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My new babies: Lexicon LX-7's

 
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CIR Engineering




Joined: 25 Aug 2008
Posts: 4172
Location: Chicago USA & Berlin Germany

TV/Projector: JVC NX9 + Paladin DCR & Sony G90 : Lumagen Radiance Pro


PostLink    Posted: Sat Nov 21, 2020 7:44 pm    Post subject: My new babies: Lexicon LX-7's Reply with quote


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Against my better judgement I rolled the dice and bought a pair of Lexicon LX-7's on eBay that were "for parts, not working." Much to my surprise it wound up being the best gamble I have ever made on eBay.

I want to get these reanodized in black and have the silk screen redone. If anyone knows a one-stop-shop that I can mail the faceplates to I'd appreciate the reference. Otherwise I will do them locally as there are plenty of options in Chicago.

https://www.ebay.com/itm/Lot-of-2-Lexicon-LX-7-LX-7-Power-Amplifier-Amp-lot-READ-DESCRIPTION/264907986069

The photos were blurry in the listing and this was the description:

Quote:
Lot of 2 Lexicon LX-7 LX 7 Power Amplifier Amp lot. The lot is being sold as is for parts or repair. We powered both on and the blue lights come on for all channels on both amps. But when we actually tested the channels; each amp there was a couple channels that would cut in & out as well as sound distorted. We are unsure what the issues are, there could be other unknown issues as we stopped testing anything as we noticed channels were out on each amp. This lot would be good for someone that wants to possibly swap channels out of one to make one good working unit or someone that wants to repair both and have 2 working LX-7 amps. For the units only as shown, no cables or accessories included. Units have scratches, scuff marks, stains, chips, dings, labels and label residue.

Please do not purchase the lot if you don't agree to buying it in as is condition for parts or repair.
Sold as shown.
Free U.S. shipping
Due to the size and weight of the amps, there will be no international shipping of this lot.
Amps will be packed and shipped in 2 separate boxes.


While the description seemed fishy, I talked to the seller and believed him afterwards. He also had feedback over 1500 with 100% positive. Even so, from the photos he had posted I thought the amps were probably in pretty poor cosmetic condition. Before buying, I also verified that the output transistors are still available from authorized resellers in case that wound up being the issue. The amps arrived and were packed incredibly well. Separate boxes as promised with enough bubble wrap to last me the next two years.

Curt had done me the favor of talking with an authorized Lexicon repair tech and who had made some great suggestions on what to test first. His tech wound up being right on the money and I had them both fully function in less than 48 hours with parts on hand.

With that done, I turned to cleaning them up and much to my surprise the cosmetics came out beautifully! Only one amp has a small bruise above the #4 channel LED (it looks like I partially wiped the "4" off using Goof Off to remove the black scrapes near it), but all the scrapes wound or being black paint or black anodization from other components rubbing them.

I quickly realized that these amps also have very low hours. They are actively cooled and build up dust quickly when used often. One amp was built in 2003 and had more use, but still low. The other was built in 2006 and must have less than 100 hours on it; looked almost brand new inside.

I run my amps at 240 volts so the next thing I had to do was figure out how to convert them. This took half a day and was done except... in my jubilation I reinserted one of the amp modules too soon after I powered the amp down and I blew out a channel Sad I had stupidly left the amp in standby when I plugged in the module and probably didn't let the 100,000 uF of capacitance drain off completely. I heard crackles and sparking and was like, "oh shot."

Lexicon flat out refused to give me schematics even with my contacts at Harmon. So I had to repair the module the hard way with brute force tracing of contacts and diagnostics. Luckily I found a blown opp amp quickly and replaced it and the other four opp amps in the same circuit just in case to bring the channel back to life.

I replaced the loudish ball bearing fans with Noctua "NF-A9 PWM chromax.black.swap" fans of very similar specification. I am so happy with these amps. It's been a nice feeling to have something go so well Smile

Here are pics:









These things are absolute beasts and are difficult to even pickup and put into the rack due to their size and weight. They have been independently proven to be capable of running 200 watts per channel continuously without distortion. When new, they sold for $6000 each between 2003-2006.

You can also bridge four channels on each amp to make each amp have a pair of bridged outputs at 400 watts per channel. I'm running my L, C, R this way. This still leaves me with two extra unused channels as I am currently running 7.2.2. I think some ButtKickers may be in the near future.

I'm in love Laughing

craigr

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Phone: 865-405-6892


Last edited by CIR Engineering on Sun Nov 22, 2020 4:16 am; edited 6 times in total
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CIR Engineering




Joined: 25 Aug 2008
Posts: 4172
Location: Chicago USA & Berlin Germany

TV/Projector: JVC NX9 + Paladin DCR & Sony G90 : Lumagen Radiance Pro


PostLink    Posted: Sat Nov 21, 2020 7:50 pm    Post subject: Reply with quote

This is what my matching MC-10 looks like. You can see why I would like to redo these LX-7's in black.



