View Full Version : Renovation of Celestion 66 Studio Monitors
Not posted for a while but I have been working away on the x-overs.
After much listening I took time out to re assess the whole project.
It seemed to me, with Tri-Amping and changing the Tweeter to the Seas unit, I was getting further and further from the original character and what made these speakers special and so well regarded, so I put the original Celestion tweeters back in. I had found only a slight improvement by using the Seas driver so for originality I reverted back to the HF2000.
http://www.jkwynn.co.uk/Project_Images/66/66_44.jpg
After taking the 66's to the NEBO5 bake off, the consensus of opinion was that the mid range needed bringing forward as it was not quite strong enough. I swapped the MF500 mid drivers for the later MD500's which I already had, as I knew these were more forward sounding. As measured, the earlier drivers are superior, having a much higher frequency limit and flatter response, the later driver has a larger power handling but falls off a cliff at the cross over point. The later driver, with its accompanying components does sound more forward though and in larger rooms and at higher listening levels does seem to integrate better, giving a more solid mid range. I changed the x-over parts to suit both these driver changes as shown in the picture above and this had the desired effect.
Without doubt this is the best they have sounded. I used a mixture for the crucial 24uf series cap in the mid range filter, approx 95% Mundorf ECap (Plain) Bipolar electrolytic and 5% Ansar Supersound Polyprop. This produced the right balance, the PP adding a bit of extra body without the problems of using a total value of Polyprop. I'm very happy with the sound now and the circuit/parts/layout I settled on can be seen in the PDF file linked here:
http://www.jkwynn.co.uk/Project_Images/66/66_XOver.pdf
So what have I learnt from all of this?
Some may not agree with my reasoning as to the causes of various issues but their existence as short comings can not be denied.
Firstly, swapping the electrolytics for Polyprops just does not work, I tried Sonicaps, ClarityCap ESA, Ansar and Solan, none sounded any good and there is an increase in volume for the mid range that then needs addressing as the PP’s don’t have the required ESR, so in basic terms, they let more music through.
Second, putting fixed value ESR simulating resistors with each PP does not help. I tried every combination suggested on the diyaudio site but with no positive outcome. They bring the output level down but then sound less transparent than basic electrolytics. Also you can’t replicate ESR with a fixed value part as it’s a variable value that changes with frequency and current. Also the dissipation (damping factor) in electrolytics is not present in the Polyprops so the circuit sounds more resonant. The resistors also shift the cross over point/slope to the extent where you can hear holes in the spectrum when listening to Piano running up and down the scales. To sum up, they sound terrible and are a backward step.
Third, re positioning the x-over coils and moving the board away from the bass driver magnet has a small but noticeable positive effect. As does dividing/isolating the circuit elements and Tri-Wiring them, but again these are only small gains.
Last, place more trust in the professionals that designed these things in the first place and “If it aint broke don’t fix it”. If I had followed this advice and replaced like with like I would have saved a lot of cash and hundreds of hours which could have been better spent. I can hear “Reffc” saying I told you so. :D We live and learn Paul. Anyone that is thinking of re capping a set of 66's should benefit from my experience and check out the parts list and layout linked in the PDF file above.
At least I have learned from my experience and ended on a positive note, as the 66’s are sounding very nice indeed. I get a lower bass lift in my smallish listening room and I have London Grammar on the turntable at the moment and really enjoying what I hear.
So that’s this one done and dusted, time to move on to my Yamaha speakers and I can enjoy the Celestions while I am working.
The Barbarian
25-02-2015, 20:20
Hi Ken
O you poor man, looked like a bit of a nightmare. Im lucky my smaller speakers only have 2xInductors, 2xCaps {3.3uF & 8.0uF} they will cost me around £9.50 per speakers for Ansars..
It was exactly that Andr'e
I'm going to keep it simple with any replacements on the Yammies.
DarrenHW
26-02-2015, 06:15
At least I have learned from my experience and ended on a positive note, as the 66’s are sounding very nice indeed...
:exactly:
Great thread though I've enjoyed reading it, thanks for sharing.
I woun't say "I told you so" Ken, as there's nothing quite like learning for yourself so me being a smartarse wouldn't contribute anything ;)
Glad you got it all sorted though. it's justification for the truth (that some just still won't accept) that the component values matter MUCH more than component brand or type. I'm of the opinion that there's actually no "sound" as such to any brand of capacitors (although there are some that exhibit very slight differences, these usually having an explanation) , just a set of electrical parameters which define what they do within a circuit. There is absolutely nothing wrong with using electrolytics providing that one changes them every 10 to 15 years. Even re-capping something as complex as 104/2 crossover boards should cost no more than £150 total for example, or just over half that amount if DIY.
My advice I think was to remove the boards to a more sensible location, space out the inductors (and position them more sensibly) and do a like for like cap replacement to restore factory spec (and better it). This appears to be where you have ended up, and I'm sure that you'll receive many years of pleasure from these.
The issue with the SEAs tweeter is more likely to be in the crossover design Ken than any shortcomings of the tweeter itself. Crossover design requires things like phase integration and step response to be spot on, and whilst you may be able to approximate crossover values or even measure in room with a mic, it wont get you close to where you really need to be. That requires anechoic simulation, accurate phase alignment and sensitivity matching. It's actually quite a difficult thing to do and almost impossible without the right gear. Had you lived closer, I'm sure I could get them to match (and sound) great for you. As it is, I'm just happy for you that you have them back in superb fettle.
Hi Paul
Yes the simple mods/refresh I ended up with was pretty much what you had sugested all along and sounds better than anything else I tried.
My final version is detailed in the linked PDF file on post #251.
I was way disapointed with the advice over on diyaudio, I tried just about every mod/combination being suggested and they all gave poor results, some changes were really taking a backward step and sounded worse than my unmodified boards using the old Elcaps. So anyone thinking of following the advice over there be ware.
My speakers sound much better than with the old Caps now, cleaner sound overall, with a crisper top end, more kick to the mid/bass and seamless integration. Hopefully, back to how they sounded when they left the factory.
When it comes to the Seas tweeter, the modified values I used for caps/coil worked very well with these and they do sound better than the original HF2000. It's just that the improvement is only small as the original units are pretty good anyway, so for originality reasons I went back to the HF2000's as I will be selling the 66's on when my Yamaha NS1000M's are finished - I only have room for one set of speakers. The improvements I got were mainly down to the choice of electrolytic caps and by using the later MD500 mid driver, this is what gave that little bit extra that was required.
I am semi retired so this is a hobby for me, the renovation has been very satisfying and I was determined to get a result, plus it kept me off the streets. :)
P.S. For anyone wanting to use the Seas Tweeters, as good replacement HF2000's are getting harder and harder to find, I have detailed the part changes required on my linked PDF file on post #251
I put these up for sale on Fleabay a few minutes ago if anyone is interested.
Only room for one set of speaks and the Yammies are staying!
Got a link to your action sale, Ken, so we can keep an eye on it? :)
I think you should do well, mate, and good luck! :cool:
Marco.
Thanks Marco
You can't do that anymore, items you are selling come up with selling info that no one else can see, you don't see the same page as everyone else. At least thats the way it appears to me.
Edit: Sorted it, you have to log out first.
This is the add:
http://www.ebay.co.uk/itm/Celestion-66-Studio-Monitors-/291398325322?hash=item43d8b1944a
Cheers, mate. The link was all I was looking for, which can be obtained from simply copying and pasting the information from your browser onto here. I’d be hoping for around the £1500 mark, or more :)
Marco.
No matey, thats what I was trying to say, the seller sees a different page and the link is different, I see details about the add and how many people have viewed it when logged in. When I log out I see the page everyone else does. Worth remembering.
