Not home made... I paid decent money for these back in 1985..$1250 plus customs fee.
So that`s nearly $3000 in todays money.
They are Dayton Wright XAM-4`s
Anyway, no PCB's, not even soldering lugs. Just a crow's nest 
!
I don't mind substituting non standard values by multiple paralleled capacitors or resistors. That's exactly what I'm about to do when building my pair of JBL 3134 crossover networks. But glueing components right to the enclosure boards is a no-go to me.
Best regards!
!I don't mind substituting non standard values by multiple paralleled capacitors or resistors. That's exactly what I'm about to do when building my pair of JBL 3134 crossover networks. But glueing components right to the enclosure boards is a no-go to me
.Best regards!
I hate Solen/SCR with a mad passion. The only place I think they are good for is the second pole on low pass filters. Use Mundorf MKP's instead, or Audyn. A little more expensive, but worth it.
ESR = Equivalent Series Resistance. It means that real capacitors are not perfect. They are 98% capacitance + 2% resistance (this is to illustrate, not absolute).
Don't attempt a 1:1 cap replacement in that big bank of caps. Figure out what it is first. Parallel caps add, but series divide. If I see it correctly, you have 3x 100uF in 2 banks.
If that is true, it is equivalent to 150uF.
ESR = Equivalent Series Resistance. It means that real capacitors are not perfect. They are 98% capacitance + 2% resistance (this is to illustrate, not absolute).
Don't attempt a 1:1 cap replacement in that big bank of caps. Figure out what it is first. Parallel caps add, but series divide. If I see it correctly, you have 3x 100uF in 2 banks.
If that is true, it is equivalent to 150uF.
I hate Solen/SCR with a mad passion. The only place I think they are good for is the second pole on low pass filters. Use Mundorf MKP's instead, or Audyn. A little more expensive, but worth it.
ESR = Equivalent Series Resistance. It means that real capacitors are not perfect. They are 98% capacitance + 2% resistance (this is to illustrate, not absolute).
Don't attempt a 1:1 cap replacement in that big bank of caps. Figure out what it is first. Parallel caps add, but series divide. If I see it correctly, you have 3x 100uF in 2 banks.
If that is true, it is equivalent to 150uF.
ESR = Equivalent Series Resistance. It means that real capacitors are not perfect. They are 98% capacitance + 2% resistance (this is to illustrate, not absolute).
Don't attempt a 1:1 cap replacement in that big bank of caps. Figure out what it is first. Parallel caps add, but series divide. If I see it correctly, you have 3x 100uF in 2 banks.
If that is true, it is equivalent to 150uF.
The mids have a bundle of 4 Nichicons 100uf 50v soldered together with a Vishay bypass cap soldered to them.
The subwoofer has 8 Nichicon 100uf 50v soldered together.
It was recommended that I use one Audyn 027-125 from Parts Express rated at 100uf 400v to replace the 4 that in there for the mids.
Can I use two of the Mundorf MKP 100uf 100v to replace the 8 Nichicons 100uf 50v going to the subwoofer ??
The subwoofer has 8 Nichicon 100uf 50v soldered together.
It was recommended that I use one Audyn 027-125 from Parts Express rated at 100uf 400v to replace the 4 that in there for the mids.
Can I use two of the Mundorf MKP 100uf 100v to replace the 8 Nichicons 100uf 50v going to the subwoofer ??
Thanks for helping Kay.
I was wondering that exact same thing. I`ve read many times while trying to order what I need that film caps don`t age and it`s best to just leave them alone.
As to those Nichicon caps, do you have any in mind that you would like to see put in ?
Funny that World Class Designers were happy with good quality commercial stuff bought over the counter and modern armchair "designers" **agonize** over Audioph ... ile über-expensive weird components with dubious faith-based "specs"
Those old "fools" trusted specs and measurement over "witness statements" and "personal opinion", go figure
You assume the capacitors are of exactly the same values regarding ESR, capacity but these caps are high tolerance ones. A higher capacity of one of these and/or a different ESR means the currents are not even at all! That times two give serious deviations in the resulting ESR and, in turn, a great impact on the SQ. I underestimated the effect too for quite some time but measurements and sound quality. You'd be surprised how much better it sounds if such a 4-pack becomes replaced with a single one better quality series cap. Really, you should try it.