I've got to get on that.

craigr

_________________
JETI Specbos 1211 Spectroradiometer
Photo Research PR-650 Spectroradiometer
Klein K10-A Laboratory Grade Colorimeter
X-Rite i1Pro2 Spectroradiometer & Spyder Colorimeters for JVC auto-calibration
Murideo Fresco SIX-G HDMI 2.x Multimedia Generator
Murideo Fresco SIX-A HDMI 2.x Analyzer
*NEW Light Illusion ColourSpace XPT Version β Color Calibration Software
Light Illusion LightSpace XPT Pro Version 10.x Color Calibration Software
Sencore CR7000 CRT Tube Analyzer / Rejuvenater
Authorized Dealer for Lumagen & just about everything worth buying Wink
www.CIR-Engineering.com - craigr@cir-engineering.com
Phone: 865-405-6892
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CIR Engineering




Joined: 25 Aug 2008
Posts: 4172
Location: Chicago USA & Berlin Germany

TV/Projector: JVC NX9 + Paladin DCR & Sony G90 : Lumagen Radiance Pro


PostLink    Posted: Sat Nov 21, 2020 8:02 pm    Post subject: Reply with quote

Finally and ironically, I ordered two brand spanking new JBL Synthesis SDA 7200's that arrived a couple days before the Lexicon LX-7's. I took one of the 7200's out of the box because something was rattling around in it (turned out one of the rack mount ears was not secured, but all OK). The 7200's are D class amps and even though my hearing sucks now, my old audiophile sensibilities have trouble accepting a class D amp in spite of their outstanding reviews.

The 7200's weigh less than half what the LX-7's do and feel like toys compared to them. Granted the 7200's are probably around 90% efficient while the LX-7's are probably around +50% efficient because they are of course class AB.

I have not even listened to the 7200's because I think I am going to resell them as brand new in the box from an authorized dealer. Tough decisions... real first world kind of problems Mr. Green

I also have the Acurus amps that I replaced, I really didn't need amps to begin with. I was running three A250's and two A200x3 in the rack with a spare A200x3 for backup. I've always loved those amps too and am not sure I want to part with them either. I bought the first A250 new back in 1995. They have a transformer buzz though that I can't get rid of because of the awful DC on our terrible power here on my street that the Lexicons do not manifest.

craigr

_________________
JETI Specbos 1211 Spectroradiometer
Photo Research PR-650 Spectroradiometer
Klein K10-A Laboratory Grade Colorimeter
X-Rite i1Pro2 Spectroradiometer & Spyder Colorimeters for JVC auto-calibration
Murideo Fresco SIX-G HDMI 2.x Multimedia Generator
Murideo Fresco SIX-A HDMI 2.x Analyzer
*NEW Light Illusion ColourSpace XPT Version β Color Calibration Software
Light Illusion LightSpace XPT Pro Version 10.x Color Calibration Software
Sencore CR7000 CRT Tube Analyzer / Rejuvenater
Authorized Dealer for Lumagen & just about everything worth buying Wink
www.CIR-Engineering.com - craigr@cir-engineering.com
Phone: 865-405-6892


Last edited by CIR Engineering on Mon Nov 30, 2020 5:46 pm; edited 1 time in total
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kal
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PostLink    Posted: Sat Nov 21, 2020 8:23 pm    Post subject: Reply with quote

Wow! Nice find Craig. Lexicon makes some fabulous equipment.

Kal

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AnalogRocks
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PostLink    Posted: Sat Nov 21, 2020 11:46 pm    Post subject: Reply with quote

Meh sure, but I see amps on Amazon 1000 watts for $99 Laughing
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CIR Engineering




Joined: 25 Aug 2008
Posts: 4172
Location: Chicago USA & Berlin Germany

TV/Projector: JVC NX9 + Paladin DCR & Sony G90 : Lumagen Radiance Pro


PostLink    Posted: Sun Nov 22, 2020 12:06 am    Post subject: Reply with quote

I also need to find a parts machine so if anybody has an LX-7 that is nonfunctional or only partially functional let me know. I don't care at all about the cosmetics on it.

craigr

_________________
JETI Specbos 1211 Spectroradiometer
Photo Research PR-650 Spectroradiometer
Klein K10-A Laboratory Grade Colorimeter
X-Rite i1Pro2 Spectroradiometer & Spyder Colorimeters for JVC auto-calibration
Murideo Fresco SIX-G HDMI 2.x Multimedia Generator
Murideo Fresco SIX-A HDMI 2.x Analyzer
*NEW Light Illusion ColourSpace XPT Version β Color Calibration Software
Light Illusion LightSpace XPT Pro Version 10.x Color Calibration Software
Sencore CR7000 CRT Tube Analyzer / Rejuvenater
Authorized Dealer for Lumagen & just about everything worth buying Wink
www.CIR-Engineering.com - craigr@cir-engineering.com
Phone: 865-405-6892
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CIR Engineering




Joined: 25 Aug 2008
Posts: 4172
Location: Chicago USA & Berlin Germany

TV/Projector: JVC NX9 + Paladin DCR & Sony G90 : Lumagen Radiance Pro


PostLink    Posted: Sun Nov 22, 2020 4:07 am    Post subject: Reply with quote

kal wrote:
Wow! Nice find Craig. Lexicon makes some fabulous equipment.

