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Pass Labs X260.5 Class AB monoblock amplifiers review

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I have heard so many wonderful things about the products from Pass Labs, that I was very intrigued, to say the least. I have heard from many sources, that their products sound excellent, are very well designed, are beautifully built and that they are extremely reliable. I’ve also heard great things about the company’s main man, Nelson Pass. Things like, he’s an excellent transistor designer, to he is very humble, to he’s a very giving man – he contributes some of his designs and publishes them in public forums. I have also read somewhere, that many feel that he is “one of the best audio designers still living”. This is very high praise for both the Pass Labs products, as well as the founder, Nelson Pass. The facts seem to support these statements, as Nelson has received several patents for his circuit and amplifier designs. He has designed products for Threshold, for other companies like Nakamichi, well as starting Pass Labs, many years ago.

I know two audiophiles in Toronto that have Pass Labs equipment and both of these people, just love their amplifiers and preamps. Up until the time that I received these monoblocks for review, I have not really had very much experience with Pass Labs products. I’ve heard them here and there, at a dealer here in Toronto, and also at a couple of audio shows, but I haven’t really heard any Pass Labs equipment for longer than about 5 to 10 minutes. The systems that I did hear them in for brief periods of time, sounded very good.

So like I said, I was very intrigued about Pass Labs enough, that I called our esteemed publisher and asked if I can review the X260.5 monoblock amplifiers. I have been using monoblock amplifiers for several years now, and I prefer their lower noise floor, better isolation, and the fact that, with monoblocks, you can place the amps closer to the speakers, therefore reducing the length of the speaker cables between the amplifier and speaker. So after speaking with Constantine, in a very short period of time I received a pair of these monoblocks, and I put them through their paces.

When I received the Pass Labs X260.5 monoblocks, I noticed that they were packaged very well and I received them in excellent condition. When I took them out of the box, I started to admire the amplifiers’ sheer beauty. They looked very well put together, the chassis was sturdy and strong (heavy as well), and aesthetically, they also were very pleasing to the eye. The front panel was silver in color, looked like it was made from aluminum and it was very thick. In the center of this front panel, there was a rather large-ish power meter which was backlit in soft blue lighting, very elegant indeed. Just below this meter, is an ON-OFF switch, which switches the amplifier on from stand-by mode. The thickness of the front panel was also larger than most products that I have seen and have come across. It is also very elaborate and is machined very well. All this gave me a feeling of “pride of ownership”. To the left and right side of the chassis are the heatsink fins. The fins extend outwards and upwards from the center of the amp, at roughly a 45° angle, which is a nice aesthetic change from the more traditional vertical fins that extend outward at 90° from the chassis.

The rear panel is very well laid out. Towards the bottom there is an 15-amp IEC receptacle, as well as the master on-off power switch. There is also a 12V trigger for automatically turning the amp on. Two sets of binding post are available for the people that bi-wire their loudspeakers. Personally I am a mono-wire type of guy. Towards the bottom of the panel, there is a fuse-holder which allows one to change the fuse without opening up the inside of the chassis, a very convenient and useful feature, if the fuse ever blows. A very unusual item was a ground post, which is very unique in a power amplifier. I also noticed that the rubber feet at the bottom of the chassis were rather large, having a large diameter and taller than most rubber feet that I see on power amplifiers.

There are no carrying handles on the front panel, but there are two on the rear panel. I thought this was a great design choice, due to the fact that the front panel looks very elegant without the handles, yet there are handles at the rear panel which makes it extremely easy to move this rather heavy amplifier around. It is also easier to remove the amplifier out of the box, as a result of these handles.

Both RCA, as well as XLR inputs, are accommodated at the rear panel. One of the exceptionally nice things about these XLR and RCA inputs is that there is no toggle-switch there, to switch between the RCA and XLR connectors. I believe this is a great benefit, because it eliminates one switch from the circuit, the part of the circuit which is at the very input of the amplifier. One of the worst places you can put it in. If you have done as much modifying of equipment as I have, you soon realize that you can hear a switch in the circuit very easily. Just like you can hear the difference between different input connectors, binding posts, different wires, even different solders. Most switches, even in high-quality high-priced equipment are vastly inferior. It is really great that Pass Labs has figured a way to switch from the XLR to the RCA inputs without the need of such a switch. Very impressive. A unique feature of the XLR is that, if you choose to use the RCA input, you have to put a U-shaped jumper in the XLR input socket. If you use the XLR input, as I do, you need do nothing other than to simply plug the XLR connector in the socket. This review was done with the XLR balanced connection exclusively.

The Pass Labs X260.5 amplifier produces 260 watts into 8 ohms and 520 watts into 4 ohms, with the first 5 watts being in Class A. The amplifier produces 26 dB of gain. If you go on the Pass Labs website, you will see that the model X260.5 is part of what they call the .5 series. In addition to the .5 series, there are also the newer .8 series, both are available at this time. The amplifier is built using JFET transistors for the front end, and MOSFET at the output stage. The amplifier runs hot at the heatsinks, not overly hot mind you, but it does run hot. If you put your fingers on the cooling fins, you can leave them there for approximately 3 to 6 seconds, before having to move your fingers.

I removed the top cover to see the interior of the Pass Labs X260.5 amplifier. The first thing I noticed, is that there was very little wiring throughout the amplifier and what wiring there was, was short in length. The wires were connected to the circuit boards using solder in all the connections that I noticed. This is excellent. Most manufacturers use these cheap tin/steel “push-on” connectors, which make a terrible connection and sound like garbage. Yes, I have experimented and the push-on connectors do sound like that. And these cheap connectors are used in even very high-priced audio equipment. This, to me, is inexcusable. Way to go Pass Labs, for not using them.

At the front of the Pass Labs X260.5, there is a good sized toroidal transformer. Most amplifiers usually have a few large storage capacitors in their power supply. In this amp, there are smaller capacitors, but there are many of them. The circuit boards are located towards the rear of the amplifier, right next to the rear panel and the input and output connectors. Overall, the construction is top-notch, the amplifier is extremely well-made. The circuit boards were also very well laid out and very neatly built. True to what I’ve heard about Pass Labs products, these amplifiers worked perfectly, with no muss, no fuss, and no surprises. Just like the Pass Labs literature states, “They also possess greater reliability. These amplifiers are harder to break and easier to repair, if they ever do.”

To illustrate how durable these amps are, let me give you an example. Now this procedure is something that, I do not recommend that you do. The Pass Labs X260.5’s are so well-made and well-designed that when I removed or inserted my XLR interconnect cable into the XLR input, while the amp was on, I heard nothing, there were no clicks, no thuds, nothing, silent as a tomb. In view of all the above, it sure felt like these amplifiers are well-designed, well-made, and felt like they were bulletproof.

2 Responses to Pass Labs X260.5 Class AB monoblock amplifiers review


  1. Hans-Peter Schmid says:

    As the owner of a Pass X-350 that I bought in 2003 I can only agree that Pass’ products are made for eternity. Twelve years of trouble free daily use and a sound that I still enjoy as much as on the first day.

    My amp does react to the support I place it on. Mine sits on a sturdy Copulare rack isolated by stacked pairs of Aurios feet. This arrangement opened up the top end and gave me a more relaxed sound from top to bottom, or bottom to top – I have a hard time placing the amp in either camp in the
    context of my system.

  2. becka says:

    a review of the .5 series is so late and irrelevant now that the .8 series is out…. how about catch up?

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