AudioCircle
Audio/Video Gear and Systems => Tube-o-phile Circle => Topic started by: Niteshade on 25 Nov 2009, 11:43 am
-
I think this is a good topic to air out. There are way too many stereotypes that are damaging and as many that give credit where no credit is due. Then we have mythology and voodoo lurking around the claims as well.
We've all experienced different things and this isn't about telling someone they're crazy or that, "You certainly couldn't have experienced that!" I'm not out to make accusations, just explanations for what has been experienced.
Here is an example:
Tubes sound "tubey". : This is a generalization stating that tubes sound fat- lots of midrange. Tubes have very little signature of their own. Fatness is a trait of the output transformer and its reaction to negative feedback and the load (speaker). The rest of the circuit has some to do with it too- but not as much.
-
I think changing to tubes after only having SS for years can lead one to say the word "tubey" as they might be overwhelmed by the musicality of the sound and grab that descriptor first. After you spend time with tubes it is a difficult decision to decide to leave them. Way more life to the music with than without IME.
-
I believe it is accurate to claim that amps and preamps from different manufacturers have unique sonic signatures. If I could audition several SS amps and preamp combinations in my room I am confident I could find one that would make me happy. However, I enjoy having the ModWright Transporter and a tube preamp ahead of my SS amps. Rolling tubes in either the Tranporter or in the Preamp allows me to distinctly change the sound from the system to suit my preferences. People that have not experienced tubes and tube rolling are missing a very exciting part of what this audio hobby has to offer.
Ken
-
A myth in some circles (pardon the pun): Tube equipment is unreliable.
That is too much of a blanket statement. What can make tube equipment unreliable?
1] Poor assembly practices. I have seen cottage gear with glued in (large) filter caps. Using the wrong value power resistors to save money, leads not trimmer properly, etc... Same things can happen with SS gear! Stay away from birds nests is a good blanket statement.
2] Improper biasing: Tubes run hot and stress all other components. SS amps can suffer the same consequences.
3] Bad circuit: Equates to stressed parts in many cases.
4] Amp not set up right: Suffocated amps will burn out quickly. That fancy wooden cover on some vintage Fisher and Scott gear isn't good for their health! Placing amps on inside shelves isn't a good idea either.
5] Vintage amps: It is not recommended to just plug them in and start using them until they are checked out.
Much of this is common sense, but often overlooked. A good tube amp or preamp will last for decades. Routine capacitor checks every decade or so are advisable. (Same with SS amps)
Tubes are user serviceable. It's easy to keep a tube amp going!
-
Based on your first post, do OTL tube amps sound, well, less 'tubey'? I've never heard one but I know Bobby from Merlin uses JE OTL's in his demos.
-
SET, SEP, Push-Pull, OTL, 45's, EL84's, Class A, 3 watts, 10 watts, 15 watts, etc... what's an old SS guy to do? ... help me, I'm drowning in strange terminology and surrounded by "wives tales." :o
They say that ignorance is bliss. When it comes to tubes, I've got the ignorance part down good, but it's not very blissful from where I sit.
Thankfully, I have Blair and you other tube circle guys to help me understand what otherwise would be impossible for me to learn and understand at this point in my life. Just keep in mind that some of your readers (like me!) don't have the experience and knowledge that you guys take for granted now. Trust me, it's not an easy transition to make. You know, it's that "change" thing. :|
-
Tubes have very little signature of their own. Fatness is a trait of the output transformer and its reaction to negative feedback and the load (speaker). The rest of the circuit has some to do with it too- but not as much.
Perhaps, but some users report that changing the tubes in their amp resulted in a much fatter midrange, everything else, inlcluding the output transformers, being the same.
Steve
-
SET, SEP, Push-Pull, OTL, 45's, EL84's, Class A, 3 watts, 10 watts, 15 watts, etc... what's an old SS guy to do? ... help me, I'm drowning in strange terminology and surrounded by "wives tales." :o
They say that ignorance is bliss. When it comes to tubes, I've got the ignorance part down good, but it's not very blissful from where I sit.
