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For 6AS7G tube rollers here ..... - Page 96

post #1426 of 3855
Originally Posted by GrindingThud View Post

Wow...the 337 can supply 10A of heater?

Yes it can although it does mean pushing things. I measured it up and everything stays within normal specs though I will say it runs hot after 5 hours. The 337 is really overdimensioned, very nice engineering and a very nice amp too, certainly at the price. If they'd have marketed them better it would have been a huge hit imo. Once again, be sure to check power supply chain specs before trying these tubes, they're no drop inreplacements for 6AS7 or 6080.
post #1427 of 3855

I just received 2 Chatham JAN-CAHG 6080WA and one of them is not working.:(

post #1428 of 3855

Bad luck !


By the way I'm selling a bunch of those 6080WA in the classified.

post #1429 of 3855

Some 6528 tube listening impressions:


My pair of 6528 have been burning in for the past 24 hours in my DV 337, driver tubes are the Tung Sol 6SJ7 mesh plates, here are some brief impressions:


- Sound stage is somewhere in between the expansive 5998 tubes and the more intimate 6080WB graphite plate tubes

- They have the 'heft' of the 6080WB in the sound, yet clarity is a bit better.

- They're detailed but not as detailed/fast as the 7236 or 5998, yet more than most 6080/6080WB tubes.  Advantage vs some 6080 and the 6080WB:  there's no 'smearing' of the sound.

- Bass is very good, goes REALLY deep but doesn't have the boom and slam of a 5998.  Treble and midrange are very good, among the best I've heard with just a touch of warmth.


I'd say these are ideal with music that doesn't rely on fast, slamming bass and guitar riffs but where the midrange is important.  Glorious with vocals and chamber music.  Would also pair very nicely with jazz/blues.


All the above to be read with a big, fat 'imo' in front of it obviously.  Also note that the DV 337 is a very neutral sounding tube amp.


WARNING:  The 6528 are heavy current users and NOT a drop in replacement for 6AS7/6080 type tubes in any amp.  It's absolutely imperative that you check if your power supply chain can pull them off, else you risk a meltdown.  Also, these are hefty and need a min. 2 minute warmup.  During this period and especially with sensitive cans, I'd recommend leaving the amp volume on 0 and not connecting the headphones as some sharp 'popping' transients come through.  Check if it won't harm your amp to run for this period without connected load.

post #1430 of 3855
Originally Posted by Xenophon View Post

Well, everyone believes what he/she wants obviously.  But my religion is that differences in amplifier topology (feedback/no feedback....), driver tubes used, different operating point of the tubes and the resulting load line , variations in output transformers....will have a seriously higher impact.


For instance according to a Tubecad simulation (found by many builders to be pretty much on the mark) for a triode-strapped KT88 you can get a second harmonics component (no feedback used) ranging from <2% to >10%, depending on the voltage, bias point, impedance match with the output transfo...  I mention that tube because I'm modelling with it now but the point is:  these factors are imo much more audible than small variations based on the age of the tubes etc.  


But as I said, it's more of an art/religion than science at this point, it would take some double blind testing and I'm not the proselytising type.



Originally Posted by JamieMcC View Post

Comparing a Mullard 6080 to a Mullard KT88 considering the price differences


Interesting and I am not disputing the above as I know it is correct from my own build experience.


One of the things I find interesting about the Valvo/Mov/GEC 6080 is that it is was manufactured in the same factory using the same plate structure as the highly regarded GEC 6AS7G which is sonically on a whole different level to its 6080 version. The two plate structures look/are identical except for the getters. 


As this is a bb about  6as7g/6080 tubes in particular, observations, characteristics and discussion about this tube type are kind of what you should expect to see here.



Originally Posted by Xenophon View Post


You're right of course, apologies.


Just wanted to point out that many other variables come into play, when I started out I was of the opinion that the tubes were the decisive factor, have learned a couple of things since then.


Hi guys.


Please excuse me for butting in here, but my (most unexpected!) foray into 6AS7G land seems to have been the exception that (dis)proves the rule, and shows that your "starting opinion", Xenophon, was not entirely far off the mark...first a very brief history...


Although not in the same league as most of the other units in this thread, I believe my humble Little Dot MKIV SE has actually displayed the vast difference tubes can make...viz. after a year on the LD tube rolling thread, and having gone from stock EF91,92 & 95 drivers (mine being Mullard M8100) with 2x 6H30Pi-EH powers, thru premium 6DJ8s with (vastly overpriced) 6N30P-DRs, and 6SN7s as power tubes, the improvements have been immense...(we did, of course, have to modify tubes due to different pin-out).


But none of these has given the same massive leaps that came first with my C3GSs as drivers, and secondly a (lovely) pair of Chatham 6AS7Gs in the hot seat - hot being the operative word here! Amazingly, we only had to provide an external heater power supply plus tube adapter for the 6AS7Gs to be accepted... without an ensuing pall of smoke, lol.


I (and others - with the MKIII) have run our units for many hours now without any signs of objection...cases get quite warm, but nothing too drastic. And the difference from what the amps were originally designed around is nothing short of phenomenal.


And so we, at least, have been fortunate to enjoy units punching way above their weight...and the 6AS7Gs have certainly provided a magical, not to mention highly unexpected, boost to that enjoyment - testament to my opening statement...


