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Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-10 21:28
by Charlie1
Anyone got experience comparing these two?

Also, any thoughts on 32 vs 32.5?

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-12 22:10
by pdcman
A can of worms this one!
I preferred the 32.5 due to increased clarity and openness. Others preferred the 32 due to perceived musicality.
I also preferred the 160 to the 250. I could never get on with the ‘rubber band’ like bass on the 250; never seemed fully in control to me.
You will get others who would go for the other options. You must listen for yourself I’m afraid, it’s the only way to be sure.

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-12 23:24
by Charlie1
Thanks pdcman. I have a serviced 32.5 (which I'm yet to hear) but now curious about the 32.

I also have an unserviced 12S and hope to compare them using an unserviced BD 160 shortly (all being well).

I somehow doubt I will find either as musically coherent as the Nait 1 but you never know. I briefly heard a modified 160 with Kan 1s and that was a nice pairing.

So did you end up with 32.6/160 yourself at any point?

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-15 13:32
by PerFlemming
I believe 32 & 32.5 is the same preamp

NAC 32.5 changed to dual rail for Hicap use

Many original 32 were simply upgraded to 32.5 status at a later stage

I once had an old 32 which was changed to 32.5, assumely by Naim.

They are great preamplifiers, forerunner to NAC 72

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-15 17:07
by anthony

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-19 09:30
by Briain

Back in the day, I ran a 42 and 250, then I replaced the 42 with a 12s as though - from memory; it was a long time ago - the 42 sounded a little 'smoother' and more refined, I thought the 12s was the more musical of the two. At the time, one of the 'standard tricks' that we all performed was to cut short pieces from scrap Linn arm cables (we had a cupboard full of traded in Basic arms - as in the original LVV basic with the detachable head-shell - so we had loads of spare cables for them) and solder one end to the back of the RCA input sockets and the other directly to the MC input PCB's (thus no longer 'dragging' the signal through the motherboard and then the connectors from motherboard to the MC daughter-boards. I did think about a 32, but to me, looking inside it appeared to pretty much like 12s boards in a larger and nicer box (I never directly compared them, but of the other chaps from the shop also used a 12s - also with a 250 and Isobariks - had compared them and seemed in no rush to change anything) so I just stuck with the 12s and spent the rest of my money on music and booze.

Of course, being me I also removed the balance control (replacing it with fixed resistors; I always meant to try comparing it without the fixed resistors, but I never got around to it) and the plan was to then build a separate regulator stage for each daughter-board (and slightly increase the DC input to give me the required headroom for double-regulation) but then the LK1 came out and I preferred the mid-range of the Linn unit (it separated out instruments a little better). Another reason I moved to the Linn amps was that I wanted to go active and at that time, the price of 3 x LK2 power amps wasn't too far removed from the price of a single Naim 250 (so I ended up activating my Isobariks with LK2's).

A few years after that, one of my friends was looking to update his system the owner of our shop (who I still occasionally work with and who regularly visits for coffee) had just refurbished an original Naim 250 (the one with the bolted on side and top panels, rather than the one piece extruded sleeve) so we sold him that at a 'mates rates' price (it was actually closer to being the bargain of the century). That model had quite a large quantity of internal wiring (the power output and regulator transistors were mounted on the back panel and wired back to the amp and regulator boards, respectively) and I always wondered what sorts of sonic differences it made by eliminating most of that wiring (the newer ones - with the single extruded sleeve with bright alloy edges - had the transistors soldered directly onto the power amp and regulator boards and used U shaped alloy heat conducting brackets to shunt heat to the base of the sleeve) but sadly, I never had the chance to compare the two vintages. That said, when I installed it at my friends house (at the same time fitting a black Ittok to his LP12) the system certainly sounded mighty darned tuneful, and then some (he had speakers that I was unfamiliar with; one of the Castle models, from memory).

I'm decades out of date, but it would be really very interesting to hear these older Naim power amps (well, ones that have been refurbished) against the current power amps (Linn Lejonklou and Naim).


