Celestion Ditton 33 issues

[emi23]

Hi there, my first non-welcome post...

So I bought some good old ditton 33s, all the drivers work but I suspect they haven't been played much for a very long time.

They are a bit light on bass and are very bright and a little harsh in the top end. Might this be an old crossover capacitor issue? They are paired up with a Marantz PM4001 for the moment until I've finished building my valve amplifier.

Perhaps it could be the amp or just a speaker placement issue? I've a mulitmeter, are there any crossover measurements I could take to work out if there are bad components? I haven't yet been able to track down a schematic...

Any help would be much appreciated!

[Rare Bird]

The '33' are bright anyway but not harsh! There should be half a dozen caps & one Resistor per 'X-Over board'..i'd swap them out but leave the Inductors alone.

I find a supurb sounding yet economical way of Rebuild these X-Over's is using Ansar 'Supersound' Polypropylene caps & Mills 'MRA12' Non inductive Power resistors :thumbsup:

[DSJR]

Like 'ee said :)

[emi23]

Thanks! So I'm assuming you think that's the problem. What do you make of the maplin polypropylene capacitors (http://www.maplin.co.uk/audio-grade-polypropyleneaxial-capacitors-393)? The bass is much more sensitive to speaker placement than I'm used to, I think that's solved that issue!

[Rare Bird]

Hi Ed
No im not assuming that's the problem but out of experience old caps & nasty resistors want outting, i never use cheap polypropylenes.

Ive used those Ansars for years, they sound superb, they bring everything clearly into focus without addiing to the original sound & of course don't look that dissimular to the original caps apart from the size that is..

The oddest thing is people don't seem to be that bothered about the quality of power resistor they use on X-Over boards, i say it's crucial to have a very good non inductive type, again ive tried a few & found those Mills 'MRA12' to be superb (please use the 'MRA12' high wattage Resistor over the smaller 'MRA5' one they offer even though you don't require the extra wattage)

:thumbsup:

[walpurgis]

They may be too early, but do the tweeters have ferrofluid in the gaps? When that dries out it can bind the coils and distort the treble.

[Rare Bird]

No they don't..

[emi23]

Hi Ed
No im not assuming that's the problem but out of experience old caps & nasty resistors want outting, i never use cheap polypropylenes.

Ive used those Ansars for years, they sound superb, they bring everything clearly into focus without addiing to the original sound & of course don't look that dissimular to the original caps apart from the size that is..

The oddest thing is people don't seem to be that bothered about the quality of power resistor they use on X-Over boards, i say it's crucial to have a very good non inductive type, again ive tried a few & found those Mills 'MRA12' to be superb (please use the 'MRA12' high wattage Resistor over the smaller 'MRA5' one they offer even though you don't require the extra wattage)

:thumbsup:

I managed to track down a schematic

http://www.diyaudio.com/forums/attachments/multi-way/103121d1203870889-celestion-66-needs-mid-range-ditton-33-crossover-diagram-bw.jpg

Which means it would cost me £103 to recap just one of the speakers using Ansars, or £60 if I used the cheaper Solens :stalks:. I had no idea it would cost so much just for some capacitors!

I'm going to have a dig around and measure them all to make sure they actually need replacing.

[Rare Bird]

Edmund the Schem isnt showing.
Well if you keep the old you will never discover how good these speakers actually are.

Up to you buddy.

[emi23]

Oh, it's this link:

http://www.diyaudio.com/forums/attachments/multi-way/103121d1203870889-celestion-66-needs-mid-range-ditton-33-crossover-diagram-bw.jpg

This might be a bit cheapskate but could I just put in some new electrolytics and replace them every few years? Is it just that they fail easily or do they actually make a big difference to the sound?

[istari_knight]

Oh, it's this link:

http://www.diyaudio.com/forums/attachments/multi-way/103121d1203870889-celestion-66-needs-mid-range-ditton-33-crossover-diagram-bw.jpg

This might be a bit cheapskate but could I just put in some new electrolytics and replace them every few years? Is it just that they fail easily or do they actually make a big difference to the sound?

