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La Scala distortion help needed


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48 minutes ago, AudioDon said:

Thanks for everybody's help.  I think I've found the problem. 

 

My La Scalas with the AA crossovers have L-pads for the tweeter and squawker.  Mine were originally sold along with a Rodgers electronic church organ.  Both of the L-pads are really dirty. At one point I touched one to adjust it and heard the distortion or crackle. 

I'm in the process of cleaning them now, perhaps even removing them

Scratchy controls are the same as bad connection. As I said in other  post bad connection usually problem. As you said you may just want to replace them and see if you like the sound. If you want to keep them they are not that expensive at Partsexpress new. Deoxit works great but is not cheap. They also could be taken apart and clean with electronic cleaner and extra fine sandpaper. Either way you choose it will be a inexpensive fix compared to drivers. 

 

Now that know what a bad connection sounds like if you ever hear that sound again you can start checking all connections for cleaning and tightening. 

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On 6/9/2021 at 3:50 AM, AudioDon said:

I tried hooking up the leads directly to the horn by bypassing the X-over and it's still there.

 

This has probably fried your mid drivers.

 

Putting a full range signal directly to the mid drivers is not really recommended!

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4 minutes ago, Schu said:

I've had four LSii's (two pair) and they sounded VERY different than each other... the only difference being a resistor in the HF section of the XO on the 70th's, supposedly.

 

 

Which sound did you prefer?

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22 minutes ago, Islander said:

 

Which sound did you prefer?

the original LSii's had issues... I am not sure what it was exactly.

whether it was a resonance or a bad XO network, they were very harsh and extremely fatiguing when I first got them. I was distraught at first, but I decided to try and work with them because they did have that tight focused LF sound.

 

firstly, I just listened to them at slightly lower volumes than I was used to listening to my Cornwalls... that helped. then I started to get used to the extreme resolution and clarity and began searching out alternatives to source material and front end amplification and preamp. That lead me away from class D and into Tube amps, and that helped tremendously as it completely changed them into a different animal. After that I kept at it and tried better end preamps and tube amps and it got to be really good but they still could not match the 70ths.

 

when the great deal on the 70ths came about, I jumped at that chance and as soon as I set those up, they were wondrous and rewarding. It was like a completely different speaker with the similar attributes to the original LSii's. I was so surprised that I compared every aspect that I could between the two speakers, but they appeared to be very very similar... the only thing I could see was the difference in the XO, and a difference in the raw materials of the case/speaker wall. The original speaker had a very large grainy loose MDF when looking 'on end' from the exposed back, and the 70th's had a VERY smooth and much finer and tightly packed grain material finish 'on end' and to me it looked as if they had changed the MDF formula... but I was assured it was the same by the community. A knock test on the speaker walls also revealed an audible difference between the two speaker types in terms of their Timbre.

 

29683972028_8276664cd4_k.jpg

 

original LSii XO

43508631052_0d2d0e48c8_k.jpg

 

 

 

70th LSii XO

42650351955_1b56e02604_k.jpg

 

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So did you install R1A resistors in the non-70ths, to get that great sound?  And did you wonder about the possible effect of installing R1B resistors in one or both pairs of speakers?  Just wondering.

 

In the case of my LS2s, the whole HF section is disconnected, because I'm using K402 horns with K-691 drivers, EQ'd by a Dx38 and powered by a pair of Yamaha MX-D1 power amps.  And they sound great, although I still haven't reset the Dx38 from the K-69-A settings.  Once that's done, I'll run YPAO and get all the speaker delays set.  At present, they're set according to the tape measurements that I took, which is apart from the delay between the K-691s and the K-33s.  The Dx tales care of that.

 

Those are mighty complex crossovers, compared with A or AA types.  I've got AAs in my 1974 Scalas.

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3 hours ago, sootshe said:

 

This has probably fried your mid drivers.

 

Putting a full range signal directly to the mid drivers is not really recommended!

Thanks. I did it at low volume and the drivers are fine

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16 hours ago, AudioDon said:

Thanks. I did it at low volume and the drivers are fine

They should be fine then.  I've done that with tweeters, squawkers and woofers but always at low volumes and just long enough to see if the drivers were ok.

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7 hours ago, CECAA850 said:

They should be fine then.  I've done that with tweeters, squawkers and woofers but always at low volumes and just long enough to see if the drivers were ok.

Excellent. That's what I've done in the past with other drivers

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9 hours ago, CECAA850 said:

They should be fine then.  I've done that with tweeters, squawkers and woofers but always at low volumes and just long enough to see if the drivers were ok.

 

A bit of common sense goes a long way in avoiding damage and expense in all kinds of instances.  I wish there was more of it around.

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