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In the Forum: Audio Discussions
In the Thread: Another light for the LS tunnel: transformer-attenuators?
Post Subject: Placette Active & PassivePosted by George on: 3/14/2007
I have had a Placette Active for some 5 years now and it was quite a revelation when I put it in my system. According to Guy Hamel one of its most important features is its powerful op-amp output stage with an output impedance of 10 ohms. Since I have to drive 8 meters of RCA cable this was of high importance to me.

Recently I had a brainstorm (very small) and bounced it off Guy (who is a terrific person to talk to) and he thought it would be worth trying. Since I was driving such a relatively long length of RCA cable (thus subject to noise pickup) I thought why not run the Active with no attenuation (full strength signal) and put a passive Placette right next to each amp. Actually I bought RCA male/male couplers and plugged the Placette right into the amp.

Note that I have inverted the usual order of attenuation then output to output then attenuation. Guy told me this has no disadvantages and should in my case increase the signal/noise ratio. This also allows the the sources to see the constant impedance of the Active and allows the strong outputting Active to drive the Passives which don't have to drive very much at all.

To me there was a worthwhile improvement which may or may not be due to the
theories stated above and which may only apply because of my 8m of cable.

This is somewhat like what Romy is talking about with a voltage divider but since I have no DIY skills I need to use plug and play components.

If I had known of this setup originally I could have bought an active output unit without the volume control stage from Guy and then simply added two passives at not too much more than the standard Active. If I still like this setup after 6 months I will probably sell my Active and replace it as stated just to simplify things.

Note: the passives operate with their own remote and the Active can be set up to operate on a different remote so that its volume setting is not affected by the passive's remote.

Any comments or criticisms are welcome.
George

PS From the Lamm website I just saw this instruction about the 2.1:
NOTE: 6N6P tube should be replaced every year

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