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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
morningstaraudio's avatar
morningstaraudio
154 posts
 
Magfan,
I believe some of the op-amps are to small to just plug into the EE DAC PLUS, that is why the need for the Brown Dog adaptors.So you do not have to solder the smaller op-amps into the MiniMax.

No, you then do NOT have to solder the BD adaptors into the sockets. You should never put your soldering in any of the components in the DAC PLUS. Very sensitive inside the DAC.
That is the reason for the BD adaptors so you don't have to solder.

Thanks,
Bill
magfan
1,583 posts
 
Chips are built to case standards.
8pin is a dual opamp while 4pin is a single, usually 1/2 a dual.
Putting a replaceable module in a socket is probably good for the opamp rollers, of which there are many...and more coming.

SMT? I'd not try to manually solder one on a bet.

I'm sure, one day, NOS OPA2134s will be 100$ each and unavailable except if you 'know somebody'.

I'm stocking up now, and waiting for the crash.
bobxsherman
4 posts
 
Mgfan,

Singles are actually 8 pin also.
magfan
1,583 posts
 
Right you are.

My bad.

Here is an example of a 5 pin case, SOT-23

http://octopart.com/mcp6021t-e/ot-microchip-419137

Other dual inline cases go up in pincount.
I see references to Quad Opamps....14 or 16 pin?

Now, where did I see a 4 pin case?
sibelius
256 posts
 
Quick follow up. I swapped out stock opamps with 2604 and 827's. My impression is that there is more detail with a tightening up of the soundstage. Between SS mode, tube removal and the opamp changes, the DAC is indeed a step up from the stock unit. Grand total was $80 for opamps and extraction tool. Took me all of 10 minutes to perform the opamp "operation". Highly recommended for EE DAC plus owners. Note that this voids your warranty. However, it really is plug and play if you get the opamps pre-mounted on the brown dog adapters.

Have some National Semi Opamps coming for some additional experimenting. Fun stuff.
More to discover