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Old 18th January 2013, 01:49 AM   #271
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Default A slight delay in parts ordering

Last night, when I was supposed to be ordering my parts for the ditton 44, I went to check out an amplifier. Wow! I was really impressed! I ended up coming home with it. Now it sits proudly where the Sansui 9090 was sitting. For me it was an epic moment. I had found that sound. Ave Maria was magical. Shine On You Crazy Diamond was perfect. And Billy Idol hasn't sounded like that since I heard him on my sister-in-laws Quad system with Kef 104s in the 80s. I'm sure Quadraphenia will be awesome again too!

It seems my instinct was right. The McIntosh and the Sansui just didn't have enough current for these 4 ohm speakers. The harshness is gone in the highs and the lows are fuller and have much more depth. It is in the words of someone else online, "as though a veil had been lifted."

It is a Kenwood Supreme 500, recently restored. It isn't minty, but it is in pretty good condition, with 30 some odd years of life behind it.

I know this is all a little off topic, but please bear with me. I am mentioning it because I started with 4 ohm speakers and because of that, I have been going on this adventure.

I hope that other newbies to vintage audio will take this lesson I have had back with them. My speakers sounded great at low volumes, but I was never happy as soon as I turned up the volume a little higher. I was overdriving the amp, but didn't know it because the only symptom I heard was the shrillness or harshness of the highs. The Kef's sound great now. I can't wait to hear the 44s.

Speaking of the 44s, because I bought the 500, I will have to wait 2 weeks until my next pay before I can put in the order. In the meantime, hopefully Lucas A will have seen your post, Alan, and have an answer for us about the Midrange in the Ditton 44s.

I think I will likely sell the Sansui 9090. As for the McIntosh 1900, she is a keeper. I love the way she looks and the sound she generates, and if I need to have it louder, I will play it on the Kenwood.

I am lucky living in Ottawa, because it seems there is more high end audio available in this city than any other in Canada, likely because of the high tech community here in the 70s onwards.

All my best!
Attached Images
File Type: jpg Kenwood Supreme 500 3776.jpg (333.7 KB, 245 views)
File Type: jpg Kenwood Supreme 500 3775.jpg (860.5 KB, 242 views)

Last edited by TechnoDweeb; 18th January 2013 at 01:57 AM. Reason: Pictures did not load
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Old 25th February 2013, 01:36 AM   #272
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Good day all!

I received the parts yesterday, so this afternoon, I did one speaker. It sounds a little less loud in the lows, than the original speaker, and I'm afraid I had to adjust the parts a little bit for the order options I had. I wanted to get all the parts from one place, and Solen.ca had the closest list to what I wanted. I don't mind that too much, as it is a learning experimental stage I am in right now, and I want to hear the differences. I decided to put in electrolytic caps on the low frequency, and had to use 68 uf for that.

It has been about 20 years since I last did soldering, and I was quite rusty, but I think it worked pretty well. Putting in the two resisters in the midrange section required that I remove a couple of jumpers and adjust the inductors positions, but presented no real problem. I think the updated crossover sounds clearer and cleaner in the mids and highs. The lows, I'm not so sure. Need to spend some time listening.
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Old 26th February 2013, 01:59 AM   #273
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Alan,

Last night, as I was listening to my mismatched Ditton 44s, something you said in one of your posts struck me. You recommended we place the resisters off the board, and away from any other components, so they wouldn't touch anything, for even cooling purposes. I did that, but as I was listening, I realized that the foam damper that goes into the speaker is pressing against the top of the crossover.

What do you suggest for dealing with that?

It is thick enough foam that the back of the woofer pushes against the foam and right onto the crossover.

I didn't do the other speaker tonight, but went to dinner with my son and played pool, very poorly... Tomorrow night.

Last edited by TechnoDweeb; 26th February 2013 at 02:00 AM. Reason: Forgot a sentence, it is late!
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Old 27th February 2013, 11:15 PM   #274
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First impressions, the highs and mids sound great, with possible the highs a little too sharp. Definitely the bass is uncontrolled. The second speaker I did had some fuzziness when I compared the two after only doing the first, so it definitely needed a re-cap. Do you think an 88 uf cap would be way too much? Fortunately, I got the 68 uf caps for half price, so it was a $20 test that I will recover some time in the future. In all, it took me about 5 hours to do both speakers. I ran into a few problems near the end of the second one, mainly because I was tired at that point, and made a few mistakes on the second one, but caught them while double checking my work.

