Through the ’50s and ’60s, Altec’s 436 compressors were often modified and hugely influential. But this keenly priced homage does more than clone these vintage devices.
The LANG Electronics name is now owned by Heritage Audio, and with the P.LANE Type 436 variable‑mu valve compressor they’ve moved the brand’s focus from New York to a “London studio” where a “particularly talented band from Liverpool” recorded during the 1960s. It doesn’t take Sherlock Holmes to figure out the reference to EMI’s recording studios on Abbey Road, and omnipresent in those studios during the 1960s were a number of Altec Model 436A & 436B valve‑based variable‑mu compressors, imported from the USA in 1958 and modified in‑house by the EMI engineers. Heritage Audio’s engineers have taken their inspiration from a slightly different variant, the Altec 436C, which was developed in the early 1960s by Altec themselves, in response to the widespread practice (on both sides of the Atlantic) of modifying their earlier units.
Vibe & Valves
Aesthetically, the P.LANE 436 nails the 1950s vibe of the vintage units, with a 2U grey fascia, chicken‑head knobs, circular analogue meter and red jewel power indicator lamp. To the far left of that meter, which displays up to 30dB of gain reduction, sits a detented, passive rotary input level attenuator, followed by a smaller vertical pairing of Attack and Recovery (release) selection switches. Each gives access to six settings, but the Recovery switch has an additional five Hold positions too, of which more later.
To the right of the VU meter another vertical control column consists of a six‑position DC Threshold control and two screwdriver‑adjustable trim pots: one called Zero, to set the meter’s 0dB point, and the other Balance, to rebalance the triodes of the P.LANE 436’s variable‑mu valve, to minimise any low‑frequency artefacts that may arise as that valve ages. Sitting next to these you’ll find the detented, passive rotary Output Attenuation control, and this is followed by an on/off toggle switch and the jewel lamp. At the rear are the expected XLRs and the less expected parallel 6.35mm jack sockets carrying the balanced audio I/O, a 220/110 V mains voltage selector, and a fused IEC mains socket.
As with all of the Heritage Audio products that I’ve reviewed, the PCB layout, its components (all full‑size, through‑hole) and the overall construction are of exemplary quality. A compact toroidal mains transformer is bolted vertically to the right‑hand end of the chassis. The main PCB carries the analogue power supply, side‑chain and audio circuitry, together with the P.LANE 436’s three valves. The Heritage Audio‑designed, LANG‑branded input transformer features a high‑nickel alloy core and a mu‑metal shielding can, and sits on a small board at the left‑hand end of the chassis. The output transformer, another in‑house design this time equipped with an M6 silicon steel core, to help create colour and harmonic distortion at the output stage, is bolted down behind the main PCB next to a large heatsink.
The increasing lack of availability of quantities of reasonably priced, high‑quality NOS (new old stock) vintage valves in both the short and long term is a growing challenge, for both equipment manufacturers and guitarists like myself. Heritage Audio, though, seem adept at overcoming this challenge, as illustrated, for example, by the substitution of 16 6BA6s for eight 6386s in their Herchild 670 compressor. Such availability issues required the substitution not only of the 6BC8 variable‑mu valve from the 436C’s gain cell with a NOS Russian‑made 6H5P (which Heritage Audio’s Peter Rodriguez describes as “performing like a premium selected 6BC8”), but also of the original’s output stage double‑triode 6CG7 by a JJ‑manufactured E88CC. Known as a 6922 in the US, the E88CC is an upgraded version of the standard ECC88/6DJ8 that was originally developed by Mullard in the UK, in part for use in computers. The only valve from the 436C that didn’t require substitution was the 6AL5 dual‑diode in the side‑chain, which generates the compression control signal and remains readily available as NOS.
The XLR audio I/O are duplicated on quarter‑inch jacks to make connection convenient.
In My Ears
Gain staging with the P.LANE 436 requires some consideration. The input and output level controls are passive attenuators and, counter‑intuitive though it may seem, these equip the P.LANE 436 with a kind of automatic make‑up gain. To obtain greater amounts of gain reduction, you have to reduce the input attenuation, thus allowing more signal level into the compressor. This increased input signal (assisted, no doubt, by the 20dB of gain through the P.LANE 436 when no compression is taking place) helps to compensate for level lost due to compression. Finally, the output attenuator allows you to set the level leaving the unit. Since both attenuators sit after their respective transformers, with maximum input and output levels of approximately +24dBu at less than 1% THD, you can drop the hammer on both input and output transformers and still be able to avoid overloading the next link in the signal chain.
The attack times are given as “15ms to much slower” and increase linearly over the six switch positions. When it comes to recovery times, the picture is slightly more complex. These are given as 300ms‑6sec, increasing in a linear fashion from switch positions 2‑6. Position 1 on the Recovery dial (designated as SF or SuperFast) is the outlier, as this sets a recovery time of 150ms, a speed unknown in the Altec 436C.
