RTR III E speaker repairs

[timmeh1994]

Hi
wondering what it would take to fix up a pair of old RTR series 3 model E speakers. They dont sound too bad but the woofer in one is busted. Mum seems to think that they are great boxes and she worked in stereo supplies years ago. I would love to be able to get them sounding awesome again.


Thanks in advance :)

[thekid]

First -Welcome to AR!

Not sure what you mean when you say the woofer is "busted". If the voice coil is fried and you get no sound then really nothing can be done and it would need replacement. You could certain look on E-Bay for a replacement woofer that you could just drop in. Now if you are talking about the surround have a tear then you might be able to re-foam it. However while i am not familiar with the RTR Series III I did have a pair of Series IV's which I credit for infecting me with the vintage bug. Not a world beater soundwise but it looked impressive. In any case the surrounds on that woofer was cloth and if you have cloth surrounds on them then I would not recommend you try to re-foam them. My advice short of you getting an incredible deal for a driver off of E-Bay would be to look for another set of speakers. for what it would probably cost you to get these up and running you could probably find a pair of Original or New Advents, KLH, EPI's etc that will be a significant improvement over the RtR's. I know your Mom may be attached to the RtR's but once she hears a better speaker all will be forgiven...... :D

[timmeh1994]

with the woofer it still gets some sound but there is significantly more bass coming from the other woofer in the other speaker

[timmeh1994]

http://audiokarma.org/forums/attachment.php?attachmentid=754&d=1132305509
This is a picture of the same speakers im talking about that i found someone else did up

[luvtolisten]

Nice looking speaker, they look like foam surrounds to me. Since the woofer does work, it could be the voice coil is rubbing,(does move freely, when you gently push on it with no drag compared as does the good woofer with power OFF?) or perhaps a bad connection or crossover component. I would disconnect the woofers from the cabinet wiring, and ohm them out , both, to see how they compare. If they read the same unconnected, you probably have a bad crossover component or wire connection. If they ohm out differently, the problem in in the woofer itself.

[timmeh1994]

i think im looking to replace all the speakers except the tweeter because they work fine. Im just not sure what sort of things i need to do this and what speakers i need any help would be muchly appreciated

[timmeh1994]

Nice looking speaker, they look like foam surrounds to me. Since the woofer does work, it could be the voice coil is rubbing,(does move freely, when you gently push on it with no drag compared as does the good woofer with power OFF?) or perhaps a bad connection or crossover component. I would disconnect the woofers from the cabinet wiring, and ohm them out , both, to see how they compare. If they read the same unconnected, you probably have a bad crossover component or wire connection. If they ohm out differently, the problem in in the woofer itself.
What do you mean by ohm out. sorry im a bit of an audio newbie

[luvtolisten]

What do you mean by ohm out. sorry im a bit of an audio newbie

Glad to help! Here's a video How:

http://www.youtube.com/watch?v=gTIjFJWh0_E

You can buy a cheap multimeter at Walmart for about $20, or borrow one.

Before you ohm out the woofers, ohm out the cabinets, disconnected from the amp, going across the red + and black - terminals of the cabinets and compare the readings. My guess is they will be different. Then disconnect the woofers as in the video, ohm and compare them too. If the woofers are different, the problem is in the woofer (voice coil) if they read the same, the problem lies in the wiring or crossover leading to the woofer. Good luck! Let me know how you make out.

[timmeh1994]

ok thanks. im gonna have to go find me a multimeter.

[luvtolisten]

Good, I hate to see you buy new woofers, only to find one crossover was bad. Crossovers are fixable, woofers, usually not unless they need to be refoamed.

[timmeh1994]

Sorry about the delay. Ive been busy with work and havent had time to even look at the speakers. But i did do the ohm out thing that you said to do and the woofer actually isnt too bad. I also connected it up to the amp by itself and it plays pretty good sound. Another thing is that in these speakers the bottom speaker is a passive radiator so i dont think i will be able to find a replacement for that unfortunately.

Would Ohming out the boxes do anything because i need a way to test the crossover. Any suggestions?

[luvtolisten]

Sorry about the delay. Ive been busy with work and havent had time to even look at the speakers. But i did do the ohm out thing that you said to do and the woofer actually isnt too bad. I also connected it up to the amp by itself and it plays pretty good sound. Another thing is that in these speakers the bottom speaker is a passive radiator so i dont think i will be able to find a replacement for that unfortunately.

