Thursday, July 8, 2021


Neve 1073 SPX vs Warm Audio WA-73EQ Technical Review and Comparison

In this review I’m comparing a single channel Warm Audio WA-73EQ to a new AMS Neve 1073SPX. For clarity I truncated the model names in the review. Warm Audio produces another model called WA-73 which does not have tone controls, that is NOT what is being reviewed. Whenever I mention the WA-73 I’m referring to the WA-73EQ and when I talk about the 1073 it is the 1073SPX.


There is no single piece of studio equipment that elicits such strong feelings and intense online arguements as the Neve 1073 preamp. Introduced in 1970 the original 1073 used multiple plug-in modules inside the enclosure cartridge and the wiring was all detailed by hand. Detailed hand wiring was used to hold all the wires in very specific, shaped paths very similar to the construction and wiring used in military hardware. Even the potentiometers and their frequency selecting switches were premium components. 


In a vintage Neve analog mixing console the 1073 preamp on each channel does a lot of the heavy lifting. The 1073 is the component that raises teensy tiny little microphone-level signals up to line level and then shaped them with tone controls. It is also the tone control when the engineer switches to “line input” on a channel strip.


Warm Audio is a company that made a name for itself by creating a market leading low priced copy of the 1176 FET compressor. Making copies of things that are dramatically lower in price than their namesake has been a successful formula for Warm Audio. I bought one of their 1176 and then I bought another because I liked the first one so much. The company would not have grown as fast as it did if their products did not perform to professional levels and deliver truly good sounding results. 

Warm Audio designs their products in Texas and uses foreign factories to reproduce the gadgets for budget prices. They build their products in large quantities so they can secure the lowest component prices. 

Low component prices does not necessarily mean lower quality components. Warm Audio has made a big deal about the audio transformers they use in their products and Cinemag in California has benefited from this. 

Warm Audio has featured transformers manufactured by Cinemag in many of their products but for the decidedly British sounding WA-73EQ they went to Carnhill transformer company in the UK. Carnhill has produced ’73 style transformers for several Neve clone builders so they were a logical choice for components users might embrace based on brand recognition. 


AMS Neve owns the rights to “Marinair” audio transformers, you won’t find these trade marked proprietary components in any other brand of gadgetry. Marinair is just one of the unique features you’ll only find on real AMS Neve branded products.

The original 1073 preamp was a product of Mr. Rupert Neve who was a lifelong advocate of transformer coupling between studio components. Mr. Neve featured transformer coupling in all the major products he designed. 

The Neve 1073 SPX is derived from a component which was originally intended to function in a larger mixing console system. The last 20-years of DAW evolution made the practice of ripping the 1073 preamp-cartridge out of the console and converting it into a standalone component a common thing to do. DigiDesign, the originator of the Protools brand made a lot of DAW frontends that had dreadful sounding preamps in them. Users quickly realized if you wanted to record a good sound you needed a good preamp so they flocked en’masse to the fattest sounding preamp ever created, the 1073. 


After ALL the vintage 1073 preamp cartridges were harvested and repurposed as DAW front-ends other vendors stepped in to fill the market demand for 1073-style preamps. Companies like Vintech and BAE created their own ’73-style products to fill the void with clones priced from $1300 to $3500. 

The “line input” on a Neve 1073 is transformer coupled. On a vintage Neve console this is the path you got when you switched a channel to line-input. The line-input transformer was optimized for line-level signals. The “mic-input” on a Neve 1073 is also transformer coupled and utilizes its own optimized microphone-input transformer.

Output transformer at top, two black input transformers bottom

The output from the Neve 1073 is also transformer coupled with a purpose built component. When utilized in the context of a vintage mixing console the line output stage from the 1073 preamp fed to the fader and routing controls on the associated channel strip. 

The modern AMS Neve 1073 SPX is a standalone product designed and purpose built to function as a single channel front-end for a DAW. The user can process a line-level signal by using the line-input to line-output jacks. This allows the 1073 EQ magic to be applied to any source regardless of the preamp used to elevate mic-level up to line-level. 

