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Modified RF-25 cross overs, Mundorf supremes and North Creek Inductors

I've been listening for a hour or two every night this past week, the capacitors are settling in nicely. This was the best money that I've spent on my system since I put it all together. The imaging is so improved from what it was. I guess I should get back inside my amps and upgrade the Solen capacitors to something better. The choice of components in your projects is very important. If you are thinking about starting an upgrade project, read these forums and get direction. I'll post any changes on the amps at this address on DIY. http://www.audiokarma.org/forums/showthread.php?t=224767&highlight=300b+set
 
Hi. I followed the topic from the begining. Congrats Dave. I believe this is a significant sound improvement, as you said.

Well, I have a similar pair of RF-25, and I would like to upgrade them in the same way. Did you work over the original Klipsch crossover design or a diffrent one? The two coils per plate calls me the attention.

Thanks in advance for your help.
 
Hi Fatsound, The RF-25's came equipped with different model cross overs. The first thing you need to do is remove the 4 screws that hold the speaker terminal/ cross over in place on the rear of the speaker and tell me the value of the capacitors, they are all yellow in color. and then how many ohms the tweeter resistor is, it is also labeled. SET12 and I figured that Klipsch made a mistake on the first cross overs and then set out replacements to those that had problems. Tell me that information and then I'll go on. otherwise mistakes could be made.
 
Fatsound, You have the early RF-25 crossovers. I had a tweeter problem shortly after purchasing my speakers. Klipsch sent me 2 new drivers and 2 new cross overs. SET12 and I looked those early cross overs with wonder because everything on the replacements they sent me was different except the chokes! Values on the new cross overs are as follows. C1 24.uf C2 2.0 uf and C3 4.5uf. The resistor is 5 ohms. Between the two cross overs if you run the values through a calculator program make no sense. I figured that Klipsch screwed up when they built them, no proof though and they claim to know nothing about it. The layout schematic of the new vs old is the same. The cross overs I built use 2.2uf in C2, C3 is 4.7uf and C1 is 22uf with a 2.2 across it. I pulled the 2 ohm resistors from the originals and used them for now. I had ordered 5 ohm duelunds but the tweeters didn't show enough for my ears that way. I think 2.5 ohm would be perfect for me. I looked all over for inductors and ordered the 10 ga from north creek. Expensive for a spool of wire but I coughed up the cash and am not sorry. I hope SET12 will jump in here on the cap values, he can explain them much better than me.
 
Thanks for the explanation Dave.
My RF's simply have a little bit agressive sound in the mid highs, a forward sound, not a great soundstage. A very rich live sound indeed. I think a more relaxed sound, more open, it's only a matter of good components, like you demonstrated. So, I would follow the same layout: re-cap (C1=22uf, C2=2.2uf, C3=4.7uf), re-coil, etc. One thing: one of the coils seems to have a solid core.
 
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Those coils are so wimpy! Take a nice amp and then squeeze the sound through that tiny wire. Think about it!
 
Yes, you're right. A local dealer suggested me some time ago the same: the current flow and the subsequent filtering effect.
 
Dave C said:
Those coils are so wimpy! Take a nice amp and then squeeze the sound through that tiny wire. Think about it!
Click to expand...

Dave, :scratch2: I take great pleasure :D in hearing you instead of me describing the typical speaker Inductors of today as wimpy :yes:

Dave, could you resend me your rf25 schematic with the 5 ohm resistor that your using, can't seem to find it!


Fatsound said:
Yes, you're right. A local dealer suggested me some time ago the same: the current flow and the subsequent filtering effect.
Click to expand...

Its not only the gauge of wire but the iron core inductors introduce hysteresis distortion which George at North Creek described as a form of compression, which is exactly what happens to the speakers sound stage and the large Air Cores just expand this. Its as though most speakers in contrast are like an 8mm home movie vs going to the Cinema for a CinemaScope film presentation.

The large Air Cores also help the speaker start and stop on a dime, forget the so called amplifier damping factor concern, IMO a speakers control is more related to its inductor quality than amplifier damping factor number.

For a Rock recording to pound me in the chest with the speed and impact of a jack hammer from an amplifier with a damping factor of 2 makes me :scratch2: and think something else has got to be going on here!

Try reading a little of this guy's reaction http://www.audioasylum.com/forums/hug/messages/14/147282.html

And no Iron Cores for me, I'm a believer big time in what George has to say here http://www.northcreekmusic.com/COILS.html

"No great discovery was ever made without a bold guess" (Isaac Newton)


Exactly how I got started

Cheers

SET12
 
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Hi.
I am not defending solid cores or gauges, Set12. Just noticed one in the original crossover. That's all. Now that you mention it, that piece of iron maybe help this speakers run in a more home theatre environment, their natural ecosystem. In a musical oriented environment, as you said, the air core it is more suitable. Good comment Dave, very timely. Thanks.
 
