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ARCHIVED FORUM -- April 2007 to March 2012

This is the first Archived Forum which was active between 17th April 2007 and 1st March February 2012


Latest post 03-14-2009 7:49 PM by Eugene. 12 replies.
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  • 03-07-2009 11:48 PM

    Baked cross/Now repaired

    Pulled this out of a RL 60.2. Just got the speakers the other day. Knew something wasnt right. Could only produce about about half the sound of my other set of 60's.

    So what are the recommended caps and resistors for replacement and where from. 


    I live in the US


    I looked at the specs in the service manual I downloaded but am unsure. A lot of typos has me a bit skeptical.

  • 03-08-2009 5:05 AM In reply to

    Re: Baked cross

    I would pull out the crossover in the other pair and compare. It is actually not that complicated a crossover - I would replace the capacitors and the resistors and leave the coils alone. In the UK there are a number of suppliers - in the US, Radio Shack comes to mind. Just look at the ratings on the good cross over and copy them.

  • 03-08-2009 5:09 AM In reply to

    Re: Baked cross

    Just dug out a picture of the cross over of one of mine - looks a bit different to yours!

  • 03-08-2009 8:00 AM In reply to

    Re: Baked cross

    The other cross has the exact same problem. Waht is specifically need is the resistance values on the burned one.

    The B&O spec says 15 ohm @3 Watts, but it also tells me to replace my caps with 23 volt caps. That aint right !

    All Radio shack does anymore is sell overpriced cell phones and ipods. what little stock of parts they do carry are overpriced and second rate.

    What I was able to find at Madisound where a set of Clarity SA caps that should work. Can match up the Values and increse the Voltage to 250vdc.

    I will probably raise the wattage a bit on the resistors as well. Why put on a dinky little 3 if it is going to burn itself back up again.

  • 03-08-2009 8:12 AM In reply to

    I was just about to post a link to my RL60.2 recap thread from January, but it seems to be another victim of the "pics gone after forum upgrade" problem.

    Anyway, I still have the pics and this is the actual crossover I found in mine:

    Except for the tweeter network, it was the same as in the service manual. These were apparently a very early pair, though, since the crossovers were built on chipboard instead of a "real" PCB. I have to admit I didn't check the resistors very thorougly, and of course the coils can be anything since they are not marked. However, if the actual crossovers match either the schematics or what I have drawn below, I guess it will be safe to assume that the component values are the same as well.


  • 03-08-2009 8:50 AM In reply to

    Re: Baked cross

    Thanks it does in fact match I was able to put the cross under direct light and using a Magnifying glass amke out 10r & 10%

  • 03-08-2009 9:37 AM In reply to

    Re: Baked cross

    You mean your R2 is currently 6.8+8.2 ohms in series instead of a single 15 ohms? It will be fine to replace them with a single resistor if you are able to increase the power rating. The original split was probably done to divide the load between the two resistors, hence a lower wattage could do.

    You should try and find non-inductive resistors, though. The larger power rating resistors are often made by winding resistive wire over the core, and they will have some inductance as well, which will affect the operation in audio frequency applications like this.

    One solution to increase the power handling would be to use four 15 ohm resistors instead of one (two in series, and two of these combinations in parallel). That would divide by four the actual power a single resistor has to be able to dissipate, and probably even 1W resistors would do.

    Anyway, the original damage must have required a prolonged play at near the maximum power these speakers can handle. If you don't feel like doing that daily, I would expect the original specs to be more than enough Smile


  • 03-08-2009 10:18 AM In reply to

    Re: Baked cross

    I was thinking Mills non-inductive resistors At 12 watts, I can also get Munfords at 10 watts. All at 1% tolerances.

    As far as caps go I found Clarity at 250VDC or Janztens at 400VDC (Cheaper). and also some super cheap 100 v caps.

    What I see on my board is a total of 4 resistors and 4 capacitirs.

    The burned one is probably a 1,0 & 10% a 6R8 (6.8) at 5 % the two little green guys are maked 1R0 5% and 22R @ 5%

    The Capacitors are 2 6,8mfd63V, 1 22mfd63v and 1 10mfd63v.

  • 03-08-2009 10:37 AM In reply to

    Re: Baked cross

    I know it's hard to tell, but is it possible that someone has been there before you and changed the resistors? Except for the burnt one,  the values would match if you take the woofer & midrage networks from the service manual, and the tweeter network from my drawing. I could see why it burned if it really was 1.0 instead of 15 ohms!

    Anyway, the resistors you was thinking of acquiring are probably just fine, and the caps as well. In mine, I used Intertechnik & Audyn MKT caps, all spec'd at 160 volts. That is definitely enough - the larger ones can be physically difficult to fit, even though there's quite a bit of space inside the RL cases. Here's how mine looked after replacement:


  • 03-08-2009 11:09 AM In reply to

    Re: Baked cross

    Like I said under direct lighting I could make out the markings that looked like 10R at 10%. doesnt appear to be any spacing between the 1 and 0 where a comma would go.

    Make probably more sense if I add up values assuming my crispy critter is a 10 ohm resistor. I come up with a sum value of 39.8 ohm spread accross the board, which is more in line with what I have on my older original series redlines that used a single 39 ohm 3 watt resistor.

    If on the other hand its only a 1 I come up way short on total ohms campared to what I have on my older set. That doesnt really seem to fly when little changed other than the ABR being replaced with a mufffler pipe.

    When I opened them up they looked virgin I dont really thing anyone else has been inside. Cosmetically this set looks about as good as you could expect from a twenty year old set.


  • 03-08-2009 12:40 PM In reply to

    Re: Baked cross


    Make probably more sense if I add up values assuming my crispy critter is a 10 ohm resistor. I come up with a sum value of 39.8 ohm spread accross the board, which is more in line with what I have on my older original series redlines that used a single 39 ohm 3 watt resistor.

    Well I must've misunderstood you earlier - you cannot calculate them like that. The different resistors are in different networks on the crossover, and do completely different jobs. You can think of the RL60.2 as three separate loudspeakers in one case connected in parallel (woofer, midrange, tweeter). Each of them has their own crossover network, working completely separately from the others. In other words, don't alter the design, just replace components with original (or upgraded) values.

    That said, it is quite possible that the burnt resistors were 10 ohms instead of 15 like in the schematic and in my RL60.2's. B&O used to tweak designs along the years, and not all of the changes are documented in the service manuals. But I'm pretty sure it can't be 1 ohms as the other components are still the same!



  • 03-08-2009 2:37 PM In reply to

    Re: Baked cross

    I got the blowtorch out and was able to pull all of the resistors out. An up close inspection under the light revealls clearly that the burnt resistor is a 10r 10% resistor.

    That said I can get non inductive  10W Munsford resistors that will match up all 4 precisely.

  • 03-14-2009 7:49 PM In reply to

    Re: Baked cross/Now repaird

    The speakers sound wonderful.

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