Thankfully, I have Blair and you other tube circle guys to help me understand what otherwise would be impossible for me to learn and understand at this point in my life. Just keep in mind that some of your readers (like me!) don't have the experience and knowledge that you guys take for granted now. Trust me, it's not an easy transition to make. You know, it's that "change" thing. :|
I share the tube terminology dread to this day, but here's my simple tube story:
In the mid-80's I was borrowing every solid-state amp (Crown, Bedini, Yamaha, etc.) I could find and listened night after night to no avail. When my local dealer showed me a Moscode hybrid amp with glowing tubes I laughed at him. He insisted I borrow it. I smugly hooked it thinking "this is a joke". Ten seconds later I said "this ain't leaving!"
I still have it, despite my son's attempts to hijack it. :thumb:
-
I have had the opposite experience. I've gone through several tubes and noted how similar they were. The change I saw was mostly where they started to compress and break up. Compression might be thought of as fatness, but I don't perceive it that way myself. Currently, there are some VERY nice 6L6GA's (1940's) in a self-splitting amp of mine. They sound exactly like JJ 6L6's to me. Very clean with a late breakup. Another unit in my collection has metal JAN 6L6's producing up to 50 watts per channel and doing it cooly. They remind me of Russian 5881's (the millitary coin base models). Very clean & rugged.
Factors that can dramatically change an amp's performance when a tube is changed:
1. Plate voltage
2. Screen voltage
3. Reaction to an ultra-linear circuit
4. Feedback ratio & circuit
I firmly believe the circuit and output transformers have the most influence on the effects of tube rolling. For example, the same tube that sounds fat on one system might sound clinical in another or very transparent in yet another.
Tubes have very little signature of their own. Fatness is a trait of the output transformer and its reaction to negative feedback and the load (speaker). The rest of the circuit has some to do with it too- but not as much.
Perhaps, but some users report that changing the tubes in their amp resulted in a much fatter midrange, everything else, inlcluding the output transformers, being the same.
Steve
-
OK, I'll ask... what's a 6L6? :duh:
-
There are several circuit configurations to choose from. You named many of them. Then there are limitless ways of implementing those topologies.
I don't like it that the choices can be confusing and make people turn the other way. This, unfortunately is true and not a wives's tale. The way to combat it to decide what will be the most compatible with your existing hardware. This step alone is HUGE in the process of elimination. Need power due to 85db efficient speakers? That throws 2A3's, 300B's. 45's, El84's out the window. Time to look at big Single Ended Parallel (SEP) and push-pull amps (including push-pull-parallel) using 6550's, KT88's, 6L6's, EL34's and a few others. There are other factors to look into- this was just a basic process of elimination step.
SET, SEP, Push-Pull, OTL, 45's, EL84's, Class A, 3 watts, 10 watts, 15 watts, etc... what's an old SS guy to do? ... help me, I'm drowning in strange terminology and surrounded by "wives tales." :o
They say that ignorance is bliss. When it comes to tubes, I've got the ignorance part down good, but it's not very blissful from where I sit.
Thankfully, I have Blair and you other tube circle guys to help me understand what otherwise would be impossible for me to learn and understand at this point in my life. Just keep in mind that some of your readers (like me!) don't have the experience and knowledge that you guys take for granted now. Trust me, it's not an easy transition to make. You know, it's that "change" thing. :|
-
I have not listened to an OTL but really want to. Would someone with an OTL like to talk about theirs? :D
Based on your first post, do OTL tube amps sound, well, less 'tubey'? I've never heard one but I know Bobby from Merlin uses JE OTL's in his demos.
-
Here is a good link: http://en.wikipedia.org/wiki/6L6
There are several variations of the 6L6 and the family is quite large. There is even a triode grandfather to it. I can't recall the designation. Will let you know when I can locate it. It's a neat tube.
OK, I'll ask... what's a 6L6? :duh:
-
I have not listened to an OTL but really want to. Would someone with an OTL like to talk about theirs? :D
Based on your first post, do OTL tube amps sound, well, less 'tubey'? I've never heard one but I know Bobby from Merlin uses JE OTL's in his demos.