Anything over £800 is good, but lesser examples have been going for well over a grand so fingers crossed. I hope my location in the North East doesn't put those rich buggers in the South off, due to the distance they will have to travel :D
Hot Damn!:stalks:
If I had a bigger room Ken... I know these are too big having seen them in real life but go ahead and remind me how tall they are on the plinths again.
It must be love with the new Yammies eh?
Hi Rich
They are 1140 mm tall (114 cm) by the time the spikes settle into the carpet.
Yes I was very impressed with the Yamaha's, upper mids and top end is so clean and bass is deeper and tighter than the 66's.
The 66's have more slam and punch in the mid range. Not much in it now I have the 66's sorted, I am enjoying them a lot and will be sad to let them go, but need the space.
..I was lining myself up for a bid but they have sold, i was wondering how I could explain to my wife that I had two pairs of 66s in the house.
Btw. This has been one of the best threads on AoS despite a distinct lack of technical knowledge from me.
Cheers
John
Thanks John, they are going to find a home fairly local to me, so staying in the North East.
How did your concrete bases turn out, did you get them painted?
Well the 66's sold and were collected at the weekend.
The buyer allready had 44's and had spent nearly 2 years looking for a nice set of 66's, he had seen many pairs on his travels, but said mine were the best he had seen both cosmetically and sound wise, he was over the moon with the demo I gave him and his wife seemed to like them as much as he did.
Sorry to see them go, as they really were sounding good, but they found a good home and the decks are now cleared for work on the Yamaha NS1000M's. :)
Thanks John, they are going to find a home fairly local to me, so staying in the North East.
How did your concrete bases turn out, did you get them painted?
Hi Ken, your buyer got a bargain.
I finished my concrete bases and spiked them...still got to give them a cosmetic finish though.
Thanks
John
ToTo Man
11-05-2015, 17:17
Fascinating thread! I'm about to embark on a similar project myself. I've got most of the parts, just need to put it all together. The one thing I am missing is the original foam damping that goes inside the cabinets. Does anyone know the spec/dimensions of this foam and the best place to source it? I suppose I could always stuff the cabs with lambswool but I don't know if this would adversely affect the sound… Thanks! :)
Fascinating thread! I'm about to embark on a similar project myself. I've got most of the parts, just need to put it all together. The one thing I am missing is the original foam damping that goes inside the cabinets. Does anyone know the spec/dimensions of this foam and the best place to source it? I suppose I could always stuff the cabs with lambswool but I don't know if this would adversely affect the sound… Thanks! :)
I wouldn't sweat it, Richard. White BAF wadding as used in air-conditioning filters will do much the same thing. Get it at the electromechanical wholesalers. You can stuff quite a lot in. It makes the cabinet effectively 20% bigger and damps out the standing waves which cause colouration. Though actually a polyester pillow might achieve the same effect. Generally a reflex or ABR design will use less stuffing than closed box, since it relies on a certain airflow in the bass. The BBC would glue something rubbery to the side, top and bottom panels too for panel damping, but that is another topic.
ToTo Man - I supose it depends how original you want to keep it all.
The acoustic foam Celestion used is nothing special, it is just 40mm medium density, that can be picked up at many markets or upholstery stores, note it is not the expensive high density used for chairs that whithstands collapse and has a good memory and springs back to shape, this is too dense.
I have a small piece of the original foam which I cut out to allow for the extra height of the iductors when I reoriented them. If you PM me with your details I can send you this if you want it to help you match up the grade of foam. I can also do a sketch to show exactly what shapes were used and where they fitted, so let me know if you want this.
If you are thinking of re capping do not replace everything with Polyprops, tried it and it sounds terrible in this circuit.
Replace like for like as I explain in my parts list. The big value series cap in the mid range pass band filter is the most important single part on the board and is the hardest to get right. I tried dozens of combinations to get the mid range right for my taste. I settled on using the later MD500 mid driver, this is slightly more forward than the earlier MF500 and gives more body and percussive nature to the mid range. You wont notice much difference at low volumes, but turn the wick up on full Orchestra or Black Sabbath and the earlier driver sounds a bit light weight. You will have to use the correct value cap for this driver, after much trial and error I found 95% Mundorf ECap (LL Lytic) and 5% Ansar Supersound (PP) to make the total value worked best for this MD driver. All Lytic is bright and thin, all PP or even more than apout 7 to 8% and it starts to sound resonant due to ESR/Damping being different to the original Elcap Lytics used. All Polyprop will alter the crossover point and slope as well due to ESR differences, it creates an audible hole in the range when listening to piano scales. The small amount of Polyprop gives a little extra body and richness to the mids without the inherent problems associated with a value made wholey of PP.
I added 3mm bitumen pads to the inside of the top and bottom panels.
I hope that helps :)
ToTo Man
20-07-2015, 11:43
Thank you both for your helpful advice. I have recently managed to acquire the complete set of original foams for the 66 cabinets (fortunate or what??!! :) ), so will be able to begin my project very shortly.
I appreciate the tips on recapping the crossovers. I wasn't planning on touching them unless there are audible signs of issues with them (my fingers are crossed that are ok!).
they are up for sale on ebay,
http://www.ebay.co.uk/itm/Celestion-Ditton-66-Studio-Monitors-Speakers-fully-restored-/331937325250?hash=item4d4901a0c2:g:avcAAOSw0UdXrDn f
Well spotted Jamie, yes those were mine and still looking good.
yes it was the 3 terminals at the back that gave them away,ive contacted him regarding the plinths,he may sell them separately.
rodthebod
21-11-2016, 17:43
Hi John
I’ve have been reading your thread on the Art Of Sound site concerning the renovation of the Celestion 66 Studio speakers. I’m out in Malta (semi-retired) and have the opportunity to get hold of a pair of Celestion 66’s. They are from 1972 (looking at the date on the red electrolytic capacitor on the crossover board).
My problem is that they have been left in a corner of a bedroom by the existing owner for the last 10 years and the damp caused by the excessive humidity in the winter time has taken its toll. I am in Malta and it gets very humid in winter.
One cabinet, the chipboard has blown up at the base so much so that the bottom has fallen out and the other is showing signs of severe damp damage too.
I can look at getting some duplicate cabinets made locally in the same 18mm grade veneered chipboard, I would do these myself as I have made several speakers in my youth but have no proper wood machining kit here in Malta. Would you say this is the best course of action, going for a complete cloned pair of cabinets and not messing with the materials/build? I know from experience that it is a sensible thing to take heed of what a manufacturer uses in production, especially top of the line models, having come from a hi-fi manufacturing background myself. Or is a custom design in plywood a better option.....
I haven’t bought them as yet, both HF2000 tweeters are open circuit so I need a pair of these or the Seas 19TFF1 which I know you prefer.
Another question, the speakers have the lower power rated 50w HF500 midrange units, on your circuit diagram (tri-wire) you stipulate the 22uf with 1+1uf to make up the 24uf for the HD500, what value do you recommend for the HF500 (28uf?+?+?) as this is the only driver I have to work with. I’d like to acquire the HD500 mids in the long term but that’s probably not likely these days.
I really appreciate your work done on the Celestion 66’s and the excellent informative thread.
Look forward to hearing back from you.
Rod
are you sure they are chipboard?
mine appear to be solid,i think its only the baffle board that is chipboard.
rodthebod
29-11-2016, 15:34
Hi Jamie
I can see why you would think they are solid because the edging is wood veneer and gives that impression.
