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Listing of Opamps for EE Minimax DAC Plus

Phil from Cimmaron Technology sent me a list of approved Opamps for
respective positions on the board of the EE Minimax DAC Plus; prices
include the Brown Dog Adapters provided by Cimmaron. I have been using
in the U1/U2 position the OPA2604 and in the U6/U7 position the OPA827.
I have not Opamp rolled this unit much, as I have been busied with other
components for review. I attest that the DAC Plus in SS output with the
tube removed and these opamps is sensational.

(NOTE CAREFULLY the warning at the bottom NOT to use the AD 8620 in the U1/U2 positions!) Also note that the positioning of the opamps/adapter is always with the small square solder point on the topside of the Opamp at the upper right hand when the unit is facing the installer. Finally, it is recommended that an opamp extraction tool and an anti-static device be used when removing/installing Opamps.

Is it "worth it"? YES! YES! YES! :)

RECOMMENDATIONS OF OPAMPS FROM CIMMARON TECHNOLOGY:
For U1/U2
Single-channel op-amps mounted on the 020302 SO8-to-DIP8 single-to-dual
channel adapter:
qty 2 each required

020302-OPA627 $48.00 x 2 = $96.00
020302-OPA827 $38.00 x 2 = $76.00
020302-AD797B $48.00 x 2 = $96.00

. . . also for U1/U2
Dual-channel op-amps mounted on the 970601A SO8-to-DIP8 adapter
qty 2 each required

970601A-AD8620 $23.00 x 2 = $46.00
970601A-OPA2604 $13.00 x 2 = $26.00
970601A-OPA2134 $10.00 x 2 = $20.00

For U6/U7
Single-channel op-amps mounted on the 970601A SO8-to-DIP8 adapter
qty 2 each required

970601A-OPA627 $28.00 x 2 = $56.00
970601A-OPA827 $23.00 x 2 = $46.00
970601A-AD797B $23.00 x 2 = $46.00

The AD 8620 should not be used in the DAC PLUS.
"On some forum there was a suggestion to use the AD8620. for positions U1
and U2. While this is a dual op-amp, it is only rated to use up to
plus/minus 13 volts. The circuit in the EE Mini Max DAC and DAC Plus is
plus/minus 15 volts."
douglas_schroeder
sibelius
256 posts
 
After several days of mixing and matching the Dexas and Bursons in the Minmax plus it has become pretty clear that I prefer the Dexas in both U1/U2 and U6/U7 in both tube and SS mode. The Dexas have a crispness and clarity that I really enjoy in my system while being much less fatiguing than any of the IC opamps I've tried. Those looking for more body and weight to the music should try out the Burson's.

After a bunch of experimenting, my current default listening setting (subject to change) is tube mode with NOS Mullard and all Dexa opamps. In addition to the stock EH tube, I have tried Amperex, Mazda/Cifte and Mullard. I prefer the Mullard but all NOS were a clear improvement over the stock tube. Will more than likely try a few other tubes for curiosity sake. For those looking for the utmost clarity and resolution, going all Dexas in SS mode with tube removed is a great choice as well.

That's it for now.
tbcatjr's avatar
tbcatjr
3 posts
 
With the exception of the discrete opamps, I perfer the 49990's. Would the Dexa or Bursons have the resolution of the 49990's with more body? Thanks
jmbatkh
103 posts
 
Hi,
I used the 49990s happily for several months on my Plus. I liked them a lot but tried the Dexas anyway (Bought from the mfr. site for about $245 total).
The upshot- I easily preferred the Dexas (after 50 hr break in). Interestingly, they sound most like the 49990s of anything I've tried- detailed, very fast and transparent.
But they also are a bit easier and organic sounding- not softer or rolled off, but more analog-like? They also do a better job of letting through the ambience and tiniest harmonic details. Overall, they sound a lot like the 49990s but more refined. Is it worth the $? To me they made the sound a bit more relaxed, which was what I was looking for. So in my case, yes, they were worth it. Day and night difference, once size fits all? Not in my opinion. Good luck!
sibelius
256 posts
 
I agree 100% with Jmbatkh's assessment. The discrete opamps I've tried (both Dexas and Bursons) sound more analog like than any of the IC opamps I've tried. I don't think you will necessarily get any more resolution with Dexas over 49990's but the presentation is more relaxed and organic. I can listen to the Dexa upgraded Dac Plus for hours without any listener fatigue.

The Dexas sound to me cleaner and clearer with more sparkle than the Bursons. The Bursons will add more body and weight to the music with better bass than the Dexas. Both are wonderful and dependent on personal taste.
tbcatjr's avatar
tbcatjr
3 posts
 
Anyone know which opamp is the right channel, u1 or u2? thanks
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