Solid State and Tube Listener Challenge

shootout

There was definitely some very nice equipment brought out for comparison testing. Some interesting conversation, and lotsa good food. I think everyone enjoyed themselves, i couldnt think of a better way to spend a gloomy saturday afternoon. Quite a few surprises too, those little T amps sounded great, but to my ears the award has to go to the little Marantz 8B, it was a very nice match with the K-horns, the marantz just seemed to do everything right on the horns. :yes: Thank you for the invite Dave, i had a good time, and learned a few things too. :thmbsp:
 
In the third round, the heavyweights did battle. The Mark Levinson went first, and adeptly handled all the selections. With the Khorns, I find the bass a little dry, and the highs to be slightly astringent. The best music for the Levinson/KHorns is complex orchestral works, but I stayed away from this due to the nature(and time commitments required) of the shootout.

While the Levinson was impressive, the Audio Research D115 really shined, with a richer bottom end and deeper soundstage. Walking on the Moon highlighted the difference for me, and evidently others caught the strong presentation as well.

After a short break, the Levinson was sent to the bench and the crowd surged forward, demanding the AR square off against the Marantz, by popular acclaim.
 
While the Levinson was impressive, the Audio Research D115 really shined, with a richer bottom end and deeper soundstage. Walking on the Moon highlighted the difference for me, and evidently others caught the strong presentation as well.

While not the same setup as you and not tube vs SS, I do slightly prefer my Audio Research 100.2 over my Levinson No. 23. I am a bit surprised though about the bottom end. That is one area where I think my Levinson has shined above all others so far. It seems to have a heft/weight, and grip, that I just don't perceive on my other stuff. I'm talking the lower, low end, not midbass richness etc.
 
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With the Khorns, I find it produces a very athletic, lean bass, Whoaru. It is a much different story with the Thiel 3.6s, or just about anything else. The Khorns have so little motion(woofer travel) that at times it feels there is little meat on the bass bones.
 
Dave, what a great event!! It was nice to catch up with those I have not seen since last year's gathering, and there was plenty of great food and drink to boot. :yes:

Well, onto to the event. :banana: :music:

Various people rotated in and out for the first three rounds and then the shootout of champions. I counted the average listening audience to be approximately 15 people at a time.

In the first round, the majority of the crowd voiced their preference for the Trends 10.1 tripath amp (with an upgraded stand alone PSU) over the pair of SET amps. After all, the little Trends (the size of a matchbox) won StereoMojo's 2007 blind digital amp shootout among 14 different amplifiers, and with an upgraded power supply, the little amp is no slouch. To my ears, the little Trends was almost as smooth as the SET on the top end (and amongst the smoothest solid state I have heard), and the Trends was superior in detail and bass definition.

The second round was a route. To my ears, the Monarchy class A solid state sounded thin and edgy. On the other hand, the rebuilt Marantz 8B was smooth as silk, detailed in spades, and forceful at the same time. Having previously heard (and loved) this particular 8B in its original form, Craig Ostby's rebuild (NOS Valves) truly did a great job in restoring this beauty to its legendary status. Even though it was detailed on the top end, the 8B truly lived up to its moniker as the "king of the midrange." The crowd voiced its approval for this amp after the very first song. "Natural," "realistic" and "just like being there" were numerous comments heard by the crowd about the 8B.

The last round was much closer. On the lower end, I actually preferred the bass of the Mark Levinson as sounding much tighter, and I thought that the bass of the Audio Research D115 was just "slightly" bloated. On the top end, however, the Levinson sounded a bit dry and slightly thin to my ears, and the AR tube monster sounded almost as sweet on the top end as the 8B. Given that the D115 was such a powerful tube amp, I was impressed with the amount of detail on the top end, and the lushness of the midrange was only exceeded by the Marantz 8B. As Dave mentioned, the crowd preferred the Audio Research over the Mark Levinson, and this may also be a function of the speakers being run (horns love tubes).

Ah......the speakers. As some of you may know, the test speakers were a pair of 1962/63 Klipschorns with JBL 2404 tweeters and a sweet pair of Universal aftermarket crossovers designed by Al Klappenberger (ALK Engineering). Kudos to Dave - his Khorns sounded great. :D They were very revealing, yet they adapted to the variety of musical formats with ease. Other than the various amps, the Khorns were the star of day.