Worth a read: http://www.harbeth.co.uk/usergroup/showthread.php?1335-Refurbish-capacitors-inside-speaker-crossovers

Electrolytics in crossovers do degrade over time, only yesterday I serviced my brothers speakers [purchased in 1994] where a 5.6uf measured closer to 18uf ! You will need to replace every single one.

Even if you replace them like for like you will hear an improvement as they are so out of spec... Andre's suggestion of SuperSound & Mills is spot on but IMO only if they are mint condition & you really like them... I would be inclined to search out some 44's before investing that much in a pair of 33's. If I were you I'd replace all of the original caps with "Alcap Low-Loss" from Falcon acoustics but change the tweeters caps [8uf & 12uf] for Polypropylene.

They will be back "to spec" for another 20 years but with improved treble.

http://www.falconacoustics.co.uk/alcap-claritycap-solen-audio-capacitors.html

[emi23]

Thanks, that's a good read. The low-loss Alcaps don't seem to go above 25uf so instead of paralleling 4 of them to get the 90uf, would it be that much worse to use the 100V standard loss versions? If so, I might go for this arrangement:

Tweeter caps (8uf, 12uf): Solen 400V Fast Cap
Midrange (16uf, 30uf): Alcap 50V Low-Loss
Bass (72uf, 90uf): Alcap 100V

Which comes to about £20 per speaker, for capacitors that at least have the right values and should sound OK, they are already better than the originals after all. I'm going to measure them all to make sure it's worth it, but given that they are nearly 40 years old it seems probable, just waiting for my new multimeter to arrive.

[istari_knight]

Standard 100v Alcaps are fine for the large values. For the sake of a couple of quid I really do recommend changing them all regardless of how they measure.... That said, knowing old Elcaps I would be very surprised if you find one within tolerance.

[Artmin]

Hi Ed, have you done any more work to the 33s? I have just rebuilt the tweeters & recapped the crossovers in mine.

As they were den speakers & the cabinets aren't mint, I initially didn't want to spend a fortune on capacitors either, so I replaced them with ALCAP electrolytics. I felt the HF lacked definition & immediately changed the HF ones to Monacor MKPs & what a difference. The notes suddenly separated. I too think that they are quite bright though. In fact I am running with a 1 ohm power resistor in series on the tweeters at the moment.

One question I would like to ask you is do you know the dc resistance of your HF1000 tweeters? When I bought them the tweeters weren't working but I managed to get a reading off one voice coil at 3.4 ohms. There is a datasheet floating about somewhere that states they are 4 ohm. I compared these to the HF1000s in both pairs of 15XRs & they have a reading of 7 ohms. I am wondering did Celestion have two different versions, 4 ohm for the 33 & 8 ohm for the 15 XR. The 7 (or 8ohm) versions are certainly much brighter when in the 33s than in the 15 XRs. I see there is one on ebay at the moment with a resistance reading of 4.4 ohm?

I will be going to visit my Uncle in a couple of weeks who also has a pair of 33s (& 662s), so I will throw mine in the boot to compare.

[emi23]

Hi there artmin.

So most of the capacitors were still within tolerance, but some were leaking and having already bought replacements, I changed them all. I've been running them for a few months and I really love them. I couldn't tell if it made a huge difference to the sound but they will last for a long time now and I'm definitely planning on keeping them! I'm still working on the valve amp that will hopefully be ready by christmas. Until then they are still paired with the Marantz which I think is bringing out their brightness a bit much. Hopefully the valve amp will soften up the high end a bit. I'm still trying out different placement options, they are very sensitive to placement. I think the stands they used to come with were about a foot high and angled slightly upwards. Does anyone have these or know about them?

[Mike_73]

The '33' are bright anyway but not harsh! There should be half a dozen caps & one Resistor per 'X-Over board'..i'd swap them out but leave the Inductors alone.