I love my Atma-Sphere OTL amps!
They definitely don't sound tubey...they sound crystal clear and direct with the right amount of texture, tonality, and realism. The amps (I own M-60's and MA-1's) are incredibly engaging and transparent - music simply flows from them in a way no other amp has in my system (and I have a tried a lot). The cast a huge and deep sound stage (when present in the recording) and allow one to hear deep into the music.
BTW, the bass on these amps is very, very good. While it might not have quite as much grip and control on the very lowest octaves as some big ss amps, its fast, articulate, natural, and without any bloat or fatness.
Once you hear an Atma-Sphere amp with the right set of speakers, it is hard to go back to listening to anything else. aa
George
-
Just to keep track, here's the 'tales' so far:
1. Tube amps sound 'tubey' aka: fat
2. Tube amps are unreliable
3. It's difficult to choose an amplifier because there are so many options
4. Tube rolling: Designates a specific quality for that brand//type/edition of tube
#4 is not really an over generalization because it's true (relative to the amp it's being tested in) As stated earlier, that same tube could sound totally different in another amp. It all depends on how the circuit interfaces with the tube. What could be over generalized is saying something like, "This tube ____ always sounds cold, fat, whatever...."
Here's #5: Tubes take the edge off digital sources.
My answer is simple: Some tube amps/preamps might. You're hearing the design, not a concrete trait of the tube(s) specifically. It has been my experience that tube gear can be brutally revealing. This also goes back into the whole tube warmth thing. That trait is an exception and not the norm. I have heard tube amps more sterile and clinical than SS amps. Yeah- I have heard GREAT SOUNDING SS gear that can beat some tube stuff into the ground. Well, I suppose saying that tube gear is ALWAYS better than SS gear is over generalization #6. :oops: No sense in being biased! I'm sharing experiences and being honest about it.
We have to choose what works best for our needs. What's I'm trying to alleviate is turning down something due to assumptions that have been kicked around for years and years. Don't miss out on something good just because someone says, " NO! You don't want tube gear- It runs too hot, breaks down all the time and it's too warm & fuzzy!" What a crock! Solid state gear isn't always clinical and cold either. Both have pro's and con's. Sometimes it's best to run a hybrid system.
-
Just to keep track, here's the 'tales' so far:
1. Tube amps sound 'tubey' aka: fat
2. Tube amps are unreliable
3. It's difficult to choose an amplifier because there are so many options
4. Tube rolling: Designates a specific quality for that brand//type/edition of tube
#4 is not really an over generalization because it's true (relative to the amp it's being tested in) As stated earlier, that same tube could sound totally different in another amp. It all depends on how the circuit interfaces with the tube. What could be over generalized is saying something like, "This tube ____ always sounds cold, fat, whatever...."
Here's #5: Tubes take the edge off digital sources.
My answer is simple: Some tube amps/preamps might. You're hearing the design, not a concrete trait of the tube(s) specifically. It has been my experience that tube gear can be brutally revealing. This also goes back into the whole tube warmth thing. That trait is an exception and not the norm. I have heard tube amps more sterile and clinical than SS amps. Yeah- I have heard GREAT SOUNDING SS gear that can beat some tube stuff into the ground. Well, I suppose saying that tube gear is ALWAYS better than SS gear is over generalization #6. :oops: No sense in being biased! I'm sharing experiences and being honest about it.
We have to choose what works best for our needs. What's I'm trying to alleviate is turning down something due to assumptions that have been kicked around for years and years. Don't miss out on something good just because someone says, " NO! You don't want tube gear- It runs too hot, breaks down all the time and it's too warm & fuzzy!" What a crock! Solid state gear isn't always clinical and cold either. Both have pro's and con's. Sometimes it's best to run a hybrid system.
I think most of your wives tales seem to be true in a general sense - obviously, there are exceptions, but in general I think they hold true.
1) Tubes sound tubey (i.e. - good)
2) Tube amps are less reliable - they use expendable components, require adjustments, are built with less automation which increases quality, but also invites the random bad solder joint.
