NAD 3020i

Serial Number T302I 12444

Circa 1991

For Sale $888

FMI HiFiHealthCare@Gmail.com

NAD (New Acoustic Dimension) was established in 1972 by audiophile engineer Martin Borish. The company really hit the radar in the early 80's when they introduced the 3020 Integrated Amplifier. It received high praises, even in 'Audiophile' circles for the performance of it's phono stage. 

The 3020 achieved a legendary status as a Giant Killer of it’s day, especially the phono circuitry that is still to this day one of the quietest and detailed RIAA circuits ever found in a device priced under $1000. 

The conservative rating of 20 watts is on face value very misleading when you consider this amp can drive loads all the way down to 2 ohms, squeezing an impressive real world power of over 70 watts out of a push pull design featuring very robust drivers!

Given that one of the foundational principles of NAD was to bring a high end audio product within reach of the MidFi consumer, one would not expect to see such overbuilt aspects as the 3055 output transistors that are employed here! These are the same power transistors that were being used in the competitions amplifiers boasting outputs of 60 watts rating.

NAD kept costs reasonable by using quality off brand capacitors such as ‘Elite’; ‘Giant’ and ‘Teapo’, many of which still measure ‘in spec’ some 35 years later! The ability to forecast where and which components to compromise on while still achieving the renowned sound was as much an engineering achievement as it was sales genius.

There were many iterations and refinements to the design, culminating with it's final, and perhaps best version, 3020i. The 'i' stood for 'Improved' and came to the table with newer style robust binding posts, as well as the following...

Improvements over earlier NAD 3020 versions

Feature

NAD 3020 (original) NAD 3020i

Output Power

~20W RMS @ 8Ω

Still ~20W RMS @ 8Ω, but revised power supply and greater dynamic headroom

THD (Total Harmonic Distortion)

~0.03%

Slightly lower THD and better SNR (depending on source)

Phono Stage

Excellent MM stage

Improved MM phono stage with better RIAA accuracy

Speaker Terminals

Spring-clip terminals

Binding posts (higher quality)

Tone Controls

Bass, treble, loudness

Same layout, refined tone circuitry

Aesthetics

Gray-green face, toggle switches

Updated NAD chassis, slightly sleeker with soft push buttons

Today many of the ‘compromised’ components such as the original capacitors have outlived their life expectancy by well over 15 years however, that presents an amazing opportunity to take this well designed circuitry to ‘Next Level’, by replacing these off brand outlived components with the very best modern equivalents with a price no object (almost) mentality!

We have gone through every electrolytic in the Power Supplies as well as the Flat Amp, Tone Amp and Power Amplification circuitry and carefully chosen the ‘best’ capacitors for the job at hand including some of the best capacitors made for Audio applications such as Nichicon Gold and UKA series as well as the highest quality Stacked film Poly Cap’s for such critical applications as the input from the phono cartridge for example. The Power Amp was also augmented by adding stacked film Poly capacitors in parallel with the main 3500 uF power caps right at the output transistors where they reduce the ESR and add refinement to higher frequency filtering capacity, where much of the soundstage details live.

Here we see the new Nichicon Gold Caps that were selected to upgrade the Main Power Supply Rails

All of the Original Output and Bias Transistors were removed and the heatsink and junction faces of the transistors were thoroughly cleaned and then upgraded with modern SilPads that will not dry out and offer better heat conduction characteristics than the old school mica and thermal paste. This helps insure future reliability and optimal performance due to predictable heat management.

Every electrolytic in the power supply and amplifier stage were replaced and upgraded to high end modern replacements.

Here we see the same attention being applied to the small signal and tone section.

On to the coveted phono amp, we applied extra care in component selection, using the highest quality Polypropylene stacked film capacitors in critical signal areas such as the front end that receives the minute signals originating from the phono cartridge.

The entirety of the internals were cleaned and reassembled. 

The Bias (Idling Current) was adjusted in accordance with the manufacturers instructions and DC offset (Center Voltage) verified.

So, all, well and fine but how does it perform?

Proof is in the puddin' and after burning in for a couple hours, we put it through it's paces.

The Manufacturer rated the amplifier section for 20 watts per channel with no more than 0.02% distortion.

The graph below represents the left and right channels THD at rated power.

Here we see, the amplifier flawlessly meets that specification.

One of the underlying characteristics of the 3020 was it's available headroom.

As we see here, we can easily drive over 50% more power out of this piece than it's meager rating all while maintaining complete control of linearity across the full audio spectrum.

This graph shows complete control pushing 32 watts clean into 8 ohms.

Even pushing 50% more than rated power, we still see distortion on both channels well below 1%!!!

Doing some serious 'stress testing we find we can reach over 32 Watts into 8 ohms with both channels driven.

AND...

Over 45 Watts into 4 ohms, with both channels driven!