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Pass Labs XA30.8 class A stereo amplifier Review, Part II

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Pass Labs XA30.8 Review, Part II: “Driving the Quad ESL”


I shared in Part I of the Pass Labs XA30.8 review that the reason for getting the stereo amplifier in was because I knew I had a pair of Wayne Picquet’s restored Quad ESL (the 57) coming in to listen to. So I was trying to figure out what amp I wanted to use with them. Years ago, when I owned these legendary speakers my two favorite amps to use with them were the Bedini 25/25 and even better, the original 25-watt Electrocompaniet; two Class A transistor amps. I was not able to find anyone who had either of these two to spare, so I begin to look for a current production amp that was a low-wattage Class A amp.

One of the things that you need to know about the original Quad ESL is that they are inefficient, have an almost impossible impedance curve to drive and can only handle about 30 watts without the panels being harmed. In my past experience tube amps, even Quad’s own amplifiers just can’t keep the mid-bass from getting out of control. So theses requirements left me with fewer choices than I had expected. The amp I settled on after much research was the Pass Labs XA30.8, so I requested one for review and the people at Pass Labs were nice enough to send me one.

So, I went over to my college audio-bud Ken Askew and picked up the Quad ESL as restored by Wayne Picquet. I should stop and thank Ken for making it possible for me to relive some really special audio memories. I had not had a pair of original Quad ESL in any of my listening rooms in a little over 30 years. So, the big question was would they sound as good as I remembered or had they become better and better in my mind over the years?

If you’re not familiar with the original Quad ESL, the patents were issued in 1954 and the first pair was sold in 1957. This is why they are sometimes called Quad 54 or 57, but that was never their name or model number. The ESL was the world´s first full-range electrostatic loudspeaker. In the 25 years of its production, 60,000 Quads were sold. The design was radical, incorporating panels sandwiching an ultra-thin sheet of PET film. They are 31 inches tall, 35.5 inches wide and10.5 inches wide at the bottom where the transformer and power supply are located. The electrostatic panels themselves are slightly curved, covered with metal mesh on each side and about 1.5 inches deep. The metal covers most often are black or bronze colored, but I have seen a rare pair of white and silver.

I listened to the Quads with four different amps: the Pass Labs XA30.8, the 47 Labs 4733 Midnight Blue Integrated Amp, the original Quad II mono blocks and the reissued Quad II mono blocks. I’ll talk about each of these in my Beatnik column of the Quads, but let me say that the XA30.8 was the hands down winner.

So, where was the XA30.8 better than those other amps? Well let’s start with the fact that the speakers sounded more powerful with it driving them. Yes, they seemed to play a little louder with the Pass Labs XA30.8 but this sense of power was there even at very low volumes. The next area where it was the better amp was in the bass. The Picquet Quads with all the amps had better bass than I remember my single Quads having, but with the XA30.8 they had better and more powerful bass than I remember even my stacked Quads having. They still won’t play as loud as a stacked Quad setup though. The bass on the Quads with the XA30.8 was deeper, revealed more air around and within bass instruments, was tighter than either of the tube amps.

The Pass Labs XA30.8 also walked away when it came to the way the Quads produced a correct soundstage. I surely never remember the Quads producing this kind of soundstage. It was room filling, wide and very deep. The way the Quads float an image in space is magical and this was far better with the XA30.8 than any of the other amps.

Voices are the forte of the original Quad ESL and again they sounded the most tonally correct with the XA30.8. This combination was truly lifelike on voices, both male and female. The midrange of the Quads with this amp was exceptional as long as you are happy with a mid-hall prospective; this is the prospective of the Quads not the XA30.8 which doesn’t sound mid-hall in the least with my Teresonic Ingenium XR Silver.

Violins, flutes, piccolos and cymbals all sounded very musical with the Pass Labs XA30.8 on the Quad. They never sounded strained or strident, but very sweet, natural and full of air. The top end was extended, open, airy and as I have mentioned in part one of this review it was well controlled. This top end is partially responsible for the fine detail and the tightly focused spatial presentation my system portrayed with this amp-speaker combination.


Specific Examples

Let’s start with Ella and Louis, on cut 2, “Isn’t This a Lovely Day,” this combo let me hear the beauty and lushness of Ella’s voice and the gravely sound of Satchmo’s voice. The voices sounded very alive and his trumpet had nice bite without ever getting out of control. This is the kind of music that the Quads are made for, and while in my system I listened to the whole album more than once. This was one of the albums where the original Quad II amps came close to the Pass Labs, but the XA30.8 held the bass line together better and had better PRaT than with the Quad IIs.

Elvis is Back is the album that has Elvis’ version of “Fever” on it. This is a cut you would think is not ideal for a single pair of Quad ESL. If you’re listening most of all for slam, tightness and power, then you are right. If instead your are listening for emotion, timbre and the feelings Elvis is trying to convey, then this combo is very good. Quad ESLs are never going to give you the slam many of us equate with this LP regardless of what amp you use, but the combo of the Pass Labs XA30.8 and the Quads really sounded great on this cut and on the rest of the LP. I had never heard the disk sound better.

In 1986, North Star Record release a recording of Arturo Delmoni playing the violin called, Songs My Mother Taught Me. I remember vividly the first time I heard this album. It was at a Dr. Norton’s house in Auburn, Alabama. On his Futterman amps driving a pair of Quad 63, I was simply blown away by the beauty of the violin and piano. Twenty-seven years later I acquired that very LP thanks to a friend in Auburn. Let me tell you this is another LP that lets you hear what Quads are all about and especially the original ESL. This LP sounded great on all four aforementioned amps, but the fullness without overhang that the Pass Labs XA30.8 played with was hands down the winner. The sound was organic, smooth, quick and the violin just floated in a cushion of air behind and above the speakers.



If you want to read more about the sound of the original Quad ESL and about the two versions of the Quad II mono blocks, keep a watch out for my upcoming review of the speakers that will cover these in more detail. To conclude this part of the review, of the many who can afford it like the ASR Emitter amp on the Quad ESLs, they cost nearly five time more than a Pass Labs XA30.8. No, I didn’t have the Quads when I reviewed the ASR Emitter but considering that I prefer the Pass Labs on my Teresonics leads me to think the Pass Labs XA30.8 should be as good or better and it surely is the better bargain. This amp and a pair of Wayne’s Quad ESL can be yours for around $10k. That’s amazing!

Shortly, there will be a third and final conclusion of this review. Part III will return to the sound of these amps in my reference system. There are some things I have learned with time that I feel I must share. Stay tuned!

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3 Responses to Pass Labs XA30.8 class A stereo amplifier Review, Part II

  1. Myron says:

    Hello again Jack. My potential deal on the Wavac ec-300b seems to have fallen through , hence I am now thinking of buying a new xa30.8 to drive my Orangutans ( when they arrive , still a week or so to go ) at your suggestion. My local dealer (who is very good and accommodating) does not have one on Dem unfortunately. So it’s kind of a case of buying blind ( or deaf in this case ). I wait with baited breath to hear your part three of the trilogy. It would be great for me if you could have a think about how they might match with the Orangs. My pet hate is sibilant high frequencys, particularly with Voice. Thanks for the insightful review.

  2. Mike says:

    Hi Jack,
    Please compare and contrast to the SIT 1.

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