Help for Tannoy Canterbury Xover welcome.

[Heinz R]

I slipped into this section just now. My question is about a 1993 Tannoy Canterbury. So it's not really "past masters" yet. We moved 15 years ago. Shortly before I detached the C1 condenser from the Xover. It is a type Tannoy 1091 Xover of this 15" Canterbury. I had fluff in my head at the time and wanted to swap this cap for a "better, more modern" one. Then the Canterbury was nicely dry stored in my office for very long years. Recently I wanted to reactivate them. To my great horror, the beading was totally destroyed and disintegrated. This first series of the Prestige had no hard edged beads. But I found a very competent specialist company in northern Germany who expertly installed new original beading. By the way, the original Tannoy surrounds actually came from Germany.
Now comes my problem. Due to the move, I lost the original C1 capacitors for the pair. It is the capacitor that goes directly from the amp connection to the autoformer. Now I don't know the original capacitance value. I found Xover schematics on the web for the Westminster Royal. It uses 6.8 uF. But I remember that the value could be smaller for the Canterbury. I have not found the 1091 schematic for the Canterbury anywhere. Lookwood told me to use 4.6 uF because that's what the HPD 385 had in the 70s. But I found photos on the net of someone using wickedly expensive Duelund caps. The article was in positive feedback magazine. There you can see 5.6 uF. But what is correct? At the moment I have 4.6 uF installed, but it might not be right, the tweeter sounds a bit thin with it. I would be very happy if someone knows the correct value or could even post or PM the schematics of the 1091 Xover.

[Puffin]

I would suggest buying a range of cheap or cheaper polycaps and try them until you find the value that suits your tastes. You can then buy whatever exotic caps you desire. Below is a range of caps and prices.

https://wilmslowaudio.co.uk/monacor-...ene-capacitors

OR for more £

https://wilmslowaudio.co.uk/jantzen-superior-z-cap

Changing crossover caps for expensive ones is not always a match made in heaven.

http://www.tnt-audio.com/clinica/cro...apping2_e.html

[mbic]

Have a look on this website https://www.hilberink.nl/speaker.htm

[Heinz R]

Thanks Puffin. I am aware that "better" caps do not have to sound better. I am just looking for the correct capacity. A year ago I fitted my 1977 Klipsch LaScala with new capacitors. After the original Aerovox motor run caps started leaking oil, "Sonicaps" polypropylene types were installed 12 years ago. I never really liked it and have been using polyester types for the last year. They don't have a very good reputation, but their ESR is comparable to the original Aerovox caps. Especially in frequency ranges that are not transmitted but contribute to the correct overall impedance of the Xover (e.g. in the 200 Hz range with a cap that is a high pass filter from 6000 Hz). Horns in particular often benefit from a softer Q. This assessment was shared by Roy Delgado, chief engineer of Klipsch Heritage and Cinema Speakers. I must say that now I like the LaScalas a lot again. Here my threat re the LaScala caps, I am KT88.

https://community.klipsch.com/index....t-impressions/

Polyester types are also used in the 1993 Tannoy Canterbury and I would order them again (I remember the yellow type but not the value). I have had 4.7 uF polypropylene types for two years now but it sounds bright and a bit harsh. I will...after all the research try 5.6 uF. No one knows for sure so far but a photo from Positive Feedback magazine shows a Canterbury with Duelund caps of this value. The answer yesterday from the company "MainlyTannoys" was also that they don't know exactly but are 99% sure that it is 5.6 uF. Polyester caps are not too expensive so I will also try 4.7 uF types.

Thanks also to mbic, I know the Hilberink page, he has listed the 1091 Xover type but no circuit or values are shown.

[Tannoy385]

Heinz R,
I've checked on my crossover 1091 (Canterbury 15 - Tanoplas foam surround).
C1 value is 6.8 µF. Part number is PHE 280 DG 768 (last 2 digits are the capacitance value).
Same capacitors values (3 off) are used for C5 to make up the 20.4 µF on LF.

As far as Canterbury goes, a few component value differences exist between original Tanoplas version (xover 1091) and later "hard edged" versions (HE / SE).

On HF: C1 (Tanoplas) = 6.8 µF. Later versions = 5.6 µF
On LF: C5 (Tanoplas) = 20.4 µF (same for Tanoplas Westminster). Later hard edge versions (both Westminster and Canterbury)= 30 µF

Also, R5 resistor (1Ω) exists on Canterbury Tanoplas version but not later hard edge versions. Interestingly though, resistor exists on ALL versions of Westminster Royal (Tanoplas and hard edge).
I can only think bass attenuation due to the horn on Westminster and bass attenuation on Tanoplas Canterbury due to its higher compliance vs later hard edged version.

Hope this helps.

I would be interested to know from the experts on here such as Cooky what difference there would be sonically between the 5.6 µF and 6.8 µF cap and also what effect the 1Ω resistor would have if omitted.

