opa 627bp in MHZS cd33

I am newbie to the club here, like u i also brought a CD33 and follow some of your mods, which made it sound good, but when i put it next to my friends Linn karik-Perpetual P3a, his sounds more space and more musical then my poor CD33, although the CD33 makes the vocal more forward sounding then my friends setup.
Coming to the point, can i improve my my CD33 with a lite Dac-AH or the P3A Dac(which i can get secondhand) which 1 to buy?

Dear KKwan

Because you already have the MHZS player, you should buy an external DAC like the lite DAC-AH. Now you can play vocal music straigh from the MHZS player and instrumental music from the lite DAC-AH.

A little mod for the lite DAC-AH i can recommend. Bypass the opamp section by taking the left/right output straigh from the I/V resistors with a 10 uF condensator. The DAC-AH improves in detail and space.

For all the MHZS owners, the best mod is the opampless/passive filter mod. For just $ 1,- on parts you got a lot of more detail.

Here we mod about 30 MHZS players and everyone liked this mod the most.

Look here:

http://gathering.tweakers.net/forum/list_messages/1283078/0

For the next one you need to register.

http://www.roehren-und-hoeren.de ... 178&start=0

Hello alfcat, viewer and music11.

A little update, here in the Netherlands there are a lot of problems with the MHZS players. There are a lot of people who had a defect DAC. The voltagestabelisor for the DAC oscillates and runs hot.  Then the voltagestabelisor fails. and the DAC burns. You can reconnice a bad running stabelisor by its to high tempature. To solve this  selfoscillation problem ad 2 x 100 nf capacitors at the bottom of the stabelisor.



For those who has a defect DAC or like to upgrade to a much better DAC and sound. Look at the picture below.



For more pictures look here:

http://gathering.tweakers.net/forum/list_messages/1283078/6

[quote:354beed58b="alfcat"]Dear Koifarm,

Have you figured out what actually caused the "can't read" problem with these MHZS players?
CAT[/quote]
Dear Alfcat,

Until yet i have solved all the " no disc " problems. The connector from the white flatcable of the drive makes in the middle of it no contact. I provide some pressure with a tongs in the middle, put the cable back in and mostly the problem is solved. Sometimes i must do it twice.

I do not know the CEC players, but it is great you like them. I still like my modified shanling CD-T100se. This month at a meeting in Germany they liked my shanling also.



more pictures look below.

http://www.roehren-und-hoeren.de ... asc&start=0

Music111, just the enclosure is a look a like of LITE.

Inside is my hybride class D amp with SMPS supply and 64 step volume remote control. ( 2 x 400Watt).





In his own thread: http://www.hififever.com/forum/v ... mp;highlight=hybrid

Look here: http://www.diyaudio.com/forums/showthread.php?threadid=123485

music111, i can not tell you the effect of your changes because you do not specify with capacitors you want to replace.

Changing the powercapacitors is very useless if you do the passive mod next.

In the link i send before are the 3 most noticeble mods i have heard in the past 3 years.

- Passiv mod( more detail and better staging)
- Change capacitors in audiopath.( less warm with softer hights)
- change anodevoltage of the tubes from 80 to 100Volt( more dynamic )

And there is the never ending story of tuberolling.

But before that you must clear with yourself what you want to change of the sound of the MHZS player. It is useless to do every mod there is if you do not have a goal.

Below the discription:

We do the following mods:

1 – Remove the opamp and filter( it calls the passive mod)

2 – Bridge and replace capacitors in the audio path.

3 – Higher the anode voltage from 80 to 100V and replace the buffercapacitors.

It all takes a hour of work, and give you much more detail, bigger staging and it is like the curtain is falling down.



1-     passive mod.



C11 and C12 must be bypassed on the other side of the board and a few other points must be short. See below.



Connect the yellow points with solder tin.

Then remove the 3k9 resistors and the opamp. See below.

  

These are the light blue parts. And ready is the the passive mod.

It is possible that the output signal is lower then before to correct that you have to replace two resistors a channel see below.

   

Replace the green 33K for 22k/1/4 Watt and replace the 68K for 82K/1 watt and the output signal is higher. My recent experience is just replace the 33K for 27K and leave the 82K resistor as it is.

2-     Brigde and replace the capacitors in the audio path

Replace C7 and C8( see first picture ) for PIO Capacitors of 0,27 uF or 0,33 uF. Good and cheap brands are Sprague Vitamine or Russian pio k40-2. Replace C13 and C14 ( output capacitors ) for PIO Russian 2 uF (2 x parallel 1 uF) or Neutral MKP between 2,2 uF and 10 uF like Clarity Caps APW. See below.

  

C11 and C12 we already bypassed in the passive mod. So we have just two capacitors a channel.

3 – Higher the anode voltage from 80 to 100V and replace the buffer capacitors.

   

Replace zenerdiode D1 for a 100V/min. 2 Watt type, Replace C1,C2, C3 for 220uF/160V ( Panasonic or so ). We also replace D2,D3,D4,D5 for scottky diode’s like BYW100/200.

  

On the other board you have to replace C4 for 220uF/160V.

This mod is only for the MHZS 33 and 66, the MHZS88 already has a higher anode voltage.

I hope this description is useful for you.

Ronny

Change C7 and C8 for jensen oil they are 0.47 uF. Change C13 an C14 for WIMA 2.2 uF/250V MKP( these are very neutral and better then the elco's). And do the passiv mod. You will like it.

C numbers reffers to my photo's.

Alfcat, the best link i have is here:

http://www.hififever.com/forum/v ... mp;highlight=t100se

But now i use the 6n6p tube. I can adjust schematic, photo's and discribtion. I shall do that after the weekend.

Music111 after one month you have still garantee, let you send a new drive. But first check the lens by dirt and the cables by connection. I do not know a better replacement.