Stacked Quads in small room?

[PJ03029174]

Cheers guys, 4ohms parallel it is. Any idea about the additional load the Townshends will introduce?
Thanks
Pete

 

[montesquieu]

Sorry to resurrect this thread but I'm a bit of a dummy technically.

I just picked up two pairs of ESLs, looking to stack this time (I've had single pairs before). Amp is a VAC Pa60C KT88 push-pull, 30w in triode mode, 70w in pentode. A single pair runs beatifully on triode.

I don't understand the above posts arguing about wiring in series or in parallel. First, what does this mean? I assume by in parallel, you mean two sets of wires run direct from the power amp (or do you mean two power amps?). And in series, you mean one set of wires from the power amp, into the first one, then piggy-backed onto the second pair?

What I don't understand is the difference electrically in these two approaches ... do they differ in terms of impedance and the load on the amp? I read above that this may result in roll-off, I assume there is some theory behind this assertion?

Keen for any info people have on this!

 

[PigletsDad]

OK, lets start with difference between series and parallel.

To describe this I am going to call the speakers for a chanell s1 and s2, and each has + and - terminals.

In parallel, a wire runs from amp+ terminal, to s1+ and then s2+. Amp- is connected to s1- and s2-. In this arrangement, current from the amp is shared with both s1 and s2.

For series wiring, we go afrom amp+ to s1+. Another wire runs from s1- to s2+, and the final one runs from Amp- to s2-. Note that the complete circuit requires the same current to flow through both in succession.

The effect of parallel connection is to halve the impedance that the amp sees - the same voltage coming out of the amp causes twice as much current to flow.

Withe series connection, the impedance is doubled, but each speaker sees half the supplied voltage.

 

[montesquieu]

thanks hugely for this.

Wow I didn't even consider the series option. I guess parallel would be best through?

My amp has 2, 4 and 8 ohm taps, which would be best for use with the 30w triode option?

 

[EmptyBelly]

When you say 4 ESL 57, are you talking about 4 pairs in stacking or 2 pairs?

You can run 4x 57s off one stereo amp, I have and do. It's a Chinese valve amp, modified to suit 240V. I've also used decent tranny amps in the same role. The difficult load at HF is noted but this is at very high freqs where there is little power to speak of.

57s need to be clear of the back wall but can approach a side wall without getting boomy.

 

[Disarmamant]

When you say 4 ESL 57, are you talking about 4 pairs in stacking or 2 pairs?

2 pairs