Thanks again to Dave and Colleen for again hosting this annual event!! Cannot wait until next year. :beerchug:
 
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Thanks, Jazzman. It doesn't seem like it was two years ago. We need to do it again, only this time make it a little harder. :D
 
Transistor and Valve difference

A fascinating thread and a good read, but I expected to read WHY valves (tubes) and transistors sound different and not just which has the most pleasing sound.

When I was young and worked in electronics at the Cavendish Laboratory in Cambridge, I built both valve and transistor amps. I built in 1968 - and still have and use - a pair of Mullard 5-10 amps with a pair of Mullard 3 valve pre-amps. They still sound spectacular.

My electronics mentor - who invented switching power supplies by the way - explained that the conductance for a valve can be a straight line between zero conductance and full conductance. To imagine this draw a straight line from left to right for a short distance (zero conductance) - label it M - then extrapolate the line dead-straight at 45 degrees slope (and it must be 45 degrees) up to the right (operating conductance) - label it N - and then draw the line vertical for a short distance (full conductance or saturation).

A class A amplifier uses the middle of that slope - between M and N - as its basis for amplification. The straighter the slope, the less the distortion. Class B and others push and pull against that slope. Class A valve hi-fi amplifiers are common.

Then, he said, there is no transistor on the planet (this was many years ago but I suspect it is still true) that has a straight conductance slope - i.e. the line between M and N is curved slightly or is not exactly 45 degrees (or is too short to be useful as an amplifier as is found in switching transistors). As a result, class A transistor hi-fi amplifiers are rare or non-existent ("...To my ears, the Monarchy class A solid state sounded thin and edgy" - see earlier post by Carl G) and the resulting design of class B is to apply a push/pull conductance circuit whereby the conductance slope curves of two matching transistors (or valves) effectively cancel each other out - i.e. by applying the same weakness in reverse they compensate for each other's lack of purity. That's one of the reasons the transistors must be closely matched and why valves need matching less so. Valves are inherently superior here - and remember this applies right through every valve/transistor in the chain.

This may explain why some amps sound better at different frequencies (slight variations in conducting slope straightness or feedback) and why an amp may be suffering if the output bottles or trannies are not meticulously matched.

I may have some of the language wrong now (it was a long time ago) but that explanation has stuck in my mind and has seemed to apply whenever I design, build or repair amps to this day.

I would welcome any further comment or questions (even if I am proved wrong), but thought I would add this as an interesting corollary to the subject for the neophyte.

Update.
My lovely step-daughter just bought - for her husband - a Samsung iPod player with twin ECC83 (12AX7) double-triode valves / tubes in the pre-amp section. I know it seems gimmicky, but Samsung obviously knows that they really do produce truer sound than transistors.
 
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Excellent read/thread. I owned a pair of Marantz Model 9 RI mono's and thought they were mighty fine. I sold them and thought I was going backwards with a ARC VS110 as their replacement...not so, the ARC surprised me in a good way.

More verve/control, much faster and tighter bass...it took the new tubes to burn in before the mids fully developed and the soundstage came into its own and the same for the highs.

I just dropped in a set of NOS 1967 6N1P-EV's that kicked it up another notch.

Not saying that the model 9's are not worthy, they are and sounded the best with the KEF 104/2's which are a bit more efficient than the Magnepan 2.5's.

That said, the model 9's are a bit colored and forward in a good way, but I really like the neutral qualities and dynamics of the VS110 and yet it still has the soundstage and sweetness of tubes.

Don't get me wrong, I could live with SS and have a worthy 1975 BGW 500D that has been restored and with some under the hood upgrades, but it still doesn't have the soundstage like tubes. I've also had recently a Parasound HCA1500, a Bryston 4sst2 for comparison.

Again, nice thread done well and without hurting anyone's feelings...a hard thing to accomplish in this hobby.

Jim
 
Forgive my question if I missed it, but I am curious what was used as the source equipment? Was there a preamp used or all directly connected? Were any switching devices uses to A/B them?
 
Dan, we used an Acurus L10 preamp that had been massaged, and an Arcam DVD27 CD player, playing only cds, and hand built Canare patch cords. Switching was done by me, jumping banana terminated Radio Shack 12 gage speaker wire between amps after each two or three song selection for each round, on both amps. All of the amps were located in a back room where no participants were allowed until after the complete judged session.