However, I can confirm that the cabinets are all 18mm chipboard including the two horizontal braces inside (but slightly thinner 16mm thick) The sides, top and bottom are veneered both faces, exposed face in teak and inside in a cheaper non cosmetic veneer. I have have the worst cabinet stripped down completely and with the bottom fallen away the construction in simple tongue and groove with rebated front and rear panels. They are surprisingly lightweight when empty, but this probably is a key element with the sound produced, I believe all the Celestion range was based around this lightweight choice of cabinet?
Hopefully Ken will come back to me with some advice (I don't know why I called him John!), I am making up new cabinets with the help of a local chippy using American walnut veneered chipboard based on the original makeup as I feel it's important to follow what the designers did to achieve that 'special sound'.
Just looking at ordering the new caps based on Ken's experience, I measured the old values of the caps on one of the crossover boards today and some of the film caps are over 4 times the correct capacitance! Weirdly the only electrolytic (24uf) used in the whole circuit, in the midrange, is within spec the rest are miles out! These crossovers are from 1972 as stated on this can.
Have you changed anything on your crossovers?
Hopefully the MF500 mids I have will sound OK, as I haven't heard these speakers work with all the drivers working, let alone one of the cabinets being in one piece.
I think I'll work along the lines of using external tri-wire crossovers to aid 'tweaking' as having inductors anywhere near magnets isn't a brilliant idea, but understandable due to practicality.
Both HF2000 tweeters were blown when I aquired these speakers, I've stripped them down and sure enough they have gone a few millimetres from the coils either side (expensive fuse). I've soldered triple wires stripped from some old 42 strand speaker cable I have which makes up about the same overall thickness as the original wire and gives a more resilient connection.
I made a tool from 50mm aluminium bar to cut double sided tape 'rings' 41.5mm/27mm. These are used to secure the mylar domes to the fibreglass rings adhered to the magnet face but I'm in two minds about how to go about sticking these together not having a jig. I may just go for the option of using contact adhesive instead of the rings to give me enough time to put the assembly together run a test signal through them and have the luxury of moving the dome fractionally to achieve 'no distortion' then let the glue cure. Trouble with double sided tape is it's all or nothing and once they're stuck together that's it, if you get it wrong you're stuffed, it was difficult enough to get them apart to start with and that's with 45 year old glue.
Wish me luck!
Quote:
"Just looking at ordering the new caps based on Ken's experience, I measured the old values of the caps on one of the crossover boards today and some of the film caps are over 4 times the correct capacitance! Weirdly the only electrolytic (24uf) used in the whole circuit, in the midrange, is within spec the rest are miles out! These crossovers are from 1972 as stated on this can".
The ONLY film caps used in the crossover were in the HF filter, ALL the others were electrolytics. Those Black caps with Red ends are Elcap electrolytics. If they have LL on them they were Low Loss electrolytics, I had a mixture of std and LL on mine, dependant on location.
From the original Celestion schematic - the HF filter film caps were in two bunches wired in parallel C6/7/8 = 4uF total and C9/10/11/12 = 6 uF in total.
Did you get my email regarding the cabinet rebuild?
rodthebod
12-12-2016, 17:16
Hi Ken
Thanks for coming back to me, not been checking the site as I should hence the delay. So the 'elcaps' are all electrolytic, that probably explains why they are so far out of tolerance.
Didn't get the email about the cabinets.... strange, I'm busy sorting the cabinets now, have all the panels cut and am just routing the holes for the drivers.
Maybe try sending again
Rod
Hi Rod
I just made the point that if you were building completely new cabinets, then the consensus seems to be that Furniture grade Birch Ply (Norwegian Baltic Birch is the ultimate) is the best for speaker building, if you can get it local, but at a price.
The second point I made was that the original design in veneered chip board was relatively free of resonances and unwanted colouration up to fairly high volume levels. So a copy of the original cabinet would be good and a lot cheaper. Do not replicate the overhanging lip on the top edge though, as this has been proven to interfere with tweeter dispersion, it sounds better without it. This comes down to originality for most folks, but with new cabinets why build in a known problem.
I just priced some 24mm Birch Ply for my current project at £195 for an 8'x4' sheet plus delivery. I'm considering routed overlapping joints for edges and internal braces, fully glued with no screws or dowels, as a belt and braces rigid sealed box for a 12" woofer capable of high excursion. I'm hoping this is the last speaker I ever build, but never say never in this game.
rodthebod
13-12-2016, 11:09
Hi Ken
Yes, never say never, so true. I decided to go with the chipboard because its proven with the units used and to be honest birch ply out here on a tiny island in the med is extremely expensive, not exactly cheap your end either! 18mm Veneered chipboard in African walnut worked out at just 38 euro for a 4x8' sheet. I'm using some 18mm offcuts for the rear panels and internal braces as there isn't enough African walnut for the whole job.
As far as the lips go I've already cut them with the overhang as original but you've got me thinking...... I haven't glued them up yet.
Do you really think tweeter dispersion suffers that much? I suppose I could fix the missing lip, if I cut them off, to the top and bottom of the grilles then when they are not in use it would make them look more original.
Looking at the chipboard baffles it's surprising how little material is left after rebating for the steel grille panel only 12mm thickness on the outer edges as on the original, I am tempted to put in some more internal bracing top to bottom along the front internal corners, maybe using some 2mm aluminium angle section bonded with polyurethane mastic, what do you recon, it will stiffen things up? Do you think the cabinets would benefit from more rigidity around where the bass drivers and mid are mounted?
Thanks for the feedback
Rod
I'm not sure about adding metal stiffeners as to how they will resonate and if you fix them to the panels with a compliant material they wont stop the panels moving anyway. Any additional bracing is going to reduce the cabinet volume as well. I would keep it as original, which worked well, I never had a problem with the cabinets performance. The only mods I did was to add 4mm bitumen panels to the top and bottom panels, which using a hand on while playing test, seemed to vibrate more than the others and I lifted the base panel off the floor by fitting "Soundcare" feet to the bottom.
I read, I think it was on DIYaudio, were someone published dispersion plots for the tweeter with/without the top cabinet lip (No Grill fitted) and dispersion was clearly effected. Others have said they can hear a difference and a common partial fix is to add some foam etc to the underside of the lip. With it being so close to the tweeter, I'm guessing the reflected sound is interfering with the more forward firing output as well. It's been discussed elsewhere in detail and I added the foam wedge, which seemed to help, maybe by absorbing and reducing the reflections. Its at best subtle in its effect, no lip is better and no one would design it that way these days, but the choice is up to you, for the valid reasons you give.
rodthebod
13-12-2016, 16:00
Hi Ken
Sold! The top lips are coming off then and no stiffeners, I'll leave the bottom lips as I need it to fit the grilles when not in use, very useful info thanks, 4mm bitumen panels will go in too - these can be bought at Wurth suppliers for reasonable cost compared to 'audio suppliers'. Good luck with your new build, what drivers are you going for and is it based on an existing design? On the build I would always go for rebated/stepped joins to increase strength and get a good joint, makes gluing up much easier too, as long as your cuts are accurate.
I'll be ordering crossover parts based on your last design, but using the existing MF500 drivers, is there anything that can be done to help with your making the mid range come more forward without the expense of buying two MD500 drivers (they seem to be rarer than hen's teeth) I've used ansar caps for top end before - nice sound but I don't have much experience with three way + designs, at least not using caps and inductors. I don't want to go mad on the expensive brands, whats a good trade off with performance and price? Postage to Malta can get expensive from some companies.
if you get rid of the top lip how are you going to hide the top edge of the grills? i doubt the difference would be that much over how awful it would look with no lip.i had good results before using ansar supersound polys and alcap electrolytics,i would also use kens tip and go for 1% polys for the mids.it worked well on my 44's.
rodthebod
13-12-2016, 18:07
Hi Jamie
Being from the ex designer fraternity I appreciate an aesthetic approach, I would probably affix a finisher 'the missing top lip' - a top capping, if you will, to the top edge of the grille cover itself. I'll have to plonk one of the damaged cabinets in front of me and visualise this before going ahead with the grille cover in hand to get a better idea. Sometimes changing something small can make a huge visual change......a feel for the product integrity or identity, what it's about.
