DESCRIPTION

The LCR MKIII is a high quality, dual-mono, pure analog phonograph preamp. This topology allows a unique application of smaller inductors that yields an ergonomic approach to LCR (L=Inductor, C=Capacitor, R=Resistor) phonograph reproduction. Vinyl minded audiophiles are growing in numbers with collectable, vintage releases often bettering the best digital formats and new vinyl issues being added to catalogs with increasing frequency. It is known by many in the audio community that LCR RIAA correction is a preferred way of capturing the experience and atmosphere of the original performance.

The passive LCR network is a topology that brings out the detail of small instrument inflections yet keeps a musical cohesiveness in context of the performance and room. Advanced hi-speed op-amps allow for transformerless direct drive of the LCR network. Current sources are employed to bias each amplifier stage into class A operation.

The LT1358 op-amp is still made in a through-hole package allowing this preamp to be made with only a few strategically placed surface mount parts. One set of dedicated inputs allows for the simplest path to the op-amp input. There are no switches between your cartridge and the amplifier. Discrete series/shunt power supply regulators are used with one dedicated to each amplifier IC power supply pin. Also for ease of current delivery the pass element of the series regulator is vastly over-rated in current capacity. No power supply ground shares audio grounds or left-right channels. Critical components in the audio section are hand matched.

All assembly is done in the USA. 

 

SPECIFICATIONS

RIAA Equalization type: Passive LCR  Inductor based filter network


Gain: 42.5dB

 
Input impedance: 50k Ohm


Output impedance: 20 Ohm
 

Input capacitance: 120pf
 

Full scale output level before visible clipping: 

  • @1KHz  9.6V rms with input of 69mV rms

  • @100Hz 9V rms with input of 16mV rms

  • @10KHz 3.083V rms with input of 105mV rms

 

RIAA response:         

Third party measurement from Sound Logic LA Service - Duke Aguiar  using Audio Precision equipment

+- 0.5 dB 10-100KHz @1mV  input - inverse corrected  

                     (click image to enlarge)

   

         


       

Lounge Audio analog raw measurement using: 

LEADER LAG-120B Audio Generator
LEADER LMV-181A AC Millivoltmeter
BK Precision DYNASCAN 1801 Frequency Counter

@20 Hz, 0 to -1 db referenced to RIAA compliance
Trim @20KHz to +0.62 db over RIAA compliance

                     (cliick image to enlarge)

 
 


 

 

 

 

 

Signal-to-noise ratio: -74db with1/f noise dominating (ref. to 1Vrms output)
 

Distortion: 0.15% THD @ 0.774Vrms 1khz output. Composed mostly of 2nd and 4th harmonics.
 

AC Adapter: 120VAC 60Hz, 16VAC, 1000ma Wall Cube type.
 

Amplification Type: Class A biased Op-amp. Input to output non-inverting
 

I/O’s: RCA jack

 

Dimensions: Height 3”, Width 7 1/2”, Length 5 9/16”

Weight: 3lbs 6 ounces net.  6lbs for shipping 

 

Features:

 

  • Hi-speed, video bandwidth op-amps for accurate transient response

  • Separate discrete voltage regulators for each channel to reduce L-R channel  interaction

  • Shunt regulation on DC power lines

  • Hand matched high/low frequency inductors and capacitors for left /right channel accuracy

  • Film capacitors used in audio path

  • Hand crafted in the USA

Please note that we reserve the right to make improvements or modifications as parts’ manufacturers allow us or force us.  For these reasons, the design and specifications are subject to change without prior notice while keeping very high quality standards for all products we manufacture

Duke-Lounge Audio Freq For website.PNG
Lounge LCR RIAA Response.PNG
 

SILVER WIRE

LCR MKIII Silver wire will give you much more transient response, resolution and frequency extension than the LCR MKIII.  The LCR MKIII Silver wire gives you more space around the instruments and more sense of pace, rhythm and timing.

The specifications for the LCR MKIII Silver wire are the same as the LCR MKIII except for the gain which is 44db.  The circuit design is the same for both products but the LCR MKIII Silver wire has point to point silver wire in certain parts of the audio, ground and power supply area. The LCR MKIII Silver wire also has more power supply filter capacitors and some key resistors are upgraded. 

The LCR MKIII Silver wire uses the same chassis as the LCR MKIII Standard option. Robert writes "silver wire upgrade" on the bottom of the chassis and signs and dates the unit.

 

SHIPPING

We ship via USPS Priority Mail 1-3 days with signature confirmation in a large flat rate box (12x12x6) anywhere in the US. 

 

We ship to any APO/FPO or DPO. We do not ship to proxy logistics companies.

We handcraft the unit at our location and it takes us about a week to ship the preamp from the moment you place the order.

The preamp will have about 8 hours of break in time but it will need some more once you receive the preamp.  You don't need to play music, just have it plugged in.  You will notice better and better frequency extension and less stridency within a couple of days.

We offer a 1 year warranty on parts and labor, including shipping.

 

We offer returns on non-defective units within 15 days of delivery.  If in original condition, with all accessories intact and original receipt we will refund full purchase price minus 10% re-stocking fee.  On non-defective returns, we do not refund shipping costs. Units damaged from use or mishandling will be pro-rated.

 

FAQ

Can the LCR MKIII be used with an MC cartridge?
Not directly.  A step-up amp or a step-up transformer (SUT) would have to be used.  Lounge Audio offers a step-up amp (see Copla).  Jensen and Cinimag are two transformer manufacturers that make SUTs for MC applications.


Does it use a wall wart for power?
Yes.  We ship our units with an AC to AC power adaptor 16VAC or 18VAC (either voltage works fine) 500mA or higher. 
All our products have linear power supplies internal to the unit, an older and less noisy method. Keep in mind that our power adaptor is only a transformer. Everything else such as rectification, the raw filtering and the voltage regulation, is built into the LCR. 
We QC each power adaptor ourselves before shipping


How do I turn the LCRMKIII on/off ?
There is no switch.  We suggest connecting it to a switchable  power strip with all other devices, and  switch the power strip on/off.  You can leave the unit on 24/7 with no adverse effect.

Compatible cartridges

We, at Lounge Audio, are not able to test every cartridge out there but see a list of known cartridges that we use in our lab and/or have been reported by our customers to work well with the LCRMKIII:
Audio Technica AT-440ML
Dynavector 10X5
All Grado moving magnet carts
Grace F9E
Ortofon 2M series
Ortofon VMS 20 Mk II
Rega Exact cartridge
Shure M44g
Shure M97
Shure V15 series
Sumiko Blackbird
Sumiko Blue Point
Clearaudio Maestro V2

What kind of LCR network is used?
Is it an OEM module? The LCR network is a discrete circuit assembled with the rest of the preamp so it is not an OEM module. It is based on the schematic used for the Tango EQ-600P LCR module.

Why are there so many separate ground paths?
Grounds are important, yet they are commonly overlooked. Noise or residual audio current from one leg of a ground can contaminate an adjacent leg. This is why separate ground lines are used for all aspects of the audio circuit.

Does the LCR MKIII have balanced operation?
No, this is an unbalanced unit on both input and output.
 

 

DOWNLOAD THE LCR MKIII USER MANUAL

 

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