The schematic for the AMS Neve 1073SPX is ©2006, I assume this means the product has been the same throughout the years which have elapsed since and that the modern 1073 signal path is the same as indicated on the schematic. 


Lets take a look at what each of the contenders offers by directly comparing features.


Top is Neve 1073 SPX, bottom is Warm Audio WA-73EQ

The Neve 1073 has microphone input jacks on the front panel and on the back panel. The XLR on the front panel is a Neutrik combo style jack which can accept XLR or TRS connectors. When you use the front panel XLR input the signal feeds the Marinair microphone input transformer, when you use the TRS input it feeds the Marinair line input transformer. A pushbutton labeled “Front” selects whether you want to use the 1073 front panel inputs or the rear panel inputs. The maroon colored gain knob selects whether you’re using mic, line or D.I. input. The D.I. input always takes precedence over the Mic IP and Line IP regardless of the position of the button labeled FRONT. All these switching options combined with the multiple input sockets allows the user to leave multiple sources connected to the 1073 and select which input is in use with the press of a button.

The default microphone input impedance on the 1073 is 1200Ω, pressing the Lo Z button on the front panel lowers the impedance to 300Ω.

The WA-73EQ utilizes a single audio transformer for input coupling. The front panel XLR input and the rear panel XLR input are connected simultaneously to the input transformer. When line input is selected on the front panel of the WA-73 a pad is inserted so the same Carnhill input transformer can be used for both mic and line input. The only line input socket is located on the rear panel, there is no front panel line input. 

The WA-73EQ has a button on the front panel labeled TONE. When the tone button is out the microphone input impedance is 1200Ω, when the button is pressed the impedance is reduced to 300Ω. Warm encourages experimentation with the two impedance settings to find the right tone.

On the Neve 1073 you get three different signal paths to choose from, each of which is optimized for the signals to be processed (mic and/or line). The microphone and line inputs each have dedicated transformers that are purpose built for the different source characteristics, signal level and impedance. Advanced switching options lets you have mic or line connected on the front panel and simultaneous mic and line inputs on the rear panel with all of these options selected by pushbutton and rotary switch selections. It's complex and brilliant. 

On the WA-73EQ you get two signal paths which change in response to which of the two inputs are selected. For mic input there is no pad, for line input a pad is inserted to allow the same input transformer to be utilized for both mic and line input functions. Warm Audio saved the cost of one additional transformer by combining mic and line inputs through the same part and eliminating the line-input transformer.


In addition to the front panel TRS line input socket, the Neve 1073 SPX has an additional front panel 1/4” input jack which is suitable for connecting to the output of a musical instrument such as an electric guitar, bass or keyboard. When this input is selected the signal bypasses the input transformers and connects directly to the preamp section. The output flows through the EQ(provided it is ON) and finally departs the rear panel XLR output via the Neve Marinair output transformer.

Top: Neve 1073SPX, Bottom: Warm Audio WA-73EQ

A LIFT button on the front of the 1073 provides a break in the ground connection on the D.I. input and according to the manual may provide relief from ground loop hum. The Neve 1073 schematic indicates that the D.I. input has a differential preamp front end. This is how they can lift the ground and not have a transformer in the D.I. circuit. 

A button labeled -20 activates a pad on the D.I. input of the 1073. In the default position (button not pressed) the input impedance of the D.I. input is approximately 1MΩ. You can think of this like the input on a Boogie Guitar amp, very high impedance, it does not load down passive guitar pickups or change their tone. When the button is IN a -20dB pad is inserted before the D.I. input so you can plug in a higher level source, the input impedance drops to 10kΩ with the pad engaged. You would not want to use the padded input with a passive electric guitar because the 10k impedance would load down pickups resulting in poor high frequency response. This setting could be useful for a high level keyboard output, active sources don’t care about the terminating impedance dropping to 10k. 

The WA-73EQ has a front panel 1/4” unbalanced input which is suitable for connecting to the output of a musical instrument such as an electric guitar, bass or keyboard. Warm Audio does not provide any schematic so it is not clear whether the D.I. input uses the input transformer or not. The output flows through the EQ (provided it is ON) and finally exits via the Carnhill output transformer.

