quite easily removed from the chassis too (a few screws) so you can whip either of the PCBs out in a couple of minutes and go to work on them should you want to go further than simply opamp / valve rolling... I'm going to have with this puppy  

Other opamps I'm going to try are AD-843 (on brown dogs) AD-744 class A biased (on Brown Dogs) OPA602 (on Brown Dogs) AD-797 (on Brown Dogs) AD-8620, AD-823, AD826, OPA2227, OPA2228 and my current favourite audio chip the LM4562 (superb audio chip!)

I'll visit this thread from time to time and will post pictures..... great forum you guys have  8)

All the best.

Mike.

[quote:780bfb31ef="WINDWSS"]hi mike,

nice to hera from your sharing on modification.

By the way how much better the opa2107 compare to opa2132? How about comparison with opa627Ap? just a bit supprise the opa627 is not in your future testing list, is there any special reason?

AD797 seems not as good as opa627 in cd33 (my friend's comment after using it)

By the way, it seems that a lot of people like to use panasonic FC, but i personally feel that it is too soft n bass a bit loose, can improve a bit at high frequency when bypass with ROE mkp/mkt i prefer to use BC(Formerly philips) e-cap : )

kindly share with us after your testing on various opa and other modification. Thank you!

SS[/quote]

Hi WINDWSS,

2107 has a very similar sonic signature to the OPA627 and also has the advantage of being a dual channel chip (dil8) It is slightly less chocolaty sounding than the 627 and I have loads of 2107 so seems logical I use them  

This KSS-213Q pickup concerns me a bit, it says "SONY" on it but I know Sony don't make such a pickup. Also, most of the capacitors used look like fakes to me and the so called "OPA2604" also looked like a fake. Is this quite common with some Chinese equipment? I have also read that the Chinese made KSS-213Q can be pretty unreliable (either last quite long or stop working pretty fast) is there any drop in replacement that can be used? It certainly looks like quite a flimsy pickup to me.

Again, the reason I use Panasonic FM is because I have hundreds of them, I also like the sound of them which is why I use them in all my Musical Fidelity Mods http://www.rock-grotto.co.uk/xcanpropage.htm members of my forum also seem to like them http://rockgrotto.proboards39.com/index.cgi  I have a few ELNA cerafine I will fit in strategic places in the CD-33 but really don't want to spend too much time on it to find the laser breaks down after a short period.... any info you have on the KSS-213Q would be most welcome.

All the best.

Mike.