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[FIXED] Cornwall 1 bad crossover help


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1 hour ago, KT88 said:

This looks very practical and smart. But still I would solder the caps on the copper piece directly to the wires so that they touch,

great advice

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  • gsgleason changed the title to [FIXED] Cornwall 1 bad crossover help
26 minutes ago, KT88 said:

This looks very practical and smart. But still I would solder the caps on the copper piece directly to the wires so that they touch, you can just as easily swap the caps. Otherwise you have double contact resistances.

 

Always solder. The crimp connectors too.  I remove the silly plastic piece, crimp, solder then heat shrink.  A kit like this is helpful. 

 

https://www.amazon.com/560PCS-Heat-Shrink-Tubing-Eventronic/dp/B072PCQ2LW/ref=asc_df_B072PCQ2LW/?tag=hyprod-20&linkCode=df0&hvadid=198097502341&hvpos=&hvnetw=g&hvrand=3626950542201931339&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9030751&hvtargid=pla-385502389148&th=1

 

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52 minutes ago, tigerwoodKhorns said:

What about the vintage Russian square paper in oil.  Are these specially sealed or will they have a high ESR with age? 

 

All the square Russian PIO capacitors I have used for crossover networks were hermetically glass sealed.

 

I have tried MBGO, MBGP, and KBGP

 

If my memory is correct the third letter 'G' in the name type means that they are air tight hermetically glass sealed.

 

The first letter 'K' is Aluminum foil where as 'M' is Metallized paper.

 

The Second letter 'B' is paper insulation

 

The fourth letter I can't remember, something to do with the type of case and or it being made specifically for "Boreal Climates"

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20 minutes ago, captainbeefheart said:

 

All the square Russian PIO capacitors I have used for crossover networks were hermetically glass sealed.

 

I have tried MBGO, MBGP, and KBGP

 

If my memory is correct the third letter 'G' in the name type means that they are air tight hermetically glass sealed.

 

The first letter 'K' is Aluminum foil where as 'M' is Metallized paper.

 

The Second letter 'B' is paper insulation

 

The fourth letter I can't remember, something to do with the type of case and or it being made specifically for "Boreal Climates"

How do they sound?  (loaded question, I know)

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On 1/9/2022 at 4:42 PM, Crankysoldermeister said:

Russian capacitors from the cold war era used a glass to metal hermetic seal. Shelf life is forever. 

Almost as long as “C-Rations”

 

819E4459-D55C-4FCC-B507-A68EECAA83CE.jpeg

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The original post was edited, so I don't know what was said, but the GE motor runs are polypropylene, the Aerovox were polyester -- and I believe the capacitors that @thebes ended up using were the Russian PIO. 

 

The PIO sound the best to me, but it became a hard sell. I can always thank Bob and Al for convincing everyone that they were terrible and that I was hearing things. 

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On 1/16/2022 at 6:40 AM, gsgleason said:

Hello everyone.  I have an update.

 

I received the cross caps today and just did updated the problematic crossover.

 

The issue is fixed.

 

I'm going to do the other tomorrow and then do some listening.

 

I don't know if it's my imagination, but the speaker with the updated network seems less bassy, but looking at the schematic that shouldn't be possible.  It could absolutely just be the room and whatnot. 

 

It's a bit brighter than the one with the original but still working network.

 

The 2.2 measures right at 2.2 on my multimeter, and the 3.9 measures at 4.

 

Thanks for your help.  I'll report back later.

PXL_20220116_051432001.jpg

 

 

Hi @gsgleason

 

it's a bit late sorry, but you could do better than 3.9µF and 2.2µF.


I don't know if it was explained to you, but to make a 2µF capacitor simply use a 1.8µF capacitor with a second one of 0.22µF in parallel, that will give you 2.02µF theoretically with the tolerance +/- x%.

