Tubes, Wheres the "sound"

[Chuck Elliot]

Then there is stage feedback. In this case there is no global feedback from output to input. Rather each stage provides its own "feedback".

It takes more tubes, but each stage has as its load a matched tube. Non-linearity is present it both triodes in the stage, but cancel for better performance.

This circuit is a gain stage followed by a cathode follower stage to provide low output impedance.

[novisnick]

Another question,,,,,,,,I don't know Schiit about this stuff! Does it show?? 
  
Why should I use a dedicated tube phono pre amp vs a tube pre amp and lets say a XPS-1?

Can someone point me in the right direction to answer these questions I have?

Is it fair to guess that using a tube pre amp and a phono pre amp give me enough or too much tube sound? Or does all that depend on my ear, which im assuming but have no idea.

[Gary Cook]

Nick.....really.......in your pair of XPR-1's you have 2 of the cleanest solid state amps available.................and yet you want to feed it with distorted input.

I'm disappointed


Cheers
Gary

[novisnick]

Apr 6, 2016 2:01:45 GMT -5 Gary Cook said:

Nick.....really.......in your pair of XPR-1's you have 2 of the cleanest solid state amps available.................and yet you want to feed it with distorted input.

I'm disappointed


Cheers
Gary

You should hear all of the chocolaty goodness eminating from my speakers! As clean as my fully balanced system is, something about the mix of gear makes it sound a little better, real/imaginary?  Maybe the highs are a little to accurate for me, the tubes seem to cut that edgy sound out, smooth it out I'll say.

Maybe just different. Mids has smoother  transition between highs and lows. No loss of bass at all, the Studio 100's excell in that area anyway.

Maybe just spoiled and looking for a different sound. These tubes, phono pre amp and vinyl really sound great, not tiring at all. I can listen for days and not get enough!

Im not sold on digital, im told different tubes from the phono are installed and I haven't flipped for those. If it were my McIntosh, I would swap the tubes out to find out if thats what it is that I like and dislike. Not sure the tubes are even swappable.  

Im still searching for answers as you can tell from all of my questions that litter this and other forums.

Thanks for your input, I get it. 

[monkumonku]

Apr 6, 2016 2:01:45 GMT -5 Gary Cook said:

Nick.....really.......in your pair of XPR-1's you have 2 of the cleanest solid state amps available.................and yet you want to feed it with distorted input.

I'm disappointed


Cheers
Gary

Yes but that distortion will be accurately reproduced by the amps.

[KeithL]

Actually that's not it....

The amount of "tube sound" a piece of tube equipment adds to your music really depends mostly on the circuit design itself.

With POWER AMPS, all tube amps have a significant influence on the bass response with most speakers - because ALL tube amps have very low damping factors when compared to solid state amps. (The damping factor on tube amps typically ranges from about 2 to about 4; and there are NONE that I know with a DF higher than 8. In contrast, most modern solid state amps have a DF between about 200 and about 1000. While the reality is that you're probably not going to hear a difference between a DF of 100 and one of 1000 with real speakers, the difference between a DF of 4 and a DF of 40 is pretty noticeable with most speakers. The amp with the lower DF will usually sound like it has more bass, but the bass is muddy and indistinct.) In addition to this, tube power amps often impart other colorations characteristic of tubes as well. For this reason, virtually all tube power amps (certainly all of them I've ever heard) do in fact sound noticeably different from uncolored solid state power amps. (But some do indeed sound much more colored than others - presumably because they were designed to.)

Now, PREAMPS don't have a damping factor rating - because they aren't connected to an electromechanical device which needs to be damped. Beyond that, the job a preamp does - simply add some gain to a line-level signal -  is electrically simpler to achieve. For this reason, it's quite possible to design a tube preamp that is virtually uncolored, and so is virtually indistinguishable from a solid state preamp. (In fact, designing a simple preamp that is very neutral is not at all difficult - using either tube or solid state circuitry. About the only reason to avoid tubes is simply that, at a given level of performance, it will cost more to use tubes, and they may eventually wear out.)
 
