3 channel amps in the UK?

[Sendu]

They play plenty loud in most rooms to me, but will not reach insane levels.

How do you protect yourself from going too loud? I don't actually intend to listen at THX level (probably 10dB down), but if everything can handle that much I'm at least assured it won't blow up at my own listening level.

Is there a way to judge if I would run in to loudness problems?

I had a quick read of the Quad ESL-2912 manual and didn't quite get their placement recommendation. At least 60cm from back wall (I presume they really mean front wall), but ideally 1/3 room length. Ok, I can manage that. But then they say angle toward listener, so the rear of the speaker is pointed at a side wall, yet they also say side wall distance doesn't matter, and close to a side wall is best!
Does it make sense because the positioning is to avoid low frequency standing waves, and those don't depend on which way the speakers are pointing?

 

[TLS Guy]

Does that mean I can get a Quad Artera Stereo and forget about all these other amp options?

At 140W it's more than enough to drive either the Martin Logans or Quad ESL to THX levels (assuming the speaker doesn't cut out...). And if speaker load won't disturb the amp, job done, nothing else to think about?

This amp also has a reasonable (compared to other options) cost of just £1400. At that price I could get 2 if I need a 3rd channel .
Is there a reason to consider anything else?

Yes, that is correct. The Quad current dumpers are the very best I know of. I think the best domestic amps you can own. I have used those current dumpers since the 1970s exclusively and never regretted it!

 

[PENG]

That Quad amp is no more powerful than the SR8012. I would stick with the good old 300/500 W class AB amps.

 

[Verdinut]

I was looking at the specs on that Artera Stereo amp. Quad only specify THD levels at 1 kHz. What are the real figures between 20-20 kHz? Also,, I am not impressed even with the published figures at 1 kHz! I don't think Peter Walker would have approved such spec publishing.

The QSC DCA 1622 Class AB amp has better specs and is probably not more expensive. I'm sure it wouldn't have problems driving electrostatic speakers (Ref. Post #30).

 

[AcuDefTechGuy]

That Quad amp is no more powerful than the SR8012. I would stick with the good old 300/500 W class AB amps.

I was looking at the specs on that Artera Stereo amp. Quad only specify THD levels at 1 kHz. What are the real figures between 20-20 kHz? Also,, I am not impressed even with the published figures at 1 kHz!

Yeah no kidding.

140W into 8 ohms @ 1% THD and 1kHz, not even 20Hz-20kHz. Kind of pathetic for an audiophile amp.

SNR is 115dBA, probably at full power and 1kHz just like everything else they spec.

Might as well go with an AVR from Denon, Marantz, or Yamaha.

 

[PENG]

I was looking at the specs on that Artera Stereo amp. Quad only specify THD levels at 1 kHz. What are the real figures between 20-20 kHz?

For 20-10 kHz, the specs are:
100 W @ 0.03% THD, so it is basically a 100-120 W amp, again, no more powerful than the SR8012.

No bench tests found for recent Quad amps, but the beloved 909 got a "FAILED" grade from the only test I could find.

http://www.milleraudioresearch.com/download2007/reports/yb07/quad_909.html

I would love to see one with well above average measurements.

 

[Sendu]

That Quad amp is no more powerful than the SR8012. I would stick with the good old 300/500 W class AB amps.

The concern isn't power. The SR8012 is already powerful enough on the face of it. The concern is there being a possibility of an unusual load. TLS Guy claims the current dumping approach means it can definitely handle the most difficult of electrostatic loads.

Can any of the other amps, merely by dint of having high wattage?

 

[PENG]

The concern isn't power. The SR8012 is already powerful enough on the face of it. The concern is there being a possibility of an unusual load. TLS Guy claims the current dumping approach means it can definitely handle the most difficult of electrostatic loads.

Can any of the other amps, merely by dint of having high wattage?

You cannot have "high" wattage unless you have high current and voltage. Yes it is possible to have very high voltage and low current and still give high power, but most well designed amps achieve high power by being capable of both high voltage and current.

So it is absolutely about power if the concern is difficult load. A 100 W rated Quad will be far more likely to have trouble driving speakers that have impedance dips (need high current) and peaks (need high voltage capability) as well, than most well designed 200 W/300 W rated amps such as the MCA 325 and A31 you mentioned.

The 909 is of the same current dumping design, and it failed the tests by the British lab. I posted the link to the measurements, did you read it?

Tested by the the same lab, the Denon AVR-3805 passed the 1 Ohm test.

