[tvad4]

I installed a Leben CS-600 integrated amp today. It's driving my long-time favorite Von Schweikert VR4 Gen III HSE loudspeakers. The CS-600 is powered by an Empirical Audio Power Cord connected to a Hydra 2 conditioner which is fed by a Purist Audio Dominus Ferrox power cord from a 20a dedicated circuit. The source is a Modwright Sony 999ES Signature Platinum edition with tube rectified power supply. Interconnects are Stereovox HDSE. I'd have preferred to use my Purist Audio Aqueous Anniversary or Venustas interconnects, but they are slightly too short for the temporary audition position of the Leben.

The first impression of the Leben is it's fairly compact size, especially compared to the amplifier it replaced. However, it's heavy!  60 lbs, and a good portion of that weight attributable to four sizable transformers. I off took the ventilated, beautifully-powder-coated top to swap tubes, and the top alone must weight 3 or 4 pounds. No lightweight aluminum here.

The power tubes can be a wide variety of types. Stock tubes are Sovtek 6L6GC producing 30 wpc. My demo unit was also furnished with a matched quad of SED Winged "C" EL34 for tube rolling (28 wpc). Other power tubes that can be used are 350B, KT88, and 6550A. The circuit is self biasing. It's a pleasure to know replacing four power tubes will cost no more than about $200 for a set of premium RCA 6L6GC, or $80 for a matched quad of SED EL34.

Input/Driver tubes are 6CS7. Again, replacing these tubes with NOS RCA, Sylvania or GE vintage tubes runs about $5/ea.

One damper tube (I'm assuming this is a rectifier) is a 6CJ3. About $5 for a vintage NOS GE 6CJ3.

Five sets of RCA inputs, plus a tape loop, and a set of RCA inputs for a preamp if one chooses to use the CS-600 as an amplifier only. Or, the preamp inputs can be used as a direct input for a source with enough gain to not require a preamp (like my Wright Sound WPP200C phono preamp). When the direct connection is selected, the volume control knob functions, but the rest of the CS-600 features like balance control, stereo/mono, and bass boost are bypassed.

The Leben also has a rotary switch that changes the output of the speaker taps between 4, 6, 8 and 16 ohms. Nice.

Once connected, I was stunned at the silence of the amp. I mean dead, stone-cold silence with my ear to the tweeter. I have never owned any tube gear that was this quiet.

Thus far, the amp has no problem driving the VR4 loudspeakers (89db/1w/1m, 6 ohm nominal, 3 ohm minimum). I can't say it will crank as loudly without distortion as my Moscode 401HR, but the times I did that were rare, and resulted in volumes of 110+ db in a 16x19 foot room. Fun to do on occasion, but not normal listening for me. Without using the decibel meter, I'd guess my listening this evening was in a decibel range in the high 80s to low 90s. I listen nearfield...about 8.5 feet from the drivers.

This should be a fun two weeks.

[lonewolfny42]

Another plus....it looks good !! Have fun Grant....

[Loftprojection]

I heard the cs300 in a store once, very very sweet, I'm jealous.  If I was not so lazy I might have bought one but the lack of a remote volume control turned me off!

[Plink]

Once connected, I was stunned at the silence of the amp. I mean dead, stone-cold silence with my ear to the tweeter. I have never owned any tube gear that was this quiet.

I didn't listen enough to comment on the sound but I can say I was also stunned at how quiet it is.  Amazing!

[WEEZ]

tvad,

I'm jealous.

I'm anxious to hear further reports...

WEEZ

[JoshK]

I love the looks.  And yes the 6CJ3 is used as a rectumfrier.  Only one though?  That is curious, usually two are used.  They are much better than many/most coveted rectifiers and cheaper to boot. 

[JoshK]

but a damper diode isn't a full wave rectumfrier (not a double diode, only a single) like most 5u4gb, etc. 6CJ3 is a single diode, so it is only a half wave RF if used alone.

[JoshK]

I actually remembered that I saw a schematic once where a single damper diode was used in series after a silicon rf bridge.  The idea was that the dd would be slow to conduct as it warmed up creating a slow start on the B+ like a tube rectified psu, but had (closer to) the efficiency of a silicon rectified psu (dd's have a much lower voltage drop than typical tube rectifiers).  It could be...

[alotaklipsch]

Tvad, there is a pair local for about 1200, think I should buy them?

[iluzun]

I own a pr. of Castle Conway III's which I drive w/a Primaluna Prologue II that makes for a wonderful sounding system.  Very warm, inviting, yet w/detail & nice extension.  A really nice system to listen to.  I feed it from a Toshibas 9200 dvd player, but it also sounds good w/just a cheap cd/dvd combo and startlingly good when fed via a Naim cds3/psu combo.  I've never heard the Howards as they r the next step up from the Conways.  I'd like to hear those upward firing tweets!  Castle is now 'defunct', so get 'em while you can.....

Regis

[iluzun]

Ohh, & that Leben too!  Very nice.....

[iluzun]

My bad.  Musta been thinking about the Neat speaker line, I've got a pr. of Vitos.  Kinda a 'Brit head', as I've a couple of Naim rigs & some ProAc 1sc also.  I think I got the Conways from May,  great price too!  Anyways I think the Castles sound as good or better than the proac when matched up w/tubes.....

Regis

[WEEZ]

Congrat's, tvad! That is one classy amplifier...

WEEZ

[finsup]

Thought I'd put a period on this topic.

I sent my check to the dealer for the CS-600. Sold the Moscode 401HR. Sold the Lamm LL2 Deluxe. Have a sale pending on the VR4 Gen III HSE. All outstanding equipment, and excellent together. I just decided I wanted something different.

However, my system now with the Leben and Castle Howard S2 speakers has never sounded more whole, more musical and more satisfying. Music fills the room in a completely liquid, effortless manner, totally fatigue free. The Wright Sound WPP200C phono pre running directly into the Leben's preamp inputs is really exceptional.

More enjoyable sound for a total cost of nearly $6k less than my previous amplification/loudspeaker combo (in actual dollars spent). Victory.

Of course, 10 months from now, all could change. It tends to happen in this nutty hobby. But, for now, this is as satisfied as I've been in four years of the chase.

Check out a Leben matched with some relatively high impedance speakers (Castle Acoustics, Devore, even horns). You might be pleasantly surprised.

 

OK, so only three months and time for a change.     The Leben lasted in your system less than the Moscode.  It's all good, though.  I need guys like you to cycle through euipment so we can learn about your experiences and maybe pick up one (lightly?) used on the market.  Darnit, don't have the thirty eight hundred and change you are asking for it.    Will you take a payment plan?