Tube Rolling w/Crack

[jrihs]

Further back in the thread I wrote that the 6H5C was not as good as the 6H13C. After reading Bolivars comment above I went back to give it another try. It still seems more laid back (mushy bass?) but is seemingly improving so I guess it may need more break-in. I admit that my previous comment was probably premature.

The 6H13C seemed alot like my WE 421a and perhaps not as much bass as the "military version"! if that's possible. Still the 421a rules, but not by that much.

It can be expensive to be a beginner in this hobby. For instance, everyone says that mullard 12au7's are warm (sometimes they say too warm) which did not seem appealing to me given my tastes, so I went right for the german, french, and dutch tubes (love them all), anyways I got the ones I wanted. Time to try a mullard and got a good price on a used 57? long plate, halo getter and wow...warm is not the qualifier I would use, amazing body and depth yes but not mushy at all (which is what I had assumed warm would mean). Sooo, guess I will to try a square getter long-plate, then I'll want back-ups....then I'll discover something else! Not wild about the 12bh7 (yet) but the 6sn7's with the adapter I got on ebay are looking pretty good!...love it but its adding up $$$.

One thing about these russian tubes...the quality seems to vary (regardless of source) so far. I usually buy in pairs (3 pairs so far from ebay) and invariably either one is bad or has uneven getters (which doesn't seem to affect sound). Just fyi.

Cheers

[Laudanum]

Juts curious ... Are the 6H13C and/or 6H5C higher gain tubes like the 5998 and, I assume, the WE 421?  Higher gain compared to the 6080 or 6AS7 that is.

[jrihs]

Hey Bolivar! Regarding my last post, I believe I know why the 6H5C is not quite as nice sounding as my 6H13C's. It is in fact, the later that is the military version. This is evidenced by the boxes the two came in (13's are plain cardboard - military, the 5's are commercial packaging). This is also evidenced by the relative availability of the 13's, which are much more common I think...due to the soviet military industrial complex? Also, the 13's have a diamond mark denoting military...AND, I now remember reading somewhere that the 13's were in fact the military rugidized version...

Thank goodness for my senior moments...hmmm...but my ears are getting better.

I can recommend the 6H5C's now (reversing previous comments up a few posts), but not as much as the 13's, and those not as much as the 421a's

[jrihs]

Laudanum...not sure about the gain but I thought I saw something about this earlier...maybe...but I will look!
Anybody else know?

[Laudanum]

Thanks jrihs, I went ahead and looked up the 6H13C.   It appears to be a higher gain tube like the 5998 based on a couple datasheets I found.  Im not comparing sonics, just amplification factor.  Couldnt find anything of confidence on the 6H5C (6N5S).  I wonder if it could be a lower gain variant rather than just a non-military spec tube.

Anyway, someone with both can maybe chime in ...

[Doc B.]

Bear in mind that in this application the output tube is operating as a cathode follower, the gain of a cathode follower stage will always be less than 1. That is to say, the 5998 doesn't really have more gain than the 6080 in this applications, it just loses less gain.

[jrihs]

Thanks Doc, that,s good to know!
Laudanum, What you say about the 6H5C (6N5S) makes  allot of sence! I have to jack-up the vol. when that one goes in. Not so with the 13's or the 421a.

[Bolivar]

Alright, seems I've read some misleading info regarding these russian tubes somewhere. I'm by no means an expert.

Who'd guess the internet could be wrong about anything : )

[jrihs]

No worries man...I'm a rookie myself...Hey it got me to go back and check that 6H5C tube, gave it a second chance. Now I think I understand it better, and to trust my ears more ;>
Nostrovia! er, um cheers!

[Laudanum]

Not really misleading Bolivar.  Both appear to be fine as direct substitutes so no problems.  I didnt check all the specs and I couldnt find much of anything on the 6H5C (6N5S) except for a Russian data sheet and another sheet that had partial spec comparison between the different US and Russian tubes based on the tube numbering.  If I remember, that one may have listed the 6H5C with lower amplification factor.  I think that sparked my wondering if the 6H5C would really be the 6AS7 "sub" in terms of gain and the 6H13C the higher gain version ... maybe even intended as the Russian 5998 "equivalent".  Of course, some of this is just a guess on my part.

Seeing how there is a sonic difference between the 6AS7 and the 5998 that goes beyond that of "gain", I am curious of your impressions, jrihs, regarding the sonic differences between the two Russian tubes.
A lot of detail isnt necessary, but if you get a chance, maybe a little more detail on the sonics of both tubes.   And dont worry about "audiophile" jargon, it's not my forte either and to be quite honest, I dont really aspire to become fluent in audiophile-ese. 

Thanks

[jrihs]

I'll get on it! As a preliminary, both have more bass (than the 421a). which may or may not be a good thing. I say that because neither have really tight, clean bass (on the crack). and the 6H5C is flabbier than that of the 13 to my ears. Good overall body which pair up well with Telefunkens...and mullard 12au7's as well. The 6H5c does require higher volume to get things focused...which does happen. Both are nice in other areas though. More on that later....To busy this weekend!

[Laudanum]

Seems more and more like the "5" is closer to a 6AS7 and the "13" closer to a 5998.   Maybe I'll pick some up down the road.  In the meantime, I'll stay tuned to this thread as always.  Thanks jrihs.

[jrihs]

Yeah that's probably the case...

[Dr. Toobz]

Interesting. I have a 6N13S/6H13C tube in my Crack and my perception has been that electrically, it appears identical to the 6AS7 and 6080 tubes I have, but certainly different than the 5998. I know this because when experimenting, it acted the same way into a low-impedance load (Grados) as the 6AS7 family of tubes, whereas plugging in the 5998 led to a pronounced difference in bass and upper-midrange frequencies, presumably due to the higher gain (which leads to a lower output impedance in the cathode follower). The 6N13S seems to be a warmer and less sharp-sounding tube than the 5998. I'm not sure if this is due simply to the fact that it seems to act like a 6AS7 and yield a higher output impedance, which may interact differently with my headphones, or the fact that some have stated the tube has uneven curves, which may suggest higher levels of second harmonic distortion compared to the 5998 or even a "proper" 6AS7.

In any case, I think these are a good deal, as they can be had rather cheaply compared to even a good NOS 6AS7, let alone the WE 421a.

[jrihs]

They certainly are a good deal on ebay, even if quality is a 50/50 proposition. Avoid the guy from lithuania on ebay, his current stock is sketchy. The guy from bulgaria is fine though, I've had good luck with though he just has the 6H5C's...NOS,NIB