In use the WA-73EQ D.I. input works great and I’ve recorded many tracks with it. The Neve 1073SPX also sounds great when using the D.I. input. 


The Neve 1073 EQ circuit has been copied and cloned extensively. It is a complex circuit which delivers a pleasing audio response. The equalizer circuit uses capacitors and inductors to create tone control boost and cut curves. These inductor/capacitor equalizers have a very unique tone in the higher frequencies. 


On the 1073 bass and midrange EQ sections the outer ring around each tone control selects the frequency to be affected. The inner potentiometer knob adjusts the amount of boost or cut applied at the frequency selected. 

The 1073 high frequency tone control is a fixed frequency shelving type equalizer providing +/- 16 dB of boost or cut at 12kHz.

A single pushbutton switch activates the EQ section or completely bypasses it.

Top: Neve 1073 SPX, Bottom: Warm Audio WA-73EQ

On most mixing consoles the EQ knobs are flat when they are pointed at 12 o’clock position. On the Neve 1073 the knobs point straight down towards 6 o’clock position.  They still turn clockwise for boost and counter clockwise for cut but it looks a bit strange and different on the 1073.

The High Pass filter on the 1073 has a unique sound, it is very smooth. The High Pass filter features switchable positions of OFF, 50Hz, 80Hz, 160Hz and 300Hz. This filter is switched into the circuit when the EQ is ON, it has no effect when the EQ is OFF.


Warm Audio did an amazing job creating their clone of the 1073 EQ. The WA-73EQ provides all the exact same frequency centers as the Neve 1073 with two exceptions. Warm Audio added two additional switchable frequency selections in the high frequency tone control. Where the Neve offers a fixed frequency selection at 12kHz, the WA-73EQ treble control provides a three position outer frequency selector which adds 10kHz and 16kHz options. 

Warm Audio WA-73 EQ circuitry

The High Pass filter on the WA-73 offers the exact same switchable settings as the 1073, OFF, 50Hz, 80Hz, 160Hz and 300 Hz. On the WA-73 the high pass filter is not switched by the EQ ON-OFF button. Unlike the Neve 1073 the WA-73 High Pass filter can be switched by itself so you can high pass a signal and still leave the EQ out of the circuit. 

A single pushbutton switch is provided to switch the EQ section in and out of the WA-73 signal path. 

Just comparing the EQ feature sets on the surface the Warm Audio WA-73EQ gives you two additional frequency settings on the Treble tone control and additional high pass filter options. I like the way Warm Audio rearranged the EQ knobs from left to right as Bass-Mid-Treble and the boost/cut knobs point towards 12 o’clock when centered. This may be different than the vintage Neve design but it feels more normal to someone who grew up on Soundcraft mixing consoles (aka ME). 


The Neve 1073 features a 1/4” send and return effects loop on the rear panel. These connections are TRS balanced send and return. The send is active all the time and may be used for an effect send or an additional output. The insert-return is activated when the front panel INS button is pressed in. 

The Neve 1073 insert loop can be switched from before the EQ section to after the EQ. This is accomplished with the PRE button which is located directly under the INS button. 

Having the insert loop as balanced audio connections provides great connectivity with professional signal processing. Virtually all of my signal processors utilize balanced audio connections to reduce ground loops. I like being able to patch any of my compressors directly across the Neve insert loop. 


Warm Audio provides an unbalanced insert loop on the rear of the WA-73EQ. The loop can be switched in or out of the circuit with a front panel button labeled INSERT. 

I’m not sure why Warm Audio decided to make the insert unbalanced except to save cost. Stomp box effects are the only purely unbalanced signal processors in my studio. If I patch my balanced LA-2 compressor across the unbalanced insert loop on the WA-73 I get unwanted ground loop hum. Ground loop hum and awkward cable connections make the unbalanced insert loop on the WA-73EQ useless to me. 

Warm Audio says the Insert-Loop is after the input transformer and initial preamp stage. I assume this means it is fixed before the EQ tone controls on the WA-73EQ. There is no pre or post EQ setting on the Warm Audio ’73 insert-loop.

With its balanced line-level send and return insert loop the Neve 1073 SPX provides more straight-forward options for processing signals passing through the preamp.


Comparing Output Controls

The Neve specifications say the 1073 SPX is capable of driving a 600 ohm load to a level of greater than +26 dBu. Without specifying a load the spec means less but since they told us it can drive a 600Ω load electrical engineering types can see this unit has got some serious output drive potential. Most modern DAW systems top out at +20 to +21 dBu so the Neve has plenty of clean headroom to drive any system to maximum level. Even the Apogee Symphony II inputs with their +24 dBu input level handling can be fully saturated with the Neve 1073 SPX.

The WA-73 output level is not specified in the printed specifications but a look at the front panel gives us a clue. The LED output level indicator has a red LED marked +20. Since we’re given no additional details we can only assume it means that the WA-73 tops out at +20dBu of output level. 

The Neve 1073 has a seven section ouput level meter which is switchable to three different points in the circuit by pressing the output fader knob repeatedly. LEDs are provided to tell you where the output level is coming from. The highest indicated output level is +24dBu but the specifications say it goes all the way to greater than +26dBu so even if you’re hitting the highest output LED you’ve still got almost 3dB more of headroom before the 1073 runs out of clean output.

The WA-73EQ has a five section output level meter with the highest level marked by a red LED labeled +20. It is unclear if the red LED means the unit is clipping or is about to clip. In use I’ve lit the red +20 LED on the WA-73EQ and the signal did not sound gross or distorted.

The Neve 1073 has a single XLR output on the rear panel which is fed by the output transformer. The polarity button is between the output transformer and the XLR output socket on the 1073. 

The WA-73EQ has an XLR output socket and a TRS output jack which are wired in parallel. You should only use one or the other but it is a nice convenience having the TRS as well as the XLR. In spite of the lack of technical details about what the WA-73 can actually deliver output-wise it has been a solid performer in our studio for over two years delivering excellent sounding recordings.

The WA-73EQ also has a polarity switch but there is no information about where it occurs in the signal path.

Another amenity Warm Audio added to the rear of the WA-73EQ is a ground-lift switch. The instructions say it eliminates hum by interrupting ground-loops and eliminating current flow on shielded cables. I’ve never used this ground-lift but it’s there if I ever have a problem.


The Neve 1073 comes with a small external universal AC power supply. It automatically adjusts to whatever voltage you’re connected to from 100-to-240 VAC at 50 or 60Hz. This covers most countries around the world and is easliy adapted by using the appropriate IEC power cable. 

The connection between the 1073 and the remote power supply is via a small DC barrel connection like you see on stompboxes and pedal boards. This cable is fixed at the power supply end and plugs into a socket on the rear of the 1073. There is nothing to lock the cable in or to prevent it from coming out of the 1073. The DC connecting cable is very short and the power supply has no mounting holes for support when the preamp is rack mounted. 

Presumably keeping all AC power outside the 1073 enclosure could lead to overall lower induced noise.

I like the universal power adaptor but I think the implementation is not well done. I’d prefer a locking power supply connector on the rear of the 1073, a longer DC power connecting cable and some mounting holes on the actual power supply so it could be securely mounted in a rack installation. 


Warm Audio armed the WA-73EQ with an inbuilt AC power supply which connects to power with a standard IEC type power cable. 

A small recessed red slide switch is provided to select 115 or 230 volt wall current at 50 or 60Hz. 


I started my A-B sound comparison testing with a brand new Shure SM-58 vocal microphone. Using the front panel mic inputs I moved the output of the microphone back and forth between the two preamp mic inputs. Both preamp outputs were directly connected to separate balanced line inputs on my DAW. This allowed me to record the output from each preamp on their own tracks so I could scrutinize the results carefully. 

Using high resolution JLM peak reading meters I matched the output levels to within 1dB of each other.

Neve Tone Controls

On the Neve 1073 just switching the EQ in and out of the circuit had a subtle but noticeable effect on the tone. Since there is no OFF switch on the high frequency EQ of the 1073 and no center detent to indicate a flat setting I assume there is always a tiny amount of boost or cut going on when the EQ is in the circuit. Also, as I pointed out earlier, the 1073 high pass filter is only in the circuit when the whole EQ is in the circuit. The high pass filter has its own OFF position within the context of the overall EQ.

