Zero Distortion: Stacked Quad 57s

[JohnP]

Love the EMIA gear. Were you able to discern the contribution of the plasma tweeters to the system performance?

The plasma tweeters add a great deal to the overall sound. They add air and nuance, and with orchestral performances and good recordings, they reveal more of the hall ambience.

 

[JohnP]

Great write up of a very unique system. I see an Edgar seismic sub, is it hooked up? That sub supplied the best bass I've ever heard.

The Edgar sub was hooked up. It integrates well with the Quads. The sub has a filter that passes approximately 45Hz and below. The Quads have a high pass filter that passes approximately 45Hz and above.

 

[JohnP]

yes why I said I would like to listen to it without EQ as well

The system sounds much better with Dave’s EQ included, not close.

 

[JohnP]

Dave,
Did Bonzo report it accurately that you bypassed the use of the Acapella ION TW-S1 plasma super-tweeters’ internal PL-519 tube amplifiers in favor of your push-pull 300B to drive the modulator? Or are you simply just taking the high-level signal of the 300B amplifiers to drive the Acapella plasma tweeters’ internal PL-519 tube amplifiers?

I also cross my Acapella ION TW-1S plasma super-tweeters at 8.5KHz. I had the internal crossover upgraded in my units. The plasma super-tweeters add a lot to the sound and that is clearly evident when you switch them off.

What changes did you make to the internal crossovers in the plasma tweeters? Better capacitors?

 

[Carlos269]

What changes did you make to the internal crossovers in the plasma tweeters? Better capacitors?

Better capacitors.

 

[dave slagle]

To begin with, the Cello Audio Palette is a graphic equalizer, with low Q = large bandwidth around the center frequencies.

I think this is key. I would bet the bulk of the bad experiences with EQ's are with the 10 band units we all had in the past. In those, each band was an octave. In order to make this work steep high Q filters are needed and that is exactly the type of filter that has the 'all the king's horses' effect on the sound. Cutting the number of bands in half and allowing each band cover 2 octaves allows for simpler lower Q slopes which is a giant step in the 'right' direction.

dave

 

[Carlos269]

I think this is key. I would bet the bulk of the bad experiences with EQ's are with the 10 band units we all had in the past. In those, each band was an octave. In order to make this work steep high Q filters are needed and that is exactly the type of filter that has the 'all the king's horses' effect on the sound. Cutting the number of bands in half and allowing each band cover 2 octaves allows for simpler lower Q slopes which is a giant step in the 'right' direction.

dave

Yes that certainly is key to the Cello Audio Palette. You of course can achieve the same by reducing the “Q” in parametric equalizers to a minimum. The trade off being that the EQ is no longer surgical and becomes a wide brush.

 

[Audiohertz2]

Regardless of the approach, the effect is broad just less so or more so , not to mention the added noise and same sounding for all recordings unless , well unless EQ specific for each recording as being done currently , which is IMO the best way for ultimate expression, blah blah, blah

I’m positive this system sans EQ would be a none contender and pretty mighty with.


Regards

 

[Carlos269]

Regardless of the approach, the effect is broad just less so or more so , not to mention the added noise and same sounding for all recordings unless , well unless EQ specific for each recording as being done currently , which is IMO the best way for ultimate expression, blah blah, blah

I’m positive this system sans EQ would be a none contender and pretty mighty with.


Regards

EQ’ing each recording is an insane proposition, which is, from my OCD point of view, devoid of joy. The key is not to make adjustments per recording but to instead focus on the overall system presentation and to then let the individual tracks land where they land. Set and forget.

In my experience, you need both the broad strokes and surgical precision to achieve the desired results.

 

[dave slagle]

In my experience, you need both the broad strokes and surgical precision to achieve the desired results.

I'm with you on the broad strokes but in order to get surgical precision you either need to go digital or use steep slope filters, both of which are sonic deal breakers for me.

dave

 

[Carlos269]

I'm with you on the broad strokes but in order to get surgical precision you either need to go digital or use steep slope filters, both of which are sonic deal breakers for me.

dave

There are certain techniques and equipment, used by the great mastering engineers, to make strategic surgical precision adjustments without resorting to digital or steep filters.

 

[dave slagle]

There are certain techniques and equipment, used by the great mastering engineers, to make strategic surgical precision adjustments without resorting to digital or steep filters.

for example????

 

[Carlos269]

for example????

Making adjustments in the M/S domain.

 

[adrianywu]

Better capacitors.

I cross-over the Acapella tweeters at 7kHz. I am using an active crossover and therefore set the internal crossover of the tweeters to a very low frequency. I previously used a separate pair of 300B amps to drive the tweeters, but found an even better result using a pair of the 10W class A Nelson Pass amp camp mini. The HF response now remains fairly flat all the way to 50kHz. The tweeters are mated to a midrange horn using the Classic Audio 4" beryllium diaphragm field coil compression drivers. The tweeters have made the greatest difference compared to my previous experience with the JBL 075 and then the EV T350. There was a large gain in transparency and ambiance without the harshness of the metal diaphragm of the 075 and the "thickness" of the phenolic diaphragm of the T350.
I once heard Tim de Paravicini's stacked ESL57s with built in tube amps. He was driving the panels directly with the output tubes without transformers. He said the set up was illegal in the EU since it violated the safety rules, but he could do it for me as I lived in Hong Kong ! I didn't take up his offer.....

 

[Ovenmitt]

Very interesting thread and fantastic looking speakers. I’ve only heard Quad 57’s a couple of times and they weren’t stacked…. And they definitely didn’t have lovely EMIA touches. I bet these sound amazing!