6pack135 failure

I was also trying to trace down why the netgear ethernet over mains unit causes audible hash through the speakers... probably breaking through on the supercapDR feeding the snaxo362 cos its volume independent.

jon honeyball posted:

I think me doing rude things with some test equipment was probably the fault cause... sending impulses through the system with the volume accidentally raised wasnt wise... and thank goodness the dibble tweeters are reasonably robust, given there are no spares.

Jon,

I guess Naim have stopped selling matched pairs of Dibble tweeters, however I believe that Scanspeak are still producing the unmatched product (D2010/851100). This was a consideration in my recent acquisition of dibbles though it turns out that the existing tweeters are in rude health. 

Only time I ever manage a "current" trip was with a 250 into briks. Cost me 4 new tweeters.

Willy.

thanks for the pointer -- i have ordered two just for stock

I've also got a couple of spare tweeters stashed away, just in case...I managed to destroy a pair in the past. I mean, who could be daft enough to get the bass & treble speaker cables mixed up?

Question re tri-amping (or bi- with two-way systems) - do you use a protective capacitor between amp and driver, to reduce the risk of losing a tweeter (or even mid unit) if something goes wrong with the amp (or even you connect something wrongly). With my tri-amp playing I am using a cap providing a -3dB point about 1.5 octaves below the crossover frequency 

I went through 3 pairs of DBL tweeters. Once I had one amp blow its output devices during a lightening storm (and take a tweeter out with it). Another time for some odd reason, two amps stopped working, but powering them off for a few minutes restored their working order. Maybe some mains spuria caused the SOL to be crossed. 

Anecdotally, I once shut down one of the 250s that were actively powering a pair of Tukans at excessive volumes. It was the tweeter amp that shut down-the woofer amp was fine although the sharp cracking sound of the midbass drivers slamming against their end-stops was quite audible. 

I suspect nasty HF generated signals were selectively passed on to the tweeter amps via the SNAXO and placed them under sufficient duress to either go into protection, or to blow an output device. 

Back in the Naim chrome bumper days I was running a pair of KEF 107/2 from two 135 amps. I remember the date well. On the 17 December the LH tweeter stopped working. Not hard to tell as the system was instant rubbish.

The crossover in the speaker had failed, blowing the tweeter and wrecking the LH 135 all just before Christmas. I could have delayed things as the RH channel was OK. Anyway, I didn't and both amps went back via the dealer to Salisbury. This meant we had TV only from speakers in a plasma TV till the end of January.

Early in the New Year I contacted KEF who had no stocks of the tweeters left used in the 107/2, but they did have available two replacement crossover boards. In the meantime I was in touch with Wilmslow Audio in the Midlands who specialise in DIY speakers parts and they replaced both tweeters. to a similar spec. So we now had new boards, new tweeters  and two serviced 135s. Quite a bill for all that lot!

Initially I was disappointed but after a couple of weeks things settled down and at least I could play music again. I moved the KEFs on a couple of years later. Then I met a guy at an open day at Naim who had been running DBL's actively with a six pack of 135's. He had part exed the six pack for a 500 and returned the DBL's to passive  mode and reckoned there was a big improvement. Sometime later I had the opportunity to purchase an ex dem unmarked 500 from my regular Naim dealer and did so. This left a pair of recently serviced 135's kicking their heals. I then got really lucky as the 135's were wanted for a second Naim system and the guy had an unmarked Naim Superline. We did a straight swap and that perked up the performance of my LP12 quite a bit. The Superline was fed from my 552 but I took the plunge and added a Supercap DR as a dedicated power supply. This also gives the pre-amp a bit less work to do.

I 've always found any upgrade from Nain is a genuine improvement. Not always to the same degree as you might imagine, but I have never gone back to my dealer for a reversal.

Lotus.

"I met a guy at an open day at Naim who had been running DBL's actively with a six pack of 135's. He had part exed the six pack for a 500 and returned the DBL's to passive  mode and reckoned there was a big improvement. "

Nah, no way. Nada.

Hmmm but the 500 is a considerably superior design to a 135?

the bridged design eliminates noise in the signal earth from the speaker return currents  which no other naim amp can do not even 300dr

Isn't it great that Naim will respond in such a positive way? how many audio manufacturers do this ? Luckily Naim has bullet proof reliability. 

analogmusic posted:

Hmmm but the 500 is a considerably superior design to a 135?

the bridged design eliminates noise in the signal earth from the speaker return currents  which no other naim amp can do not even 300dr

135 is more tuneful than 500 

300 is about the same

300dr is better. 500dr is significantly better

Oh and jv said words to the effect that "Naim does a passive crossover for the few who insist on using some large American amp" 

Dev B posted:

 Luckily Naim has bullet proof reliability. 

I suppose if you say something often enough..........

.sjb

Is Phil Irish.

The 500 has tremendous scale, depth and resolution that makes the 135s sound crude and lightweight in comparison. It's evident how Naim have developed and refined their amps over the years.

I'm glad you are happy

analogmusic posted:

Hmmm but the 500 is a considerably superior design to a 135?

the bridged design eliminates noise in the signal earth from the speaker return currents  which no other naim amp can do not even 300dr

That may be so. But stuff the signal through a passive crossover & things change rather a lot! Active driven by multiple 135s, or probably anything else, will always trump a passive 500. A few months ago I thought I'd try popping the crossovers back on my DBLs & running with a single 500. Be nice to get used to that, then I'd rid myself of lots of big black boxes. I'll give it a couple of weeks. I lasted a day... The three 500s, now DRd, are something special into active DBLs.

tonym posted:

The three 500s, now DRd, are something special into active DBLs.

.sjb

500DR is way way way way better than a 500

A reminder of my scoring scale: from best to worst

500DR (Statement Power somewhere in this region, not convinced it is really better than 500DR)
300DR
300, 135 (with 250DR probably at the same point now)
250
500

Which i know will go down like a bowl of cold sick with 500 owners, but I dont care...

jon honeyball posted:

500DR is way way way way better than a 500

A reminder of my scoring scale: from best to worst

500DR (Statement Power somewhere in this region, not convinced it is really better than 500DR)
300DR
300, 135 (with 250DR probably at the same point now)
250
500

Which i know will go down like a bowl of cold sick with 500 owners, but I dont care...

 

Yeah but that's just based on anecdotal evidence with a sample of one. My definitive survey* however comes out with a very different picture as follows from best to worse:

Statement

500DR

500

300DR

250DR

300

250 black case

Nait 2 (I know it's an integrated but still deserves its place in the hierarchy)

135 olive

135 CB

250 (CB or olive).

* Based on a statistically significant sample of golden eared listeners in a controlled setting.

I'd love a pair.

.sjb

Having had  a pair of 250s then 4-pack 135, then 300 then 500, I would say that (trying to take into account the differences between active and passive systems) the 500 is better than any of those.   But the 500 is probably in needed of a service, and probably should be upgraded to DR - when funds allowed, which won't be soon.  Or should I change the 52 to a 252 or 552?  Too many options...

"Yeah but that's just based on anecdotal evidence with a sample of one."

Smile

fatcat posted:

Is Phil Irish.

I'm a Yorkshireman ...

... it gives me an excuse to be a curmudgeonly old man!

Phil