Renovation of Celestion 66 Studio Monitors

[RMutt]

I have Goodmans Magisters. They are much cheaper to buy than Tannoy or Celestion. They have a 15 inch bass in a sealed cabinet. I found the original mid and treble to be a bit 'shouty'. I wondered if the voicing for older amplification and sources demanded this at the time. The higher frequencies also had to find their way through fairly thick grille material. With modern equipment it just seems too much and I have changed the mid and tweeter. I used polypropylene capacitors throughout. I have also deployed L-pads, yes I know, a purists nightmare, but I think the results are much better than the original sound. I have them on old school stands with casters and suffer no boominess. My previous pair of modern floorstanders had to be isolated from the suspended floor in order to achieve clean bass.

[Jimbo]

Hi Jim,



So what does that tell you? That your SP2s are inherently excellent! If they weren't, they wouldn't be capable of revealing the sonic benefits of the superior kit upstream...

That's why one should never form rigidly held opinions about any vintage equipment, listened to 'back in the day', until one has assessed it in a modern (more optimised) context. DSJR, bless him, has a bad habit of doing that. No offence meant, Dave, but you know where I'm coming from... All I need to say is 'Goldring G800' or 'Shure M3D'!

Marco.

Interestingly I had intended to replace my speakers as I upgraded my equipment, as I assumed because they were old they would easily be bettered by modern designs but they simply got better and better. What was interesting was their ability to reveal explicitly every change I made right down to details I was not even aware of such as cable placement, Turntable isolation (this was done in four steps) and obviously fundamental large component changes.

[Macca]

I have Goodmans Magisters. They are much cheaper to buy than Tannoy or Celestion. They have a 15 inch bass in a sealed cabinet. I found the original mid and treble to be a bit 'shouty'. I wondered if the voicing for older amplification and sources demanded this at the time. The higher frequencies also had to find their way through fairly thick grille material. With modern equipment it just seems too much and I have changed the mid and tweeter. I used polypropylene capacitors throughout. I have also deployed L-pads, yes I know, a purists nightmare, but I think the results are much better than the original sound. I have them on old school stands with casters and suffer no boominess. My previous pair of modern floorstanders had to be isolated from the suspended floor in order to achieve clean bass.

Andrew I am using Akais which also have 15 inch bass in sealed cab. Guess what a bass guitar sounds like a bass guitar and not just a bass 'sound' as it will through so many (obviously not all) modern speakers. IMO there is no adequate substitute for direct sound from a big driver, doesn't matter how many little 6 inch cones you line up or how many ports you use. I do find the Akais can be a bit shouty when not partnered correctly although I don't think that is down to the amplification, I do need to use sources that are very clean but not 'forward' sounding.

[Qwin]

While they didn't have the luxury of modern computer programs, the engineers of the day were no fools, they did put man on the moon after all.

Good measuring and plotting equipment was available and I can't see them going to the trouble and expense of building an Anechoic chamber without making sure the speaker was well suported and adequatley wired.

Some truly classic designs came from this period and the engineers deserve due credit.

[Marco]

Except the 66 (or your Lockwoods for that matter) have always been highly rated, from when they were new models right up until now, 40 years on (more for the Lockies). It's not like we are just re-discovering these things after years of them being ignored as 'old crap'.

Indeed - why else do you think I use that sort of kit? Unlike Andre, for example, who's into using vintage gear for the sake that it's vintage (which is fine, as I understand and appreciate exactly where he's coming from), I only entertain using it in my system if I consider that it's superior (or can be modified to be superior) to most modern equipment. I ain't on no nostalgia trip!

For me, it's ALL about obtaining maximum sonic performance/SPPV. In that respect, I couldn't give a tinker's cuss whether my gear was built in 'nineteen canteen' or 1999...

However, like Andre says, there are times when vintage kit needs lots of attention in order for it to perform to its sonic potential. Honestly, as highly rated as vintage Tannoys are (especially in Lockie cabs), if you'd heard them in stock form, before I had the crossovers modified, and compared them with how they sound now, you'd have chucked them in the bin originally!