PS Somewhere, I have an ancient 'RCA Semiconductors' book and inside it is [very nearly] the circuit that Naim used for the 110, 160 & 250 power amp boards. Pretty much the only difference being that the RCA one had a Zobel network on the output stage (to make it stable) whereas Naim omitted it (for sound quality reasons) relying on the inductance of the speaker cables to do the job (likely why Naim produced the spaced pair speaker cables why Naim amps didn't sound great with some types of speakers, likely because they presented higher capacitance loads, I'd wager).

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-19 10:56
by Charlie1
Cheers Briain - an interesting read. Time flies I guess. Must have been fun - they were certainly the days to work in a HiFi shop.

And thanks for the link Tony.

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-19 12:57
by Briain
Hi Charlie1

Yes, they were fantastic times to work in a Hi-Fi shop. One side of our stock room was pretty much entirely taken up with piles of Rega turntables, NAD amplifiers (and my favourite £100 MS100 speakers; my enthusiasm for them seemed to infect customers) then the other side was heaped with Linn, Naim, Nyteck, Kef AR speakers and A&R A60s (we had other fun stuff on demo and in stock - Syrinx and Merridian, for just two examples - but the above were the ones we had multiples of within our stock room). Upstairs was a record shop (with Isbariks playing at one end) and downstairs was both a display area and a single speaker demo room (and a catacomb of cellar space with our office, store rooms and workshop at the end; it was actually located outside our ground floor footprint and extended under a Chinese restaurant). I loved demonstrating the transition from Dual CS505 through the Rega's and up to the LP12, but when CD players came out (and when new customers wanted only a CD based system) I could never quite not develop the enthusiasm to demo them (to me, they were all equally crap, so it seemed rather pointless)! :-) Actually, thinking back the problem was that we had pre-selected the best of the bunch, so the trouble was that we had no seriously mega-crap CD players (which most of them were, back in those days) to demonstrate that our demo models were only moderately crap (actually, some almost sounded quite 'nice', that was until you dug out a turntable, your feet started tapping and your smile returned).

Bri :)

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-19 13:31
by Charlie1
Sad that CD changed everything (for the worse in many ways) but hey, it's more convienient.

I think my mate has a black pair of those MS100s he bought new back in the mid 80s. If not, they are very similar. He's only last month 'upgraded' to Keilidhs - £150 from down the road - jammy bugger - and they sound great too. He won't let go of the MS pair though.

What was the A60 like? Sometimes tempted to get one just to help complete my audio equipment history lesson.

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-19 14:13
by Spannko
Thanks for a great read, Bri :o)

I also remember comparing a 12s against the newly released 52/Super Cap with a 250 into Isobariks, and I thought that the 12s was much more musical too. It’s a great little pre-amp, as charlie1 has discovered!

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-19 15:40
by anthony
I had isobarik with a 32 hi cap and 135s. The 32.5 was better but I think it needed the hi cap. Like Briain, I went to an lk1 which was more musical and had a brilliant Phono stage. It was the first time I made a profit to upgrade.

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-20 16:53
by Briain
We were on the somewhat extreme edge of things - in fact, I believe one of my colleagues was the first to proclaim single speaker demonstration rooms as being essential - in the sense that we often demonstrated an LP12, Ittok Asak, Naim 32, 250 feeding AR18 speakers (that little lot really rocked) and we often demonstrated that any half-decent speaker would sound great if fed by such a great system. We actually had quite a few £100(ish) entry level speakers (AR18, Kef, MS100, etc) and though the AR18 sounded great with a few £K of stuff driving them, I was not convinced that they always worked quite so harmoniously with entry level systems. When I tried the MS100 with things like a Rega+NAD system (or even something like a Marantz CD+NAD amp system) they sounded astonishingly good (not just musically, but somehow just very pleasing to listen to; the whole system exceeded the sum of its parts, if you know what I mean) and just about every system I sold was terminated with a pair of MS100s (as I say, I did demonstrate others, but perhaps my enthusiasm was more infectious than it ought to have been). I've not heard a pair for many decades and it would be great fun to do so again (with my 345+350 biased ears) just to remind me what the do sound like (perhaps I'd now be massively disappointed, of course).

