Leben CS600 Thread

[kasperbergholt]

How nice to have a lively thread on the 600! I turned here to ask a question, ready to wake up a dormant thread, and found people actively exchanging.

My experience with tubes in the 600: I tried several types with close and not so close matches, and in this room I'd keep the 77s by a thin margin as they give a more balanced presentation. In other rooms I preferred the original Russian 5881 because I they were a bit more bright and forward. I don't have a tester so I can't say when my tubes go bad, but now I've tested a bunch of those that would alternate in and out as the amp is in service and I know a few were bad! The amp didn't do anything espectularly bad (perhaps I was lucky) just a very minor crackle if you placed your ear at the speakers tweeter. Which brings me to a second point.

My experiences with power supply and switches: Without great evidence about it, I believe that Leben (as perhaps most tube gear) can be sensitive to mains voltage (level, stability etc). Also, as I was (as perhaps everyone else) babying tubes as the weak link, I didn't realize dust and humidity can affect switches and rotary knobs (of which we have a few). My amp is perhaps better off with new switches and pots, as some are oxidized and apparently can't be cleaned up properly.

So the question: Do any of you know how to source OEM parts for a Leben amp? As I said, I need a few pots and switches. The service people I worked with tried contacting Leben Japan but got no response (so far, after a week, perhaps that's normal waiting time, I don't know). I contacted Tone Imports in the past for questions and advice and they've been stellar, but they distribute in the USA and I'm not there anymore (I don't have a Leben agent in this country) and I didn't want to bother, again, not yet at least

Thanks a lot in advance!

Thank you for your reply, greatly appreciated! I haven't done any tube rolling on the output tubes, but I'm looking forward to it - once I feel I have a sufficient amount of preamp / driver stage tube.

Do you experience any faulty behaviour i relation to the switches and pots? And, where are you based? I once owned some Audio Note equipment, and people in more humid places seemd to experience a lot more issues than e.g. 'us' in northern Europe.
Regarding parts you could try the Leben Facebook group (https://www.facebook.com/groups/144860014972/), which to my knowledge was started by Leben's sole Japanese sole distributor, Yoshi Hontani. It has around 3,000 members, a lot of whom seem quite engaged & helpful.

Another ption would be trying to find some un-authorized 'wizard' perhaps through a forum with a broader reach than this, perhaps Steve Hoffmann's forum.

Last idea is to write to Jeff from Positive Feedback, who seem to have a good relation to Leben - e.g. publishing their guide to output tubes that work with the Leben CS-600 and Leben CS-600X and the circuit update that converts the CS-600's driver stage to use the same tubes as the CS-600X's (12AU7A and12HB7A instead of 6CS7's.

Wishing you the best of luck - and would love to hear how the project goes

 

[agustinf]

Thank you for your reply, greatly appreciated! I haven't done any tube rolling on the output tubes, but I'm looking forward to it - once I feel I have a sufficient amount of preamp / driver stage tube.

Do you experience any faulty behaviour i relation to the switches and pots? And, where are you based? I once owned some Audio Note equipment, and people in more humid places seemd to experience a lot more issues than e.g. 'us' in northern Europe.
Regarding parts you could try the Leben Facebook group (https://www.facebook.com/groups/144860014972/), which to my knowledge was started by Leben's sole Japanese sole distributor, Yoshi Hontani. It has around 3,000 members, a lot of whom seem quite engaged & helpful.

Another ption would be trying to find some un-authorized 'wizard' perhaps through a forum with a broader reach than this, perhaps Steve Hoffmann's forum.

Last idea is to write to Jeff from Positive Feedback, who seem to have a good relation to Leben - e.g. publishing their guide to output tubes that work with the Leben CS-600 and Leben CS-600X and the circuit update that converts the CS-600's driver stage to use the same tubes as the CS-600X's (12AU7A and12HB7A instead of 6CS7's.

Wishing you the best of luck - and would love to hear how the project goes

Thanks a lot for this valuable information. All three options sound good. I will make sure to report what happens.

As of the issues, I was having the typical dirty potentiometers and switches noises. When rotating a knob I'd hear through the speakers a noise as if you'd been scratching a surface; with the knobs that clicked through different positions, like the Bass boost, they'd make that noise until settled in the new value, and even sometimes while stationary. The switches wouldn't operate correctly, say the Mute switch (which I rarely used) even appeared to be " sticky " : operating the switch won't do anything unless I toggled back and forth a couple of times.

Best regards
Agustin

 

[davehg]

The FB group is pretty active and Jonathan Halpern and Yoshi regularly participate. I love my 600x. It powers some Chartwell LS3/5A and Devore O/96s speakers.

I’ve tested a few quads and settled on the TungSol 7581 which was cheap until the Russian invasion of Ukraine. I also have some Winged C EL34 and Russian 6N3CE tubes, all of which are better than the EH EL34.

 

[agustinf]

Thanks for the response. That's definitely a door to knock if I fail to get the parts from a dealer that works with Latin American countries (I got a response from one and I am waiting a quote from him if he gets to source the parts from Leben Japan). Actually, I may have gone to Jonathan first with this issue, but I thought I should leave him for last resort.

And as for the tubes, I agree on on your choices, and specially on having the EH EL34 as the least favorites.

 

[smodtactical]

I’ve done some big upgrades to the system - replaced my Lumin D2 with a T2. Big upgrade and it showcases how well layered and textured the Leben can sound. A bigger upgrade was to ditch the Devire Nines, which I enjoyed, with the Devore O/96. The Leben -Devore synergy is stellar and everything I’ve read about is true - great pairing.

The T2 helped bring the pairing of Leben with Audeze up to expectation. Still not better than the WA5, but more enjoyable now. I regrettably sold the WA5 to clear space on my audio rack, so now the Leben duels with the WA22 for headphone duty.

Dave I see you kept your leben but sold your wa5. Why is this given you seemed to like wa5 more ?

 

[davehg]

Dave I see you kept your leben but sold your wa5. Why is this given you seemed to like wa5 more ?

As a headphone only amp the WA5 was great. But I migrated back to 2 channel and had a set of 300b mono amps and a 300b preamp built with better resolution.

The Leben now powers a pair of Chartwell LS3/5as driven by my vinyl and T2 setup. The O/96 system got an upgrade to the Lumin X1.

The Leben is a keeper - so versatile and everything it touches sounds great. I recently upgraded my phono preamp and the Leben easily showed off the improvements.

I am rarely on headphones these days, and the Woo was not as good of a match with my speakers was my current setup.

 

[Sonicmasala]

Hi! Has anyone here updated their Leben CS600 to use the 12AU7A and 12AH7A tubes as used in the CS600X model? I'm contemplating doing such a mod, but thought like to hear some feedback to see if it's worth it. I do love my current amp. My worry is on the issue of getting a good supply of 6CS7 tubes at a reasonable cost.

 

[smodtactical]

Anyone compare cs600 to popular tube headamps? AIC10, envy, ha300 mk2, ha 6a ?

 

[davehg]

I compared my CS600x to the Woo WA5 and WA22. It was very good but not quite as excellent as the dedicated HP amps on more demanding HP like the my LCD3 and HD650, but perfect with the Focal Clear. Now that I’ve gone back to 2 channel, I don’t listen to my headphones much.