|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
75.128.188.58
"
I used the fully McShaned Mac MC275 loaded with all the goodies and source is the ARC CD2 and the Sota Sapphire with Koetsu Rosewood and Premier tonearm and Newform Research ribbons, R645s.
I just grabbed matched quads of British Genelex,TungSol 6550 black plates,and the Genelex reissue KT88s I had on the shelf..These are all have plenty of hours on them for this test but they all test well into the mid 90s.
They all have very nice attributes and the low end on all three tubes are pretty close and the midrange is detailed and accurate but one of these quads had the most beautiful sweep in vocal and instrumental clarity and the transition from midrange to lower highs was silky smooth and controlled and very energetic as well..Can you guess which quad it was?
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Follow Ups:
nt
I am going with the Tung Sol 6550's.
You went right.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
From past posts I knew you were very high on these vintage Tung Sol's, so I took a wild guess!
It would be nice if the reissue KT-88's were the winners.
Dave
The reissues are right up there and they have more body than the original British made ones..There isn't a night and day difference in these tubes.It's just the TungSols have such a beautiful sweep thru the mids and highs and they are well focused on the job at hand.The is with the rebuilt Fisher 400CX2 preamp and with a different preamp driving the amp or the tubes in a different amp,the results could change.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
...based on past comments and the sentence structure of this post............none other than the RI Gold Lions. Yes?
The TS 6550 black plates were the winner..I always favored those.The RI tho are fantastic and in different amps you could get different results.There is just that one aspect that I described where the TungSol black plates do so well.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Your tagline is relevant to your observations.
Do you know or have an idea what causes various tubes to sound different? Emissivity is obvious; the higher the emissivity the lower the impedance. Interelectrode capacitance could affect highs, but really shouldn't be much of a factor in tetrodes and pentodes, especially at audio frequencies. An English guy measured the harmonic distortion of a bunch of tubes and determined that statistically black plate tubes have lower harmonic distortion than other tubes (but no explanation).
One thing you wrote I suspect is most of it: That different tubes sound better/worse in different amps. That suggests interaction between the tube and the circuit. Reactance, feedback, and power supply impedance (perhaps even as a function of frequency) come to mind.
So what's left? What are the physical reasons that tubes in good condition sound substantially different from each other?
I think that a perhaps a study of gain linearity and distortion as a function of signal level and complex load might be revealing. A good study would probably be at least a Masters thesis.
I would say mechanical build structure and materials used.We know that vacuum tubes are very subject to microphonics and that plays a major role in how the sound of a particular tube is perceived..Keep in mind that we are using output tubes for this test and in this particular amp they aren't amplifying any voltage but simply swinging it from the boot strapped driver stage.As I've said in another amp which uses a more conventional output stage,the results may be very different..I personally do not find major sonic differences in output tubes that others have claimed and the reason is,there isn't the high amplification factor going on in the output stage like their is in the voltage amp or preamp stage.For whatever reason,I love the black plate tubes in my amps but synergy plays a role as you have more or less stated.
" Emissivity is obvious; the higher the emissivity the lower the impedance. Interelectrode capacitance could affect highs, but really shouldn't be much of a factor in tetrodes and pentodes, especially at audio frequencies."
That is correct because we aren't dealing with miller capacitance issues because of the shielding but I do believe that all these things come together and can alter the sonic curve of one tube vs versus the other. I have several new old stock Genelex and GEC KT88s and every one of the quads sound different from the other.My Gold Monarchs sound different than the Gold Lions and the GEC and Genelex are different yet again..There is no real answer here and synergy plays an important role. I don't care for the British Genelex because on my equipment they tend to sound dry and lifeless on certain music.OTOH,some like that type of sound so I can't be the judge for them.I basically stated what I like in a tube or an amplifier and that is a sound that comes together as one.
Lee,do you remember when Bob Carver came out with his Amazing Speaker?
The speaker produced music just fine however you would hear mids and highs and then you would hear bass.The speaker couldn't blend the music as one.That's what I like about some tubes vs the other in that some blend the music as one better than the other does.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
...I'm suspicious of current production stock because I'm not convinced today's mfgrs pay as much attention to maintenance of their machinery as mfgrs of 60 years ago did. This includes factors such as the precision of grid winding pitch and alignment of electrodes where that is a factor such as in a beam tetrode. Since such a large proportion of today's production ends up in musical instrument amps where distortion is sorta desirable, this situation probably drives mfg practices.
Some of the nicest sounding tubes I've played with are late 20s/early 30s designs like #45. I speculate that much attention was devoted to inherent linearity in both basic design and in implementation back then because circuits were primative and corrective feedback wasn't in widespread use. Just an opinion/observation w/o numbers or hard facts as backup.
Steve
I know what you mean especially after watching that Mullard film of how meticulous they were and the precision machinery used to build these tubes.
I do think competition have made the tubes a lot better and hopfully they will continue to improve..Technology with computerized trimming of elements and spacing have also played a major role in helping to improve the tubes.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Edits: 02/02/15
i miss other modern KT`ies besides GL RI in your comparison. Penta Labs, Shugunag Treasure Z and Psvane KT88 sound fantastic, even better than GL RI in MY ears.
N.
The times, they are changing...
Nunki
I think you may have been addressing me and I agree totally with you.I love all those tubes you mentioned and I sold my Treasures and I need to get another quad.I only tested these three this time because I was lazy but I agree with you that the Shuggies are fantastic..I like the Gold Lion reissues a lot of because they are durable,sound good in most amps,and are reasonable in price..The Shuggie Pentas solid plates are one of my favorites as well..This test I did is not the end all,end all.I just happened to point one characteristic I like in the black plates in the McShaned Mac Mc275...YMMV.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
...you mention that "There is just that one aspect that I described where the TungSol black plates do so well." There are other aspects where they don't do so well? Personally speaking, if the only KT88/6550 type avail was a TSBP 6550 (or even grey plate), I'd be happy as a clam.
Personally speaking, if the only KT88/6550 type avail was a TSBP 6550 (or even grey plate), I'd be happy as a clam.
Me to...BTW,you didn't guess too bad because I do highly praise the reissues.The thing is,break-in time is paramount on these tubes.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
The original US made blackplate TS 6550 have the best midrange tone of any 6550, KT-88 that I've tried. The GE 6550A is very powerful. But, does not have the natural warmth & mid-high resolution of the TS.The original British Gold Lion KT-88 has even more scooped-out midrange than the 6550 family. The KT-88 has a more powerful bass reproduction. IMHO.
I have not used the Russian made, modern Gold Lion KT-88.
Edits: 02/01/15 02/01/15
Steve
Since you and I favor the 6L6gc RCA black plates and 6550 black plate TungSols,we can call this a win..The British as I said was ok but not spectacular as the TungSols were..I think you hit it right when you said the midrange was scooped out.
"If it measures good and sounds bad, it is bad; if it measures bad and sounds good, you have measured the wrong thing."
- Daniel R. von Recklinghausen
Post a Followup:
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: