Retro Hardware: Neve Class-A Channel Amplifiers, Part Two

In the first installment of this series I introduced you to the first two silicon transistor-based, class-A Neve channel amplifiers, the models 1063 and 1064.  Before I continue with other models I'd like to discuss the sonic attributes of this series of channel amplifier which has made them so coveted and emulated in the world of modern recording.

My introduction to Neve channel amps was a pair of 1066s that belonged to my next-door neighbor, a recording engineer and producer, back in 1992.  IIRC, he paid around $2500 for the pair (which was crazy money for two old channel amps back then!).  The 1066s were his only outboard mic pres, and they sounded far more authoritative than the pres on his Soundcraft 600 console.  He (and I) generally used them on the two most important tracks when doing rhythm sessions and then used them on every overdub.  I never really thought about whether or not they were actually the best choice for a given source, I just assumed they were 'better' than the Soundcraft's mic pres for pretty much anything.  This was my first exposure to 'vintage' mic preamps, and I used them just about everything I could.  It took another year or so before my ears began to really discern the sonic impact these things were having.

Neve's are revered primarily for one thing... they make stuff sound authoritative and larger-than-life.  I think it is rather interesting (ironic, perhaps?) that these circuits that we now revere for their colorful, mass-giving sonics were never intended to produce color of their own, but rather simply capture, as accurately as possible, whatever signals were run through them.  I remember once reading a post somewhere by Neve guru (and former head of Neve's electrical design), Geoff Tanner, discussing a particular early germanium-based Neve console and saying that, despite all of its obvious color it had actually been designed originally for accurate orchestral recording!  These days one could easily fault the end result (when accuracy is the goal), but most of us would rather adore the actual sonics of the product, regardless of the intent of its designer or the limitations of the technology of the time. 

Clearly, electronics technology simply wasn't so up to the task of sonic neutrality 50 years ago as it is today!

The class-A, discrete Neve channel amps from 40 years ago provide a texture that is big and edgy, solid, if a bit clunky.  It is not a finesse kind of sound, but a texture with an ever-present bit of 'hair' to it that attracts the listener's attention, rounds off transients and has a saturated, organic lushness to it.

Neve 1066

(Okay, so describing sound with words isn't the easiest thing in the world to do.. gimme a break!).

The point is, these thing have a strong personality, one that lends itself well to tracks that we want to dominate a mix.  This characteristic, which makes these circuits so appreciated, is also what, IMO, limits them with regard to broader use, however.  (I realize I'm wandering into potentially blasphemous territory here... please don't cast your stones till I can explain myself further...). 

I appreciate delicate, pure sounding textures as much as I like over-the-top saturated, "everybody-pay-attention-to-me!" tones.  While the class-A Neve stuff excels at the latter, giving bombast and authority to key elements in a mix, when used on too many sources, the weight can often be a bit over-the-top, which can make sorting through it all a bit of a chore come mix time.  I learned this from using my buddy's 1066s on everything I could -- when everything has authority in the mix... well... nothing does.

But when you want weight, there's not much else out there that can give it quite like the class-A Neves.  Okay, back to the modules. 

Neve's 1065 is a rare channel amp that uses the 8.75" high chassis and features the same mic/line preamp and equalizer section as the 1064 on dual-concentric, continuously-variable controls.  The 1065 has no hi-pass filter, however. 

(I have only the data on a 1065 and no photo.  If anyone has a picture of a 1065 I would love to see it!)

The 1066 channel amp is up next and is functionally a 1064 with dual-concentric, continuously-variable controls in the smaller 8.75" high chassis.  The 1066 is perhaps the first of what might be considered standard Neve channel amplifier modules in this size, and it is the basis of several modules yet to come. (In the interest of fairness the earlier 1064 was common enough to be considered standard for the larger 12" module chassis, and it is the only all class-A silicon transistor channel amp of that size that I am aware of.)

Neve 1067

Neve's 1067 module is another rare oddity that is pretty much a scaled down 1066.  It has the same mic/line preamp, 10kHz high shelf and same mid frequency choices as the 1066 but has a fixed 100Hz low shelf and no hi-pass filter.  The lack of filter gives 1067's faceplate even more room to spread things out (check out the pic... plenty of room for fat fingers to get around on it!). 

Then comes Neve's 1070 module, which is also based on the 1066 having the same EQ and filter set as the 1066 but with the single 1200-ohm input scheme as the 1063 for use with all signal types (no separate mic and line inputs on this bugger).  The gain is structured for signal input levels ranging from -80dB to +10dB. 

Neve's 1070 - Single Input for both Mic and Line signals

And now we come to what is without a doubt THE single most well known Neve channel amplifier ever made (at least it's model number is the most well known)... the 1073.  Neve probably built more 1073s than any other channel amp.  Designed in 1970 it quickly became the standard module for class-A Neve desks, both large format recording desks such as the 8016 and smaller broadcast mixers like the BCM10. 

The 1073 boasts the same preamp with separate mic and line inputs as most of the other modules in this lineage (each input having its own transformer).  The EQ, however, differs from those that have come before in that its HF shelf has a higher corner frequency of 12kHz (compared to the 10kHz of the earlier models) .  1073's midrange peaking band features six frequencies: 360Hz, 700Hz, 1k6, 3k2, 4k8, and 7k2.  The LF shelf provides 35, 60, 110, and 220Hz choices, and the HPF rounds out the facilities with 50, 80, 160, and 300Hz positions.

The Benchmark - Neve's Venerable 1073 Channel Amplifier

Regarding the mid bands of the 1066 and 1073 modules (the two most common channel amp models produced by Neve in the early 1970s) I have heard it said that the 1066's mid band possessed a "constant Q" characteristic while the 1073's did not.  As far as I can determine from studying the schematics of each unit they both share the exact same design topology for all three bands of EQ, including the mid band.

Both units' mid bands uses an LC-type (inductor/capacitor) arrangement with the same electrical characteristics but different values for inductance and capacitance (so, therefore, different frequencies on each).  The 1066's design accomplishes this through the use of a 2-pole frequency select switch to tie various inductances to their respective capacitances for each frequency while the 1073 hardwires the various cap/inductor values together and uses a single pole switch to select the desired combination.  At each switch position on the two units, however, the circuit flow is identical with only component values resulting in differing frequency choices -- I don't see how the Q characteristic would differ for these bands.  I don't have an example of each model here to measure for myself, so I can only go off of their schematics to try to determine the validity of this claim.

If someone can explain how these filters differ in performance I would absolutely love to be brought up to speed, as this would be a very cool thing to learn about!  Please let me know if you have any data to support such a claim.

Okay, only a few more class-A modules left to go and then we'll hit the class-AB versions.  Stay tuned, and thanks for reading!