[Heinz R]

Hello Pedro, and welcome to AOS.
You don't know how much you helped me with your answer! Thank you so much!
I had seen a photo in the meantime where a Canterbury SE xover was tuned with Duelund caps in positive feedback magazine. On the Duelund cap you can clearly see 5.6 uF.
I had installed Mundorf silver in oil with 6.8 uF in my 1993 Canterbury in 2003 but I lost the original caps and I didn't trust my memory if 6.8 uF was correct. One of the reasons was that I absolutely did not like the sound. Everything was cloudy and "high end" softened much too soft. The "bite", the rhythm and impulse and the attack of the Canterbury was unfortunately gone with the silver oil Mundorf caps.

But now I finally know that 6.8 uF is right for C1! The reason for the softened sound is not a wrong value but the silver oil material I don't like.
I just, some minutes ago wrote the following in a PM to another very Kind member here who replied on my question and it fits here as I think:

„I think I'll experiment with polyester caps, like the ones used by Tannoy in my Canterbury Tanoplas. On my 1977 LaScala I had the best experience with polyester caps. They have a "worse" Q and fit the horns very well. With polypropylene caps the LaScala sounded very thin and a bit shrill.
Roy Delgado, the chief engineer of Klipsch Heritage and cinema speakers, whom I met personally in Hope AK in 2009, wrote in the Klipsch forum that the modern polypropylene can mess up the overall impedance of the xover. The reason is that in the low frequency range, around 200 Hz, the ESR of polyester caps is higher than polypropylene. Even though the cap separates at 6000 Hz and is not used in the 200 Hz area, it has a different effect on the overall impedance of the xover at 200 Hz. I think the Tannoy may be equally sensitive to changes as "modern" caps that are well intended but do not give in every case a well integrated result. Nothing against good modern components, but for this case I think I should change all caps and if necessary achieve the appropriate "Q" with additional resistors in series.“

So thanks again, Pedro. Now I know what to order at Mouser BTW based on your description I now can remember that the bass caps were three times the same value of the C1.

Regarding your question about the differences in comparison to the later models. Others will be able to provide better information than I can. But my thought is that it is not an improvement that the values were changed but probably an adjustment to the harder surround from the HE models onwards. There is a difference if you use 20uF or 30uF in the bass. You probably have to look at the whole xover in context. On the surface it would mean that the bass plays less high with 30uF and the tweeter less low with 5.6 uF instead of 6.8 uF. Of course I don't know how the rest of the components work and how the "Q" of the driver harmonises with the respective xover. But I am very grateful for the correct uF value so that the 1091 crossover is correct again "in its entire integrity". Because I don't think that you only change the high pass point of the tweeter if you take a smaller value, but you could change everything possible in the interaction of the components.

Lockwood offers hard edged beads in exchange for Tanoplas beads, but wouldn't you have to change the xover as well. When I got new Tanoplas beads 2 years ago, the workshop strongly advised against making a change to HE. Even the cone material could be different, the thickness of the cone etc.

[Tannoy385]

Heinz R you are very welcome.

You are correct that the overall crossover has to be balanced in terms of component selection to ensure it sounds "right" for the driver in question. This of course means that the Tanoplas vs twin Hard Edge surround will result in a different sound.

Interesting that you mention the choice of Tanoplas vs Hard Edge surround as when I had to replace the surround on the Canterbury's I gave it a lot of thought and in the end kept it original especially as it is the original cones from 1988 that are fitted to mine. That said, if you decide to replace your surrounds with the twin Hard Edge it is possible and there's the other option to use the new "blue" cones that Lockwood supply and which were fitted to the Prestige Canterbury HE / SE.

Interestingly, I have a pair of HPD385 which are almost identical to the 3889 used in the Canterbury with the exception that the physical flare profile of the HF horn is smoother (better machined) and I believe the magnet material composition is slightly different i.e., HPD is Alcomax V whereas 3889 is Alcomax III. The HPD's are fitted with an upgrade that Tannoy used to offer (via Lockwood) called THEOS whereby blue cones with the Hard-Edge twin roll surround from the Canterbury HE/SE were fitted to the HPD 385; Lockwood still offer an upgraded blue cone but not sure how it differs to the THEOS version (they used to offer for the HPD 315 12" many moons ago but now discontinued).

I have the matching upgraded crossovers to accomodate the Hard-Edge conversion and as you'd expect the 6.8 µF (C1) that you queried for the Canterbury is 5.4µF on hard edge surround version of the HPD and 5.6 µF for the Canterbury with Hard Edge. I used an active crossover though built by a UK valve aficionado called Nic Gorham of Longdog Audio. Really well built and based on the circuit here: https://www.hilberink.nl/codehans/tannoy86.htm.

Regarding the Canterbury "as is", the existing caps in the crossover are all RIFA MKT metallised polyester so should not need changing...the 2.2 uF is a Philips chicklet Polyester film capacitor. Modern caps may provide more clarity but that might be at the expense of the vintage sound.