3) It is more difficult to choose a tube amp, as there are many different designs and far fewer places to audition them.
4) Tube rolling alters the sound - has been totally true in my experience - what hasn't been accurate is the "accepted" qualities of various tubes in my specific amp, fortunately I have been happier with the cheaper end of the NOS tube spectrum.
5) Again, I think that the vast majority of tube gear takes the edge off of harsh digital recordings. It may be the design of the circuit, or the transformers or whatever - but, I think it is a characteristic of most tube amps.
I really love the tube gear I have, but I think the "wives tales" are all based on truth - just because there are exceptions, it doesn't make the generalizations less accurate. Just like I'm sure that some British car manufacturers can build a reliable car - it wouldn't convince me that the generalizations about British car reliability are wrong.
Jim C
-
I think most of your wives tales seem to be true in a general sense - obviously, there are exceptions, but in general I think they hold true.
I really love the tube gear I have, but I think the "wives tales" are all based on truth - just because there are exceptions, it doesn't make the generalizations less accurate. Just like I'm sure that some British car manufacturers can build a reliable car - it wouldn't convince me that the generalizations about British car reliability are wrong.
Jim C
I don't intend to be argumentative, but I haven't had the same experiences. Obviously, tube amps need maintenance such as replacement of tubes. Maybe some manufacturers produce gear that is more reliable than other manufacturers' gear, but I don't know about overall reliability problems based upon the use of tubes. (I also had to replace the belt and motor on my 23 year old turntable.)
I have heard George's system with his Atma-Sphere amps, and there wasn't anything tubey in the sound. George also has a Modwright Transporter in his system, which uses tubes, and I haven't ever heard about any problems with the Transporter or any Modwright equipment. George's system is the best that I have heard. Every component is outstanding, and every component compliments the other components.
For myself, I have a tube amp that was built upon a forty-something-year-old donor amp, and there isn't anything tubey or unreliable about the amp. I also have a tube preamp and a tube DAC, and both have been completely reliable. My tube gear was built by Frank Van Alstine, who has been building or modifying tube gear for more than 40 years, and his stuff is built like tanks (and sounds great, too). I also have four pieces of Frank's solid state gear, one of which is more than 25 years old, and I have a limited non-scientific tube v. solid state reference point.
My Jaguar, built in England, motor by Cosworth, and not a re-badged Mazda, Volvo, or Ford (Ford owned Jaguar from 1993 until 2008, and Ford currently owns Mazda and Volvo), has been the most reliable car that I have ever owned. The Jaguar has been more reliable than my wife's 2007 Honda Pilot and the several Subaru and Honda cars and a Mercury car that she has owned over the past 22 years that I have known her. I have owned several other British cars that weren't as reliable as my Jaguar, but the youngest of those cars was a 1969 model, and the car wasn't any less reliable than the U.S. built cars that I owned that were built 30 or more years ago.
I wouldn't mind seeing some studies about manufacturer-specific tube-equipped component reliability. I know that Jaguar came in second place in the J.D. Power 2009 Vehicle Dependability Study.
-
Every once in a while I hear the term "tube friendly" or an easy load for tube amps... what's up with that?
-
Most tube amps are not high powered. They're around 30 watts or less per channel. Tube friendly means a speaker is an easy load for the amp, just as you said. Easy loads are around 92db and up and do not have wild impedance swings throughout their frequency range.
Every once in a while I hear the term "tube friendly" or an easy load for tube amps... what's up with that?
-
Happy Thanksgiving everybody!
-
What about current and tube amps vs. solid state?
-
Could you explain what you mean? Do you mean current tube amps vs. older tube amps vs. solid state?
What about current and tube amps vs. solid state?
-
"Tube friendly" speakers are speakers that present a reasonably lnear load to the amplifier - no large swings in impedance and inductance.
I think (flame suit on) that a lot of the lack of bass perception of tube power amps comes from the fact that the power supplies tended to be a somewhat "soft" - tube rectifier (especially the ST-70 - it;s rectifier was designed to drive one pair of EL34's, not two). And power supply capacitance was much more expensive in "those days" than it is now.
