TL Audio’s Ivory 2 series 5052 stereo valve processor is a 3U, two channel unit comprising a compressor, eq and peak limiter on each. Having quickly and easily made all of the possible connections, I tested the unit on a wide variety of applications and was pleased to find that its performance lived up to its impressive spec.

The 5052 has three Sovtek ECC83 dual triode valves making up to six valve stages. One in each of the pre-amp, compressor and eq sections, repeated on both channels.

I fed the audio into the 5052 and the Drive LED indicated the valves were working (illuminating from +6 to +16dBu). Line inputs are via balanced XLR, switchable +4/+18dBu (this also goes for balanced mic inputs with switchable +48V phantom power) and unbalanced via quarter-inch jack, switchable -10/+4dBu. The unit also has two instrument inputs on the front with a gain range of 0dB to +40dB. All inputs have phase reverse, 90Hz high pass filter and a bypass for the compressor, eq and limiter as a group.

I found the backlight VUs extremely accurate and the four-point centred switch made it easy to distinguish what the unit was doing at every part of the chain. Switching is between input/output levels and compressor/limiter gain reduction. The 10dB meter pad switch is also effective when monitoring input and output levels.

The compressor is equipped with a hard/soft knee switch, eq side-chain switch, as well as the usual threshold, ratio, gain make up, attack and release. I was very impressed with the overall sound. It was lovely and smooth on vocals, crunchy on bass drums and warmed up the final mix. The compressor was very easy to use, especially with the attack/release pots not being dented, thus making it easy to dial in exactly what I wanted. The only dented pots on the 5052 are on the input/outputs in the ‘0’ centres and eq gain parameters.

Equalisation
The eq is four band with switchable peak/shelf on the LF and HF and parametric bandwidth on the LM/HM frequencies. Having a valve in the eq stage, as well as the compressor and limiter, gives it a rich sound. The eq can be positioned pre or post compressor and individually bypassed like the compressor and limiter.
The limiter is on a pull to activate pot, post fader, and has a threshold of 0dBu to +20dBu. Once pulled, the adjacent green LED lights up to show the limiter is on and as I roll back, the red LED lights up when the limiter starts to kick in.

When I switched over the VUs to monitor the limiter, the gain reduction showed accurately. This is a ‘brick wall’ action limiter and after testing it with the compressor, eq, etc, I tried using it on its own, bypassing everything else in the chain, bar the preamp. The results were very smooth. Even pushing it far beyond the usual degrees of limiting created some interesting effects, while maintaining the warm sound of the preamp tubes.

Stereo linking
The 5052 can be stereo-linked on the compressor, eq and limiter functions. Channel 1 then becomes the master for both channels. Not having to fiddle to get the same compressor, eq or limiter settings on both sides is a real bonus. I was hoping that all of channel 1’s functions would mirror to the slave, but there are a few functions that are not included. The phase reverse and pad are not linkable, but this isn’t really an issue. It would be useful to add optional input and output gains to future models.

The overall sound is warm, punchy and clean with no noise. Running audio through the 5052 pre-amp puts a glow/edge on music, even without putting the eq, compressor and limiter into the chain. I also like the layout, the VUs, especially the switching between inputs, outputs and gain reduction on the compressor and limiters. If I had to pick a downside, it would be that you can move the eq pre/post the compressor, but there isn’t a facility to move the limiter within the chain. I know it would usually appear at the end, but it would be nice to have the option to move it elsewhere for certain effects. However, this is a dual channel unit so it is perfectly feasible to run the audio through it twice. You can also purchase the optional DO-2 24 bit AD converter output card, which provides outputs from channels 1 and 2 to the SPDIF phono output.

Verdict
This is a high-end processor with high-end results, with a value for money that is hard to match. The build quality is excellent and although at 3U it’s a little larger than all the others in the Ivory 2 family, I’m glad TL didn’t compromise ease of use for size.

I’ve uploaded an assortment of mp3s to our website (below) in the media section under ‘TLAudio’. Please contact us if you would like to hear WAV versions. www.tlaudio.co.uk
www.graphicnature.co.uk