Now, to fine tune it so I am completely happy with the two speakers. Once I have gained the confidence from that, I will start on my Kef Concerto's, which I have been listening to since right after Christmas. And I have to say these are really great speakers! I walk into the house when the music is playing and my first impression is that these speakers sound so good! And they are very versatile. Everything I play sounds good, and I am hearing things in songs I've never heard before.

In my search for the right sound, I have amassed quite a few speakers! I now have a pair of Klipsch Heresy's from 1972, JBL L100T's, Kef 104aB's, and Genesis 2's. I can see why you folks out there in internetlandia are always looking for new sounds. You meet great people, see all kinds of different equipment, and hear many quality of sounds. I've also found a Bose 1801 power amp that is being restored. I realized while doing these speakers that my instincts were right in not trying to restore any amps or receivers. My eyes just aren't good enough any more for that kind of detailed work.
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Old 1st March 2013, 10:13 PM   #275
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Hi Alan,

I bought a capacitor meter yesterday, measured the original 4 72 uf capacitors from the crossovers. They were all within 72 uf up to 76 uf. So I removed the new ones I had put in and put back the originals. Now the speakers sound right. No more uncontrolled bass, and the mids and highs seem to integrate into the sound better. I'm going to continue playing the 44s and listening critically to all my favourite songs. I'm very happy with the results.

Last edited by TechnoDweeb; 1st March 2013 at 10:16 PM. Reason: correction
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Old 12th March 2013, 06:48 PM   #276
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Default results and recommendations

Hi TechnoDweeb ,

I will comment on all four of your posts 272 <---> 275 above in order.

If you absolutely had to buy all from one source , then I would have from Madisound in USA ,
and if only from Canada , then Parts Connexion despite higher price because higher quality ,
however given what you have done , let us continue ...

Your assembly procedure is good DIY , do one crossover and listen to it in comparison to the other.
This is how one hears whatever degree of improvement.

If I read correctly on the Solen web-site , all their resistors are 10 watt ,
thus should not get hot , however they are very large thus take up a lot of space.
You can cut away a little of the foam at each of the places where it touches a resistor ,
and with the remainder of the foam un-cut , its pressure against the other components of the crossover will prevent the cut-away surfaces from touching the resistors.
This type of foam must not be allowed to get hot , or it will deteriorate to eventual degree to be useless for sound absorption.
Worse , if it gets very hot it will burn - inside the speaker box.

Woofer pushing onto the foam will not cause a problem , because that woofer will not survive sufficient power to overheat before very audible distortion ,
and thus its magnet will not get hot enough to affect the foam , unless it is played for a long while at audible distortion.

{ Put your son in a pool if he continues to beat you - he may need to learn to respect his father sufficiently to realize that beating him is not the thing to do
... however if he is under 18 years of age you may prefer to tolerate his competiveness.}

Highs will appear sharper because your memory of their sound is with the interim installed electrolytic capacitors in the tweeter filter.
Celestion did not use electrolytic caps there , but used Paper-in-Oil caps in the original version and Mylar {polyester} caps in the Mark II version.
If the highs remain too sharp for your liking , then install 0.33 or 0.47 ohms in Series with the filter's 4uF cap
- at whichever end of the cap is easiest to fit it on the board.
A 5 watt resistor will be sufficient , as it will not get hot.
I would try 0.33 ohms first , and later if sound still not good even with 0.47 I would replace the Solen caps with at least ClarityCap PX series.

I did not recommend electrolytic caps for the woofer filter ,
and now you have at least heard why ...
Changing the middle position 68uF for an 82uF electro would increase the filtering ,
but not likely improve the sound much ... and I think you may realize that now after hearing result with the original caps back in.
Why did this occur ?
(1)- you are very lucky that the originals are still in sufficiently useable condition.
(2)- those black Alcap brand were specifically designed for loudspeaker passive crossovers.
They were much better made than general-purpose non-polar electros were at that time ,
and than most non-polar electros are now , including obviously Solen's.
(3)- I understand that some DIYers can be confused when they see electrolytic caps in their quite good sounding amplifiers ,
but read recommendations to not use electros in passive crossovers.
I can explain why electros can work better in amps than in passive crossovers , however it will be lengthy.
For now , consider this :- a moving coil speaker driver is a generator of signal as well as a reproducer.
It sends a voltage back into the crossover.
This back-EMF mixes with the stored signal voltage of the Dielectric Absorption of an electro cap ,
and as each is delayed in time/phase differently to the other the resultant addition of their voltages is non-linear with respect to the frequency spectrum of the original signal ,
thus the significant change of sound ,
and more-so because the speaker's back-EMF is NOT the same frequency spectrum as the original signal but includes resonances caused by the mechanical aspects of the speaker cone.
To minimize this audibly unpleasant effect capacitors with as low as possible Dielectric Absorption { DA } must be used.
In an amplifier there is no significant internal generated and delayed back-EMF ,
unless a very poorly designed amp , thus the DA effects of electros in amps is less audible ,
and in some sections of an amp circuit DA is not a major problem , eg: in the initial filtering stage of the power supply.