Warm Audio WA-73EQ tone controls

The WA-73EQ has an OFF position on each of the tone control sections so unlike the Neve you can switch OFF all three sections of the EQ using their frequency selecting rings. If you turn OFF all three EQ sections then the EQ ON-OFF button on the WA-73 has virtually zero effect. The High Pass filter on the WA-73EQ is standalone and not switched by the EQ ON-OFF buttons. 

With the output levels of the two preamps matched and all EQ and High Pass filters bypassed the sound of the WA-73 and the Neve 1073 were virtually indistiguishable from each other in direct A-B testing. After using both pieces extensively I expected more of a noticeable difference in their tonal output. I was pleasantly surprised to hear the WA-73EQ hold its own against the Neve 1073SPX, delivering delicious representaions of what I was trying to record. Engineers may obsess over minute details but the bottom line is whether a piece of gear can deliver great recordings. 

With the treble tone control set to 12kHz on the WA-73 I compared it to the Neve 12kHz tone control. The Neve had a less shrill sound when adding treble boost. The WA-73 treble control got even more shrill and harsh sounding as I pushed it harder. The alternate frequencies of 10kHz and 16kHz also sounded harsh and thin when boosted. 

In over two years of using the WA-73 on everything from vocals to drums to bass to guitar direct, I’ve never experienced anything bad from the WA-73 tone controls. The truth is, I rarely ever switch them into the circuit because the sounds I’ve captured with the WA-73 sound so big and natural without any additional EQ applied. 

Good sources + good microphones + good mic pre = good recording sound, no EQ needed.

The Neve 1073 midrange and bass tone controls have a decidedly musical character to them. The WA-73 midrange and bass tone controls have a lot of effect but to my ears it is not as pleasant as the EQ on the 1073. The WA-73 mid control sounds more like a “quack” or “wah” sort of sound where the 1073 sounds like an emphasized midrange sound. I dislike describing tone with words but these are what came to mind when listening and comparing. 


Neve does not spend a lot of time showing us pictures of the inside of the 1073 SPX but Warm Audio is quite glad and proud of the interior of their WA-73. Lets look at the insides and compare.

Neve 1073 SPX Inside

The Neve 1073 clearly has three inductors aligned with the front panel, two appear to be associated with the EQ circuitry and one for the Low Pass filter stage. I don’t see an inductor associated with the Treble tone control.

Warm Audio WA-73EQ Inside

The WA-73 has an inductor on the high pass filter circuit board and one inductor on the tone control board. In comparing the circuitry I’m left with the feeling that Warm Audio saved the cost of a tone control inductor by compromising the tone control circuit design. This conclusion is supported by the listening tests where the WA-73 always sounded a bit more shrill, harsh and less musical when large amounts of tone control were applied.

The Neve 1073 uses sealed potentiometers on the rear of the tone controls. This prevents dust from getting inside.

The Warm Audio WA-73 clearly uses less expensive open-frame pots on the rear of the tone control switches. Open potentiometers allow dust to get in there over time which causes static and noise. There is a lot of ventilation in the top cover of the WA-73 so dust will be attracted to the electronics and it has a path to get in there.

The Neve 1073 also clearly uses three discrete transformers where Warm Audio chose to use a dual-purpose input tranformer setup to save money.


This was a fun shootout. I’ve used the WA-73EQ for over two years and never had a complaint. I also own a dual channel WA-73EQ which is essentially two WA-73EQ in one box. My favorite feature of the WA-73 is how big and full it sounds with NO EQ engaged. Not that the EQ is bad, I just never needed it because the preamp itself sounds so good. With the right microphone and the right source the WA-73 delivers a big fat sound that is virtually indistinguishable from the Neve 1073. 

Switch on the EQ section and the story changes. The Neve EQ is just plain more musical in every setting. I suspect it is due to several design compromises Warm Audio made during the creation of the WA-73. None of this makes the WA-73 inherently bad but these limitations do affect what you can achieve with the box and how it ultimately sounds.

