Success Rolling Opamps in EE Minimax DAC

Douglas_Schroeder, just out of curiosity...why were 2 different opamps (LME49720 and LME49710) used instead of just one type?

Tgrisham, yup, that's the EE DAC, with the tubed output. Chris at Clarity Cable said he prefers the SS output with the opamp change, and with the volume control full tilt i agree. But I like the tubed output better under specific conditions delineated just below. You can use either with the opamp change.

I have been varying the EE DAC's output as it very subtly influences the interplay between it and the VAC Signature MkII Preamplifier. I have been working with the DAC's volume control anywhere between 1 O'Clock and 5 O'Clock on the dial. I find the use of an additional quality preamp exhilirating, and experimentation has to my ears shown that interplay between the two volume control settings can yield a preferable result to simply taking the DAC full tilt into the preamp.

Regarding the efficacy of the Opamp rolling compared to the stock unit, the upgraded opamps easily outperform both the SS and tubed function of the stock unit, imo.

Jdec, I'm not sure of the reason precisely for the difference in the two opamps for the upgrade. I believe it has to do with the different circuits for the tubed and SS operation. I would not want to speculate further than that; Chris at Clarity Cable told me precisely which Opamps and which locations to place them. He did say that one set of Opamps runs with the tube and the other SS.

I did not try reversing them, and would not advise it unless Chris or another expert gave the ok. I certainly do not want to lead people astray on the tweak. As Bill from Morningstar Audio said, if you mess with the unit you void the warranty. So, I certainly would not stray from the explicit instructions given by a pro like Chris.

My friend George and I had the great pleasure of meeting Melissa and Chris of Clarity Cable at THE Show 2011 fantastic Raven speakers). We stayed late one night comparing my CDP to the Eastern Electric DAC w/ Chris's mods.

In the estimated eight-nine years I've owned my CDP I preferred it to every other CDP and/or DAC sampled up to about ten x what I have into the CDP. Myself and the owner of a $20k EMM 2-box both preferred my CDP. I preferred it over a $10k Wadia 27ix. Maybe the $30k dCS and/or Meridian were preferred. The point is my CDP soundly trounced every Red Book playback priced anywhere near affordable.

Till that night described above. Best I could tell I preferred the Clarity EE DAC over my CDP throughout, in every way I could detect. The EE gave up nothing in any way, including pure musicality and pure listening pleasure, lack of fatigue, etc. I tried hard to imagine weakness in these areas because that's where my CDP is tops, but no, the EE gave up nothing in that regard.

Chris and Melissa and extremely wonderful and pleasant people with which to share time. It was a great visit. Their cables seem top notch. Chris is really easy to talk to, a nice treat for a specialty company.

I know this is a bit off topic but could anyone help me out a bit. I just got a used Minimax dac and when i use the tube output it has some hum/noise in the background. It only goes away then using SS output. The hum is more pronounce when the volume dial is from 0-75. From 76-100 the hum is till there but less. I tried with a Brimar tube and same, Pangea power cord still hum. Thanks in advance.

I finally replaced opamps in Benchmark DAC1 with OPA1612 and after initial brighter performance sounded a little mushy. There was a LOT of energy (slam) in the bass and extra extension but midrange became muddy.

Today I replaced them again with LME49860 (+/-22V version of LM4562) and sound went from mushy and bassy to detailed and clean. Voices are still free of sibilants but midrange is very transparent, soundstage expanded and cymbals sound pronounced and clean.

Both amplifiers are in 40-50MHz bandwidth range, both have THD in order of 0.00003% plus extremely low noise (OPA1612 has 1nV/SQRTHz) but sound is very different. Original amplifier NE5532 was very close to LME49860 (slightly less dynamic, clear and extended). If I could only cut them in half and attach bass portion of OPA1612 to LME49860 - well, my neighbors might disagree.