Just my $.02.
-
You're right- current limitations can reduce a tube amp's performance. The standard ST-70 isn't a bad amplifier. It's not a high performance amp, but does a good job on most things. Some make upgrades for them which I'm sure steps them up a few notches.
-
Nightshade
I have not listened to an OTL but really want to. Would someone with an OTL like to talk about theirs?
have you ever thought about building one up to play with?
-
Yes and no. The reason why OTL's use so many tubes is because the tubes were not designed to be used to drive low impedance loads. I realize there are desirable outcomes from this topology but prefer using transformers because they are so efficient and reliable.
Nightshade
I have not listened to an OTL but really want to. Would someone with an OTL like to talk about theirs?
have you ever thought about building one up to play with?
-
Would you consider a pentode in triode mode to be better sounding than one in tetrode mode?
The common belief (wives tale) is yes. Some people do like the sound and I will not quarrel with that. But- to say tetrode mode is worse sounding isn't right. I prefer tetrode mode because it facilitates the tube's power handling capability efficiently. I see no reason to put a 'bottleneck' on a tube's abilities. Tetrode mode can provide exemplary performance and it does with the proper circuits.
-
The afore meantioned Dynaco St-70 makes a superb case for tube amp reliability. So many still turn up at house sales and are seen at an uncles house to this day. They run in the backround in many peoples homes for countless hours. At 40+ years in some cases that an excellent record. :thumb:
-
If I may Blair, I would like to add a couple of more.
1) The component must be tube rectified. What can happen is that the rectifier tube can soften the sound too much.
2) The component must have choke(s) in the power supply. In this case, the power supply becomes more reactive when we want the power supply to be as linear as is possible.
As Blair mentions, the design is very important.
Cheers.
-
Yes and no. The reason why OTL's use so many tubes is because the tubes were not designed to be used to drive low impedance loads. I realize there are desirable outcomes from this topology but prefer using transformers because they are so efficient and reliable.
My OTL amps have been the most reliable tube amps I have owned - I don't think you should paint such a broad picture when it comes to reliability and OTL amps.
I do agree with you about OTL amps having trouble driving low impedance loads...however, you can simply add something like the Speltz Zeros and you are in business. Better yet, don't get speakers with very low impedance loads. :wink:
George
-
Hi Zybar,
I have an old homebrew OTL amp and was wondering if anyone is manufacturing 32 ohm drivers these days?
Cheers.
-
Hi Zybar,
I have an old homebrew OTL amp and was wondering if anyone is manufacturing 32 ohm drivers these days?
Cheers.
Actually, I think Zu will provide 32 ohm speakers.
Of course you don't need to go to 32 ohm speakers to take advantage of an OTL amp. My speakers (Vandy 5A's) go down to 4 ohms and are a great match with my Atma-Sphere OTL amps.
George
-
Hi Zybar,
I have an old homebrew OTL amp and was wondering if anyone is manufacturing 32 ohm drivers these days?
Cheers.
My speakers (Vandy 5A's) go down to 4 ohms and are a great match with my Atma-Sphere OTL amps.
George
Bet your Atmas will also drive the Vandy 7's pretty decently aa aa
-
Hi Zybar,
I have an old homebrew OTL amp and was wondering if anyone is manufacturing 32 ohm drivers these days?
Cheers.
Actually, I think Zu will provide 32 ohm speakers.
Of course you don't need to go to 32 ohm speakers to take advantage of an OTL amp. My speakers (Vandy 5A's) go down to 4 ohms and are a great match with my Atma-Sphere OTL amps.
George
Hi George,
I guess I was getting at the high output tube impedance should control a higher impedance woofer better than a lower impedance woofer. That and a capacitively coupled output stage would require less capacitance. Are all the OTL amp manufacturers using dc coupled now?
Thanks George.
Steve
-
I am pretty sure most OTL manufacturers are using a system where no coupling device is necessary on the output due to using bi-polar power supplies.