Kal

Yeah, these were made by Crown for Lexicon I think before Harmon had acquired both Crown and Lexicon. Lexicon makes some excellent pre/pros now along with receivers, but not really any great separate amps. I feel like these are gems.

...now, where can I get them reanodized in black Laughing

craigr

_________________
JETI Specbos 1211 Spectroradiometer
Photo Research PR-650 Spectroradiometer
Klein K10-A Laboratory Grade Colorimeter
X-Rite i1Pro2 Spectroradiometer & Spyder Colorimeters for JVC auto-calibration
Murideo Fresco SIX-G HDMI 2.x Multimedia Generator
Murideo Fresco SIX-A HDMI 2.x Analyzer
*NEW Light Illusion ColourSpace XPT Version β Color Calibration Software
Light Illusion LightSpace XPT Pro Version 10.x Color Calibration Software
Sencore CR7000 CRT Tube Analyzer / Rejuvenater
Authorized Dealer for Lumagen & just about everything worth buying Wink
www.CIR-Engineering.com - craigr@cir-engineering.com
Phone: 865-405-6892
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CIR Engineering




Joined: 25 Aug 2008
Posts: 4172
Location: Chicago USA & Berlin Germany

TV/Projector: JVC NX9 + Paladin DCR & Sony G90 : Lumagen Radiance Pro


PostLink    Posted: Sun Nov 22, 2020 4:08 am    Post subject: Reply with quote

AnalogRocks wrote:
Meh sure, but I see amps on Amazon 1000 watts for $99 Laughing

doh! I should have held out!

craigr

_________________
JETI Specbos 1211 Spectroradiometer
Photo Research PR-650 Spectroradiometer
Klein K10-A Laboratory Grade Colorimeter
X-Rite i1Pro2 Spectroradiometer & Spyder Colorimeters for JVC auto-calibration
Murideo Fresco SIX-G HDMI 2.x Multimedia Generator
Murideo Fresco SIX-A HDMI 2.x Analyzer
*NEW Light Illusion ColourSpace XPT Version β Color Calibration Software
Light Illusion LightSpace XPT Pro Version 10.x Color Calibration Software
Sencore CR7000 CRT Tube Analyzer / Rejuvenater
Authorized Dealer for Lumagen & just about everything worth buying Wink
www.CIR-Engineering.com - craigr@cir-engineering.com
Phone: 865-405-6892
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AnalogRocks
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Joined: 08 Mar 2006
Posts: 26021
Location: Toronto, Ontario, Canada

TV/Projector: Sony 1252Q, AMPRO 4000G


PostLink    Posted: Sun Nov 22, 2020 9:22 am    Post subject: Reply with quote

CIR Engineering wrote:
AnalogRocks wrote:
Meh sure, but I see amps on Amazon 1000 watts for $99 Laughing

doh! I should have held out!

craigr



AND they're made of the finest quality chinesium Mr. Green

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CIR Engineering




Joined: 25 Aug 2008
Posts: 4172
Location: Chicago USA & Berlin Germany

TV/Projector: JVC NX9 + Paladin DCR & Sony G90 : Lumagen Radiance Pro


PostLink    Posted: Sun Nov 22, 2020 4:38 pm    Post subject: Reply with quote

AnalogRocks wrote:
AND they're made of the finest quality chinesium Mr. Green

LOL Laughing Laughing Laughing

That really did get a good laugh out of me. Thanks for a nice start to the day.

craigr

_________________
JETI Specbos 1211 Spectroradiometer
Photo Research PR-650 Spectroradiometer
Klein K10-A Laboratory Grade Colorimeter
X-Rite i1Pro2 Spectroradiometer & Spyder Colorimeters for JVC auto-calibration
Murideo Fresco SIX-G HDMI 2.x Multimedia Generator
Murideo Fresco SIX-A HDMI 2.x Analyzer
*NEW Light Illusion ColourSpace XPT Version β Color Calibration Software
Light Illusion LightSpace XPT Pro Version 10.x Color Calibration Software
Sencore CR7000 CRT Tube Analyzer / Rejuvenater
Authorized Dealer for Lumagen & just about everything worth buying Wink
www.CIR-Engineering.com - craigr@cir-engineering.com
Phone: 865-405-6892
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