Fatsound said:
Hi.
I am not defending solid cores or gauges, Set12. Just noticed one in the original crossover. That's all. Now that you mention it, that piece of iron maybe help this speakers run in a more home theatre environment, their natural ecosystem. In a musical oriented environment, as you said, the air core it is more suitable. Good comment Dave, very timely. Thanks.
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Natural ecosystem! myself I don't see the difference, I'd still be using networks like I use. Myself in my younger days I would be out to movie theaters 2-3 times a week, I prefer my home theater sound to be as CinemaScope like as I experience in a theater not like an 8mm home movie size. Iron core inductors simply shrink the sound while large air cores give life size reproduction (this is providing the rest of the system has this capacity) which is more convincing to me IMO than the typical tiny point sources of HT today and given a choice between spending money for HT processing vs funds being spent on the crossover networks and using the same speakers for 2 channel theater sound reproduction, I'll take the high quality 2-channel over multiple speakers at a lower quality for multichannel sound. While the RF25's have small woofers I might add that DaveC has said that by adding the large air core inductors it was as though he got another octave of low end extension and with larger speakers such as the Fortes I use, the need for sub ends up being a mute point. An interesting point is with the investment in the large air cores you get far more range (in my case 30hz to 700hz) for powerful explosive dynamics than a sub that covers 20hz to 120hz. I can tell you this, but hearing it is believing.

SET12
 
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I use a stereo system with tube preamplification and it sounds acceptable. The same system for music and movies. I don't know what is he Klipsch market philosophy for their products (they have one), but the crossover they make are tiny and "wimpy". However their speakers are quite good.

Well, I want to give a more spacious stage presentation and more trasparency, solidity and more bass detail and dynamics. I Think the north creek coils and Mundorf caps are an excelent choice. And well, the mods that Dave has made is the type of mod I want for my RFs.

But for me the thing is to import all the stuff to my country (I live in Chile). That must be well defined from the start. So I'll appreciate your help and orientations enormously. :thmbsp:

Regards.
 
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Fatsound, I was hoping you lived closer so we could do some listening! The wonder of the internet has again made the world smaller. At least we can share our stories, that's a great benefit.
 
Hello Dave. Yes, the Internet makes the world smaller ... and better.

I had a lot of time thinking about tweaking the RFs crossovers, so I already had an idea about it, but I didn't "read" someone who do it. You know: practice is better than theory. Google searches do not always work, but finally found here in Audiokarma someone who had done exactly what I am looking for, and with the same speakers. When I read your impressions, was like reading my future. That was basicaly the motivation I needed.

A pity to live so far Dave.

Regards.
 
I have no regrets and would order the exact same combination if I had to do it again. I can look up the exact north creek inductors used if you want me to. I feel they are very important to the end result.
 
Thanks Dave. The data of the inductors will be very useful.

Well, I'll take the schematic directly from the original. Do you think is better a 2,5 ohms resistors instead of 2.0 ohms? I will order immediately Duelund resistors. The capacitors will be Mundorf. Duelund capacitors (looks like a swiss chocolate bar) ... maybe for the future. Coils will be North Creek. Do you think well be fine?

Thanks for your help.
 
I think the 2.5 ohm Duelund resistors would be a very good choice, this is something only your ears will tell you though. The North Creek inductors as follows. you need 2) 10ga 0.20mH $32.46 ea. and 2) 10ga .070 mH. $64.16 ea. We talked about the caps in a previous post. I used Mundorf Supremes, they worked great. If you have and questions just post them or send me a PM.
 
I am 50 years old Dave (so says my doctor, to whom I not need to see very often), so I trust your ears. 2.5 ohms will be fine. Thanks for the data.

So, I go shopping now (my Visa).
 
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Dave C said:
I think the 2.5 ohm Duelund resistors would be a very good choice, this is something only your ears will tell you though. The North Creek inductors as follows. you need 2) 10ga 0.20mH $32.46 ea. and 2) 10ga .070 mH. $64.16 ea. We talked about the caps in a previous post. I used Mundorf Supremes, they worked great. If you have and questions just post them or send me a PM.
Click to expand...

Fatsound said:
I am 50 years old Dave (so says my doctor, to whom I not need to see very often), so I trust your ears. 2.5 ohms will be fine. Thanks for the data.

So, I go shopping now (my Visa).
Click to expand...

Guy's its a .7mh inductor!!!!! not a .07mh

SET
 
Fatsound, SET is right, I miss typed! 0.70mH 10ga is the correct size! I'm very close to you in age, with me it appears my eyes are worse than my ears!
 
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