 

[Sendu]

The 909 is of the same current dumping design, and it failed the tests by the British lab. I posted the link to the measurements, did you read it?

No, it asks for a password.

Anyway, does this mean what TLS Guy is saying has no merit?

 

[Verdinut]

You cannot have "high" wattage unless you have high current and voltage. Yes it is possible to have very high voltage and low current and still give high power, but most well designed amps achieve high power by being capable of both high voltage and current.

So it is absolutely about power if the concern is difficult load. A 100 W rated Quad will be far more likely to have trouble driving speakers that have impedance dips (need high current) and peaks (need high voltage capability) as well, than most well designed 200 W/300 W rated amps such as the MCA 325 and A31 you mentioned.

The 909 is of the same current dumping design, and it failed the tests by the British lab. I posted the link to the measurements, did you read it?

Tested by the the same lab, the Denon AVR-3805 passed the 1 Ohm test.

We know that the QSC DCA 1622 ia able to drive low impedance loads but would it also be capable of driving high capacitance electrostatics such as the Martin Logans which the OP wishes to acquire?

 

[PENG]

We know that the QSC DCA 1622 ia able to drive low impedance loads but would it also be capable of driving high capacitance electrostatics such as the Martin Logans which the OP wishes to acquire?

If I were to spend that much money on a pair of speakers, I would definitely pay attention to the manufacturer's recommendations. According to the manual for the CLX, it says the following:

"We recommend an amplifier with 100 to 200 watts per channel for most applications. Probably less would be adequate when used in home theater where a subwoofer is employed. Our designs will perform well with either a tube or transistorized amplifier, and will reveal the sonic character of either type. However, it is important that the amplifier be stable operating into varying impedance loads: an ideally stable amplifier will typically be able to deliver nearly twice its rated wattage into 4 Ohms and should gain increase into 2 Ohms."

It really depends on the speakers, some, such as the Quad ESL 2912 would likely have different requirements, but I do think in general the potential issues with amplifier stability driving ES speakers are probably a little overrated, as usual, more by hearsay than facts.

 

[PENG]

No, it asks for a password.

Anyway, does this mean what TLS Guy is saying has no merit?

You have to register to get a pass word I have no comments on what TLSG said about Quad amps.

 

[TLS Guy]

For 20-10 kHz, the specs are:
100 W @ 0.03% THD, so it is basically a 100-120 W amp, again, no more powerful than the SR8012.

No bench tests found for recent Quad amps, but the beloved 909 got a "FAILED" grade from the only test I could find.

http://www.milleraudioresearch.com/download2007/reports/yb07/quad_909.html

I would love to see one with well above average measurements.

The point is that those amps are very stable and reliable. They run cool even at power and sound wonderful. There are stable into all loads, and especially electrostatic speakers which present unique problems.

If you have Quad electrostatics, then the optimal power to drive them is a Quad amp.

I have had years of fantastic service from Quad electronics. It is for a good reason there amps command a premium on the used market. Owners don't regret their purchase. Stability and reliability are major attributes in an amp for me, as well as running cool at power without crossover distortion. You really have to own them to know their quality and I recommend them without reservation.

 

[PENG]

The point is that those amps are very stable and reliable. They run cool even at power and sound wonderful. There are stable into all loads, and especially electrostatic speakers which present unique problems.

If you have Quad electrostatics, then the optimal power to drive them is a Quad amp.

I have had years of fantastic service from Quad electronics. It is for a good reason there amps command a premium on the used market. Owners don't regret their purchase. Stability and reliability are major attributes in an amp for me, as well as running cool at power without crossover distortion. You really have to own them to know their quality and I recommend them without reservation.

If I remember right, I mentioned to you before that available measurements on the Quad 909 (the one you seem to think highly off in the past) showed it did not do all that well with low impedance loads. Find me one Quad amp that measured well with 4 and 2 Ohms load and I may buy one from the used market to try it out.

 

[TLS Guy]

If I remember right, I mentioned to you before that available measurements on the Quad 909 (the one you seem to think highly off in the past) showed it did not do all that well with low impedance loads. Find me one Quad amp that measured well with 4 and 2 Ohms load and I may buy one from the used market to try it out.

When I get my shop set up again, I will get you recent measurements on a 909. I have never tested one with a 2 ohm load. They do very well at four ohm. I have no speakers that are 2 ohm. Apart from some sub drivers, any complete speaker that has an impedance of 2 ohms or less is highly suspect and almost certainly incompetently designed. I would never design a speaker that did that. My crossover designs are competent and designed not to stress amps.