If what you crave is the sweet sound of a ’73-style preamp consider the more simple and much lower priced WA-73 which has no EQ. I have not personally used it but since you can turn off all the EQ on the WA-73EQ (under test in this review) and just use the preamp by itself or with the low-cut filter I think I have a pretty good idea what the WA-73 preamp without EQ would sound like, and I think it would sound quite good. 

Head to head with the Neve 1073 SPX the WA-73EQ with EQ bypassed was virtually indistinguishable from the much more expensive unit.

The Neve 1073 SPX is made in the UK. The outboard power supply is sourced from China. The 1073 hardware is heavy and extends a couple of inches farther into a rack than the WA-73EQ. Everything on the Neve 1073 SPX feels good, the switches feel solid, the pots are smooth and the jacks work well with a variety of connectors.

Warm Audio does not go into any detail about where or how they come up with their hardware. Everyone assumes it is sourced from a Chinese factory but Warm Audio minimizes information that could distract from the most important messages, their gadgets sound good and they are low priced. 

Based on todays market you can buy two WA-73EQ for the price of one Neve 1073SPX. 

In the last few years, Neve has done something that has caused the price of the 1073SPX to come down to the current street price. I don’t know whether they cut out a bad distribution deal or added a new US warehouse, whatever they did, they lowered the price of the 1073SPX to the current $1640 street price. That is more than $1000 off the price of this same unit in 2017. 

There is not much to critisize on the Neve 1073SPX. It is built well, has a great set of useful features and it sounds fantastic. 

The two preamplifiers side by side

At less than half the price of the Neve 1073SPX the Warm Audio WA-73EQ is an excellent piece of hardware. The preamp section of the WA-73 sounds virtually identical to the Neve 1073. The Neve may have a lot more potential headroom but does it matter? If your DAW saturates at +20dB do you really need greater than +26 output level from the 1073? 

I am mightily impressed with the 1073SPX. Would I buy a single channel for $2900? Nope! But at $1600 I’m in and I like it a lot. I really like the balanced effects insert-loop with pre or post options, high headroom output, extensive metering and sweet sounding EQ. The Neve 1073SPX costs twice as much as the WA-73EQ but all the useful additions are worth the additional cost to me. Do you need these features? That is a question only you can answer after scrutinizing all available data. I know I’m saving up for another Neve 1073SPX :-)

Thanks for reading High on Technology, Good Music to You!

©July 2021 by Mark King, it’s not ok to quote or copy without written permission. 


Microphone Input: Input Impedance 300Ω or 1200Ω, gain +80dB to +20dB in 5dB steps. 

48v Phantom Power

Line Input: Input Impedance 10kΩ bridging, gain +20dB to -10dB in 5dB steps. Both inputs are transformer balanced and earth free.

DI Input: Input Impedance 1MΩ (PAD off)
10kΩ (PAD on). Gain +80dB to +20dB in 5dB steps. 

Output: Maximum output is >+26dBu into 600Ω. Output impedance is 75Ω @1kHz. Outputs are transformer balanced with Neve Marinair transformers. 

Output Level: 7-segment output level meter

Distortion: Not more than 0.07% from 50Hz to 10kHz at +20dBu output (80kHz bandwidth) into 600Ω

Insert Loop: balanced, line-level, switchable pre or post EQ

Frequency Response: +/-0.5dB 20Hz to 20kHz, -3dB at 40kHz with Eq Out. 

Noise: Not more than -82dBu at all Line gain settings
Eq In Flat/Out (22Hz to 22kHz bandwidth, 150Ω input termination), 

EIN better than -125dBu @ 60dB gain. 

External Power Supply, 100v-240v 50/60Hz


Microphone Input: Input Impedance 300Ω and 1200Ω, gain 80-dB, resister stepped gain switch

XLR mic inputs front and rear

48v Phantom Power

Maximum output level: not specified

Distortion: not specified

Insert Loop: Unbalanced Send and Return on 1/4” jacks

Output Level: 5-segment output level meter

Direct Input: Instrument-level input

Frequency Response: 20Hz-20kHz +/- .5dB

Internal IEC power supply 115v/230v power inlet