The A60 was very smooth and musical sounding amplifier and I was just about to buy one, but then Richard brought out the Nytech CA252 integrated amp and I loved the sound of it (it sounded faster and thus it was a little more fun to listen to). In fact, I remember comparing both and when switching to the A60 it sounded smoother and more 'refined' but also a little boring, by comparison to the CA252. I think I must have one of the first ones made and a few months after buying it, I made a massive power supply for it (it was in a 3U high 19 inch rack type case, so about the size of a modest suitcase) and that was when I procured my 12s (to replace the Nytech's internal preamp). A couple of years back, I put the Nytech back together (using its internal supply) and it still worked, but at some stage I'll refurbish it (change the capacitors). I've no current use for it, but it would just be cool to keep it going.

Amusingly, one of my friends had also bought an LP12 at that time and where I moved from LVV to Ittok, he bought a second hand Syrinx PU2 (at that stage, we were both using ADC Phase 111 cartridges with the stylus tray superglued into the cartridge, which was a standard shop mod that we did, and when they stopped making them, we bought the entire stock - we rather liked the sound of them - so when one went 'blunt', we simply supplied the customer another entire new 'glued' cartridge). Sadly, his PU2 developed a fault (wiring issue) so we arranged for him to take it round to Syrinx for them to take a look. Scott Strachan briefly looked at it, proclaimed that it was f****d, lobbed it into a pile of scrap and then gave him a brand new one; very cool. Anyhow, my friend was using a NAD 3020 and like I did for my Nytech, he built a monstrous sized power supply for it (his sister patiently plated the 3 DC wires for him; she was used to doing it with her hair and she made a wonderful job of it, and of course, she did so for a good bit less than Kimber would have charge for such a cool work of wiring art) and as with my Nytech, the sonic improvement was well worth the effort.

Inspired by DMC's battery preamp idea, my next trick was to try running my 12s from a pair of car batteries, but that sounded pretty crap (I later found out that lead acid batteries are quite noisy) so I built my own version of a HiCap for it (which was miles better). Of course, I should have used MiMH batteries as these are very low noise devices (but hey, one learns best by trying; reading about stuff first takes all of the fun away).

I do miss the opportunity to do stuff like that; all these modern SMD based devices really are approaching the stage where what it typically says on the base is now getting close to the truth: No user serviceable parts inside (though I'd still precede that with the word 'virtually'). :-P

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-20 20:38
by ThomasOK
Interesting replies. I went a step further than Briain and removed the main board from the NAC12S and wired all the boards, in/outs and pots directly to each other. I ended up returning it to stock, not completely convinced the mod was worthwhile, and sold it to a friend to buy a 32.5/HiCAP/135s setup to drive my Isobariks like Anthony. Then like both Briain and Anthony I sold the Naim gear when the LK1/LK2 arrived as I felt it was more musical.

I never actually got around to comparing the 160 to the 250 but upgraded directly from a 110 to a 250. This was after a friend asked Julian (while I was standing next to him) whether there was all that much difference between a 160 and a 250 as he was also considering an upgrade from a 110. Julian's reply was that it wasn't "that you'll hear this difference or that difference, as far as I'm concerned the 250 is the only decent amplifier in the world, period!"

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-21 17:05
by Briain
I'd forgotten that I also had a 110 for a while. After using the 12s with the Nytech's PA section (driving Kans) I then bought a 110 and saved my pennies (for quite a while; I needed quite a few of them to buy a 250) and the 250 was indeed an awesome upgrade.

Re: Bolt Down / Chrome Bumper NAP 160 vs 250

Posted: 2019-08-21 21:18
by Charlie1
Thanks for sharing your experiences guys!