Would Ohming out the boxes do anything because i need a way to test the crossover. Any suggestions?

Ohming the crossover wouldn't tell you a whole lot, since the values would constantly be changing, due to the characteristics of the capacitors or inductors. You would need a special meter just for that, and you would have to take each component out of the circuit to test it. I would just replace all the capacitors, since they probably are electrolytic and have served their lifetime or close to it. They aren't too expensive, you can buy the same type or upgrade to poly metalized caps. Inductors rarely go bad. It just copper wire wound around a spool. A capacitor ( especially electrolytic) can deteriorate. If you live in the U.S., "Parts Express" has caps at a good price, just be sure they are "non -polarized" (no positive or negative end).
As far as the passive radiator, you could just re foam it, it's not hard, just takes a little patience and time. Or as you've stated replace the drivers, as a guy did from another forum.
Do both woofers ohm out to the same value?

[timmeh1994]

Yeah both woofers ohm out the same about 5.8 ohms. The 5' midrange ohms at 8.3 ohms(im assuming its stuffed) and the tweeter is fine. The 5' sounded terrible when i hooked the speakers to the amp on there own. But the speaker dome(in the middle) is crushed and the surround is about to split so they definitely need replacing.

I think im pretty much right for speakers. I think i will get new midrange(5') and a new woofer for each speaker. The passive radiator seems fine so i will just see how it goes.

The only problem im having and it would be great if you could help me out a bit is what wattage speakers i need to replace them with. My amp has a total output of 330 watts and i sniffed out a service manual on the net and it says "2x 33 watt @ 8 ohms". Im realy stuck on what wattage speakers i need to replace them with because the current ones dont say anything on them except a part number which i cant find anything about.

Help much appreicated

[luvtolisten]

Yeah both woofers ohm out the same about 5.8 ohms. The 5' midrange ohms at 8.3 ohms(im assuming its stuffed) and the tweeter is fine. The 5' sounded terrible when i hooked the speakers to the amp on there own. But the speaker dome(in the middle) is crushed and the surround is about to split so they definitely need replacing.

It sounds like the woofers are fine. The midranges also sound okay, and they won't sound great hooked up directly, because although they are called "midrange" it's actually it's more of a lower frequency tweeter, to handle the gap between the tweeter and woofer. But if the dome is crushed and spilt it's probaly time for a new midrange. You'd need an 8 ohm midrange.[/I

I think im pretty much right for speakers. I think i will get new midrange(5') and a new woofer for each speaker. The passive radiator seems fine so i will just see how it goes.

[I]Personally, I would keep the woofers, for now anyway, take one step at a time. I have read where some folks like the sound of that woofer, and it would save you some $$$. Besides, it would be more difficult to find a direct replacement, you'd have to take it a step further then finding a midrange, you'd have to know the cubic ft. of the cabinet which is critical.

The only problem im having and it would be great if you could help me out a bit is what wattage speakers i need to replace them with. My amp has a total output of 330 watts and i sniffed out a service manual on the net and it says "2x 33 watt @ 8 ohms". Im realy stuck on what wattage speakers i need to replace them with because the current ones dont say anything on them except a part number which i cant find anything about.

What amp do you have? Wattage isn't as critical as the frequency range you need. You may need to modify the the crossover. What is are the values of your crossover for the midrange?
I'm guessing your crossover should look something like this:

http://www.silcom.com/~aludwig/Sysdes/xover_series.gif

C= capacitors, should have a number before "uf" which tells you the value., L is the inductor it should have a number before "uh" or "mh". I would definitely replace all the capacitors, they have more than likely drifted out of spec by now.

Help much appreicated]


I'll try, but I am but no means a guru at this. Do you live in the U.S.? I'd be able to point you in the direction for more help.

[timmeh1994]

Gday yeah maybe replace just the midrange and see how it goes. i think i have found a part that could work but im not too sure. I dont no if u guys have Jaycar Electronics over there but heres a link to the part i found on the aus site.

http://jaycar.com.au/productView.asp?ID=CW2192&keywords=cw%2D2192&form=KEYWORD

Im not too sure weather my amp would drive this speaker and what effect the crossover would have on it. My amp is an old Optonica(sharp) sm-5200 with 330 watt output power. The manual says 33 watts per channel at 8 ohms.

