Stereophile review of restored Chrome Bumper system

Art Dudley wrote a review of my chrome bumper system (32.5/hicap/250) using his Quad ESL speakers and Garrard 301 turntable.

Here’s the link for those who are interested:

The premise of the review was to see what a vintage system is capable of when it gets restored to the absolute peak of its abilities by gurus like Chris West at AV Options, cost no object. Art reaches his own favorable conclusion in the context of his particular source/speakers, which I have never heard. In the context of my own source/speakers (Rega Apollo/Chord Qutest/SL interconnect and ATC HTS 7) the sound quality is stunning in absolute terms and the total cost of ownership is very favorable relative to brand new gear.

I originally put this system together because I got on an olive kick a few years ago, which turned into a chrome bumper kick. After cycling through ~25 Naim pieces, having some restored and some not, and hearing the impact of restoration as well as discovering the importance of synergy over simply going with the most expensive box I could afford in each part of the chain, I wanted to assemble a classic combination with proven synergy and max it out.

When I got on this kick I did not appreciate the importance of service/restoration. I assumed I would cobble together a 52/135 or 82/250 system on the cheap and that would be that. Well, I acquired a late 1990s olive 250 and after a while I couldn’t deny that it didn’t live up to the hype. I did not understand why people raved about the 250. I retreated to a 140, had it serviced to the max, and wow what an improvement (to my ears) over the 250. Fast forward past several other amps I tried to the fully restored chrome bumper 250 - it had an agility and groove that the unserviced olive 250 couldn’t come close to matching. Now I got why people loved the 250. I landed on the 32.5/hicap/250 system after leaning heavily on AV Options and old forum discussions for advice about which combination to assemble.

I think when buying vintage gear it is better to buy less “box” than you budgeted for, and invest the difference in a legitimate restoration. Between the cost of the gear itself, new SNAIC and DIN/XLR, and the cost of the restoration, I am probably in it for $6-7k, which is about the cost of buying a used 52/135 set, and less than buying a brand new 250 DR. I am fairly confident this system is better in almost every aspect than the average random unserviced 52/135 you could cobble together. There are probably unserviced 52/135 combos that sound better, but it’s in the hands of the stereo gods as to whether you get lucky with a good unit. You can’t tell just by looking at the pics in the listings. My olive 250 was immaculate but it was just not very good.

Also, I would stick to the tried and true combinations rather than venturing into mullet territory. The classic combos are classic for a reason. I would even try to maintain “purity” in terms of 100% olive or 100% chrome bumper. I had a fully restored 72 and did extensive A/B listening vs. the 32.5. The 72 is truly amazing and in a 1x1 matchup it’s the better preamp. It’s no accident there are three DBL systems I know of that use a 72. However, the 32.5 (at least to my ears) had a certain raw synergy with the CB hicap and 250 that the 72 lacked. Synergy is what gives you that last bit of magic from the music.

One thing in the review I would quibble with is the conclusion that the Naim/Quad combination is lousy at scale. I suspect that is down to the Quads. I ran the 32.5/hicap/250 on my old Allaes (my Dad has them now) and they would blow your hair back with a wall of sound. I had to switch to ATCs because we moved to a new house where the living room is not big enough to accommodate floor standers. I can’t use stand mounts because I have a 1 year old.

It’s remarkable that Naim made products like this that have stood the test of time in terms of sound quality, build quality, and aesthetics. Great credit also goes to AVO for their ability to restore the gear to better than factory new condition while preserving Julian’s vision for what music in the home should be capable of.

There is one other important conclusion from my journey, although it’s one that the review was not intended to address. There is absolutely nothing like a system with a Naim source, Naim amps and Naim speakers. I briefly ran the CB system with a CDX/XPS and Allaes before we moved.

The final frontier - if I ever have the space and the courage - is to get a pair of SL2s and go active with another CB 250. If music is the drug, a system like that might deliver the overdose!


Thanks for sharing the link. I love Dudley’s writing style…his Nait 2 article from a few years ago was a fun read…

1 Like

Thanks snarfy - I’d not read that review before.

And enjoyed reading about your experiences. 25 bits of Naim kit is quite a journey.

Agree with you about the synergy, both pre/power and speakers. In addition to Naim speakers offering great synergy, I’d add first-gen Linn speakers with bolt down or CB gear. Kan 1s into my CB 32/SNAPS/250 sounds really well balanced - within the limitations of the tiny Kan of course.

I also own serviced 32.5 and Hicap so tempted to try them again based on your enthusiasm.

1 Like

I’m glad you enjoyed it!

I lost a decent amount of money cycling through all those boxes - the shipping companies always get their piece even if you don’t lose money on the boxes - but made a lot of unexpected discoveries, such as my clear preference for the 72 over the 82, as well as the genius of the Nait 2. I had to sell my olive Nait 2 and and go through some other products to realize just how unique its sound is. I eventually found a CB Nait 2 and had it restored.

I would love to hear a pair of Kans in good condition. Never tried it because of the fear (perhaps misinformed?) that they can’t be restored.

What are your sources?

1 Like

Tell me about it, but like you I’ve also learned a lot which wouldn’t have been possible otherwise.

Still think Nait 2, and even more so the Nait 1, are the most coherent amps I’ve yet to hear from any manufacturer. They also preserve the rhythmic qualities of music better than anything else I’ve heard. Shame they struggle so much with some rock music, unless you find the most efficient of speakers like the big Audio Notes.