Another point I personally found, given my particular set-up, was that contrary to skylab's findings at the start of this thread, the Chathams  - for me anyway - perform rather better than the RCAs. Obviously, personal preference comes in here, along with driver choice and amp topology, but the Chathams opened things up noticeably, giving an even more "3D/holographic" soundstage and managing to bring out even greater (micro) detail, via instrument separation that gave a beautifully clear presentation, without sacrificing focus/imaging...a sound I had never thought possible from such a lowly machine...(Mind you, I have helped things along a little by providing a decent source - the ESS Sabre DAC in my Audiolab 8200CD - plus pure silver wire in all signal leads, including the HD650's cable and the tube adapters I made myself. A decent mains conditioner also helps, I am sure...)...Sorry if this is too off-topic!


Would like to just show you the results of the past year's experimenting...


post #1431 of 3855
Did I once say I liked RCAs better than Chathams? I can't imagine that I did. But if I did, I've long since changed my mind. I prefer the Chathams.
post #1432 of 3855
Originally Posted by Skylab View Post

Did I once say I liked RCAs better than Chathams? I can't imagine that I did. But if I did, I've long since changed my mind. I prefer the Chathams.

What is your opinions with the Chatham 2399/ts5998 and ts7236? And the bendix 6080? Mainly rolling for hd800 across many genre from dubsteps to pop to orchestra... thanks!
post #1433 of 3855

^^^ "Chatham 2399/ts5998" <= many would say that Chatham 2399 and TS 5998 are identical sounding tubes ,I would say they are similar sounding but not "identical" ,2399 is physically smaller tube and in my opinion 5998 sounds full in comparison to slightly  Laid-back 2399 


ts7236 <= is often referred to as SSD sounding ,it has pretty "crisp"/sparkle in treble and solid "Fat and punchy " bass


bendix 6080 (slotted-graphite ) <= is all about soundstage ,it sounds little syrupy in my opinion but if paired with the right driver tube it can be lot of fun (sounds way better on DV336SE then Crack) 



just my 2c

Edited by spacequeen7 - 6/28/14 at 9:04am
post #1434 of 3855

Originally Posted by Skylab View Post

Did I once say I liked RCAs better than Chathams? I can't imagine that I did. But if I did, I've long since changed my mind. I prefer the Chathams.


Hi Skylab.


Sincere apologies for not getting things quite right...I was reading an old (2008!) post where you compared several amps using the 6AS7G, and I must admit I was a little confused as I was sure that I read in later posts of your liking for the Chathams...they obviously grew on you! And I can certainly understand why...Would I be right in believing the Tung Sol that looks just like an RCA -  with shield around the bottom - is not quite up to the Tung Sol/ Chatham without said shield and with copper posts? Would appreciate your opinion.

Below is the post I mentioned...



"Of the US Makers, RCA-branded 6AS7G’s are by far the most common, and they sound good. Tung-Sol also made 6AS7’s, and they are a little better sounding IMO than the RCA’s (they are also constructed a little differently), but they are much harder to find, and not worth paying an enormous premium for. GE, Sylvania, Chatham and Raytheon also made 6AS7G’s, but they also don’t seem to offer anything the RCA’s don’t sonically, IMO"


ps. Such a shame the GECs have hit the stratosphere...would have loved to hear what they can do, given the fabulous sound I'm getting from the Chathams (then again, perhaps that might be pushing this poor, long-suffering LD one step too far, lol!).

Edited by hypnos1 - 6/28/14 at 9:10am
post #1435 of 3855
Originally Posted by spacequeen7 View Post

^^^ "Chatham 2399/ts5998" <= many would say that Chatham 2399 and TS 5998 are identical sounding tubes ,I would say they are similar sounding but not "identical" ,2399 is physically smaller tube and in my opinion 5998 sounds full in comparison to slightly  Laid-back 2399 


That's interesting. My 2399 is slightly larger than my JAN-5998 manufactured in 1962, and slightly smaller than my Jan-5998 manufactured in 1968:



post #1436 of 3855

indeed, that is no reference

post #1437 of 3855

interesting ,I recently had 2x2399 and 3x5998 they were all the same size 


post #1438 of 3855

In my opinion, whatever is silkscreened on the tube had more to do with sales and marketing than anything else, as it was applied after the manufacturing process. In the end, tubes manufactured in the same factory at about the same time are going to sound virtually the same. With the acquisition of Chatham, do we know if these tubes were manufactured in more than one factory over the years? If so, that would account for some of the sonic differences people hear. Moreover, as these tubes were manufactured over many years, new advances in materials and technology, as well as feedback from the field, resulted in periodic incremental construction changes. Tubes manufactured in the early 1960's will likely sound different than tubes from the late 1960's.


I do not know when the 2399 tubes were manufactured, but I believe I see D-getters inside mine. And as my 1968 tube has O-getters, the 2399 was certainly manufactured earlier. But whether they were manufactured before, or after, my 1962 tube, which also has D-getters, I do not know as I don't have any other 5998's to compare it to....

post #1439 of 3855

I am pretty sure these were not manufactured by GEC... Does anyone know who made them?

post #1440 of 3855

I noticed that the tubes have 2011 stamped on them. Notice that the tube pins are very shinny and the black base underneath is very clean. The tubes just can not be very old. 

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