[ricardojoa]

Hey guys,
just wanted some opinions.
I just got myself a tube preamp a few days ago and have it connected in between the CD player and the AVR multichanels inputs.
I have not had any experience with tubes but so far i did not hear any difference in sound except that the bass is weaker.
Can the AVR acting as a power amp be the bottle neck?
I would have thought that at least it would change the tone a bit.
 
It is spacetech lab tube preamp QA115.

[Freo-1]

Hey guys,
just wanted some opinions.
I just got myself a tube preamp a few days ago and have it connected in between the CD player and the AVR multichanels inputs.
I have not had any experience with tubes but so far i did not hear any difference in sound except that the bass is weaker.
Can the AVR acting as a power amp be the bottle neck?
I would have thought that at least it would change the tone a bit.
 
It is spacetech lab tube preamp QA115.

Using a tube preamp with the AVR is sub-optimum.  There is likely an impedance matching issue.  My past experience with AVR's is that the multi channel input never sounds as good as using the digital input. The buffer op-amps compromise the sound.  Best to have a separate power amp with the right input impedance.

[Ericus Rex]

Hi Ericus Rex and all Audio Circle members.
Distortion is not the correct word,
but it's something like: Over saturated ? ? ?

Guy 13

What I was talking about was an electric guitar's rock distortion.  I think some call it overdrive but I know what you mean when you say over-saturated.  I was not at all talking about Harmonic Distortion, which guitarists care nil about.  But's it's all technically distortion; a change in the shape of the waveform between input and output, excepting the difference in amplitude of the two signals.

[Freo-1]

Haven't had time yet to read your link, Freo.  Soon.  But I'll add my $0.02....

The first thing that strikes me about a tube system when A/B-ing with an ss system is the size of the stage presented.  A friend of mine used to be a Parasound and Rogue dealer and we A/B'd an all Rogue setup with an all JC Parasound setup one day.  Sonically they were both very good.  Sure the tubes had a more liquid midrange, blah blah blah but the Parasound sys was very close.  However, the Rogue setup presented a far larger soundstage, the speakers disappeared more and there was clearly much more 3d 'air' around each of the instruments.  Going back to the Para setup the sound became more directional, from the two speaker points, and the depth of the stage became much shallower and all instruments slightly more congealed into a flat plane.  The tube system was far more like a good concert venue where you close your eyes and hear sound coming at you from all directions; not just from the players themselves.  This comparison was done using the same source, speakers, cabling and music between the two.  Only the amps and preamp were swapped out.

Have you had a chance to read the links yet?  I think they provide some technical background as to why tubes sound different to solid state.


There were a lot of reasons as to why tubes have been replaced by solid state for the masses, but improved sound quality was NOT one of them   
 

[jupiterboy]

I wonder about high-frequency harmonic distortion and the sympathetic response as it manifests in the audible frequency range. Tube amps seem to keep spatial information intact, or even over emphasize it, and also preserve the recorded decay of sounds differently.

I have not listened to many great SS amps, however, so consider my limited exposure.

[Ericus Rex]

Have you had a chance to read the links yet?  I think they provide some technical background as to why tubes sound different to solid state.


There were a lot of reasons as to why tubes have been replaced by solid state for the masses, but improved sound quality was NOT one of them   

Finally got around to reading it.  Thanks for the nudge.  There's a lot in there I don't agree with, as both an audiofool and a musician.  One example is how he claims that most tube designs haven't evolved in decades; I think he specifically states 'tube designs have changed relatively little...'.  That's a bit like saying car designs haven't changed much in the past 100 years since they still have pistons, brakes, tires and transmissions.  All tube circuits require some similar parameters...just like ss circuits.  There are many tube designs that are very up to date and sonically are very different from amps made 50 years ago...like my Rogue ST-100.  I'm always rather annoyed by that generalization.  Great designers are cutting edge regardless of which topology is used.  There will always be copyists who rely on the older designs of others.  I do, however, agree with his pros/cons - tube/ss page.  All the SS advantages involve convenience, lower cost and efficiency.  The tube's advantages are mostly in regards to sonics.  As audiofools which should we be more concerned with?

