ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Hi all
Firstly what a brilliant forum..been so much help to me even as a guest.
I`m new here so hope I`m posting in the right area for a first post..couldn`t see a welcome forum.
Straight in at the deep end with a question if that`s ok?
I have a pair of RL 60`s and RL 140`s both of which I picked up cheap on an auction site and both with the usual problems.
I have rebuilt the crossovers on the RL 60`s using JB caps (I`m no millionaire) and I`m very happy with them, However I didn`t replace the resistors and have read a few posts saying they should also be replaced. They have a slight tendency to "squawk" if thats the right word..and I suspect the resistor. Is this correct?
The Bass radiator obviously was shot, so I followed the guide and converted to Bass reflex..seems ok to my untrained ears.
The RL 140`s are in a much sadder state. I`m mid way through re foaming. Like the 60`s I want to rebuild the crossover and this time I want to replace the resistors from the outset.
Here`s the big question then. Can anybody tell me which resistors to buy for these two speakers? I have looked and looked at the resistors in the RL60`s and I just can`t see any obvious indicator as to what to buy. I can solder and I can read so like for like no problem. I have no hope trying to work out mathematically what I need, so I`m hoping somebody here can just say..yep get these they will be fine.
Once again sorry if I broke any rules or posted in the wrong area.
Here`s hoping
Andy
Welcome to Beoworld!Unless the resistors are burned or physcially broken, there's absolutely no reason for replacing them.They don't go bad from aging like electrolytic capacitors do.Martin
Hi
Thanks for the reply. My resistors look ok, not burnt or broken. Is there any benefit for upgrading them just in case or does someone know the readings they should be showing on a meter.
I`m no expert, but the tweeters especially on one side do sound like they may be being over driven almost. If thats even possible
Replacing the resistors with new ones of the same spec will not upgrade or better anything.Replacing the resistors with new ones of different specs will take the whole filter out of spec.Wirewound resistors are rarely causing any troubles and it's even rarer to see them changing their values.The original resistors will be fine.
Sound problems, muffled, distorted, missing treble etc. will in almost all cases be caused by agingelectrolytic capacitors.In rare cases and if driven hard with old (read: ohmic) capacitors, a driver can burn and that will typically be themost sensitive one = the tweeter.
Replace the capacitors and take another listen. First then can you diagnose eventual remaining faults.
Martin
Hi Martin
Thanks again for the help.. I will look elsewhere for the issue as its plainly not the resistor.
I have already replaced the capacitors on the Rl 60`s and it is one of these that is causing the issue. If not the resistor, is it likely to be the tweeter itself?
On another note I sat down to work out which caps I need for the RL 140`s The refoam is done! I notice they have 2 different voltage ratings (63 and 100)
I know you shouldnt change the MFD of the caps, but can I go up to the same voltage on all of the caps and can this viltage be higher than the 63 and 100volts that are specified?
Swap the tweeters if you doubt one is weak.
If pushed hard, a Beomaster 8000 is capable of outputting something like 110V AC to the speakers wires.(Don't touch the speaker wires when playing at high volume!).Even if you rarely (if ever) play at these levels 63V components are still a bit underdimensioned if you ask me.
The capacitors in the readymade kits are all 100V for the same reason.
Sadly..for my neighbours at least, I do like to play my music if you get my meaning
I have already started searching for a replacement tweeter..the original is a Philips T8..how critical is a like for like replacement? There seem to be a lot of Philips T8 tweeters about but non the same as mine. I`m thinking its mainly down to the mounting system and the actual tweeter is very similar?
As a child of the 70`s / 80`s I always wanted a B&O system but could never afford it! Now I`m older and the misses is more forgiving, I`m filtering it in bit by bit..speakers first.
I have twin amps each driving 2 seperate speakers. Sony F670ES and Sony F570es. Not sure how you guys rate these amps, but they are tanks. I have a Goldring record deck and a Marantz sig.cd 62 mk2
First up for replacement....For cost reasons I had two sets of Wharfedale Xarus 5000 speakers, but they are pretty poor and in my opinion sound like they are playing in the bottom of a cess pit or back of a cave!
