The Leben CS300XS Thread
Jun 30, 2012 at 3:52 AM Post #1,202 of 2,299
Powerful amplifiers usually have a higher basic noise than less powerful amps (with basic noise I mean the noise you get independent of volume). Also generally more noise with tubes than solid state. So if you search for an amp with low noise to use for earbuds, high power tube equipment should be the last place to look.
 
However, the importance of noise can be overvalued. I have seen Head-Fier's "testing" equipment by turning the volume to max and listen with earbuds without music playing, and at levels that would cause permanent ear damage if they played music. The important thing is if the noise affects the quality of the musical presentation or not at realistic volumes and the quality of the reproduction over all. This is partly a subjective evaluation and not only about the objective level of noise that can be measured. An odd thing is that questions about noise and hum is often evaluated subjectively on Head-Fi and with different methods. Look back in this thread (and many other threads as well) and you can find wildly varying answers about the hum. I imagine some persons answer by listening at max volume without music and others by listening to music. And some answers are based on defective tubes!
 
Jun 30, 2012 at 6:32 PM Post #1,204 of 2,299
I tried with my Westone ES5 and UE18 pro. I got a low electrical noise but not hum, more like current flow noise, with the more sensitive ES5 . The Ue18 pro was quite silent withiout music on through the Leben.
 
Aug 4, 2012 at 3:24 AM Post #1,206 of 2,299
Hello,
 
It may be a bit off-topic but I wounder if anybody might know what output tranformers Leben is using in this amp?
I would be mostly interested in the transformer core material and the wire used to make it.
 
Thanks and regards,
Vencel
 
Aug 4, 2012 at 9:21 AM Post #1,207 of 2,299
Leben builds their own transformers, they do not buy them from someone else. So check out the info on their website.
 
Aug 4, 2012 at 10:32 AM Post #1,208 of 2,299
Hello,
Thanks for your answer. Unfortunately I could not find information about the output transformer material. I just wonder if Hyodo san uses amorphous cores or just the simple silicon iron core.
Unfortunately I did not have the possibility to listen to any of his amplifiers but I am quite interested in the CS300XS. If only it would also have a phono stage. This way it would be an all-rounder integrated amp :)
Regards,
 
Aug 6, 2012 at 2:06 AM Post #1,209 of 2,299
Through these two years since I have come into ownership of the Leben CS300XS, and lately the McIntosh C2300 preamp, I have tried more than a dozen pairs of 12AX7s, including without limitation the Sovteks, the Mullard 1950's AX7s, the Telefunken smooth plates and ribbed plates, Mazda, Sylvannia, the 1950's Amperex long plate "D"-getter, JJs, Gold Lion reissues and Miniwatts.
 
But ultimately, the three pairs of which clearly stood out from the rest, in terms of sound quality, IMO, are:
 
- Telefunken 803S
- Mullard 10M (gold plated pins version)
 
These tubes, though rarer than most other tubes mentioned above, can still be found on the market occasionally and I suspect many tube owners from the past still store them. They are particularly detailed and Hifi oriented - if you are looking for that kind of characteristics in 12AX7s, look no further.
 
So, what is the remaining pair? Aren't the Telefunken 803S or the Mullard 10M famous / rare enough? Yes - maybe less heard of than the above due to rarity - but this - IMO, is the TRUE holy grail of all 12AX7s. I came across them during the visit of a hi-fi audiophile friend. He was interested to listen to my Esoteric - McIntosh - Dynaudio system (see signature for details) and was happy to let me try some of his vintage tubes on my McIntosh preamp. He went all SS now so the 12AX7s to him is more for collection than real use. There is currently a pair up of these for sale on eBay, but the measurements are not very good. This pair is now very strong. Once plugged into my system, I know well that I won't unplug them from my McIntosh (well actually I did later as I wanted to try them on my Leben). While the 803S and 10M delivered great details and with the Mullards 10Ms being the widest bandwidth 12AX7s I have heard, they are in no comparison with these tubes when it comes to human voice and musicality. Nor does any of my previous tubes such as the Amperex could even compare with these for musicality (and the Amperex long plate D getters were known for this). So coherent and musical, not overly warmish but not overall Hifi - these are the tubes which I have been looking for my Dynaudio speakers. I would try it with the Leben one of these days, but due to rarity I would hesitate to use them solely for headphones.
 
Ladies and gentlemen - introducing the vintage Gold Lion B759 12AX7s - the true holy grail among all 12AX7s, and matched within 1% at above 80. As I said, there is a pair currently selling on eBay but its matching or strength is no comparison to my pair. If you happen to find a pair locally, don't hesitate - get them regardless of the price. They sound good. You will hear it. This - IMO - is the ultimate 12AX7.
 
 
 
 

 
 
 

 

 
I couldn't help opening up a bottle after being astonished by the improvement brought about by a tiny pair of tubes.
beerchug.gif

 

 

 

 
Aug 6, 2012 at 9:41 AM Post #1,210 of 2,299
Those pics...wow...yummy :D
 
Aug 6, 2012 at 9:57 AM Post #1,211 of 2,299
Quote:
 
Ladies and gentlemen - introducing the vintage Gold Lion B759 12AX7s - the true holy grail among all 12AX7s, and matched within 1% at above 80. As I said, there is a pair currently selling on eBay but its matching or strength is no comparison to my pair. If you happen to find a pair locally, don't hesitate - get them regardless of the price. They sound good. You will hear it. This - IMO - is the ultimate 12AX7.
 
 

 
You mean the pair for $1499?  I would go for them but I know that Skylab has his eyes on them!
 
Aug 6, 2012 at 10:54 AM Post #1,212 of 2,299
Yeah they are all yours Minches...they're a little beyond my tolerance for pain :D
 
Aug 6, 2012 at 11:16 AM Post #1,213 of 2,299
I think that if I was ever crazy enough to buy a tube like that I wouldn't use it.  So, what's the point?
 
Aug 10, 2012 at 7:31 PM Post #1,215 of 2,299
Back in the CS300XS club. I picked up badwisdom's unit. Interestingly, it has the same hum/static noise my previous unit had. There's definitely some interference at my place.
 
I currently have it plugged into a Running Springs Haley line conditioner. But the real secret is the Vertex AQ Jaya filter (plugged into the Haley). It reduces radio frequency noise and microphonic distortion. This is a night & day difference folks. If you ever see one for sale in the UK, snap it up.
 

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