[Guy 13]

Finally got around to reading it.  Thanks for the nudge.  There's a lot in there I don't agree with, as both an audiofool and a musician.  One example is how he claims that most tube designs haven't evolved in decades; I think he specifically states 'tube designs have changed relatively little...'.  That's a bit like saying car designs haven't changed much in the past 100 years since they still have pistons, brakes, tires and transmissions.  All tube circuits require some similar parameters...just like ss circuits.  There are many tube designs that are very up to date and sonically are very different from amps made 50 years ago...like my Rogue ST-100.  I'm always rather annoyed by that generalization.  Great designers are cutting edge regardless of which topology is used.  There will always be copyists who rely on the older designs of others.  I do, however, agree with his pros/cons - tube/ss page.  All the SS advantages involve convenience, lower cost and efficiency.  The tube's advantages are mostly in regards to sonics.  As audiofools which should we be more concerned with?

Hi Ericus Rex and all Audio Circle members.
One other/last advantage of tubes over ss is the fact that anyone
can replace a tube, not so for a IC or transistor.

Guy 13

[Freo-1]

 I am not sure tube designs have actually made major improvements (like solid state has) since the heyday of tubes in the late 50’s and early to mid 60’s.  Certainly, the parts quality of caps, resistors, diodes, etc has improved markedly. Can’t say the same for new production tubes.  Sadly, the new production tubes (in general) do not measure up in overall quality, longevity, and are rather pricey. 
 
I will say that I agree that designs have continued evolve since the solid state supplanted tubes as the primary audio delivery device.  I would also argue that many of the most significant advancements for tube topology has been seen in the DIY arena, where tubes that were originally designed for television or military applications (e.g. - Nuvistor) have been successfully applied to audio amps/preamps.
 
I also agree that the advantages with using tubes are related to their sonic attributes.  The circuits tend to be much simpler than solid state, increased linearity, low noise WHEN a signal is applied, higher voltage rails, harmonic performance, and distortion/clipping characteristics. 
 

[jupiterboy]

Differences in detail delivery between my first (AMC CVT3030) and my second (EE M88) are significant. I do not know what to attribute this to, however. I suspect it is a better preamp section.

[Freo-1]

I continue to be amazed at just how good a properly designed tube amp can reproduce music.  Since getting the 110 watt 1625 mono blocks, I have gone back and listened to many older recordings that I have not played for quite some time.  The level of clarity, holography, and tonal balance is most remarkable.  One can subjectively hear deeper into the mix with that I have never been able to achieve with solid state.  Vocals have a clear concise presentation that is almost spooky. 

The high voltage rails used provide outstanding dynamics as well.

http://www.audiocircle.com/index.php?topic=122136.0

[OzarkTom]

Futterman OTL's from the 60's still beats most of the transformer driven tube amps of today. They still have clarity and detail that most tranny amps of today don't have. Plus when driving ESLs, always use OTL's. That makes the best combo.

[rollo]

  Tubed ,SS and Hybrid Amp designs can provide the goods. The key is what Amp with what speaker. Some speakers loads will determine the better choice in Amps.
   If one desires a tubed sound but the speakers respond to SS better than one can add tubes in the preamp area. Personally I use three amps with different speakers. For the Pipedreams Hybrid class "D" for the Snell EIV Audio Research Classic 60 or AR DR250 for the Lenehans Cyber 211SET with GE 211 tube. There are tradeoffs nothing is perfect. One must decide which tradeoffs matter most.  At the end of the day those combos worked out best for me.
   If one desires tubes, Hybrid or SS just make sure the speaker has a synergy with the choice you make. Both formats can and will provide emotional impact if done right.
   If anyone would like to hear what I'm talking about my home is open to all. Well if you live near me in NYC.



charles
   

[Freo-1]

Futterman OTL's from the 60's still beats most of the transformer driven tube amps of today. They still have clarity and detail that most tranny amps of today don't have. Plus when driving ESLs, always use OTL's. That makes the best combo.

Those NYAL amps were pretty unreliable, not worth the trouble IMHO. The OTL's being developed by Music Reference should be much better in that regard.

Tubes, Class A, AB SS, and Class D all sound different.  NONE of them sound exactly like real music (but depending on the speaker/amp combo, one can get pretty close).  Each has their strengths and shortfalls.  The type of speaker one prefers often can drive the decision on which amp to use.  For my present reference speakers, high powered tube amps work better than solid state amps, or class D.