When you said you had good results, do you mean from the original crossover components? I've just tried the one working 66 cab as a centre speaker in my cinema system - all original crossover and drivers except for the tweeter which I temporarily swapped for one of my old company units (original HF2000 is fried but I managed to rebuild it eventually - glue still drying!) It's very good - seamless sound, I'm impressed already before even trying them as a pair. Any recommendations on the flavour of caps, ie: brand?
It's a while since I built a complete cabinet, but I have a table router now, so the joints will be cut on that.
I'm using the mid and Tweeter from a current model, Quad S-1 bookshelf speaker, mated with a 12" Scanspeak Woofer in a 50 ish Litre sealed enclosure. It's actually a Fountek Ribbon Tweeter in the quads. I've been beavering away in the background since the MiBO bake off in November, you can see my progress on my blog below, I will post the whole project here when I get started on the cabinets in the spring. I'm calling it my Semi Active Project (SAP), a crossover/power amplifier using Hypex class "D" modules is already drawn up, ready to power it when I find funds and time to build it and the active and passive crossovers are built and running in a lash up.
http://www.jkwynn.co.uk/SAP_HTML/SAP_Thumbs.html
CAPS
I would stick with Ansar, from Crincklewood Electronics, search Ansar Supersound on FleBay were they do most of their selling now, their website does not respond lately. For me they are the best balance of cost/performance and you would have to spend several times more to get to the next level. I don't spend that kind of cash on caps, as I think the same amount spent elsewhere on the system can reap greater benefits, due to diminishing returns etc. The ONLY Polyprop or film caps in the Celestion circuit are the two values in the HF circuit. All the others are electrolytics. You can add up to 5% PP to make up the big value series cap in the Mid range band pass, this has benefits, but take it to even 10% PP and the negative attributes creep in. DO NOT replace the elctrolytics with Poly Props. I wasted a couple of hundred quid trying lots of things that didn't work as well as the original old Elcaps in my circuit and that was one of them. If you want to keep the signature sound of your speakers, use like for like replacements. I found the Mundorf eCap electrolytics to be a good replacement for Elcaps and on the parallel fitted items, in the bass etc, even Alcaps from Falcon Accoustics worked well, though some of the values are getting hard to find now.
Mid drivers can be found occasionally, I was lucky and found a couple of pairs of Tweeters a pair of mint woofers and a pair of MD500's straight away on Flebay.
The Bang and Olufsen Beovox 5700 used the same Tweeter and MD500 Mid driver, I bought a tatty pair of cabinets with 4 good drivers for £80. At one stage, I had 3 good pairs of tweeters two pairs of MD500 and one pair of MF500. Unfortunately, I sold off all my surplus drivers. They do come up though.
I wouldn't know where to start, in terms of making the MF500 more forward, without simply attenuating the other drivers, which is not ideal. If you were fully active you could just turn up the amp powering the mids, but that does not help with your set up. This is a more complex task than I would care to guess at, fitting the later driver is far simpler. ;)
I was thinking you were making new grills, if you want originality, stay as you are, just making the point that improvements can be had if you want to go that way.
rodthebod
13-12-2016, 18:18
All good stuff about crossovers, thanks, these class "D" amps seem to be cropping up a great deal now, are they really that good, I saw previous posts about NEBO and how impressed people were with the tiny D class integrates - Paradise or something similar.
I'l check out your blog.
Hi Jamie
Being from the ex designer fraternity I appreciate an aesthetic approach, I would probably affix a finisher 'the missing top lip' - a top capping, if you will, to the top edge of the grille cover itself. I'll have to plonk one of the damaged cabinets in front of me and visualise this before going ahead with the grille cover in hand to get a better idea. Sometimes changing something small can make a huge visual change......a feel for the product integrity or identity, what it's about.
When you said you had good results, do you mean from the original crossover components? I've just tried the one working 66 cab as a centre speaker in my cinema system - all original crossover and drivers except for the tweeter which I temporarily swapped for one of my old company units (original HF2000 is fried but I managed to rebuild it eventually - glue still drying!) It's very good - seamless sound, I'm impressed already before even trying them as a pair. Any recommendations on the flavour of caps, ie: brand?
no, i wanted to try kens electrolytic/pp mix for the mids,the stock cap was 24uf,ken recommended a mix of 23uf electrolytic and 1uf pp for a bit of sparkle to the mid,this was done along with fresh ansar super sounds for the hf.this is the crossover for the later ditton 44's to be clear.
http://i1267.photobucket.com/albums/jj548/jamiecreig123/20151031_094038_zpsbeslthlm.jpg
rodthebod
13-12-2016, 18:55
I think this is going to be a slightly more expensive pre Christmas cap order - hope she understands, and she's just bought me wine gums for a treat... oh the guilt.........
All good stuff about crossovers, thanks, these class "D" amps seem to be cropping up a great deal now, are they really that good, I saw previous posts about NEBO and how impressed people were with the tiny D class integrates - Paradise or something similar.
I'l check out your blog.
Paradise is a phonostage, I think you might mean the 'Mini T' amp. It is tiny and cheap and sounds more than adequate with an easy load. It failed badly into some Ditton 66 though.
rodthebod
13-12-2016, 19:42
Hi Martin
That's the one, Mini T, should have known Paradise is the phono pre, I'm just about to build an EAR based phono myself. What exactly happened when the 66's asked to be fed?
I tried lots of variations with the PP/electrolytic mix for the big mid range value.
1% to 2% PP sounded best and up to a max 5% was acceptable and allows a bit of flexibility with stock values available to make the total required.
By the time you get to 10% it sounds bad and strangely enough doesn't get much worse the more you add, I started at 50% then 30% etc.
The Mini T mentioned is a class "T" amp and powered my 66's to reasonable levels before running out of steam. If you don't need loud, at about £100 it is a bargain for the quality you get.
Many manufacturers are moving to class "D" and using OEM boards from Bang and Olufsen under the ICE branded technology or from Hypex, NAD's latest top end Amp uses Hypex modules for instance and it's not cheap at just under £4000. The modules are usually coupled to switch mode power supplies, which creates a very light weight yet powerful package, but occasionally heavy weight linear supplies are used. Like any class of amp there are good and bad examples of the technology. Class "D" seems particularly good for powering bass and many Pro Audio manufacturers have gone this route for PA and DJ use were lots of cheap watts are needed. I heard a couple of HiFi class "D" amps at last years NW Audio show, coupled to some decent kit and they sounded pretty damn good to me. At the MiBO meet, Ali's open baffle speakers had a 2000w class "D" powering the four 15" bass drivers and I think everyone was impressed with how they performed. So yes, class "D" is good, though not maybe to everyone's taste, then again what is. :)
rodthebod
13-12-2016, 20:41
I've only ever experienced class D amplification with a subwoofer we were trying out years ago as maybe using ourselves (2002 ish maybe) was amazing for the size of cab and really made one hell of a noise for a 340x340x340 enclosure 12" driver and a bass radiator in this little cube - B.K Electronics were letting us try it out - very impressive. Still have the enclosure and drivers but the class D amp packed up and I feed the drivers with an external amp now - still makes an impressive sub, even more so when you take the overall size of it into account. It was a german manufacturer I think.....
walpurgis
13-12-2016, 20:53
I've got a little Chinese D Class amp much the same size as the Mini T. It sounds pretty good as long as it's not driving anything too demanding. It drove my Tannoy System 800 speakers well enough, but they are 94db sensitivity.
rodthebod
13-12-2016, 21:00
I think that's the key thing here, if your not driving anything too demanding <91/2 db then the virtues of the tech shine through, I'm guessing. I can only talk about valve amps (EL84 based) about sensitivity. Haven't heard the latest swathe of class D amps myself, I would if I were closer to the UK....