A capacitor meter cannot detect faults in capacitors , though its reading can give a clue as to whether there may be a fault.
As all yours measure close to original value they probably don't have major faults , and as reinforced by your listening.
For now I recommend you put the two that measure largest capacitance into the middle position of the filter ,
and the two that measure lowest in capacitance into the output of the filter - that is where the woofer is connected.
That is better for sound if none are significantly leaking charge ,
but if any are significantly leaking charge they will cause less harm to your amplifier if they are in the output position of the filter.

To test for leaking charge , remove all from the crossover.
Obtain a new or little used 9 volt battery .
Use some pieces of wire and Alligator clips or similar and connect each electro cap separately to the battery terminals for a few minutes.
Disconnect the cap and place it somewhere its connecting leads cannot be short circuited to each other , eg: place on DRY wood , plastic , cardboard , paper.
Next you will need a DC voltmeter , or a Multimeter with a DC voltage range.
Set the range to measure 9 volts well and then measure the voltage of the disconnected battery , and write that somewhere so as to not forget.
Wait at least 2 hours , then measure the DC voltage remaining across each capacitor - each one separately - not all connected together.
If any measure more than about 1 volt less than the battery they are deteriorated.
If any measure more than about 2 volts less than the battery I recommend you do not use those ones.
The longer you wait , the more the caps will discharge ,
and if you measure them after 24 hours there will likely be very little voltage remaining ,
but if a cap cannot hold about 90% of its voltage for at least 2 hours than I recommend to not use it.
{ The only exception to that is for large electros in the initial filtering stage of an amplifier , where after about 2 hours about 80% of initial charge holding may suffice.}

Eventually those old electros will fail.
If you cannot afford Polypropylene caps for the woofer filter ,
then consider Solen's PEMT Polyester capacitors - they are much lower price ,
and a bit thinner than the Solen polypropylenes , though slightly longer.
Buy 33uF and 39uF and connect in Parallel pairs :- 33//39 = 72uF.
Connect the resistors I originally recommended in Series with each of these Parallel pairs for each filter position.
Polyester caps have less DA than electros , including less than the old Alcaps , thus you will get clearer bass sound , BUT it will not be as clear as with Polypropylene caps.
NOTE:- I am not recommending this as optimum , I am recommending it as a Compromise.
I would not do it , except in loudspeakers with mediocre quality drivers.

Similarly , I will not use any type Solen caps in midrange and treble filters until I am convinced their quality has been improved.
{ It may have been , but I do not know , however quite obviously they are better audio quality than the old caps that were deteriorated in the 44s ,
but if you were to hear the 44s with at least ClarityCap PX series to midrange and tweeter ...}

Given all those other classic old loudspeakers you have , I recommend you try ClarityCap PX at least in those if their drivers are still working well.
In the 3-way speakers you can use Solen or Axon True Cap in woofer filters.

Post some more here after you have tested your old caps for leakage , or made any other changes.
__________________
Alan

Last edited by alan-1-b; 12th March 2013 at 06:59 PM. Reason: to correct a spelling mistake
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Old 20th March 2013, 01:52 AM   #277
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Hi Alan,

Thanks for all the great advice. I don't think I would have tried this without you advising me every step of the way.

To clarify, I did buy Fast Capacitors 250v PA Series Metallized Polypropylene for the mids and high frequencies. I only bought the electrolytic's for the low frequency, in part to experiment, and secondly, because I had a very tight limit on my credit card after my Christmas cheers. That is also why I wanted to buy from only one source. I have no regrets though, and have learned a lot! My next recap will be using Clarity Caps. Most likely will be the Kef Concerto's. I have read that you love these speakers, and I have to agree. Initially, it was close, but as my ears adjusted to the Kef's, I grew to love them more and more. There are still two more flavours of Kef's I want to try out. Eventually.