The speakers were customized 1963 Klipschorns with Jensen P15LL woofers(stock), 2470 JBL mid drivers through ALK trachorns, and JBL 2404 tweeters, all run through ALK extreme slope crossovers and attenuaters.

For a system with this level of resolution(especially the speakers) it was relatively easy to notice the characteristic differences between amps. Carl, Sam, David, Bob, Mark, Al, and Steve all correctly identified every right selection, so there was a high degree of internal correlation amongst the AK members who attended.
 
Dave,

Thanks for the reply, I was interested in knowing what the entire chain of equipment was for the test. Sounds like it was all done rather well. I'm curious if you have any more "Challenges" I'd like to read about them.

Dan
 
We have a 1957 atomic brick ranch house, and my wife has kindly given me the run of the basement. You gotta work with what you are given.

I now have a bookcase completing one corner, and a false corner screwed into the second speaker. All is good.
 
Vacuum Tubes Added Anonymously

This I believe counts as a test to see if people can tell the difference when vacuum tubes are inserted in an audio chain. This I did in 1990 while working at a radio station in Baltimore, Maryland.

THE PROJECT:
The following is a summary of a project conducted in 1990 by this author while Chief Engineer at a radio station in Baltimore, Maryland. Although the radio station audio was in stereo and had a clean sound it lacked realism and depth, something that this author remembered from mono Hi-Fi systems of the 1950's. The studios and audio chain were all analog from music source to transmitter and after considering any differences in equipment configuration it was decided that the primary difference was the use of vacuum tubes back then.
Utilizing a few decades of vacuum tube experience, a project was started at home to build a vacuum tube gain controlled amplifier or more commonly called a compressor. The design was all 12AX7 triodes including a gain control stage; triodes were selected because of their second and third harmonic characteristics.
The reason for building a gain controlled amplifier rather than just a simple buffer amplifier was to gain loudness. One of the pitfalls of radio broadcasting is the fact that every station Manager and Program Director want to be the loudest station on the dial. This usually results in a lot of clipping and processing of the audio with the resulting harsh high end. Using a triode as a controlled stage requires controlling the grid bias and varying the stage gain. Using grid bias to control gain has about a 30db useful range sufficient to maintain an average level. As the triode goes farther into biased gain reduction it produces increased second and third harmonics, the second harmonic adds warmth to the audio while the third adds loudness.
The plan was to create the vacuum tube gain controlling amplifier, place it in front of the existing audio processing then reduce the processing and clipping in the existing processor. The existing processor would be limiting the audio signal only enough to prevent over-modulation without adding a harsh edge to the sound, the vacuum tube processor would then make up for the loudness.

THE RESULTS:
In order to get honest listening results to see if anyone would notice any difference, the new gain controlled amplifier had to be installed without anyone's knowledge. One night after midnight the all tube gain controlled amplifier was secretly installed in front of the existing Optimod 8100A processor. The Optimod was set so its internal input broadband compressor did very little processing instead letting the vacuum tube gain control do all the broadband processing. The high frequency clipping was also reduced.
The next day listening at home, the sound of realism that was missing could now be heard, it was a subtle difference with the addition of second harmonic content generated as the tube processor performed gain control. Listening also revealed that although the amplifier was controlling gain, louder passages still sound louder even though the actual level is being reduced, this is attributed to the extra harmonics adding loudness.
A few days went by and then compliments started coming in on how good the radio station sounded including calls from other radio station engineers. One day a music consultant once employed by the station walked in and said he was driving through town and wondered what we were doing that sounded so unique. Opening the back of the equipment rack his mouth dropped open when he saw all the glowing vacuum tubes.
Not only was this a success but a big success as the radio station ratings climbed up and beat out most other stations in listenership and higher ratings means more ad revenue for the station. There is no doubt that by just adding the use of vacuum tubes had improved the audio such that more people listened longer.
 
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Fun but why?

Sounds fun and fun is a good enough reason, but hope no one takes it seriously. I mean what does it matter if one can identify things? All that matters is what sounds good to me in my space with my music. And by default same for you and you and you.
If john loves his 1950s leak valves but George hates them and wants a SS Krell that is fine ain't it?
 
If you can't recognize basic differences, then you shouldn't be doing any critical listening. There is nothing wrong with enjoying your system, but there is a certain point in the hobby that requires discernment as well as enjoyment.
 
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