But hey, it's good these things are now available, back in the day..........
walpurgis
13-12-2016, 22:33
Haven't heard the latest swathe of class D amps myself, I would if I were closer to the UK.....
Order one on ebay from China with the correct spec power supply. They are really cheap and I've found the Chinese sellers very dependable. You might be surprised by the sound quality.
I think there is some confusion here between the small class "T" amps of 20 watts or less into 4ohm and the true class "D" amps which can put out much more, dependant on build. The Tripath or clones of the "T" amp are a form of class "D" using a particular chip of very limited output, this is the type which RichB used with my 66's. I was talking about the more powerful versions here, the Hypex modules I'm considering are 180w, 400w or 700w into 4 ohm. My lay out uses four of the ucD180 modules and two SMPS to run these and my active crossovers. Sub woofer plate amps are a typical application for this type of module due to small size, weight and low heat output. I'm a fair way off building my unit but will post it all when I get to it.
walpurgis
13-12-2016, 23:31
My understanding is that they are all Class D, Tripath included. Not sure why they are labelled 'D' though, as they are not digital. In fact, I'm not aware of any true digital amp on the market, although they may exist. I know Pioneer were working on a true digital design. But I can't see a great advantage in having one until digital speakers come along and ideas for those have been on drawing boards for years.
class d are switching amps as opposed to gain amps if memory serves Geoff. Think they d gets classified as digital because of the on off bit.
walpurgis
14-12-2016, 00:20
class d are switching amps as opposed to gain amps if memory serves Geoff. Think they d gets classified as digital because of the on off bit.
That was my understanding too. The high speed switching producing the signal 'envelope' rather like AM radio as opposed to true digital.
If AM is digital, then we've had 'digital' for a hundred years.
rodthebod
14-12-2016, 10:25
Hi Ken
Slightly off topic this but I've just been looking at your amazing projects on your site and the Project turntable with Terminator arm caught my eye, impressive use of parts sourced btw.
I have a Goldring G99 which has been in a cupboard for years, have checked out the various sites and it seems this has potential - using the motor, bearing platter and top plate. When you did your Technics based deck would you say using the plywood plinth reaped benefits over the mass loaded concrete plinth on your other deck? I'm deliberating what kind of plinth to do with the G99, and the tonearm.......
This really took my attention, the Terminator arm you used. I've been looking into making a unipivot tonearm using magnets (not a new concept I know, Schroeder etc) probably 12" but then the parallel tracking air bearing arm principle seems much better and ultimately easier to setup. I remember trying an air bearing arm back in the 1980's - imported from the U.S. I think, in fact I'm pretty sure it was the first one out there - concentric bearing design - noisey pump I remember. I only had it on loan for a limited time because it was in high demand for reviewers etc. but boy did it do things, or rather let the music just come on through. It's funny how you remember vividly when things impress you, or is that old age. Can't remember the manufacturer though.
How does the terminator arm perform, is it easy to setup, has it any querks? The end solution certainly makes for a nice compact and clever design, that appeals to me, even though I'm building whacking great big 66 speakers with 12" drivers which are the largest I've ever had, always used 5.25" drivers in the past.
walpurgis
14-12-2016, 18:59
Don't cannibalise the G99. If you want bits, GL75 items will do the same job and can be bought fairly cheaply. The G99 and G88 turntables are appreciating classic units and well worth keeping complete. They sound superb as they are anyway. Just bung yours in a good base/plinth with a decent arm and you'll have a top class deck! It'll be worth quite a lot of money.
rodthebod
14-12-2016, 19:14
Thanks for that Geoff
Worth a few quid, wow! it's been stuffed on a cupboard for years, but I've had the thing working with the Transcriptors Fluid arm that was on it and an old Shure V15 Mk2, I'm waiting for a new stylus gauge to turn up so had to guess tracking weight, but yes it plays really quite well. I had to put it on some foam as it was so susceptible to airbourne vibration, (and it's on a wall shelf) It's totally original in the Goldring Teak thin plywood plinth, date on the green underside of top plate is 1968. Runs pretty consistently at 33/1/3 considering its not been used for so long it's quite amazing, they really knew how to build these things.
You're right, and I'd rather not rip something apart that's working well and original and worth a bit in that condition which should only appreciate.
I know someone local who has a Lenco L75 with matching arm totally original, I think they would sell it, what are they worth?
Any suggestion on plinth material, I'm quite keen on this air bearing arm concept, or am I being too ambitious.
Cheers
Rod
walpurgis
14-12-2016, 19:44
Not bought from ebay, a sensible price for a GL75 is maybe between £100 and £150 depending on condition.
G99 units have been fetching £400 to £500 lately and the Fluid arm is worth getting on for the same these days. Even a good V15II will fetch a pretty penny now.
To get all the 'ins and outs' for Lenco turntables, you really need to visit the Lenco Heaven specialist forum.
Yeh, don't do to much to the G99, which is a nice looking and decent sounding deck. I think a nice wood plinth is all you need.
The concrete worked well, but was just too damn heavy, the deck was heavier than a 3'x2' paving slab and awkward to position and adjust.
The plywood deck is no lightweight though and I like it, coupled with the Isonoe feet it works well.
Terminator Arm
I was having a lot of problems with end of side distortion (ESD) with my Technics arm, I even drew up an alignment protractor using the Technics geometry, which is slightly different to the usual bunch. It helped but I wasn't happy. I also looked at the Schroeder arm and even bought some of the materials to start the project, when I came across the Terminator design. The sled moves horizontally on an air cushion, like a hovercraft and the arm is slung below this using two pivot points for vertical movement. The combination works very well, and you get consistent results across the whole of the record, which was cut using a linear tracking device anyway. There is full adjustment available, even azimuth and it is different, but not difficult, to set up, you can adjust VTA on the fly to easily find the cartridge sweet spot. Once you have got used to the setting up procedure, it is very quick and easy to set up a new cartridge. It is a very capable arm and would do justice to cartridges way above of my upper price point. It uses a fish tank air pump, which I have mounted in the next room, so the very slight hum is not a problem for me. Some folks build a soundproof box to put the pump in and hide it in a wall unit or other furniture cupboard, near to the turntable.
Check out Vics site and the genuine testimonials for this great arm http://www.trans-fi.com/terminatortonearm.htm
Hi Martin
That's the one, Mini T, should have known Paradise is the phono pre, I'm just about to build an EAR based phono myself. What exactly happened when the 66's asked to be fed?
Hi Rod
IIRC we had been using an Avondale amp with the 66s. and getting a really good sound. I went out to the bar, came back and asked 'what has changed? It just wasn't right anymore, especially the bass which was just wrong. I'd guess this was simply down to a lack of power rather than the type of design.
rodthebod
14-12-2016, 20:33
Thanks for the feedback again Ken, the air bearing parallel tracking concept really is attractive, all other methods with pivot arms are a compromise. I remember the parallel tracking arm from about 30 years ago and the final track on that favourite LP was the best surprise, it always seemed to loose its sparkle with a 9" pivot based arm.