The Canterbury 15 is from a golden age, the pair I have were the first ever built and a one off called the "Prestige Royal" (before they chose the name Canterbury) and suffice to say I will never part with them.

I might however be fitting my upgraded HPD's to one of the sets of modern Tannoy Legacy Arden cabinets I got from the Tannoy factory in Coatbridge before it closed - a little side project if you will. Anyway, good luck with the Canterbury and I'm sure you'll have them back to spec pretty soon. You may even be able to get new old stock on e-bay if that is an option.

[Heinz R]

It is interesting that in the later Westminster, HE, SE etc. the value of C1 remained at 6.8 uF, even though it was reduced to 5.6 uF in the Canterbury.

https://jeffsplace.positive-feedback...st-capacitors/

And it is also interesting that the xover schematics for the 70s HPD 385 all show 4.7 uF, no matter which speaker cabinet. I don't know the reason. Back to the Prestige series, is it that the Tanoplas Canterbury 15 has a value of 6.8 uF because almost all of them were sold to Japan at that time and that the chassis sounds nicer with that, but that it can't go as loud?.which is not done for most in Japan anyway?

[Heinz R]

Heinz R you are very welcome.

You are correct that the overall crossover has to be balanced in terms of component selection to ensure it sounds "right" for the driver in question. This of course means that the Tanoplas vs twin Hard Edge surround will result in a different sound.

Interesting that you mention the choice of Tanoplas vs Hard Edge surround as when I had to replace the surround on the Canterbury's I gave it a lot of thought and in the end kept it original especially as it is the original cones from 1988 that are fitted to mine. That said, if you decide to replace your surrounds with the twin Hard Edge it is possible and there's the other option to use the new "blue" cones that Lockwood supply and which were fitted to the Prestige Canterbury HE / SE.

Interestingly, I have a pair of HPD385 which are almost identical to the 3889 used in the Canterbury with the exception that the physical flare profile of the HF horn is smoother (better machined) and I believe the magnet material composition is slightly different i.e., HPD is Alcomax V whereas 3889 is Alcomax III. The HPD's are fitted with an upgrade that Tannoy used to offer (via Lockwood) called THEOS whereby blue cones with the Hard-Edge twin roll surround from the Canterbury HE/SE were fitted to the HPD 385; Lockwood still offer an upgraded blue cone but not sure how it differs to the THEOS version (they used to offer for the HPD 315 12" many moons ago but now discontinued).

I have the matching upgraded crossovers to accomodate the Hard-Edge conversion and as you'd expect the 6.8 µF (C1) that you queried for the Canterbury is 5.4µF on hard edge surround version of the HPD and 5.6 µF for the Canterbury with Hard Edge. I used an active crossover though built by a UK valve aficionado called Nic Gorham of Longdog Audio. Really well built and based on the circuit here: https://www.hilberink.nl/codehans/tannoy86.htm.

Regarding the Canterbury "as is", the existing caps in the crossover are all RIFA MKT metallised polyester so should not need changing...the 2.2 uF is a Philips chicklet Polyester film capacitor. Modern caps may provide more clarity but that might be at the expense of the vintage sound.

The Canterbury 15 is from a golden age, the pair I have were the first ever built and a one off called the "Prestige Royal" (before they chose the name Canterbury) and suffice to say I will never part with them.

I might however be fitting my upgraded HPD's to one of the sets of modern Tannoy Legacy Arden cabinets I got from the Tannoy factory in Coatbridge before it closed - a little side project if you will. Anyway, good luck with the Canterbury and I'm sure you'll have them back to spec pretty soon. You may even be able to get new old stock on e-bay if that is an option.

Hi Pedro, for some reason I missed your detailed and eloquent post. Thank you for all the additional and valuable information. It is obvious that the crossover has been adjusted because I think that probably the SPL of the HE cone is different in the transition range of about 1,100 Hz, and also the Q will have quite different values. Yes, I wanted to keep my beloved Canterbury from 1993 with "vintage sound". I installed a Kemet 6.8 uF polyester cap last weekend the type I had already successfully used for my 1977 Klipsch LaScala. Now the sound is really as nice as I remembered it. It is very interesting what you write about the different ways to repair or change the beads and cones. BTW I had a pair of HPD295 drivers with original crossover in a self built cabinet for a long time in the 1980's as a student with used Quad 33 and 405. I committed two big sins in my audio and music youth. Firstly, I sold those HPD295 10" Tannoys in about 1990 (and secondly, as a 19 year old in 1978, I sold my then second-hand cheaply bought original Fender Superreverb from the early 1960s...).
Sometimes I think that in terms of clarity and emotion of the mids, this combination of HPD295 with Quad, bought without much knowledge at that time, was the best system in my life until today. Perhaps it's also partly the fond memories of my youth.
Below is a picture, unfortunately blurred, of my xover of the Canterbury now.