"SIGMA" amps

[HoraceW]

Anyone know anything about the Trio/Kenwood "SIGMA" amplifiers? Heard one recently at a friends house and was quite taken by the performance for a 30 year old amp. Thanks in advance.

[Reid Malenfant]

I used to own one. They have a seperate set of connections for the speakers, though these are in no way speaker cables carrying current, what they actually are is a set of cables that take feedback from the speaker terminals.

Effectively it's as though there is no speaker cable in the system with the extra cables connected & the amp is connected directly to the speaker terminals.

What I seem to remember was some of the cleanest, taught bass I have had the pleasure of hearing from any stand mount loudspeakers.

I can't remember the model number, but it was about an 80W per channel amp with a nice glass cover that folded down along the bottom half of the front panel :)


Picked it up from a car boot sale :eyebrows:

[sq225917]

Similar to what DPA did then?

[Reid Malenfant]

Similar to what DPA did then?
Yes, though the only DPA amp that I know of with the same kind of arrangement was the 70W monoblocks. As these were in effect a bridge amp it made things very easy to implement.

If it was done on others I'm unaware of the situation.

But yes, same principle :)

E2A:- It wasn't the DPA I was thinking of, Thanks to Nat I just realised it was a DNM :doh: :eyebrows:

[Haselsh1]

I remember owning a Trio Sigma Drive amplifier around 1983 which was around 120 Wpc. The bass control was absolutely astonishing and the sound effortless.

[nat8808]

DNM also did this or had an idea to do this with a third wire as part of the feedback loop so it is seperate from the main signal.

[HoraceW]

Thanks for the feedback, much the same as I experienced. The amp was the KA-1000 with large separate power supply box