Uhm, that's not correct. Firstly, the 100V are not the Vac rating, it's the Vdc rating. The Vac rating is 100:1,43=70V. And if you add the safety margin of at least 10V for longevity and that the tolerances will have an impact on the distribution of the voltage drop on the caps too, it's even lower, let's just assume another 5V (which is not much at 4 capacitors), then it's 55Vac, 378W at 8 Ohm. But that's just calculated at purely resistive load - which we know, the speakers are definitely not! Even the crossover itself adds a lot phase changes.
E: And the impedance does not stay purely on 8 Ohms, it fluctuates to sometimes very high values, depending on the crossover and drivers.
Secondly: That sounds quite a lot but what's the alternative? It's not about what that gives, it's about what you get without that 'contraption'. Let's compare it with a single capacitor. If it would be the same single 50Vdc rated capacitor, it's just 35Vac, subtract the standard 10V safety margin and you reach 25Vac which results in just 78W/8 Ohm. That sounds like it will be reached quite easily and with the phase shifts it can reach higher voltages, so it might be even as low as ~50W until the max voltage is reached. And that's not much at all! Please, have a look at this article.
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Those old "fools" trusted specs and measurement over "witness statements" and "personal opinion", go figure
Indeed, there are so many over-hyped speakers, I don't get it. You don't buy after numbers, you should buy by how good it actually sounds. I don't understand the hype of extremely old ..oh, sry, 'vintage' drivers either. Yes, there were some really good ones but just because it's old doesn't mean it's actually good. Back in the day there were some amazing speakers but there were also a sh*tton of crap on the market. A simple or crudely assembled crossover does not automatically mean it's one of the crappy speakers though. The manufacturers had to save money and if it works, it was probably 'good enough'. I prefer a nice XO board too but in the end it doesn't really matter if the parts are glued to the wall or are placed on a board. The parts glued to the enclosure got at least the advantage the coils are far enough apart and aren't inducing currents into eachother.
As far as build quality goes these are shameful. They sound great though.
They were never EVER designed with repairs or upgrades in mind.
They were wrapped like a mummy, are no 'grills' that you can remove at all, only a single piece of cloth and the cloth used in this 'cocoon method' was stapled about a hundred times to the back of the enclosure, then a panel was nailed and glued over it so you could not remove this 'grill cloth' without cutting open and ruining the cloth itself.
The drivers were/are all glued/epoxied in. It`s particle board and it becomes one with the driver with I guess is fine UNTIL you have to change one out !
The subwoofer baskets have been BELT SANDED on the sides to fit into the enclosure !!
I remember having to take one of the speakers back up to Canada soon after purchase to have one of the 6.5" mids replaced, I was mortified to see what they had to do to get it out.
While I was standing there, they had to cut off the cover and they had to CHISEL out the defective driver with a HAMMER !
I remember Mr Wright complaining that the driver cost HIM some $30 odd dollars to replace.
He blamed a Carver amp that I borrowed from a friend as the culprit.
After that though, they sang beautifully for many many years which leads me here for a well deserved refresh.
They were never EVER designed with repairs or upgrades in mind.
They were wrapped like a mummy, are no 'grills' that you can remove at all, only a single piece of cloth and the cloth used in this 'cocoon method' was stapled about a hundred times to the back of the enclosure, then a panel was nailed and glued over it so you could not remove this 'grill cloth' without cutting open and ruining the cloth itself.
The drivers were/are all glued/epoxied in. It`s particle board and it becomes one with the driver with I guess is fine UNTIL you have to change one out !
The subwoofer baskets have been BELT SANDED on the sides to fit into the enclosure !!
I remember having to take one of the speakers back up to Canada soon after purchase to have one of the 6.5" mids replaced, I was mortified to see what they had to do to get it out.
While I was standing there, they had to cut off the cover and they had to CHISEL out the defective driver with a HAMMER !
I remember Mr Wright complaining that the driver cost HIM some $30 odd dollars to replace.
He blamed a Carver amp that I borrowed from a friend as the culprit.
After that though, they sang beautifully for many many years which leads me here for a well deserved refresh.
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So now I`m lost. I thought I was zeroing in on what I needed. I have close up pictures of the cap connections if that will help.
I just want to order the replacement caps so I can move forward.
Thanks Tim.
So, I can use 2 caps rated at 100uf 100V to replace those 8 100uf 50V for the subwoofer and then 1 100uf 100V to replace the 4 for the midrange then correct ??
Just want to get the parts needed on the way...
Sorry, no schematic. Here`s a close up of the cap bundle for the mid range.
One side shows them soldered to what I`ve been told is a Vishay Film cap.
The other side shows them soldered together.
I hope this helps.
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