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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
douglas_schroeder OP
3,281 posts
 
I have been waiting impatiently for my Discrete Opamp Rolling article to be published at Dagogo.com; now it's up for the world to see.
It is my latest foray into Opamp rolling, this time with the lovely discrete Opamps.

A couple of notes:
There was one mental faux pas where in comparison of prices I said, "ten digit" but meant ten thousand or five digit. Should get corrected today.

I focused on redbook playback in the article, but the same results apply to the DAC being used with file playback, streaming audio, etc.

I did not get into the option of shortening the long leads of the Burson Opamps, but I have indeed spoken to Burson/Dexa to obtain additional sets for my office rig. I'm looking forward to that upgrade!
douglas_schroeder OP
3,281 posts
 
Following up on my threat (actually, a promise) to put the discrete Opamps in my office rig, the sound is good enough that for all but the most ardent perfectionists it would be quite acceptable.

My office rig: Sonos with a Buffalo .5G NAS for my CD collection ripped; Cambridge Audio Azur 840C, Peachtree Audio Nova, Eminent Technology LFT-VI with pair of SHU STF-1 subs. Wireworld cabling throughout. This is not what I would call an extreme system, but a competent one. However, the discrete Opamps installed into the EE DAC (this is the older version, not the Plus version as I wrote about in the article; the Plus version is much better holistically) elevates the system vastly. It sounds closer to what I accomplish in the review system than previously. Particularly the magnetic planar speakers are sounding much better than prior, more tight and distinct.

BTW, the tube mode of the Nova obscures the pristine nature of the EE DAC; I run the Nova with SS mode and the tube removed from the EE DAC.
sibelius
256 posts
 
I've been running the Dexas in my DAC + for about 6 weeks and there is no question that the discrete opamps produce a sound that is much more analog like than any of the IC opamps I've tried. Based on Doug's review I have also ordered the Burson discrete opamps and will do a comparision between the two when they arrive.

I will say that at least in my system (Shindo amp and preamp, Tonian Labs (12" PHY) speakers) some of the IC opamp combinations seem to have more absolute resolution than the Dexas but the Dexas just sound more natural with less listening fatigue.

I still prefer listening to my analog gear over digital but the DAC +/Dexa combo has greatly improved my digital listening experience. For under $2K, the sound has exceeded my expectations and represents an excellent value.

Will report back later when the Burson's come in...
vapor1
107 posts
 
Thanks to Bill for hooking me up with the DEXA's! They do exactly what I want in the sound, more relaxed AND more resolution. In essence they reveal more nuanced details, but do so in a way that makes extended listening even easier. I'll be doing some comparisons with my BMC DAC1, and while I don't expect the EE to come out on top, I do expect it will be very close in many ways.
douglas_schroeder OP
3,281 posts
 
The results with the original Minimax DAC in the office rig are as expected, beyond expectations. I have rolled in the Dexa duals into the U1/U2 positions and the Burson singles into the U6/U7 spots and the performance uniformly elevated across the frequency spectrum.

Particularly notable is the extra weight and definition with the bass. I have smallish subs in the rig but the Bursons, as with the reference rig, add quite a bit of robustness and presence without sacrificing definition. Tonality continues to improve as well.

Once again, note that one should roll both pairs of the original IC Opamps. Using discrete Opamps in all four locations dramatically improves performance, despite the fact that one could leave the stock IC Opamps controlling tube output untouched. Just as it may sound illogical to remove the tube, so also it seems illogical that replacing the IC Opamps for tube output would affect the overall performance, but it does, and in no small fashion.

This may prove to be among the most affordable answers to the "Class D Amp Problem", that being a white-ish, thinner sound. I am very much enjoying the performance of the Peachtree Audio Nova with the EE Minimax DAC now along with the Eminent Technology LFT-VI speakers. This is the best magnetic planars in an affordable rig have sounded in a long time. And I'm not even using Redbook, but Sonos with a NAS.

(I have reviewed products from these brands for Dagogo.com)
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