I have owned several pairs of Naim NAP 135's over the years. All have been of the chrome bumper series which were manufactured from about 1984 to 1989. The olive facia 135's were manufacturered for several years after this, until Naim chose to change their lineup; gradually phasing out the aluminum extrusion casing of its earlier products.

I have always used Naim 135's with Naim control amplifiers and Naim Hicap power supplies, finding the latter to be the best match for extracting the most from these amp's.

Like many other owners of the Naim 135, this author has found the 135's sense of pace, rythym and timing to be unsurpassed. The 135's take the basic Naim sound and build on it, adding a wider and better defined sound stage, while exhibiting a significantly greater sense of control over all types of music.

If the 135's are anything, they are dynamic.

And they are not just for full range speakers like Naim's DBL's, either. The 135's sound great with quality vintage bookshelf speakers like the Rogers LS 3/5A, Harbeth HLP3 and Linn Kan.

I used the 135's to power a pair of 15 OHM Rogers LS 3/5A's back in the early 1990's and was amazed at how great this combination sounded, using a Naim CDI compact disc player as the front end, and a 72/Hicap as the control amplifier.

I have read a number of reviews regarding those who have used Naim 135's in active systems, using both 4 and 6 pack setups. The general consensus was that using 135's actively improved significantly on just the passive 135 setup, however, the cost of adding two to four additional 135's was prohibitive for many hi-fi enthusiasts.

And the 135's in passive mode are quite good on their own. In this author's experience, the 135 added to what the NAP 250 already had, by offering a better sense of over control of the music

While the NAP 135's were only rated at 5 watts more per channel than the NAP 250, this author also found that the 135's produced better bass, and did not run out of steam the way the 250 could with certain types of music when played at very loud volumes.

Of course, I am referring to other speakers used in my system at the time, and not the LS 3/5A's which never played particularly loud, however, imaged better than any conventional enclosed speaker I have ever used.

Even in the present day, I can't imagine any speaker other than an electrostatic
imaging better than an LS 3/5A, regardless of its cost.

As for the NAP 135, they can still be had for a resonable price, and should be on the short list of any hi-fi enthusiast who enjoys a sense of realism to their music, that is absent in most audio systems in the present day; albeit some very expensive ones.

Given that these amplifiers can range in age from about 20 to nearly 30 years old now, it's important that they are serviced at least every decade. The Naim NAP 135, like all Naim components of its vintage will need an expensive service to restore it to its original specifications, so this should be taken into consideration at the time of such a purchase.

Overall, the 135 is a beautifully constructed amplifier using top grade components, and its exemplary performance is characteristic of this.

I really enjoyed mine while I owned them.

These mono-blocks historically were probably best in their price range. Their sound is still relevant today. They are conservatively rated at 75 wpc, designed to play loud not as in Krell or Nelson Pass but plenty loud for playing any type of music in a medium size room.

It's the same amplification used in NAP-250 which is the stereo version. These will outperform NAP-250's. Each box gets its own transformer and power regulation. NAP250 does not offer fan ventilation and it's internal star ground wiring is not as well implemented as the 135's. Both 250 and 135's are very successful & well-proven designs, superb build quality, PRAT in spades and a very dynamic sound signature.

Depending on the speakers, pre-amp, improved external PSU's and source equipment they can become more transparent and engaging. I have used them with different components showing a more recessed sound stage or a more forward one. WIth improved source 135's can compete with much more expensive ampliifiers in today's market.

The chrome fascia units go back to the mid-80's. The olive fascia is 90's and early 00'. The 2001 and later units have the best sounding amplification boards. If you see a used pair for sale, grab them because for a substantial fee (not from Naim) they can be vastly improved.

Considering what they sell for these days I can't think of any weaknesses. These are designed for long-term use. I am still using my chrome fascia 135's I bought used from Gene Rubin in the early 90's, they have been powered up 24/7 since their purchase.

Unless you disable the protection circuitry inside (which will short the amp if you cross your speaker wires .. not recommended) it's best to use the Naim NAC5 speaker wire (min 10 feet) - inexpensive but a very good speaker wire that you can also use with non-Naim amplification.

This amplifier was designed over 15 years ago and is really at home within a high end Naim system.
You will need at least two to drive your speakers. I have gone active with my SBL's with 4. You can go to 6 but that's another story.

The cabinet is standard large Naim with a asingle on / off button and the backlit logo. unlike other naim amps it has a fan with a port on the back of the unit. It's very heavy weighing about 30lbs. Four of them are back breaking.

Although measured output is about 75 watts these amps can reach prodigious sound levels with no distortion at all.

How do they sound ?
They have rhythm. RWhat do i mean by that. They seem to pick up the beat of music in a wonderfully natural way and hold your attention. I get more involved in the performance or track with these amps than anything else I've ever heard.

The Krells' present great sound stages and are greta hifi amps. These if I can be so bold are great music amps. Those who criticise these amps claim they are shut in. I disagree.

They get better at louder volumes, should never be turned off and sound different when they are warmed up.

After about 8 years of owning them I can imagine no other amp in my system.

Blues, rock, techno, jazz, classical. I go from Mozart to lauryn Hill via John Coltrane and Crystal Method. It all sounds great.

Hope this is useful - Email me if you have questions
Robert

If the fundaments of musicality are about playing in tune and in time, the NAP 135 is faultless. No other amplifier I have heard lays so bare the intent of the musicians.

The amp has a tremendous start-stop ability and towering no-nonsense authority.

Brings out the best in loudspeakers that go right up to the wall and you need absolute control of driver excursion.

Other amps may finish off sweeter or more spacious but in my opinion, are limited to certain types of music.

I've been given to understand that the new NAP500 add some cosmetic lustre wihout compromising on the elements that the 135s do so well, and have even more power.

Rob is absolutely right!