 

same for 4µF: use 1.8µF + 2.2µF in // => 4µF (In your case you can improve your 3.9µF by putting a 0.1µF in // for 4µF)

 

 

 

Good job for the your news networks and yes it's normal 2.2µF will be brighter than 2µF

 

;)

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@mustang_flht

 

Really the point was just to see if new caps fixed the issue without dropping $100, which it did.

 

It seems that people will endlessly debate capacitors around here, so instead of worrying about all that, I just got something that was a) good enough, and b) available, to get the speakers functioning to the point where I could see if I wanted to keep them.

 

Unfortunately, the problem I have now is that when I switch from the cornwalls to the RF5s, (which I've had and loved for a while), the sudden change makes them sound thin and harsh, as if they're missing an entire spectrum of sounds.  Seems the 3 way design is superior (probably no surprise there).

 

My issue right now is the cornwall lows seem to have some reverberation to them unlike the RF5 which sound much tighter to me.  And they're monsters.  Honestly way too big for my space.

 

My current plan is to sell the cornwalls and wait for a deal on a smaller heritage speaker.

 

Edited by gsgleason
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10 minutes ago, gsgleason said:

@mustang_flht

 

Really the point was just to see if that new caps fixed the issue without dropping $100, which it did.

 

It seems that people will endlessly debate capacitors around here, so instead of worrying about all that, I just got something that was a) good enough, and b) available, to get the speakers functioning to the point where I could see if I wanted to keep them.

 

Unfortunately, the problem I have now is that when I switch from the cornwalls to the RF5s, (which I've had and loved for a while), the sudden change makes them sound thin and harsh, as if they're missing an entire spectrum of sounds.  Seems the 3 way design is superior (probably no surprise there).

 

My issue right now is the cornwall lows seem to have some reverberation to them unlike the RF5 which sound much tighter to me.

 

My current plan is to sell the cornwalls and wait for a deal on a smaller heritage speaker.

 

As said earlier, give the caps more play and should mellow out.

Good job replacing yours.

Please PM me if more information wanted.

Thanks!

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4 hours ago, Crankysoldermeister said:

The PIO sound the best to me, but it became a hard sell. I can always thank Bob and Al for convincing everyone that they were terrible and that I was hearing things. 

 

I completely agree the PIO caps are great in these speakers. Bob is great but he had really poor hearing in his older years. I don't know Al.

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13 hours ago, tigerwoodKhorns said:

How do they sound?  (loaded question, I know)

 

Not very far removed from how the original Polyesters sounded, and who knows if I could tell the difference in a blind test but I felt the PIO had a smoother sound with instruments like Trumpets and crash cymbals that can get harsh/fatiguing sometimes. I just wanted to keep listening to music with them all night long.

 

I recommend Polyester to be safe but have no qualms telling people to go PIO. The consensus among people are the KBG aluminum foil types get more praise but I couldn't tell any difference between them and the Metallized paper types. Paper is paper and will give the same characteristics in dielectric properties. You can achieve higher capacitance values and better stability with metallized paper types, they are the technically advanced capacitor type. Basically instead of layering paper and aluminum foil they impregnate the paper (or any dielectric) with the metal giving better uniformity and more surface area.

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13 hours ago, captainbeefheart said:

 

All the square Russian PIO capacitors I have used for crossover networks were hermetically glass sealed.

 

I have tried MBGO, MBGP, and KBGP

 

If my memory is correct the third letter 'G' in the name type means that they are air tight hermetically glass sealed.

 

The first letter 'K' is Aluminum foil where as 'M' is Metallized paper.

 

The Second letter 'B' is paper insulation

 

The fourth letter I can't remember, something to do with the type of case and or it being made specifically for "Boreal Climates"

This quite ubiquitous available KBG-MN types are declared also to have sealed glas boxes. TBH the price is ok at least in the US, I will give this type a try to compare to my Polyester types. ESR should perhaps be relatively equal.

 

https://tubes-store.com/product_info.php?cPath=35_41_86&products_id=1430&osCsid=gihao15af6lfd0uabdo106pg60

 

 

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