[luvtolisten]

Gday yeah maybe replace just the midrange and see how it goes. i think i have found a part that could work but im not too sure. I dont no if u guys have Jaycar Electronics over there but heres a link to the part i found on the aus site.

http://jaycar.com.au/productView.asp?ID=CW2192&keywords=cw%2D2192&form=KEYWORD

Im not too sure weather my amp would drive this speaker and what effect the crossover would have on it. My amp is an old Optonica(sharp) sm-5200 with 330 watt output power. The manual says 33 watts per channel at 8 ohms.
Without knowing your crossover, I can't guarantee it would work, but it looks like it covers enough of frequency range, it shouldn't matter, so my guess (and that's all it is with the information given) is yes, it would work.
Your amp is a good vintage amp, although quoted at 33 watts, it's underrated and more like the 40-50 watt range, so it should drive that midrange speaker fine.
I see they also sell capacitors at your website, you'd be doing yourself a big favor by replacing the caps, even if it's with the cheaper ones. It would make a difference in the sound, let the crossover work as it was designed to.The caps wear out just as the midrange did, just not visible.

[timmeh1994]

Without knowing your crossover, I can't guarantee it would work, but it looks like it covers enough of frequency range, it shouldn't matter, so my guess (and that's all it is with the information given) is yes, it would work.
Your amp is a good vintage amp, although quoted at 33 watts, it's underrated and more like the 40-50 watt range, so it should drive that midrange speaker fine.
I see they also sell capacitors at your website, you'd be doing yourself a big favor by replacing the caps, even if it's with the cheaper ones. It would make a difference in the sound, let the crossover work as it was designed to.The caps wear out just as the midrange did, just not visible.

This is my quick drawing of the crossover. I have marked one of the boxes on the skematic as a circuit breaker, mainly because it has a reset switch on the outside of the box which goes straight into this box. There is also a photo of the crossover and the back panel.
http://i1219.photobucket.com/albums/dd422/timmeh1994/P1000333.jpg
http://i1219.photobucket.com/albums/dd422/timmeh1994/P1000336.jpg
http://i1219.photobucket.com/albums/dd422/timmeh1994/P1000338.jpg

if you could point me in the right direction that would be great

[luvtolisten]

It looks like your crossover is a 1st order, with a capacitor to cut off the low frequency of the midrange and tweeter. The crossover for the midrange is 3300hz for the low end, and 6500 hz for the high end (or the low end of the tweeter)..
The midrange you picked out would work as is, but I would replace the 6uf capacitor with a 15uf capacitor, this would lower the cutfoff point to the midrange (which can go down to 70hz). Using the 15uf capacitor, you would bring the low cutoff of your midrange down to 1300 hz, which would overlap the woofer frequency, making it smoother sounding than the original. The specs on the midrange are better than the original, may as well use them!
I would replace the tweeter capacitor with the same value 3uf, since the low cutoff is 6500 hz, and your new midrange goes to 7000hz, which is about right.

You could use cat no. RY 6910 for the midrange (2 ea) one for each midrange.
and cat no.RY 6901 (6ea), you will have 3 capacitors for each tweeter, twisting the ends together in parallel to make 1 capacitor which will = 3uf. Do not use the the 3.3uf, it may set the cutoff for the tweeter too low, causing distortion or damage to it.

You should also buy a can of contact cleaner spray for the pots or Lpads to the midrange and tweeter. Cat no, NA1004. It will eliminate the scratchy noise from the pots, and would work well on your amp volume, tone and switch controls as well if needed (just be sure it's unplugged if you decide to, and give it an hour, making sure it's dry before you plug it back in). I always have a can around, comes in handy.

[timmeh1994]

You could use cat no. RY 6910 for the midrange (2 ea) one for each midrange.

so your saying use 2 capacitors? how would you connect these up?

And the pots are they the 2 knobs?

[luvtolisten]

so your saying use 2 capacitors? how would you connect these up?

And the pots are they the 2 knobs?

One capacitor for each midrange, just put it in place of the 6 uf. (it's 2 total for your order)

Yes the knobs are the pots. Spray them from the wire side and turn them back and forth while you do.

