Review of ATI L200 Buffer Amp

Review of ATI Stereo line buffer amp

Pros : Compact, Versatile, Excellent Sound, Accurate Controls
Cons : Turn off thump a problem, Low output impedance
Best Uses : Blending buffer amp, Mono summing amp, Variable gain voltage amp

The ATI L200 is a useful device.

Its main uses will be to buffer blended signals.

To place a mono signal in two independent outputs.

For use as a positive or negative gain stereo or mono voltage amplifier.

The L200 has two xlr balanced inputs and two balanced outputs.

It can provide up to 28 db of gain down to zero output.

Input impedance is 40 Kohm and output impedance 40 ohms which presented a problem that I had to solve.

The unit comes with a 24 volt DC power supply. There is a 24 volt DC output that can power another unit.  Be careful if you do, the outside of the DC plug is hot!

I used my unit as part of my triamped dual aperiodically damped transmission line monitor speakers.  These are a novel design of mine and are truly full range.

However the LFE signal which is mono needs blending with the signal from the low pass active filters which are stereo.

So I took the balanced LFE out from my Marantz AV 8003 pre/pro, to the left balanced input of the L200.  I opened the unit up and moved the link to the mono sum position.  Then I could blend the LFE output with the low pass outputs of the active crossovers from the two L200 outputs

However the low 40 ohm Zs output impedance drastically dropped the output from the low pass crossovers.  So I had to modify the unit to increase the output impedance.

One other problem, when power is cut to the unit a large spike appears at input and output.  The unit sent my Marantz into reset.  So I have left the unit permanently on.  The unit contains no on/off switch.

All in all the unit is nicely made, has excellent signal to noise in all modes except maximal gain where it is noisy.  It would be better if it did not have a huge turn off thump, and had provision for a higher impedance output when used as a combining buffer amp.

However when all is said and done this is a useful unit, but for the price could be improved.

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