Hi Martin, even better news this, I have as my solid state amps a pair of Les's (Avondale) RMS T65 power amps, not sure how they compare to his latest offerings (Voyagers I believe) but they really drive hard into my Revelation 2 speakers with carbon fibre drivers, more than you can stand! I am looking forward to using the refurbed 66's with my EL84 Leak TL12+ monos though, hopefully there's enough grunt.
Ken, back on the 66's did you try picking out the original HF caps which are bundles and try them close to what the capacitance should be, ie remove some, when I measured them with a friends meter they all had increased their capacitance drastically. Or would they just sound 'muddy' compared to Ansar's? I'm waiting for a new capacitance/inductance meter to arrive from China - taking ages, once I have it I'll try it out. I checked the Hi-Fi collective site out for alcaps, there are two types one is RAW and the other PLAIN, plain ones being much more expensive, which ones do I use - it'll be the pricey ones won't it? There doesn't seem a supplier that does ansar/alcaps and mundorf e-caps together, postage costs to Malta are silly sometimes from some suppliers so I'm hoping for sensible costs.
My original film caps in the HF section measured the closest to spec of any on the board.
The reason I changed them, is that they were an early film cap and not as good as a modern Polypropylene.
The originals were a bit grainy, the humble Ansar replacements were smoother and more transparent.
I have a cheap Chinese L and C meter, I use it for ball park only on inductance, it gives different readings for instance if you switch from Hi to low range and generally reads hi compared to the Dayton Audio Test System (DATS) I use and trust. It's a lot closer on capacitance.
The Mundorf ECaps come in two versions as you point out. The Plain are the best sounding and are Low Loss (LL) even a large value of say 33uf is only about £3 so not too expensive.
Some of the original Elcaps in my circuit were marked LL for low loss, check yours and replace like for like.
The large value big can in the signal path of the bandpass filter was Low loss. This if nothing else, must be a "Plain" version ECap or the mid range quality will suffer and as stated previously you can throw in a couple of % of PP to make the total value, but no more than 5%, less is more!
Stick with Alcap Lytics from Falcon for the pair of 72uF caps in the Low pass filter. Mundorf don't do that value anyway so you would have to pair up several which would cost more. Falcon are now the only supplier of Alcaps that I know of. Crincklewood Electronics do the Ansar but not the other two and HFC only do the Mundorf ECaps. Its getting harder and harder to source parts, even in the UK, you can't get 1% mills resistors here, I have to get them from the States, HFC only do them at 5% tolerance and they cost a lot. Just means I have to wait, some arrived today that I ordered in November. These are to complete the passive element of the crossover on my semi active project, they will be soldered in place tomorrow. I seem to spend half of my project time waiting for bits, got my coils from the Netherlands, but still waiting on some items from Hong Kong expected any time from mid December to Mid January! :steam:
Note: Just to be clear Elcaps/Alcaps/ECaps are three different things but all are Bipolar Lytics. Ansar Supersound are Film caps (Polyprops).
rodthebod
15-12-2016, 19:48
It is proving to be messy at best to get the components, still at least they are available judging from the sites thanks to your recommendations Ken. I'm just holding off ordering until I work out if its worth popping in a couple of good audio grade caps in my Leak TL12 + monos. They have caps fitted from about 25 years ago, I've replaced the main smoothing caps as they were failing but I need some advice on whether its a good idea to use more modern caps elsewhere - maybe its best to leave well alone until something fails, they seem to be working well since renewing all the valves?
I've also double checked the original circuit diagram and there seems to be a couple of 50uf caps missing on my amps.
rodthebod
28-12-2016, 10:56
Hi Ken
Could I just quiz you on the virtues of external crossovers for the 66's, I have external boxes for the RMS Revelation 2's speakers I have and never really thought much about it, always keeping speaker connections close to the source (power amps) and leaving the main runs to the speakers, usually 3m. I know that inductors don't like magnetic fields and are influenced by them so it's a good idea to keep the crossovers as far away from the larger driver magnets as practicably possible. Did you ever compare the sound of the crossovers when they were external to when you mounted the boards behind the EBR?
I know originality is important but as I'm building new cabinets from scratch it may be the way to go....
I followed current thinking for best practice, for mounting the inductors, in terms of spacing and orientation and had the boards in the standard location behind the big bass driver magnet, mounted below behind the ABR and also mounted external.
To be honest, I couldn't hear any significant difference in any of it, I certainly couldn't make up my mind if any one thing sounded better, or if reorienting the coils had made a difference. Other changes had made a far greater impact, so these days I just recommend the simple cap renewal on the stock boards. This gave 95% of the improvement I gained, all the extra work (the main chunk of the total) I did, made little if any difference, you are getting down to very very small changes to the sound, where you can fool yourself as to what if anything has changed and also if it is any better. In this particular set up, I think coil placement would be as much about peace of mind as any tangible benefit, so I will leave that one up to you.;)
rodthebod
10-01-2017, 12:20
Well Ken thanks for the honesty about hearing any differences with the crossovers out etc.
Been busy with Christmas visitors and just about ready to carry on with speakers - it's so been bloody cold here, and I'm talking Malta here, that the garage has been a no no for finishing the cabs off, but I'm almost there now.
Finally got the caps from Wilmslow - Ansar and Mundorf's E-caps as shown on Ken's final crossover design (the one with tri-wire config shown on this thread) with 1uf Ansar across 22uf Mundorf bipolar E-cap for MD500 midrange unit, I have the MF500 so have 29uf E-cap+1uf Ansar. BUT, they sent the 6.8uf Mundorf E-cap as PLAIN bipolar which was to go with the 22uf E-cap to make up around 29uf and 1uf Ansar for the ideal 30uf for the MF500 midrange. However, with no reason given I was supplied with a RAW version of the 22uf E-cap, it's really tiny compared to the 6.8uf cap, less than half the physical size, and measures over 10% over tolerance, it's marked as 5% tolerance. But it's the RAW vs PLAIN thing I'm disappointed about. There is no LL shown for low loss shown anywhere.
On a more positive note, all the Ansar caps supplied show almost bang on when measured (within 1-2%)
I've contacted Wilmslow to see what they will do, hopefully it is a genuine mistake and they will get me the correct 22uf PLAIN E-caps I expected - I've noticed that the PLAIN type Mundorf E-caps are around 2-3 times more expensive than the equivalent value RAW type, which is what Wilmslow charge - ie the higher rate, but why have they the RAW type in stock at all.....
Anyway I'll keep you posted. Haven't ordered the Alcaps from Falcon for the bass and mid yet, was going to try the speakers out first then decide what to do, it would have been nice to have a working pair to try before embarking on this project, but I have every faith that things will work out well.
I have the one working original Studio 66 speaker as a temporary centre speaker in the listening room and does it blow away what I was using in terms of overall soundstage and realism - a pair of 5.5" drivers in 16 litre cab vs 12" + ABR in the 66's much bigger cab, not pretty as a centre speaker but I have the luxury of a listening room for me so no WAF to worry about... heaven. The old Celestion 66 really shines through on concert music but there are things wrong in the top end/upper mid when you get into particular songs which almost certainly are the crossovers using the way out of spec old original elcaps and electrolytics, the cabs are not airtight either around the drivers, short term solution was to use blutak to temporarily bung up the bigger gaps! So impressed by this centre solution I have acquired a 12" 66 bass driver from fleabay and am looking for a midrange MF500 or MD500 to make up a centre speaker using the old cab once I use the existing drivers in my new cabs - I could live without the ABR on a centre, unless one comes up - any suggestions on what to do with the crossover to make a non ABR version centre much appreciated. From what Ken has said I would like to get hold of a pair of MD500's long term then use one of the MF500's in a centre speaker 66.