When the Recovery switch is moved to a Hold (red dot) position, the current level of compression is frozen until either another recovery time is selected or the frozen level is increased by a higher‑level transient. This function allows you to prevent either unnatural initial compression at the start of a song or the rapid increase in level when compressed audio drops suddenly below the compression threshold, either during or at the end of the track. In the case of the former, having selected the recovery time for the track, you’d play through the start of the track, switch to the nearest hold position to freeze the resulting compression level, play the track from the start, and unfreeze the compression once the track was under way. In the latter case, you’d simply switch to an adjacent hold position before the audio dropped in level, and either switch compression back in when the quiet passage finished, or leave it frozen during the fadeout.
Rather than simply adjusting the threshold, moving through the P.LANE 436’s DC Threshold control’s six switch positions also sets the compression slope, moving progressively from pronounced to gentle compression. Attack and recovery timings interact with the DC Threshold to create the compression curve, and it is that three‑control interaction that enables you intuitively to sculpt the style, character and amount of compression that’s best suited to your source signal.
Pleasure To Know
With few visual references — only the meter indicating gain reduction, and the positions (not actual values) of the controls — getting the best out of the P.LANE 436 requires experimentation, but I found that this led quite quickly to an intuitive understanding of the interaction and relationship between the controls. To my way of thinking, there are two fundamental relationships within the P.LANE 436: one between the input level and the DC Threshold; and the other between the Attack and Recovery times. The former I think of as defining the character and amount of compression, and the latter I regard as creating the style of compression. These two relationships are interdependent, so I tend to adjust their control pairings in turn and, having got the compression heading the way that I want it to, I’ll start adjusting individual controls in order to zero in on my goal.
With the P.LANE 436 there’s virtually no such thing as too much compression.
Unlike, say, a VCA or FET compressor, with the P.LANE 436 there’s virtually no such thing as too much compression. I found that there’s either too little or just enough — even if that “just enough” is keeping the compression level at its 20dB maximum. For many sources, vocals and acoustic instruments for example, gain reduction in the 10‑15 dB range on the meter seems to me to be the P.LANE 436’s sweetest spot. Having said that, it also sounds great shaving just a few dB off a bus to pull everything together.
The P.LANE 436 has a smooth sonic character that’s no doubt in part due to that steel‑cored output transformer, but it also subtly enhances the signal passing through it. Add in a compression that has the ability to exert control without destroying high frequencies, crushing the life out of a sound, or sacrificing its initial attack and punch, and the result is a compressor that, to my ears, can pull a mono bus or source into aural focus — and most of the time it does so without it being too obvious. Even the SuperFast recovery setting doesn’t break this paradigm, as its effect is to push the source somewhat more to the fore — particularly, though not exclusively, in combination with the 15ms attack time. This makes those combinations ideal partners for drums, percussion and rhythmically complex guitar strums. The one circumstance where the P.LANE 436 can sound more muffled than I’d like it to is when, irrespective of the attack time, it’s delivering 20dB of compression at the six‑second recovery time, but I doubt that I’d ever go there ‘in anger’.
Lastly, a special mention must go to the Recovery time Hold function, which stops noise rising during quiet passages as a track or source is being dynamically controlled. This was my first encounter with this feature and it worked brilliantly, though there are some practical steps that you have to take to get the most from it: when tracking, rehearsal and a cue list are a must and, when mixing, a stopwatch and an old‑school time‑referenced cue list definitely help.
Verdict
I have a real soft spot for variable‑mu compressors. I find that their slow attack and long release times lead to a comparatively unobtrusive and relaxed performance that, for me, works particularly well on vocals, acoustic guitar and bass, electric bass guitar, small drum kits and percussion. The P.LANE Type 436 may be inspired by the EMI‑modified Altecs but, really, it is best thought of simply as being a well thought‑out compressor that puts a legendary heritage and an iconic sonic character within the financial reach of today’s home and project studios.
If you can’t live without a hard bypass switch, side‑chain filters, wet/dry mixing and a stereo link, you’ll have to look elsewhere. But if you can leave those behind, you’ll be rewarded with a compression style that’s seductive and artistically inspiring. Although its slow attack and release may prevent it being your only compressor, the P.LANE 436’s characterful performance, sound quality, control flexibility and attractive price deliver a value‑for‑money proposition that you’ll find hard to equal. An original EMI‑modified Altec 436B sold on eBay in 2012 for £22,322($30,000 at today’s exchange rates), and that, in my view, makes the LANG Electronics P.LANE Type 436 an outstanding bargain that really should be auditioned by anyone considering adding a variable‑mu compressor to their arsenal.
Alternatives
The Chandler RS‑124, developed in conjunction with Abbey Road Studios, is the way to go if you crave an authentic reproduction. Retro Instruments’ Revolver and Highland Dynamics’ BG2 might offer less authenticity, but no less validity.
Pros
- Superb overall performance.
- Can control dynamics without supressing punch and high frequencies.
- Recovery Hold function eliminates compression release artefacts.
- Excellent value for money.
Cons
- Assuming you enjoy the vintage vibe, none.
Summary
An updated, attractively priced take on a 1960s variable‑mu compressor that brings a legendary heritage and an iconic character and performance into today’s home and project studios.
Information
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