The arguments in favor of using a separate phono preamp rather than one that's part of a regular preamp are really the same for tubes or solid state. The idea is simply that, at a given price point, a specialized phono preamp is likely to be of higher quality than "one they throw in with a preamp", and the phono preamp you get as part of a regular preamp is likely to be a low-cost one which is of relatively poor quality. It's also true that, in some specific situations, the phono preamp may benefit from being housed in a separate box, and powered from an entirely separate power supply... although that isn't always true. There's also the idea that, with a separate phono preamp, you have the opportunity to select the preamp and phone preamp separately - which gives you more options. (In our case, our separate XPS-1 phono preamp is virtually the same as the phono section in our XSP-1 preamp, and performs, and sounds, very much the same.)

The answer to your question, however, is that the amount of "tube sound" that is added by either a tube preamp or a tube phono preamp will depend mostly on how the circuitry was designed, and it's quite possible that neither will add a lot of coloration, so your answer really will depend on the individual components you're considering. (But, yes, any tube coloration added by each will tend to add together. However, it's also true that you might prefer more coloration when listening to vinyl.) Another consideration is that, because a phono preamp is dealing with very low level signals, and powerful equalization, it's more difficult to design a low-cost tube phono preamp that performs well. (So, especially if your budget is limited, you'll probably get better performance by combining a solid state phono preamp with a tube line level preamp.)

Apr 5, 2016 23:15:14 GMT -5 novisnick said:

Another question,,,,,,,,I don't know Schiit about this stuff! Does it show?? 
  
Why should I use a dedicated tube phono pre amp vs a tube pre amp and lets say a XPS-1?

Can someone point me in the right direction to answer these questions I have?

Is it fair to guess that using a tube pre amp and a phono pre amp give me enough or too much tube sound? Or does all that depend on my ear, which im assuming but have no idea.

[audiobill]

Summing up, one man's "clean" is another man's "sterile".

[tchaik]

Apr 6, 2016 10:49:52 GMT -5 KeithL said:

Actually that's not it....

The amount of "tube sound" a piece of tube equipment adds to your music really depends mostly on the circuit design itself.

With POWER AMPS, all tube amps have a significant influence on the bass response with most speakers - because ALL tube amps have very low damping factors when compared to solid state amps. (The damping factor on tube amps typically ranges from about 2 to about 4; and there are NONE that I know with a DF higher than 8. In contrast, most modern solid state amps have a DF between about 200 and about 1000. While the reality is that you're probably not going to hear a difference between a DF of 100 and one of 1000 with real speakers, the difference between a DF of 4 and a DF of 40 is pretty noticeable with most speakers. The amp with the lower DF will usually sound like it has more bass, but the bass is muddy and indistinct.) In addition to this, tube power amps often impart other colorations characteristic of tubes as well. For this reason, virtually all tube power amps (certainly all of them I've ever heard) do in fact sound noticeably different from uncolored solid state power amps. (But some do indeed sound much more colored than others - presumably because they were designed to.)

Now, PREAMPS don't have a damping factor rating - because they aren't connected to an electromechanical device which needs to be damped. Beyond that, the job a preamp does - simply add some gain to a line-level signal -  is electrically simpler to achieve. For this reason, it's quite possible to design a tube preamp that is virtually uncolored, and so is virtually indistinguishable from a solid state preamp. (In fact, designing a simple preamp that is very neutral is not at all difficult - using either tube or solid state circuitry. About the only reason to avoid tubes is simply that, at a given level of performance, it will cost more to use tubes, and they may eventually wear out.)
 
The arguments in favor of using a separate phono preamp rather than one that's part of a regular preamp are really the same for tubes or solid state. The idea is simply that, at a given price point, a specialized phono preamp is likely to be of higher quality than "one they throw in with a preamp", and the phono preamp you get as part of a regular preamp is likely to be a low-cost one which is of relatively poor quality. It's also true that, in some specific situations, the phono preamp may benefit from being housed in a separate box, and powered from an entirely separate power supply... although that isn't always true. There's also the idea that, with a separate phono preamp, you have the opportunity to select the preamp and phone preamp separately - which gives you more options. (In our case, our separate XPS-1 phono preamp is virtually the same as the phono section in our XSP-1 preamp, and performs, and sounds, very much the same.)