I find a supurb sounding yet economical way of Rebuild these X-Over's is using Ansar 'Supersound' Polypropylene caps & Mills 'MRA12' Non inductive Power resistors :thumbsup:

Hello,

I recently bought and old pair of Ditton 33. Reading a lot about vintage speakers my eye fell on the Celestion.
As a coincidence someone offered them a few weeks later for a fair price, so i decided to check them out. Unfortunatly the room where i tested them wheren't at the best condition but even do i was fairly impressed and took the change. After a few weeks of listening with differend kind of music and some good comparison i concluded that the sounds was a bit dim. A friend of mine told me about the crossover problem of vintage speakers and that they wear out over the years. So i started google for some information and found this post about replacing the capacitors.
Well, i would love to give them a second life and listen too there full potential. I'm handy but unfortunatly this is way out of my league.

Could anyone help me guiding by replacing the capacitors of the crossover, maybe explaining in steps what i have to do and what i have to buy to get the same result that read here. Thanks in advance.

Mike

[Reffc]

Standard 100v Alcaps are fine for the large values. For the sake of a couple of quid I really do recommend changing them all regardless of how they measure.... That said, knowing old Elcaps I would be very surprised if you find one within tolerance.

James is correct here but there's also another issue almost always missed by folk simply measuring for capacitance and that's the fact that electrolytic caps of that age, even if they ARE within capacitance tolerance will almost always have a very high ESR (equivalent series resistance) as this increases with age and cannot be measured using a simple cap measurement meter. This will dull the sound (reduce tweeter sensitivity) and throw crossover points out. Best to replace all electrolytics over say 20 years old...they can be bought very cheaply indeed. Alcap are fine.

[walpurgis]

Paul. Mike is a new member and has not said what his whole system comprises of. My feeling is that the speakers may not be the main problem.

Mike, tell us what your complete system is, including cartridge. I have a feeling your lack of 'vibrancy' in your system may lie elsewhere.

[Mike_73]

Hello Geoff and Paul,

First of all i bought the speakers with lack of experience. A bit naïve but i just wanted to upgrade my speakers for a fair price and love the idea of a vintage sound. By the way, i tested it with my own set in a fairly small room.

My set is a combination of old and young and is never thought out. The amplefier is a Denon PMA-925R, my CD player is a Marantz CD5001 and my turntable a Thorens TD 320 with a Denon DL160 cartridge and an Linn Basik Plus arm.

I'd never seek for a Hi-end sound but love to upgrade my system a bit. So if you have some tips please do but keep this in mind.


Paul. Mike is a new member and has not said what his whole system comprises of. My feeling is that the speakers may not be the main problem.

Mike, tell us what your complete system is, including cartridge. I have a feeling your lack of 'vibrancy' in your system may lie elsewhere.

[walpurgis]

That lot should actually sound OK. The DL-160 is a lovely little cartridge and well worth hanging onto. I don't know that particular Denon amp, but Denons tend to sound pretty decent. The Ditton 33s are pleasant enough and should be fine with the amp.

What speaker cables and interconnects are you using? Are you using speaker stands and is the speaker positioning good? Room acoustics can affect the sound a great deal.

[The Barbarian]

Im a bit puzzled by someones comment where they said the '33' are dull! no they aint.

[Mike_73]

That lot should actually sound OK. The DL-160 is a lovely little cartridge and well worth hanging onto. I don't know that particular Denon amp, but Denons tend to sound pretty decent. The Ditton 33s are pleasant enough and should be fine with the amp.

What speaker cables and interconnects are you using? Are you using speaker stands and is the speaker positioning good? Room acoustics can affect the sound a great deal.

I purchased my cables and interconnects at a Hifi-store and they are more than everage. The positioning and the fact that they are standing on the ground could be effecting the sound i guess.

But how about the capacitors and the fact that they are still the original. Could that effect the sound? I notice that when i use the loudness, the speakers are more vibrant. There is also difference in some type of music. With easylistening and singer-songwriters they seem to work allright. When i listen to some more distorted music like garage or punk then everything seems to blends and there is no detail. If i compair them with my old speakers (cheap Elac speakers) they have more detail and are pleasant for the ears.

[walpurgis]

There's the likely cause of your problem Mike.

The speakers will not sound right on the floor. I'd suggest getting them about half a metre up, on rigid stands. That will remove bass boom and clean up the sound enormously, it'll improve the imaging and of course the tweeters and mid units will be closer to being on your listening axis, so you'll hear detail better.

I'd stop worrying about the capacitors and concentrate on basics first to be honest.