Back to the Ditton 44s. I followed your advice and cut the foam in order to leave some space around the resisters. However I have been extremely busy, and didn't have time to test the 72 uf caps before I brought them to their new owners place. He was very happy with my work, and I ended up bringing back a Yamaha M-40 power amp. What can I say? I am obsessed!

It was a difficult decision. I had the Ditton 44s on the other side of the room from the Kef's, and by ABing them, there were some songs that the 44s shone, but most of the songs were better with the Kef's to my ears, my girlfriends ears, and my daughter's and room-mate's ears. Now that I know much better what I want, I think it will get easier.

I am going to part with more speakers, but I have a few speaker rebuild projects to do to get there. I want to do the Paisley's, restore a pair of DCM Time Window 350's including the surrounds, and possibly modify the Heresy 1s crossovers. I also need to sell my Sansui 9090. I'll eventually replace the JBLs, but I wanted some big assed speakers for the Bose when it is ready. This is really a lot of fun!
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Old 19th April 2013, 04:16 PM   #278
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Default another Correction to Schematic in #263 on Page 27 ; plus a response to #277 above

To anyone following this reconditioning of the 44 crossover:
TechnoDweeb's Schematic in #263 on Page 27 contains another error that I did not previously draw specific attention to.

C1 needs a resistor in Series - 1 ohm/5 watt , similar to C2 which is to have 1.5 ohm/5 watt in the position shown.

As I posted in #265 on Page 27 , the original Celestion HF2000 tweeter does not need a resistor, thus omit R4 ,
and as I posted in #270 , R3 is to be moved to the other side of the junction so as to be in Series with C3 before the inductors.
R3 is 1.8 ohm/5watt.
R2 is correct - use 2.7 ohm/5 watt.

--- --- --- --- --- --- --- --- --- ---

Hi TechnoDweeb ,

after all my posting about reconditioning the crossover you sell the 44s !
I should be charging a Commission , percentage of the sale price !!

If the buyer does not know about this web-site , I hope you referred him to this thread ,
because he will need to replace those old caps in the woofer filter at some point in the future.
I recommend you advise him to start with my post #260 on Page 26 and proceed through to this post ,
and buy the Axon capacitors whilst the price is good , and before they are all sold.

I hope you didn't give him the poor sound new electrolytic capacitors.
Use those in a Lo-Fi loudspeaker only !


The T27 tweeter in the original KEF Concerto is not the same T27 that was used in later KEF loudspeakers ,
thus when you upgrade the capacitors use the same cap values as in the old crossover ,
and not the different ones used in later KEFs ,
and especially not the 104AB modification , because it will not work with the earlier T27.
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Alan

Last edited by alan-1-b; 19th April 2013 at 04:21 PM. Reason: to add a sentance
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Old 20th April 2013, 07:04 PM   #279
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Quote:
Originally Posted by alan-1-b View Post

--- --- --- --- --- --- --- --- --- ---

Hi TechnoDweeb ,

after all my posting about reconditioning the crossover you sell the 44s !
I should be charging a Commission , percentage of the sale price !!

If the buyer does not know about this web-site , I hope you referred him to this thread ,
because he will need to replace those old caps in the woofer filter at some point in the future.
I recommend you advise him to start with my post #260 on Page 26 and proceed through to this post ,
and buy the Axon capacitors whilst the price is good , and before they are all sold.

I hope you didn't give him the poor sound new electrolytic capacitors.
Use those in a Lo-Fi loudspeaker only !


The T27 tweeter in the original KEF Concerto is not the same T27 that was used in later KEF loudspeakers ,
thus when you upgrade the capacitors use the same cap values as in the old crossover ,
and not the different ones used in later KEFs ,
and especially not the 104AB modification , because it will not work with the earlier T27.
Hi Alan,

I'm sorry you feel this way. I never had any intention of selling the 44s when I started this process. In the end, I loved the sound of the Kef Concerto's much more than the Ditton 44s. Also, I only sold the 44s for what I paid plus the cost of the crossover parts. I didn't make any money on them. I never expected or planned to, when I undertook the crossover rebuild. BTW, the only electrolytics that I bought were for the LF, for experimental purposes. And no, I removed them and put back the originals. At the time I ordered the parts to rebuild the crossovers, I was very tight on cash. I had bought so much audio equipment in my obsession of finding the "sound" I was looking for, I put myself in tighter financial straits than I should have. Spending an additional $50 on the better LF caps was not an option at that time.