[timmeh1994]

okay cool

and i will have to get some of that spray when i order the caps

sorry about all of the questions when u say 3 caps for each tweeter how would you have to connect them up

Thanks

[luvtolisten]

7679
The caps for your tweeter will look like this, only you'll have 3 twisted together instead of the 2 pictured, for each tweeter (6 total on your order, 3 per each tweeter) This will replace the 3K100VDC capacitor.

[timmeh1994]

Thank you very much for all of your help. Im going to go and get all the parts i need on monday(20th) hopefully.

Will keep you updated

Tim,

[luvtolisten]

Thank you very much for all of your help. Im going to go and get all the parts i need on monday(20th) hopefully.

Will keep you updated

Tim,

You're very much welcome! Yes, let me know how it goes, I hope it's a fun and enjoyable experience for you. Maybe you'll be bitten by the vintage bug as well. Have a Merry Christmas.

[timmeh1994]

Yeah im sure i will enjoy it! i have been thinking i should for a few years now and there just getting worse and worse sitting in the garage and arnt worth using at the moment. Once i get them going i will be using them heaps. They will probably replace my cheapie computer speakers or use them for my tv and stereo.

Yeah you too have a good christmas and a great new year

[timmeh1994]

gday i was under the impression that capataciters were directinonal?? would this be correct and how do i know which way to put it?? thanks

[timmeh1994]

hi
i was under the impression that capatacitors are directional? is this the case and how would i work out which end is which

[luvtolisten]

No, not for crossovers. You MUST use non-polar capacitors.That is capacitors that don't have a positive or negative pole. The speaker signal is AC. Either use the parts I called out earlier or do a search for "crossover capacitors" or "non polarized capacitors".

[timmeh1994]

Sorry to bring an old thread to life but...
my 20+ yearold amp has blown up/only left chanel works and i hate mono haha.
Im finding it pretty hard to find an amplifier that will fit with the low wattage speakers. i found a 100 watt rms amp that i thought would be good but im not sure whether it will work too well any advice. Remember i have a crossover with caps so does that lower the wattage that gets to the speaker in any way

THANKS

[luvtolisten]

What 100 watt amp is it? If it's a brand name you'll be fine. Most speakers are blown by amps rated at lower wattage. It's the distortion/clipping that most times causes speakers to be damaged. Although a amp maybe be rated at 20 watts, at .5% THD they can usually go higher, problem is so, does the total harmonic distortion (THD) which is usually the killer. It's not the power so much as the distortion.
The crossover shouldn't make any difference, (as long as you used at least 50 volt bi-polar
(non polar) caps.
Did you ever get those RTR's going?

[badhabit67]

What 100 watt amp is it? If it's a brand name you'll be fine. Most speakers are blown by amps rated at lower wattage. It's the distortion/clipping that most times causes speakers to be damaged. Although a amp maybe be rated at 20 watts, at .5% THD they can usually go higher, problem is so, does the total harmonic distortion (THD) which is usually the killer. It's not the power so much as the distortion.
The crossover shouldn't make any difference, (as long as you used at least 50 volt bi-polar
(non polar) caps.
Did you ever get those RTR's going?

That's a Good ?, I was wondering the same thing.. Most of those RtR's used CTS woofers in them,and they are a good driver. Sounds like it was a matter of just replacing some surrounds on em. With a recap,of the crossover.

[luvtolisten]

In most cases, the tweeter is the weakest link. If you are concerned, you could always put in an inline fuse, (usually about 1/4 amp for the tweeter). But you should know by the loudness level if you've reached the danger zone or over driving it, so I would say it's not necessary, just a piece of mind thing. I did it with some EPI 100's I have, after talking with a former employee of EPI, only because their tweeters have a reputation of being a bit fragile side, as they get older.
A good practice, no matter what size amp you have, is to turn the volume down to the lowest setting before you turn it off. Sometimes an amp especially the older ones, with give a last pop as it shuts down (probably the caps discharging I would imagine). Having it at it's low setting will help prevent any sudden surges as you turn it on as well, as it comes up to full power. A lot of the newer amps have built in features to avoid this, but not all the older ones. Besides, as I say, it's just a good practice.