There are just far too many commercial speakers around whose designs are totally incompetent, with Polk being very high on my list. I just don't pull that sort of nonsense. I do to 4 ohm designs with favorable impedance and phase curves as you know. Very few drivers have a DC resistance down to 2 ohms, so any speakers that do dip like that are almost certainly duds.

 

[PENG]

When I get my shop set up again, I will get you recent measurements on a 909. I have never tested one with a 2 ohm load. They do very well at four ohm. I have no speakers that are 2 ohm. Apart from some sub drivers, any complete speaker that has an impedance of 2 ohms or less is highly suspect and almost certainly incompetently designed. I would never design a speaker that did that. My crossover designs are competent and designed not to stress amps.

There are just far too many commercial speakers around whose designs are totally incompetent, with Polk being very high on my list. I just don't pull that sort of nonsense. I do to 4 ohm designs with favorable impedance and phase curves as you know. Very few drivers have a DC resistance down to 2 ohms, so any speakers that do dip like that are almost certainly duds.

Thanks, please test for high impedance too, I think some Quad ESLs have peaks higher than 20 ohms. It seems ironic though, as they also want protection against voltage higher than 40 V. In my opinion, ES speakers are like tube amps, not really needed for true HiFi sound seekers any more because of the availability of much better alternatives now, and I have the feeling you may even agree with me on this.

 

[TLS Guy]

Thanks, please test for high impedance too, I think some Quad ESLs have peaks higher than 20 ohms. It seems ironic though, as they also want protection against voltage higher than 40 V. In my opinion, ES speakers are like tube amps, not really needed for true HiFi sound seekers any more because of the availability of much better alternatives now, and I have the feeling you may even agree with me on this.

I do agree with you on this. And Peter Walker would have agreed with you on this. Peter's primary motivation was to produce tonally accurate transparent reproducers to hold other designer's feet to the fire. He must be given the credit for producing the world's first really tonally accurate speaker. The original Quad ES sent shock waves through the industry world wide. Peter was the first to admit that the limitation of electrostatics was power band response except in the high frequencies and the fact that electrostatic speakers do not mate well with moving coil drivers. That is the biggest problem for speakers like MLs.

Peter's hope was, and fulfilled, was that it would lead to better moving coil speaker designs, which it has and did, since his first electrostatic appeared.

I find the greatest compliment to my speakers is when people ask if the narrow panels on my speakers are electrostatic panels, and that is often. That is because I have gone out of my way to produce the uncolored detail and transparency of electrostatic loudspeakers. In that I think I am faithful to Peter's primary goal.

 

[Verdinut]

If I were to spend that much money on a pair of speakers, I would definitely pay attention to the manufacturer's recommendations. According to the manual for the CLX, it says the following:

"We recommend an amplifier with 100 to 200 watts per channel for most applications. Probably less would be adequate when used in home theater where a subwoofer is employed. Our designs will perform well with either a tube or transistorized amplifier, and will reveal the sonic character of either type. However, it is important that the amplifier be stable operating into varying impedance loads: an ideally stable amplifier will typically be able to deliver nearly twice its rated wattage into 4 Ohms and should gain increase into 2 Ohms."

From the manufacturer's website, for the CLX Art speaker, the recommended wattage/ch is from 20 to 450 watts. Maybe the OP should consider the QSC DCA 1622 pro amp as a suitable option. This product wont have problems driving the ML electrostatics. As stated in post #30 above, there are two QSC dealers in UK. Maybe he could rent or borrow one for trying out.

 

[Sendu]

From the manufacturer's website, for the CLX Art speaker, the recommended wattage/ch is from 20 to 450 watts. Maybe the OP should consider the QSC DCA 1622 pro amp as a suitable option. This product wont have problems driving the ML electrostatics. As stated in post #30 above, there are two QSC dealers in UK. Maybe he could rent or borrow one for trying out.

Thanks for the suggestion, but a rack mount device with fans isn't for me. I also want something I can demo and get from a typical hi-fi store with wide availability.

 

[Verdinut]

For the CLX Art, while they mention a recommended wattage from 20 to 450 watts, they indicate in their manual a power rating of 225 watts.
So I figure that a DCA 1622 could be used but the DCA 1222 should most likely be sufficient. The 1622 costs about 50% more than the 1222 but has the advantage of having more headroom and being somehow more future proof.