I received my DOUK EAR834P Valve Phono Preamp clone board from China after three-four weeks with all resistors/caps components inc. JJ valves and I have to comment that the quality is exceptionally good for the cost, haven't wired it up yet and I'm looking for a case solution and need RCA chassis plugs IEC mains connection etc.
I'll probably end up cannibalising one of my Claritas Stands Unique media PC enclosures in a big way, use the side extrusions and slice down the 3mm ali top and base plates to a reasonable size. Modelling it up now in a 3D app to get some ideas.
Ken, where do you get your RCA chassis plugs from? ebay has many types described a 'Neutrik' but the actual Neutrik site shows no bare bones type chassis sockets only the more expensive square recessed type. I just need a reasonable quality set of 4 sockets as I'll use the Phono Preamp case with the passive attenuator and a switch for CD/DAC/Turntable. I have noticed some of the cheaper gold plated sockets used on kit discolour after a couple of years which isn't a good sign.
See things are coming together.
If you have trouble getting the "Plain" Mundorf eCaps from Wilmslow (didn't know they kept them) HiFi Collective keep them.
yep ive just received mine today from hifi collective,great service from all 3 company's,falcon (alcaps) cricklewood audio (ansars) and hifi collective (mundorfs)
1 slight set back is the 1uf ansars are on bloody back order,will take a week they say :(
it would also appear that falcon no longer stock alcap LL 72uf's :( i recapped mine a while back,im glad i did now!
have a look here rod if your interested :)
http://theartofsound.net/forum/showthread.php?48768-Celestion-Ditton-66-recap
rodthebod
10-01-2017, 19:36
Thanks for the info Jamie, that was my next move getting the 72uf LL and 4uf from Falcon, any idea where there are some or something as good/equivalent fro my 66's?
Wilmslow had the 1uf Ansars in stock around Christmas, they were part of my order which I just received.
hi rod,
cricklewood audio sell them but im not sure if they are low loss.
Thanks for the info Jamie, that was my next move getting the 72uf LL and 4uf from Falcon, any idea where there are some or something as good/equivalent fro my 66's?
Wilmslow had the 1uf Ansars in stock around Christmas, they were part of my order which I just received.
The 72uF were not Low loss, just use ordinary Alcaps. You wont get LL Alcaps anyway, no one has them, don't now if they were ever made at that value.
They are used in a parallel situation and my original Elcaps were not LL.
Replacing these with ordinary Alcaps made a big improvement to the bass on mine, the originals had drifted a bit off spec.
hmm i must be getting confused then,i did do mine a while ago,looking through my old caps i cant see any LL 72uf elcaps either! sorry for misleading anybody :)
here's a question for you ken or anyone else that may know,did the 66's come with the Velcro strips to hold the grills on or are they added by people who have lost the fixing screw?
the reason i ask is that with the Velcro strips fitted it makes getting the grills located in the metal clips at the top corners tricky,they also don't seem to go tight against the body too.
ive seen pics with them and without them so just wondered.
cheers.j.
walpurgis
16-01-2017, 17:27
here's a question for you ken or anyone else that may know,did the 66's come with the Velcro strips to hold the grills on or are they added by people who have lost the fixing screw?
the reason i ask is that with the Velcro strips fitted it makes getting the grills located in the metal clips at the top corners tricky,they also don't seem to go tight against the body too.
ive seen pics with them and without them so just wondered.
cheers.j.
They were original. I remember seeing them on new ones. I believe they used smaller velcro pads at one stage instead though.
There was a bit of 'slack' in the grilles when in position.
rodthebod
16-01-2017, 17:42
The 66's, I have, had strips of foam in the rebates either side of the baffle but only in lengths of about 3" to act as padding against the grille cloth stretched against the back of the steel fabricated cover. It didn't look like old adhesive that would have been affixed to the hook part of the velcro - could be wrong it was in a pretty nasty condition but flakes of old foam were there.
The foam on the padded strips was all but eroded and thinned with age but they looked an original fitting. If tolerances are that tight then using a padding strip might be a better solution as the material on the grille covers is pretty thick anyway, you have me wondering about my rebuilt cabs now, still unassembled, I'll have to check on the gaps I have made.
I've seen quite a few pictures of the later 'woodies' with no velcro or pads shown.
ah,then perhaps what im seeing in photo's is in fact foam strips then and not velcro,you can imagine with 6 strips of velcro holding them they are a bugger to get off!
Agree with Walpurgis - The foam padded Velcro strips were standard and there in my opinion to stop any rattle of the grill frames. The grills are quite long and otherwise only held in place at the top and bottom edges.
rodthebod
16-01-2017, 18:58
I can't comment any more on this one until I have re-glued the grille covers (washed them, or rather my lovely wife has they have come up really well - as new almost) then I can measure the gaps, but it does make sense what Walpurgis and Ken are saying, it is nearly a metre in height and you would need some kind of extra support other than the two metal clamps fixings either side, under the top lip, and the single screw fixing from under the bottom lip to properly secure the rather heavy grille cover.
It's quite an over the top cover being square perforated sheet steel and thick grille cloth - certainly it's not something that would be considered by todays designs.
It would be good to see the finished refurb
rodthebod
14-03-2017, 16:04
Well it's taken some time but I finally got the new cabinets together, using external crossovers for now for ease of access, but have placed T nuts at the base of the back to allow easy mounting later. For now until I have a good listen, I've kept as original components but with the hf caps (brown one's) thinned down to be closer to what they should read collectively, these suffered the worst in being out of spec a 1.5uf reading as 3.5-4.5uf. The mid range electrolytic (bright red large can) was within spec on both channels weirdly. The black/red elcaps did fair a little worse the 72uf bass/mid caps reading closer to 95uf. I'm using the crossovers with these values for now wanting to get a feel for what they sound like.
On first hearing they sound very nice indeed, a few hours later and I am very impressed. If this is what the original crossovers sound then I'm looking forward to hearing more improvements. :cool:
walpurgis
14-03-2017, 16:16
Very good. You'll be giving Paul over at RFC competition! :)
they are looking really good mate :)
rodthebod
14-03-2017, 17:20
19703
Thanks Geoff and Jamie
Haven't applied any finish to the cabs yet, just want to listen to them as it's taken months to get them sorted with one delay after another. I'm going for a natural clear wax finish to keep the lightness of the grain and to be honest the grain of the main panels doesn't look like you typical american walnut but I had to go for what was available - still they look much more 'modern' than their original cabs in teak (which as darkened to a very rich reddy brown colour) Bottom fell out of this one!!!:doh:
It's been quite emotional listening to the 66's as I didn't get a chance to hear them before, as they fell apart on moving them from where they were stored by the previous owner.
I get nostalgic memories of how my old Gale 401's sounded when I was in my 20's............... brilliant they moved air..... and so do these speakers
Being critical........ as you do, considering these are original 45 year old crossover capacitors, the midrange seems rolled off in the higher bass and the bass could be tighter, there's room for improvement in the top end definition too, but they do sound is really good, musically balanced with a sense of scale and these speakers have good integrity (control and power). I always think if a speaker can paint an aural picture where the cabinets seem to disappear things are working properly. Not being biased in any way as these have been built by yours truly! (Built to more or less exactly the same specs as the original cabs) The material I've used seems far harder chipboard than the original cabs and far stiffer and heavier but this could be down to age and the humidity which has broken the original cabs down to something resembling soft sponge in places. Modern processes will have an effect on the chipboard material of course but if you try to lift the cabs I've built then the original one's, there is a difference - the new one's seems much denser (is that a word...) and the original lighter.
Anyway they sound good so I'm pleased.....
I'll report back when I get a chance to chance some crossover parts.
Just got my notifications working again and caught up on this.
