Ordered Leben cs300xs (Arrived with photos) - Page 3

From what I read, 12AX7 can be substitute with 5751 or ECC83, at least what I read from tubeworld.com. 

Anyone can confirm this?  What did lebenhifi said? did you ask this question to them?

Might be a capacitor like in the CS300 (think that black thing is a capacitor anyway)

5751 is just a lower gain version of the 12AX7/ECC83 so yes, these tubes can sub for each other. You may just have to crank the volume a little more with 5751...often a good thing for many systems.

I have many 80s military 5751 and they are all excellent.

I was going to wait until I received my Leben in case anything else out of the ordinary popped up. But judging from a little feedback from Skylab and some research it seems that the main difference between the 12AX7 and 5751 is that the latter tube has a little less gain (about 70% of the 12AX7) which would give one a little more control on a stepped attenuator. Meaning that you can use more steps on the attenuator to achieve the same increase in volume level when using the 5751 over the 12AX7.

Yup - that's right on.  And the slightly lower gain of the 5751 is a benefit for headphone use, no doubt.  If I were using it as a speaker amp, I'd probably stick with the 12AX7/ECC83.

most systems I have seen have too much gain to begin with.  lower gain means less attenuation, which is a good thing. this, of course, doesn't mean that 5751s are inherently superior to 12ax7.

 

True, although IMHO the 5751 is generally superior.

Which ones do you like?  I haven't tried many of the costlier 5751s and haven't had luck with cheap finds from my usual local sources.  I've had better luck finding 12AX7s.

Thanks.  I think 5751 we can buy new instead of NOS? right?

Yes, you are right--you can get current production Sovtek 5751.

My favorite are the black plate Sylvania, the triple-mica JAN Hytron, and the windmill-getter Raytheon.  But even the grey plate Sylvania, which you can easily get NOS for a decent price, are very good.

Thanks, apparently I got mine with GE 5751 already :)

Yes, I have those as well but really can't compare them to the Sovteks because I swapped them out before I even turned on the amp for the first time.

Hey Clayton,

Did you get your CS300, yet?  You'll be happy you got yours local vs. grey market if any service ever needs done.

 

May I ask what Cans are you using?  The Leben matches with with my Grados, but wonder about trying something other.

 

my best

 

Hi b2nyc,

Yes I got my CS300XS. Very very nice. I do not own Grados (perhaps my next purchase--which model do you own?). The headphones that I've used on the Leben are the Beyerdynamic DT990 / 600 ohms and the Sennheiser HD650. If I were to choose between the two it would be the DT990. And although the HD650 sounds very good on the Leben, they are not as revealing as the DT990. I wish there was a headphone that had a sound signature that was between the 990 and the 650 because the 990, at times, can be a little brighter than I'd prefer.