The answer to your question, however, is that the amount of "tube sound" that is added by either a tube preamp or a tube phono preamp will depend mostly on how the circuitry was designed, and it's quite possible that neither will add a lot of coloration, so your answer really will depend on the individual components you're considering. (But, yes, any tube coloration added by each will tend to add together. However, it's also true that you might prefer more coloration when listening to vinyl.) Another consideration is that, because a phono preamp is dealing with very low level signals, and powerful equalization, it's more difficult to design a low-cost tube phono preamp that performs well. (So, especially if your budget is limited, you'll probably get better performance by combining a solid state phono preamp with a tube line level preamp.)

Apr 5, 2016 23:15:14 GMT -5 novisnick said:

Another question,,,,,,,,I don't know Schiit about this stuff! Does it show?? 
  
Why should I use a dedicated tube phono pre amp vs a tube pre amp and lets say a XPS-1?

Can someone point me in the right direction to answer these questions I have?

Is it fair to guess that using a tube pre amp and a phono pre amp give me enough or too much tube sound? Or does all that depend on my ear, which I'm assuming but have no idea.

this is why back in the 80's i used an audio research D90b (tubes) for my panels and a krell KSA-100 (solid state class A) for the bass towers of my infinity RS1b's. since they were xover at 150 hz it didn't affect the bass much and the audio research was pretty neutral for its day. as for now, a totally neutral solid state pre-amp and amp is the only thing i can listen to. tubes are just too colored for me.

tchaik…………

[KeithL]

Those trying to become familiar with tube circuitry should be aware that the "aikido circuit" shown here is actually a rather unusual tube preamp circuit - developed by the fellow at TubeCad.
(It's a neat circuit, but you will NOT see this circuit in vintage equipment - or in most modern equipment. )

Apr 5, 2016 22:38:47 GMT -5 Chuck Elliot said:

Then there is stage feedback. In this case there is no global feedback from output to input. Rather each stage provides its own "feedback".

It takes more tubes, but each stage has as its load a matched tube. Non-linearity is present it both triodes in the stage, but cancel for better performance.

This circuit is a gain stage followed by a cathode follower stage to provide low output impedance.

(The attachment below will usually be much clearer if you click on it and open it up directly.)

Circuit 1 shows a VERY basic tube preamp gain stage.
The cathode resistor (the one going from the bottom of the tube to ground) is providing local feedback - and so controlling the gain.

Circuit 2 shows the same circuit with "cathode bypass".
The capacitor in parallel with that cathode resistor acts as an open circuit to DC, but a short circuit to AC.
This eliminates the AC feedback on the cathode, so you get much higher gain (for AC signals).
This is the basic preamp gain stage you'll see on MOST lower cost vintage equipment.
(It will give you a gain of 10x to 20x with a 12AU7, and about 100x with a 12AX7, and sounds quite good.)

Circuit 3 shows the same circuit with a cathode follower circuit added.
The cathode follower, by its nature, is a buffer - it has a gain slightly less than 1, but delivers a very low output impedance.
This is the probably the most common circuit you'll see on mid-level preamps (new or old).

Note that I omitted the circuit values, which will depend on several factors, but these circuits WILL work - pretty well - exactly as shown.

[audiobill]

To help clarify your understanding, several of the tube preamps developed by Roy Mottram and available at tubes4hifi.com, for example, were based on the Aikido circuit, with circuit refinements along with SOTA power supplies.

[copperpipe]

Theoretical question If one wanted to dabble with the "tube sound", would it be better to use a solidstate pre-amp and buy a tube amp, or buy a tube pre-amp and use a solid state amp? I realize that's an artificial restriction, but I wonder if I can get the tube sound by just using a tube pre-amp since they seem a lot cheaper than a good tube amp.

[monkumonku]

Apr 6, 2016 15:28:39 GMT -5 copperpipe said:

Theoretical question If one wanted to dabble with the "tube sound", would it be better to use a solidstate pre-amp and buy a tube amp, or buy a tube pre-amp and use a solid state amp? I realize that's an artificial restriction, but I wonder if I can get the tube sound by just using a tube pre-amp since they seem a lot cheaper than a good tube amp.