BTW, found an interesting link about amp types written from one of Audio's true legends.


http://www.pearl-hifi.com/06_Lit_Archive/02_PEARL_Arch/Vol_01/Sec_1/002_Puzzled_About_Amps.pdf

[OzarkTom]

Those NYAL amps were pretty unreliable, not worth the trouble IMHO. The OTL's being developed by Music Reference should be much better in that regard.

Original Futttermans were reliable but NYAL was not. But George Kaye will mod them and make them reliable today in case anyone wants them modded. It is still very difficult to find any used NYAL amps on the open market. Owners know just how good they are.

SS is getting a lot closer. Job 225 amp is knocking at the door and it won't break the bank. This amp is as good as everyone is saying.

[Guy 13]

Hi all Audio Circle members.
Some time ago the left channel of my Decware SE-84C+ SET 2wpc stop working.
I took a chance and give it for repair to a Vietnamese technician.
While it was on repair, I used my spare amplifier a Niteshade Audio NS-10 - 10wpc with 6L6 wired in Pentode.
Not the same, not the same sound at all.
Not that it’s bad, but it’s is quite different.
Different in the sense it misses the details of the SET.
Anyway, now my Decware is repaired, cost me 10 USD.
According to the Vietnamese technician, the output transformer was defective, difficult to believe; but anyway, now it works and it works good, very good.
With my Audio Nirvana 8” extended range drivers and my OB dipole double 12” Eminence Acoustinator it gives me pretty much the sound I want and like.
I wonder how the Omega 7F that I bought from Louis will sound compared to what I have now.
So, tubes or solid state?
I like both, but I do prefer the sound of tubes with their nice glow.
Maybe one day, I will be able to afford the Bottlehead Stereomour 2a3 and see/hear if the sound can improve ? ? ?

Guy 13

[Freo-1]

I do, however, agree with his pros/cons - tube/ss page.  All the SS advantages involve convenience, lower cost and efficiency.  The tube's advantages are mostly in regards to sonics.  As audiofools which should we be more concerned with?

Thought I would bring this back.  I would argue that we should be concerned with the overall sonics.  I would further argue well designed tube amps can provide sonically pleasing results that are unique to tube amps.  The better McIntosh SS amps with autoformers sound pretty darn good, but even those don't sound quite like a well designed tube amp.  Roger that there a fair number of lower quality tube designs that don't sound all that good. 

Yes, they need work on occasion. However, there are still many quality tube gear from the 50's and 60's still making excellent music, thanks to the ability to refurbish them.  You don''t see that at anywhere near the same level of usage with legacy SS gear.

[Steve]

I wonder about high-frequency harmonic distortion and the sympathetic response as it manifests in the audible frequency range. Tube amps seem to keep spatial information intact, or even over emphasize it, and also preserve the recorded decay of sounds differently.

Yep, I agree, spatial, soundstaging is different. There are some basic, inherent differences between SS and tube. Capacitances are "solid state" vs vacuum dielectrics. ESR is different as well. Distortion characteristics between triodes and SS are different. Topologies/designs are basically different.

Frankly, I prefer low voltage tube any day to high voltage amps I have heard. More natural to these ears, but then again overall design makes a difference. High voltage supplies are quite different, series caps, poly caps, size of caps, chokes or no chokes etc. All makes a sonic difference.

Cheers
Steve

[Tyson]

Yep, I agree, spatial, soundstaging is different. There are some basic, inherent differences between SS and tube. Capacitances are "solid state" vs vacuum dielectrics. ESR is different as well. Distortion characteristics between triodes and SS are different. Topologies/designs are basically different.

Frankly, I prefer low voltage tube any day to high voltage amps I have heard. More natural to these ears, but then again overall design makes a difference. High voltage supplies are quite different, series caps, poly caps, size of caps, chokes or no chokes etc. All makes a sonic difference.

Cheers
Steve

Which low voltage tube amps do you fancy?

[Freo-1]

I have listened to both low voltage and high voltage tube amps, and each can sound outstanding.  With my present speakers, I need to supply them with lots of good high voltage tube power.  Pentode amps with separate screen supplies and lots of filtering really make ATC speakers with super linear drivers really sing.

I have also heard SET designs with 2A3/300B tubes driving custom Klipschorns that were very musical. 

[Steve]

Which low voltage tube amps do you fancy?

My own amps as I use to design and build preamps and amps, because I use a different design philosophy than any others. I am now retired, spending some time taking care of Mom. Thanks for asking.

Cheers
Steve