Now that raises an interesting point, regarding crossovers... Why have I gone to great lengths (and expense) modifying/upgrading the crossovers on the Tannoys, but not on the 66s? Well, apart from sheer laziness, the 66s sounded superb 'as is', when I first heard them, whereas the Tannoys most certainly didn't!

Why? Because crossover component technology came on a long way from the early 1960s (when Tannoy Monitor Golds first appeared on the scene), and the mid 1970s, when the 66s were born, so in that respect, the Celestions were inherently already more 'optimised' than the Tannoys. That's not to say, however, that one shouldn't replace certain components, through age, or modify the crossovers as Ken has done, to excellent effect.

But the fact is, the 66s were already more 'sorted' as a design than the Tannoys were, which is why I've been able to enjoy the Celestions in stock form without needing to tinker with them...

Returning to the issue of crossover component technology, just as what was around in the 1970s was significantly superior to what existed in the 1960s (and earlier), so it is with the quality of the components that are available today - in fact, when it comes to things like capacitors (aside from some highly sought after vintage P.I.O types), there is simply no comparison, although unfortunately, as Ken (and others) have found to their chagrin, electrical superiority doesn't always equate to sonic superiority!

Really it is the flat earth outlook that marginalised these older designs to the point were only the true cognoscenti appreciated them. Small 2 way speakers with no bass so they sound 'fast' driven by expensive but low powered amps became 'the way to go' from the late eighties onwards, at least as far as the mainstream was concerned. A totally different presentation of the sound that led folk to believe the old way of doing speakers was inferior when IMO it was far superior.

Spot on - and that shit still irks me hugely to this day! It's also why we will continue to do all we can on AoS to remove the brainwashing and educate people as to the joys of going the vintage route!!

Right, I'm off to prepare the table outside for lunch, and enjoy the lovely sunshine....

Marco.

[Marco]

Interestingly I had intended to replace my speakers as I upgraded my equipment, as I assumed because they were old they would easily be bettered by modern designs...

That's a fatal way of thinking, Jim, especially as 90% of the time it's untrue! Hey, at least you got there in the end

Marco.

[YNWaN]

I have very mixed feelings with regard to capacitor ESR and how much of an issue it is when replacing capacitors in a crossover.

[Reffc]

I have very mixed feelings with regard to capacitor ESR and how much of an issue it is when replacing capacitors in a crossover.

It depends entirely on the speaker crossover Mark. It is way more critical with some than others. For example, you replace the caps in say B&W CM1/2's with polys, you will ruin the speakers, period. I have had correspondence with B&W directly on this topic and their strong advice is NEVER to replace any electrolytics in their designs with polys for all the reasons that Ken and I have already raised. There are other simpler designs (mostly 1st order slopes) where the value of the cap, the impedance of the driver and the crossover point are way less critical. A lot depends on the original driver impedance and crossover point, but it does matter and it will make a (measurable) difference. People who try and outsmart the (smart) engineers who originally designed these things, especially without proper measurement, are imho, for the most part shooting in the dark. Sometimes they'll get lucky, mostly they wont. Most people would also never admit to mucking up their speakers. Each to their own, but my humble professional opinion is to think carefully...at least do a few sums and see what say a 1 ohm difference in ESR is likely to make for a series capacitor in terms of the filter to the crossover point and therefore the summed response. Who knows, in some cases it may be an improvement, but bear in mind that overall response depends on the behaviour of a particular filter design across a wide frequency range and often engineers from the '70s would use measurement to tweak cap values and positions and NEVER cookbook values. You cannot design a crossover on a cook book approach. We have the advantage of T-S parameters today but measurement is still how all good crossovers are designed and tweaked. It is a pre-requisite for matching left and right sides too. That and final listening tests. Sorry to hijack the topic Ken!

[Jimbo]

That's a fatal way of thinking, Jim, especially as 90% of the time it's untrue! Hey, at least you got there in the end

Marco.

Absolutely right Marco, I can imagine just how many folk now regret chucking out their old Garrard and Thorens decks.

I know as I was one of them, had a Garrard 301, got chucked out and replaced by a Ceedee player

[The Barbarian]

Aye selling my 'TD124, Mk.II' once upon a time was a very big mistake as i so desperately want one again however since the asking prices are quite frankly a giant piss take i can't see this happening.