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Old 17th April 2007, 06:42 AM   #1
sel53 is offline sel53  United States
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Join Date: Jan 2005
Location: Lancaster, CA
Default Anyone Roll Opamps in MCD7007

Hi,
Have any of you tried different opamps in the McIntosh MCD7007 CD player? On the analog board there are six NE5532s, which from the looks of it are the reconstruction filters (don't know for sure because no service manual).

I would be interested to know if anyone else has experimented with this player, any recommendations.

Thanks,
Steve
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Old 5th June 2007, 07:46 AM   #2
sel53 is offline sel53  United States
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Join Date: Jan 2005
Location: Lancaster, CA
Hello again,

Yes, I know it is a little odd to answer my own post, but enough people have looked here and I thought you might be interested in what I have done.

I went ahead and ordered a service manual from McIntosh for my MCD7007. It turns out there are actually four NE5532s (dual opamps) and two NE5534s (single opamps) in the analog stage. In each channel, there are two FDNR (frequency dependent negative resistor) circuits that look like lowpass filters, along with an output stage for the fixed output. There are also two stages associated with the variable output.

There is another pair of NE5532s on the Philips digital decoder board; these do the deemphasis and the Bessel reconstruction filter following the DAC. There are muting transistors on both the Philips board and the McIntosh analog board. The opamps on the McIntosh board are all in sockets!

I bought and tried the following opamps on the analog board:
Burr Brown OPA2134 and OPA134
Analog Devices OP275 and AD843
National's new LM4562 and LME49710

The OPA2134/134 are very nice, smooth, clean, very strong bass. Can't really complain about them at all.

Then I put the AD843 into the output stage with the 2134s ahead. Very nice! Stronger musically, same good bass, and a bit cleaner & clearer. I replaced the 2134s with the AD275s ... yuk. Nothing good about that guy at all, so back to the 2134/843 mix.

I finally put in the LM4562/LME49710s. Wow! These are VERY nice opamps. They retain all the great bass of the 2134s, but are much more clear and musical on things like acoustic guitar strumming and plucking. Very good open sound on vocals too, especially closely mic'ed.

Along the way I liked what was happening so much that I put sockets in on the Philips board and put 2134s in there too. Again a nice improvement. After I put the National 4562s in the digital board, it sounded technically better, but the bass became "too clean" ... almost like it lost all its harmonics. So back in with the 2134s on the digital board only, which is what I have now. It is breaking in very nicely.

I also decided to change out the coupling caps in the analog stage; these were all Rubycon electrolytics. I chose the newer Rubycon ZA caps. I just put these in today so it is hard to tell everything, but they are immediately more clear and open, with no change in bass. I can hear them changing with time ... they just went into a peaky stage, but are keeping the great clarity. I'll let you know how they work out after they settle in some.

Somewhere else along the way I took out all the muting transistors. No change that I could hear, so I put them back in ... they do have a job.

This has been so much fun and provided such an improvement that I am thinking of putting in a low jitter clock next, like the Tent Labs XO series. A lot of the DIY folks have done this with other players using the same Philips digital chipset, so could work, eh?

That's it for now. Best regards to all,
Steve
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Old 5th June 2007, 02:17 PM   #3
ctong is offline ctong  United States
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Join Date: Jun 2005
Location: Clemson, South Carolina
I tried opa2132 on my sony scd-c555es and denon 2900 and it is much better than 2134. It is cleaner in the midrange and treble. The bass is also much tighter.

LM4562 seems to be an interesting alternative. I might try it sometime and compare it with 2132.
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Old 26th December 2011, 11:55 AM   #4
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Join Date: Aug 2005
Default Do You Still Have Upgraded McIntosh 7007

Hello,

I'm replying back about the upgrade done on the McIntosh MCD 7007 Cd Player. I just aquired one recently. I love to upgrade equipment. I just wondered if the Tent Lab XO clock got installed.

How do you pick up a schematic of the McIntosh MCD 7007?
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