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railtycoon

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  1. I have been going through the same thing with a pair of KLF-30s. It all started when I bought the KLF-30s about three weeks ago. I have been using a Toshiba SA-850 receiver for about twenty years and I loved it. The problem was the KLF-30s are so efficient I couldn't turn the amp down enough at night while my wife slept. The SA-850 has one of those ALPS stepped resistor volume controls with the first and second steps being too quiet and the third step too loud. I dug out my old Luxman L-5 and hooked it up, not too bad, yet I just can't leave anything alone, I have to make it better, so I ordered the titanium mid and tweeter drivers from Klipsch. This is where the whole thing came crashing down. The sound was now very congested in the upper midrange and lower treble, there was little midrange, the speakers were very strident, the only thing that sounded OK was the bass. I couldn't get decent sound and almost went back to the phenolic midrange drivers. I was so disapointed I had thoughts of selling the KLF-30s. Fate took a hand when I was offered a second chance deal on eBay on a Harman Kardon PM665 integrated amp. I bought it and it arrived yesterday. After a trip to my work bench for a once over I installed it. The clouds parted and the stereo gods smiled on my system. The PM665 was the answer to everything. The sound is smooth, seperation is great (huge improvement in the soundstage), the mids are back, the highs are balanced and articulate and bass is tighter. The volume control works as I need it to and if needed there is a -20dB muting switch. A few other things I really like about the PM665 are: 1) Turnover controls for the bass and treble, you can select 200 or 400 Hz for bass and 2K or 6K for treble. 2) The amp is truly twin powered, two seperate power transformers and power supplies, like having two mono block amps. 3) It is powerful, 150 watts/channel into 8 or 4 ohms with good headroom. 4) It has pre-out & main-in jacks. 5) The loudness control is not your typical boomy bass, screachy highs affair, it boosts only bass at 50 Hz by changing the negative feedback of the amp, very cool and very effective, but I don't think I even need it. 6) It comes in silver or black to fit your tastes (I am a silver face guy). The KLF-30s can play quiet, moderate and rip your head off with this amp and do it while making me smile. I think you would love it with your KLF-20s. I paid $155 delivered so it is well within your budget. I also have a Carver TX-11a tuner on the way, it is supposed to be one of the best tuners ever, I hope it is what was promised by the seller and that it gets to me undamaged, if so, HOME RUN! []
  2. I am new to the forum and I would like to add my two cents to the the forum about La Scala upgrades. I am not new to audio electronics and have worked as an electronic technician for the last 35 years including HiFi and music stores. A month ago I bought a used pair of La Scalas built in 1984 to use with my Harmon Kardon A50K tube amp. The previous owner had installed Bob Crites CT125 tweeters and Bob's A/4500Hz crossovers. I got the original crossovers and tweeters included in the deal. My first impressions were not very favorable. The speakers sounded great at low volume but when turned up a bit they were very bright and harsh. I corresponded with Al Klappenberger and got some very good advice. Al recommended tractrix mid range horns from Dave Harris at Fastlane Audio and new crossovers. Dave is building the new horns as I write this and I will give my opinion on them later. After a lot of research, I decided to rebuild the Bob Crites A/4500 crossovers to ALK Universal crossover specs with a couple of my own upgrades. I reused the 3654 auto transformers from the old crossovers and replaced everything else with parts from Madisound. I used Solen Fast Caps, a Solen Perfect Lay coil for the woofer and Goertz copper foil coils for the mid and tweeter circuits. I wanted a little flexibility to adjust the mid and tweeter output so added two switches to the design. The first of which contols the output for the tweeter. The tweeter switch has two positions, 0dB and -3dB. In the -3dB position, the switch inserts a fixed L pad circuit using a 2.2 ohm resistor in series with the tweeter and a 20 ohm resistor in parallel with the voice coil of the tweeter. The mid switch has two positions, -3dB and -6dB. The switch selects between the -3dB tap and the -6dB tap of the auto transformer and changes the swamping resistor across the input of the transformer from a 10 ohm resistor in the -3dB position to a 8 ohm resistor in the -6dB mode. I installed the crossovers and began the test, listen and adjustment. I had a couple friends that I play guitar with give me their opinion as I adjusted the swiches. We all agreed that -6dB for the mid and -3dB for the tweeter sounded best. 0dB for the tweeter wasn't bad but -3dB eliminated the slight "sss" that the tweeters had on some recordings. The speakers retained excellent sound at low and moderate voulume levels. Loud volume was not tested as I am using a tube amp that may be able to muster about 30 watts per channel cleanly. My opinion went from "this needs fixing" to "WOW, WOW, damn WOW" and I wonder how the tractrix horns are going to make this any better. I am assured by folks that the horns will blow my mind. When I worked at Sound World in the late 1970s and early 1980s I fell in love with JBL L-250 speakers. I could never afford them and have been looking for the type of soundstage they presented. My La Scalas now have that type of soundstage, maybe not quite the vertical height of the L-250s but certainly as much or more definition. The La Scalas disappear and I hear the music as if the musicians are performing in front of me. I will give a report on Dave's horns and post a schematic of the crossovers as I built them in the near future. I would like to thank Al Klappenberger of ALK Engineering, Dave Harris of Fastlane Audio, Bob Crites of B&K Sound a.k.a Critesspeakers.com, Greg Roberts of Volti Audio, and The Klipsch Forum for help with schematics, designs, guidance and opinions. You guys ROCK![Y] P.S. I share the opinion that the original Klipsch AL type crossovers suck! If you still use them, read all the great material about new crossovers, decide how you listen and what crossover might best fit your needs. For me, it is Al's Universals at -6dB for mid and -3dB for tweeters. You won't regret it!
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