Now that I have better amplification, I am now looking for a second pair of speakers for my second vintage audio set up. I will be selling my Sansui 9090 and the MAC1900. Although I love the looks of the MAC1900, it does not drive 4 ohm speakers or even the Paisley AE400's I have sufficiently. And since I only have limited space, I need to make room in my pocket book, and my house. With the Kenwood Supreme 500, the Yamaha M-40, and the Bose 1801, I think I have plenty of clean power. We will see once the Bose 1801 is restored which amp I will keep between the M-40 and the 1801.

I have even toyed with the idea of buying back the Ditton 66s, but I think the guy who bought them from me has sold them. Now that I have sufficient amplification, I would be able to hear them the way they are supposed to sound. Not sure what I will end up with for my second set of speakers. I may decide to go all out and get something really special with the hopes that this will kill my upgrade-itus. As things stand for now though, the Kef Concerto's are staying. I just sold the 104aBs. They never really meshed with my music preferences or my equipment, and i found the bass was lacking. I went as far as buying a subwoofer, but no matter what I tried, the set-up never really worked. The sub is gone too. But the guy who bought 104aB's loves them. Interestingly, the Concerto's although considered a really good Jazz or Classical speaker, are also really really good with just about all my music tastes except for Led Zeppelin and Billy Idol type music. And they project so well, even at very low volumes. The low frequency in them is stunning! I recently found another pair of speakers that are very comparable to the Concerto's in everything except low frequency. There isn't much information on them on the web. Wharfedale Dovedale III! The imaging is really special! It is like the sound goes into focus when I play them. Quite extraordinary!

Once I get more space, I will likely start the Kef Restoration, and will document it on a new thread here in DIY Audio. Thanks so much for all your help. I realize my flipping around like this has been frustrating for you, but from my perspective, I am just looking for the elusive "sound'. I think I am getting there.
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Old 20th April 2013, 08:41 PM   #280
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Default Response to #279

Hi TechnoDweeb ,

You have taken my comment about you selling the 44s a bit too seriously ,
as really it is entirely an owner's business what he does with his loudspeakers ,
thus if I am silly enough to spend time posting advice I get what I deserve.

Regarding Wharfedale Dovedale III , I would have to hear them again to remember their specific character , etc ...
however I think they had a simpler crossover than the Ditton 44 , thus that may be part of what you prefer in their sound ,
however a 44 can be got to sound quite a bit better than what only replacing capacitors causes ,
but to achieve more does require a lot of time and some more money.

KEF 104aB will never work with a sub-woofer , unless its ABR/Passive Radiator is removed and the resultant baffle hole rigidly covered.

KEF Concerto definitely has a different bass sound to 104aB , and also different in the midrange ,
however as different listeners prefer different aspects of sound , one has to hear to decide , as it seems you are doing ...
and also with all those amplifiers/receivers you buy ...

In general a subwoofer cannot be combined well with a vented/ported loudspeaker either ,
unless the vent/port is thoroughly blocked.

McIntosh 1900 should drive a KEF Concerto fairly well , unless you have a very large room , or want very loud sound.

Whoever is fixing the Bose 1801 for you had better get it working safely , or it will blow and damage the drivers in your vintage speakers ,
and probably the drivers in most modern loudspeakers also !

I agree that KEF Concerto sounds good even at low volume , and whilst they will play fairly loud , they are not a Headbanger loudspeaker ...
so stay with your JBLs , or a Cerwin Vega model ... hear some.

I don't know the sounds of many of the vintage USA and Canadian loudspeakers ,
and some of the UK speakers that work well for Rock may not be available where you are ,
but again , preference in sound is hard to predict unless one has given an example of a loudspeaker that one likes ...
which the person you are asking would have to have heard also.

As you didn't like the 44 sufficiently to keep , and also not KEF 104aB , I doubt you will find Celestion 66 to be what you are searching for ,
because it is like a 44 with a 104 type bass response added , though a 66 does play lower pitched bass notes to greater degree than a 104 can ,
however I think it may be the ABR bass type sound that you do not like ,
and that is fair enough , as some other listeners do not like it either ,
and I like it only for some things ... and similarly myself regarding ported/vented loudspeakers.
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Last edited by alan-1-b; 20th April 2013 at 08:45 PM. Reason: to better phase some sections
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