I rebuilt the RL60 cross overs and did a few minor repairs..mostly dust caps with small finger damage and bass radiator non existence issues, coupled them with the F570ES and the sound quality diff. was staggering!! amazing. Once I sort the tweeter issue they will be just fine.
I`m now working on the 140`s. If I am right what you are saying is voltage rating is not an issue? So within reason (and physical size) voltage can be changed as long as the capacitance remains the same. This will have no effect on the filtering? but does it mean I can burn drivers more easily? and does it matter if I use the same higher voltage for all the caps..so say 250 volts replaces all 63volt and 100volt
Also..which bit of kit should I be looking at replacing next and for what?
That`s a lot of questions..sorry
You can up the voltage spec on the caps in the crossovers - it won't change theirfilter characteristics, but you shouldn't go too high either.For most electrolytic caps it goes, that if f.e. a 100V spec'ed cap only ever sees a few volts it willnot be "excited" and it will go out of spec. Typically it will end up seemingly open circuit anddifficult - if not impossible - to "wake up" again.Foil caps are different. They will typically not contain any fluids so will not suffer from boredom ifnot brought close to their limits from time to time.
Tweeters typically blow from distortion, be that from underdimensioned amplifiers pushed too hard or from problems withthe crossovers components.Distortion contains a huge amount of harmonics, that's a lot of energy in the treble range (to high frequencies to be audible to humans).
B&O speaker drivers are generally difficult to match with modern (or any other for that matter) drivers.They are typically custom produced to B&Os specs etc.But if you decide you need a tweeter, why not go for the real thing :http://beoparts.com/2014/07/16/beovox-dome-tweeter-3/Martin
Thanks for that link Martin I am already in contact with them about the tweeter. I upgraded the caps in the RL60`S to 250v ones..do you think this may be too high bearing in mind what you say?
@ rune..I am pretty poor at electronics..I did know about the bipolar issue from reading on this excellent forum..but any and all help is much appreciated.
If I put a list together of the caps I think I will use on the 140`s would either of you be able to comment and advise on it before I buy them?
OK
Basically I am currently looking at Jantzen MKT metalized polyester film caps. I don`t know how well regarded these are but they come in 2 diff. voltage ratings and are cheap.
I think to replace the original 63v caps with 160Vdc caps..so 3.3 and 10uf @160 Vdc
and the 100v rated caps with 250 Vdc caps..so 6.8 15 and 33uf @250 Vdc
Do the voltage values sound ok. If there is a better known brand of reasonable quality budget caps out there what are they and where can I get them.
I`m currently using hificollective.co.uk
Thanks again
Quick update..I also ended up using Jantzen cross caps, simply because they had all the values I needed in stock at my budget. Ended up using 250 V across the board. The result of swapping out my old Xarus 5000 for the RL140`s and RL 60`s is so marked even a friend of mine commented on the quality..which is something for him. Thanks for all the advise..very happy old man here!
In the mean time I just bought my first full B@O system after 30+ years of waiting. It`s the Beosys 3300 and I`m very happy with it. I know its not their best and lacks some of the features of its bigger brother, but I can`t fault it yet.
I do have a question regarding the polarity of the speaker cables however. I will be running wires in wall, with fly leads between the amp and plug boards on the wall. I`m assuming the flat pin on the speaker plugs is positive? I can`t see any indication any where. I don`t want to solder up all my wall plugs in the wrong polarity
From what I read, flat pin is negative. But it really shouldn't matter as long as you do it the same way on both speakers.
Yes, you are right..a little research confirms it..plugs ordered and thanks.
I have a typo in my previous post, my new system is actually 3500 not 3300. I am now on the hunt for a record deck to suit. I believe there is an issue with pre amps with the later Beo systems? Which deck other than the beogram 3500/4500 can I plug straight in there? The 4500`s seem to be very pricey