Well I've just started to dabble and I ended up getting a tube amp from Bob Latino which I am in process of constructing. My two cents is that tubes are supposed to be a "smoother" sound because of the distortion and also that they distort gradually when pushed, rather than going up to a certain limit then clipping drastically once they reach that limit like solid state gear does.

So it would seem to me that the tube sound would be more fully experienced with an amp? Because a good preamp that puts out enough power shouldn't clip whereas the amp would be more prone to being driven to more stressful levels.

But then I'm just a noob at this so I'm only trying to think that through. That, plus justify why I started out with a tube amp instead of tube preamp.

[novisnick]

Apr 6, 2016 15:28:39 GMT -5 copperpipe said:

Theoretical question If one wanted to dabble with the "tube sound", would it be better to use a solidstate pre-amp and buy a tube amp, or buy a tube pre-amp and use a solid state amp? I realize that's an artificial restriction, but I wonder if I can get the tube sound by just using a tube pre-amp since they seem a lot cheaper than a good tube amp.

The issue, with me, about tube amps is the heat! Period!! Small cave, poor heat dispersal. Unless I want a very steep electric bill.

[monkumonku]

Apr 6, 2016 15:44:18 GMT -5 novisnick said:

Apr 6, 2016 15:28:39 GMT -5 copperpipe said:

Theoretical question If one wanted to dabble with the "tube sound", would it be better to use a solidstate pre-amp and buy a tube amp, or buy a tube pre-amp and use a solid state amp? I realize that's an artificial restriction, but I wonder if I can get the tube sound by just using a tube pre-amp since they seem a lot cheaper than a good tube amp.

The issue, with me, about tube amps is the heat! Period!! Small cabe, poor heat dispersal. Unless I want a very steep electric bill.

Yeah but much lower heating bills in the winter so you're even. Plus you can do indoor bbq's now, too.

[novisnick]

Apr 6, 2016 15:49:04 GMT -5 monkumonku said:

Apr 6, 2016 15:44:18 GMT -5 novisnick said:

The issue, with me, about tube amps is the heat! Period!! Small cabe, poor heat dispersal. Unless I want a very steep electric bill.

Yeah but much lower heating bills in the winter so you're even. Plus you can do indoor bbq's now, too.

Great idea, maybe even a Mongolian Grill in my restaurant!!
I filled in the amp vent holes and  voila!  

                                                                            



Edit;
On another note, down here at EmoSouth we can usually golf 12 months a year.

[novisnick]

So, do I go phono pre first,? Only? Or last?

[monkumonku]

Apr 6, 2016 16:01:30 GMT -5 novisnick said:

Apr 6, 2016 15:49:04 GMT -5 monkumonku said:

Yeah but much lower heating bills in the winter so you're even. Plus you can do indoor bbq's now, too.

Great idea, maybe even a Mongolian Grill in my restaurant!!
I filled in the amp vent holes and  voila!  

                                                                          View Attachment  



Edit;
On another note, down here at EmoSouth we can usually golf 12 months a year.

I bought a nice set of tubes today and besides generating some nice heat, they also look good, too.

[yves]

Apr 6, 2016 15:44:18 GMT -5 novisnick said:

Apr 6, 2016 15:28:39 GMT -5 copperpipe said:

Theoretical question If one wanted to dabble with the "tube sound", would it be better to use a solidstate pre-amp and buy a tube amp, or buy a tube pre-amp and use a solid state amp? I realize that's an artificial restriction, but I wonder if I can get the tube sound by just using a tube pre-amp since they seem a lot cheaper than a good tube amp.

The issue, with me, about tube amps is the heat! Period!! Small cave, poor heat dispersal. Unless I want a very steep electric bill.

My Eastern Electric MiniMax Tube DAC Supreme uses only a single 12AU7 tube so it doesn't generate much heat. What's more, the tube can be disabled, without cancelling the playback process as a result, at the flick of a button on the front panel of the DAC because the DAC has two whole gain stages instead of only one (one gain stage is fully Tube based, the other one uses Solid State).