Yes, they are extremely difficult to restore and I wouldn’t bother since there were so many pairs made. I’ve had several pairs and all but one pair worked very well - one (Kan II) speaker was distorting. The only issue I’ve come across that could be age related (although I suspect not) is that the early Kan 1s sound a bit strange at a certain frequency, perhaps fuelling the reputation for sounding sqwarky. Not sure if this was always the case or that the caps have drifted. Later Kan 1s with B110B driver or Kan II sound more balanced, but less musical. I’ve settled for the more balanced sound cos they are still very coherent and engaging and Kan timing is like no other speaker I’ve heard - not heard SBL/SL2. The only pair I couldn’t get on with were the final Kan II variant with kustone filling - they sounded quite boring to me.

I should add that Kans struggle with some rock music just like the Nait. The 250 helps minimise this though.

Just an LP12.

CB 32.5/Hi/250 playing now!

Back in 1980’s I think I heard active Kans at the Sound Organisation. (Perhaps someone else can recall Haimish and Roger doing this?) This was with 135s but can’t recall the preamp. I always wanted to try activating a pair, and I was told that it’s a tricky job but not impossible.
I bought the Kans but have never taken it further (they are at the end of a bedroom system with a Unitiqute - they are set at mezzanine level in the bathroom facing down into the bedroom and they certainly sound better than the ceiling mounted speakers in the other bedroom).

Couple of years ago I activated a pair of Kans for my brother. Pretty straight forward. At the time we replaced the tweeters. Can’t recall if we also replaced the bass drivers. I do know both drivers were readily available.
He powers them with a LP12/72/hicap/hicap/snaxo/2×180s and they do sound rather good.


1 Like

Not necessarily a need to activate Kans - there was an active (aktiv?!) version available. I once heard a pair on the end of a 92 and 90s with the slimline all in one crossover - IXO I think. Can’t now recall whether they were I or IIs

As others have said, it’s not hard to make Kans active. I had both passive and active. Active rules. I had a fetish for the half size CB, so ended up with 42, 2 x SNAPS, Naxo and 2 x 110s. Changed the knobs on the SNAPS to the big ones. Almost committed to a NAT to up the box count.
So a visual and aural feast. Of course these days I would go 250s, but damn it was sensational. Front end was a LP12/Ittok/Karma.

1 Like

If I were to attempt it now, I would be tempted to go retro. But that would mean resurrecting my LPs. The question is how far back can I go vintage Naim and still use a digital source?

And yes there were factory done active Kans. I was happy to activate passive ones, as back then lunatics, (like me), were ripping out crossovers and making them outboard mounted. So why not muck around with active?
I have also had passive/Active Isobariks, (bolt down 250s), and passive/Active Sara’s, (CB 160s).

I don’t have an LP12 anymore. Can’t see the problem with running a streamer like a NDX or NDX2 into a 32 or 42. There were the jumper boards to swap out the phono boards and make them line level, if you’re stuck for inputs. BTW use the tuner or aux din inputs for the streamer.
You would lose remote volume control but such is life.

That sounds like a good option so thanks for the advice.
My main system is a 52 so used to no remote control as far as the volume and changing inputs is concerned (it’s hidden away in the stair lobby behind a corner and door).

Warmed up now and all the hifi stuff is better, as expected, so more punch, definition and top-end refinement. Some tracks benefit more than others as it has more ‘swagger’. Remains well balanced with Kan 1s.

I still think it’s less coherent than 32/SNAPS/250 and therefore slightly more laboured, but it was already much less musically flowing than Nait or 12/160 so I’m gonna leave it as is for the week. No perfect world in this hifi game.

1 Like

If you really want to overdose on “hifi” see if you can round up a Krell KSA50/KSL2 to drive the Kans. Bass! Treble! Hifi! Everything!. Just not very coherent. But really impressive.
The power amp was pretty amazing with the Kans. Just needed a less glitzy pre. But then you spoil the look.
Whereas with CB Naim you get looks and music. Not sure if I agree with your assessment of 32.5/Hicap being less coherent than a 32/SNAPS, having cycled back and forth many times, (part of the fun of being a dealer at the time). I also had an early 12 bolt down fronting my first active system. The step up to a 32 bolt down was pretty worthwhile. But it was a long time ago. Today our reference points are considerably different.

There can be big variance from one example to the next, especially after so much time.

I have a NAC32.5 that is much the poorest sounding of all my shoe-box pre-amps, even though it has been serviced on at least two occasions in the past. Another NAC32.5 I have sounds like a different pre-amp entirely (it’s wonderful), although it does now sport NA729 boards, so you could argue that it is…

Hmmm, didn’t realize you could graft later series boards into a 32.5. I do wonder how far you could take the old stuff. Volume pot, upspecified capacitors? Muck around with the rubber feet.
I have some N-sats. If I had a fantasy it would be to activate with 42/110s, and have some fun. The start of this thread referencing getting your old CB fully refurbished and then some has got me thinking.

It was a factory upgrade for NAC32.5s. Initially they were called NA329s but at some point during NAC72 production it must have decided just to use the one board type, so NA729s were made available for NAC32.5s. Being daughter boards, they just slot in place.

I have a factory upgraded NAC12 that started out as a very early unit (single board), and was then internally updated to knife edge daughter board 2nd version. Later still it had the phono input updated to pins to take NA3xx phono boards, and finally the volume post was upgraded to an ALPS Blue. It’s a nice sounding pre-amp…

Of course, these are all official factory mods/upgrades. Unofficial mods fall outside of forum AUP…

In Art’s Nait review, he says “West sends off the original Holden & Fisher mains transformer and its wiring loom for a deep-cryo treatment” so there’s always that as well. Of course it might make things worse for all we know.

Does that count as a non-Naim mod or just a very enthusiastic clean? I wonder if Naim servicing ever looked into something like this.

Thanks Richard. That’s useful to know. I moved the x5 serviced cards from the 32 to the 32.5 this morning. Would be helpful to know if you were using the same or different boards when comparing 32.5 units?