Nice work :thumbsup:
). I always think if a speaker can paint an aural picture where the cabinets seem to disappear things are working properly.
.
Sounds like you are on the right track if that's happening. :)
rodthebod
20-04-2017, 06:29
Been a while since my last posting, just to keep you updated on progress I've been listening to the 66's with the crossovers externally mounted tri-wired to the drivers and the original wiring which went to the terminals inside the cabs to the Leak TL12+ power amps. I've not touched the components on the actual crossovers yet, all original apart from taking out some of the HF (brown coated electrolytic cans) caps to bering the values closer to what they should be (6 and 4uf) These caps were the worst effected by age being way over tolerance eg. 1.5uf measuring 4uf!.
I've left the speakers so I could to get used to them since building new cabinets and to be honest because they sound so good. I have all the new components ready as per Ken's spec (Alcaps/Mundorf e-caps/Ansars for the HF and strapping the 72uf midrange by 5% - see previous postings)
I would have started surgery sooner had it been for the fact I had a bit of an enjoyable revelation when visiting Victor Angelo (of Terminator arm/Salvation TT fame) place a few weeks ago. He was using a digital front end using a custom media PC powered by a good DC linear power supply and an external DAC which was based on a Texas Instruments PCM5102 DAC (battery powered) and it sounded very good indeed playing CD redbook ripped recordings. So I've been on a mission for the past weeks to get a decent DAC and digital source. Vic has all his kit listed on his web site TransFi.
My Macbook Pro has a decent Cirrus logic DAC fitted and using Audirvana bit perfect output it has always sounded OK but nothing special driving a passive preamp to my efficient Leak TL12+'s power amps. I took the plunge and got a Chord Mojo DAC having read so many good things about their products. It's another league completely to the Macbook DAC way more musical and far more detailed but it's the presentation that wins me over. I read about PC's and laptops being noisey especially with switch mode power supplies etc. and the fact Vic was using a good LPS certainly proved their worth when listening.
So having read about the excellent dedicated audiophile software available tailored for the Pi - Moode/Rune/Volumio I wanted to try 'pure' battery power - no mains problems to worry about, and hear! What's the simplest solution......a very low power PC so I went for a raspberry Pi3 fitted with a Digi HAT spdif taking the digital signal direct from the I2s bus of the CPU (dedicated transformer and clocks with galvanic isolation). Hardwired the spdif from the PCB board bypassing the flimsy spdif connector then into a mini jack to the Chord Mojo. Powered the whole thing with a decent lithium-ion powerbank 5v battery and WOW!!! Once you've tweaked the configuration (I use Moode player) to everything highest possible quality you are in for a real treat, tracks become a real music feast - only having experienced on vinyl previously. I'm spending hours listening getting completely lost in time.....
I tried a R core transformer driven linear 5v power supply to the Pi, it sounds good, but doesn't have the cleanness of sound and there is a slight noise behind everything. Trying high current LiPo batteries, as used in drones and model cars etc. seems to give more dynamics - you have to use at least 7v 2.5a output with a variable voltage regulator to give the 5v required for the Pi.
Just thinking of a way to power the spdif board independently to see if that improves things further. You have to hear some of the high bitrate tracks 24/96+ and DSD - wonderful stuff.
Anyway, I've gone off topic, but am now ready to start changing crossover components to hear the improvements, with my new front end this should be easier to tell how things change. BTW elevating the 66's by a good 12 inches really helps clean up the bass and makes the cabinets even more transparent - even though it does make them look even more imposing - thank goodness I have my own room.......
ToTo Man
18-07-2018, 22:12
I hope it's ok to post here to let folks know that I am currently undertaking a Ditton 66 refurbishment of my own. I have upload loads of measurements graphs etc that may be of use to others. If you fancy checking it out here's the link (http://theartofsound.net/forum/showthread.php?59279-Another-Celestion-Ditton-66-Renovation-thread&p=995285#post995285). Your contributions would be most welcome :).
walpurgis
18-07-2018, 22:44
I hope it's ok to post here to let folks know that I am currently undertaking a Ditton 66 refurbishment of my own.
Good idea. :)
ToTo Man
19-07-2018, 13:59
Has anyone tried the replacement HF2000 diaphragms (https://www.ebay.co.uk/itm/REPLACEMENT-COMPLET-KIT-tweeter-CELESTION-HF2000-Ditton-25-442-44-66-240-BEOVOX/322270240180?hash=item4b08cd9db4:m:mHqNQlIGIgELlpg ifaofFhQ) being sold on eBay? (There are replacement MF500/MD500 diaphragms (https://www.ebay.co.uk/itm/REPLACEMENT-DIAPHRAGM-CELESTION-MD500-MD-500-MF500-MF-500-midrange-8ohm/222440768363?hash=item33ca80c36b:g:4nkAAOSw1S9WcBK z) too). I'm wondering if these would iron out the ragged responses of some of the HF2000s I recently measured? I'd offer to be a guinea pig but I lack the fine motor skills required for a job like this.
Being a 66 owner for many years and having already renovated a pair, I SHOULD know the answer to this, but I've never been absolutely certain whether the 66 was designed around an HF2000 with 4 ohm or 8 ohm nominal impedance. Can someone please put me out of my misery on this? What would a 4 ohm and 8 ohm HF2000 normally read on a DVM? I am aware of the rule of thumb: Impedance = DCR + 15%, which would put a 4 ohm nominal HF2000 at around 3.5 ohms DCR and an 8 ohm nominal HF2000 at around 7.0 ohms DCR. Thus I'm struggling to see where my HF2000s that measure between 4 and 5 ohms DCR fit into the picture?
Also, at risk of revealing my distinct lack of EE knowledge, is it true that the HF2000 and MF500/MD500 are in wired in reverse polarity to each other? As the colour coding on the crossover wires matches the colour coding on the drivers terminals I just assumed all three drivers were connected in the same polarity?
i bought when i had mine some supposedly rare red label hf2000 tweeters,when i recapped the crossovers i stuck them in and the top end was not as good as before,i checked my work on the crossovers and all was good,so i put the old tweeters back in and all the top end came back.
a call to falcon acoustics confirmed that the red label ones were from another speaker originally,i forget which but the guy did say they were 4ohm and not 8.
the reverse polarity is done at the crossover.so black wire still goes to the minus terminal etc.
ToTo Man
19-07-2018, 16:59
That's interesting. Way back on my very first pair of 66's I had to replace an HF2000 and I bought one with a DCR of 9.2 ohms and it was significantly quieter than the HF2000 in the other speaker which was around 4.5 ohms. I then bought an HF2000 that was 3.4 ohms DCR and it was louder than the 4.5 ohms DCR HF2000 in the other speaker. This seems to be the opposite of your experience.
Out of interest, what would be the effect of reversing the polarity on the HF2000? Would the output at the crossover frequency between the MD500/HF2000 be stronger or weaker? The measurements of the last pair of 66's I renovated show a peak in the response around 5.2kHz. I wonder how much this is to do with the HF2000's raw response and how much of it is to do with the crossover polarity.
hi,
ive replied to you on the other thread :)
rodthebod
14-04-2023, 11:41
Finally enjoying my Studio 66's now running in nicely after placing onto some DIY carbon Fibre supports, elevating these lovely things really gets the best out of the bass and using carbon supports makes the cabinets more invisible audibly. I'm so surprised overtime as I listen on how great they are for a 1970's speaker.
I tri-wired the recapped crossovers so I can bi-amp or tri-amp them. But just enjoying them with the Avondale Audio mono power amps and a valve driven Conrad Johnson (clone) preamp heavily modded, paper and oil output caps are devine. They are so efficient too sooo good on classical as well as Jazz and guitar rock. Happy man.
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