[novisnick]

Apr 7, 2016 5:19:02 GMT -5 yves said:

Apr 6, 2016 15:44:18 GMT -5 novisnick said:

The issue, with me, about tube amps is the heat! Period!! Small cave, poor heat dispersal. Unless I want a very steep electric bill.

My Eastern Electric MiniMax Tube DAC Supreme uses only a single 12AU7 tube so it doesn't generate much heat. What's more, the tube can be disabled, without cancelling the playback process as a result, at the flick of a button on the front panel of the DAC because the DAC has two whole gain stages instead of only one (one gain stage is fully Tube based, the other one uses Solid State).

Sorry my friend, I was strictly speaking of the heat of a tube amp, 350*f pouring off of them is a little much for me. Thanks for the response though!

[KeithL]

The difference between a tube power amp and an equivalent solid state one is likely to be much greater than the difference between preamps. (You can spend a lot of money and end up with one that sounds pretty bad.) A tube preamp is much more likely to add just a tiny bit of "smoothness" or "sparkle"; while a tube power amp is almost certain to have somewhat muddy bass (in addition to that); and some are deliberately designed to sound "distinctly tubey". The other thing is that, even though low-powered tube power amps are already somewhat expensive, the price rises VERY rapidly when you look at higher-powered ones. I would strongly suggest going with a tube preamp and a solid state power amp. (While a neutral solid state power amp obviously isn't going to ADD any "tube sound",  it's not going to remove any tube sound added by the preamp, and it will deliver plenty of clean bass. And, if you decide that the tube sound doesn't really send you, you've still got a nice neutral power amp, which you can use with a different preamp. Or, alternately, if you decide you really like the sound of your tube preamp, it will sound pretty much the same with any neutral sounding solid state amp.)

You do need to differentiate WHICH PART of "the tube sound" you're actually looking for.....

* The slight "sparkle" or "shimmer" or "smoothness" is typically considered to be due to the higher levels of second harmonic distortion (and you get that with a preamp or a power amp).

* The gradually increasing distortion (monotonic distortion curve) is present in both, but is more noticeable with tube power amps. That's the part that causes tube amps to seem slightly more powerful than what the specs would indicate - and some people say makes them sound "more dynamic". Unfortunately, the fact that a 20 watt tube amp sounds as powerful as a 40 watt solid state amp must be considered in light of the fact that you can probably get a 100 watt solid state power amp for less cost than a 20 watt tube amp.

* The "smooth" or "loose" sounding bass is a function of damping factor - and so is mostly a characteristic of tube power amps. Most tube preamps won't won't add any of that at all.

Tube preamps are also easier to design than tube power amps, and a lot cheaper to build, which means that they're more likely to work well; and they use cheaper tubes that don't tend to wear out as often (if ever). Incidentally, take all the endless chatter about this or that tube sounding hugely different with grain of salt. Tubes were originally designed as a commodity item - and most of the current attitude towards vintage tubes is... err... somewhere between "highly exaggerated" and "just plain silly". Yes, different brands and even factory runs of tubes can have slightly different electrical characteristics, which can cause them to sound slightly different in a given circuit, and some circuits have clearly been designed to exaggerate the differences, but how that works out is mostly random. (You can easily pay an extra $200 for a vintage tube that, when it was new, sold for 50 CENTS more than another brand, or maybe 50 cents LESS, simply because some reviewer is convinced it sounds better in his amplifier. And the sad reality is that, even if it really did sound better in his amp, and of course according to his personal tastes, it's pure random chance whether it will sound better in YOURS, unless you have the exact same model. Therefore, you might as well try a handful of $10 tubes from eBay - and, with luck, in your amp, one of them will sound better than the $200 one.)

The best place to start dabbling would be a low-cost tube preamp kit from a reputable vendor - and select one that uses commonly (and cheaply) available tubes - like the venerable 12AU7 and 12AX7 and their modern equivalents.

Apr 6, 2016 15:28:39 GMT -5 copperpipe said:

Theoretical question If one wanted to dabble with the "tube sound", would it be better to use a solidstate pre-amp and buy a tube amp, or buy a tube pre-amp and use a solid state amp? I realize that's an artificial restriction, but I wonder if I can get the tube sound by just using a tube pre-amp since they seem a lot cheaper than a good tube amp.