LETS TALK ABOUT TUBE AMPS VS SS

[Don Richard]

Tube watts are not SS watts

BS

They put out a lot more voltage than we knew.

More BS. Any amplifier that isn't clipping, and is hooked up to a loudspeaker, will output the same voltage as any other non-clipping amp when the loudspeaker outputs the same SPL.

Vacuum tube amplifiers sound louder only because when they clip the distortion products sound musically pleasing (think Marshall guitar amps). This causes compression (changes the crest factor) which raises the average power level being put out by the amp. This causes the speaker put out more SPL.

[Fast1]

How about "in Wichita"!!! Please shoot me a PM. I would be most interested to hear some other Klipsches get it on. Tubed up I take it?? I am very excited.

[Fast1]

I learned back in my teens that it is better to have more power on smaller speakers than the other way around. You get better quality sound and more head room out of the deal. People said I was nuts to put that much power to an RF7 but they love it and I have never heard them clip.

I have run my bros' Paradigms here on my Rotel and they were noticeably warmer and more laid back. I would say more pleasing at low levels. Now when you get to cranking them, my Klipsches blew them right out the door and down the street. I find my self wanting MORE clarity so I switch off the "direct mode" on the receiver and bump up the treble. This makes the sound thin. I think I am getting close but need to try some other components. For all I know, my damn DVD player is doing all of this!!!

Most people that hear my 7s say it is the best they have ever heard and super clear but I think there is much more potential in them. There are a few songs I play on them that sound SOOO nice. Dirty guitar however just does NOT work! Blow you right out of the room...

One thing is for sure, we have a LONG way to go on room adjustments. I really would like to find a computer program or better understand room modes and nodes. It might be just as good to create sample frequencies and measure with a db meter to see how flat the room really is. I am guessing very few really are in which either room adjustments or EQ should be used.... I have never done that but 15yrs ago, you always just adjusted the EQ to your listening pref.

[Coytee]

How about "in Wichita"!!! Please shoot me a PM.

Then I'm afraid this won't work as you are required to be on the road for at least three hours. Now, perhaps if you agree to simply drive around town for three hours prior, it might be doable...

I would be most interested to hear some other Klipsches get it on

I speculate you will be in for a treat then.

Tubed up I take it?? I am very excited

Nope and that's part of the logic. You will hear some big guns on screechy solid state amps. You know, the kind with shrill sound, used for PA applications only.

Once you walk out of there with a sh** eating grinn on your face you will realize it's not all about tubes 'only'.

I've already emailed this thread to Bill

(there I go again, offering up someone elses house for an audition!)

[Fast1]

I will have to let you guys know that my Rotel RB1080 came to me at a super bargainbecause it had a huge dent in the back and required me to remove one of the channel PCBs and point to point wire a couple things from damage. With this in mind, I am not above modding this amp to get what I want. Of course there would be some research involved here but I am game. My crossover mods certainly helped. Wish it was that easy.

I just went and listened to the RFs again (work from home) and I seem to constantly switch from stereo and direct modes on the receiver. One is straight through and one goes through some DSP. I would consider the sound to be a bit grainy and harsh and lacks definition at lower volumes. Just like what a big speaker sounds like when it is not working. I would not expect this from the efficiency of the Klipsch though. To me, there is still much more treble missing at the top of the range and not sure why. In direct mode at low levels, they sound a little muffled.

[Islander]

I find my self wanting MORE clarity so I switch off the "direct mode" on the receiver and bump up the treble. This makes the sound thin.

I don't know about your receiver, but on my Yamaha receiver, when I switch to Pure Direct mode, the sub output is cut off, so the sound becomes too thin. Sometimes I'll listen briefly to something like acoustic guitar in Pure Direct, or when a song comes on that has annoyingly over-emphasized bass, but the other 99% of the time, I listen in Straight mode. Straight mode has no processing. Pure Direct also has no processing, but it also cuts out all the DSP or video circuits that might be running in the background, as well as the panel display, so the display only comes on for a couple of seconds when you adjust the volume or whatever.

Pure Direct mode may have a theoretical advantage over Straight (not 2-Channel Stereo, which I think does do a little processing), but losing the sub makes it too thin to listen to in almost every instance, with my system, at least.

[bhendrix]

Hi Brandon,

Sent you PM.

[Fast1]

On my Denon,direct mode is still stereo sound with the sub but no processing of the signal to the speakers so there is not bass or treble adjustment. I started using it on some things to try and get away from some hiss that I get. My bros' Outlaw is HORRIBLE with hiss! HIs Paradigms will not bring it out but my 7s sure will. I think improving my pre amp should be a first step but I also should consider upgrade on the DVD. I believe I have things setup right now to use the DACs in the receiver with better results. I know I need to make some changes but I think that pre amp is hurting me the most right now.

Problem is the rest of my system is powered from the receiver for now and I need those other 3 channels. I have debated whether to get a separate pre/pro and get amps or use a receiver for my theater needs. Just not sure right now on anything. My ears know what they want to hear but my pocket book can only get there so fast.....

[Coytee]

My ears know what they want to hear but my pocket book can only get there so fast.....

Maybe a visit to Bill's isn't the best idea then.... you might end up permanently frustrated [] []

[SWL]

I know I need to make some changes but I think that pre amp is hurting me the most right now.

I believe that it is.

[jerohm]

On my Denon,direct mode is still stereo sound with the sub but no processing of the signal to the speakers so there is not bass or treble adjustment. ... I think improving my pre amp should be a first step but I also should consider upgrade on the DVD. I believe I have things setup right now to use the DACs in the receiver with better results. I know I need to make some changes but I think that pre amp is hurting me the most right now.

You are on the right track. Modern DSP/DACs should provide the most audible satisfaction. Your Rotel (and probably a lot of other high current choices) should have absolutely no problem driving Klipschs to most anybody's satisfaction. People DO like the sound of tube saturation, but if they think that it is something more pure or accurate that they are listening to, well ... that is their right I guess.

[]

[Hashimoto]

Don, not BS. A SS amp output stage is limited by the supply rails so the clipping behaviour is really nasty. The output tube on a tube amp is working into an output transformer. It's basic electronics: an inductor stores energy and can swing way above B+. Clipping behaviour in a tube amp depends on many factors, such as the amount of negative feedback used. In addition, with triodes in the output stage, the tube can draw grid current when the grid is driven positive to provide extra power. It's called Class A2. If there is sufficient headroom in the voltage amp/driver stages, the peak power that a tube amp can supply is quite amazing.

[Don Richard]

Don, not BS. A SS amp output stage is limited by the supply rails so the clipping behaviour is really nasty.

An SS amp made from bipolar devices and using Class B push-pull topology will create lots of odd-order harmonics when clipping. Any amplifier that tries to output more than the power supply can provide will clip, tube or SS. Symmetrical clipping causes the odd-order harmonics that sound bad.

Circuits that employ transconductance devices (tubes, FETs, MOSFETs) may be easily configured to run in Class A, thus reducing high levels of odd harmonics. See the Pass Labs website for complete info.

The output tube on a tube amp is working into an output transformer.

Not always. And there is no reason that SS cannot use an output transformer. Macintosh gear has used autoformers, in the past if not currently.

It's basic electronics: an inductor stores energy and can swing way above B+.

Only when used in switching circuits (digital) There should be none of the core saturation that must occur for what you described in a properly functioning analog circuit.

If there is sufficient headroom in the voltage amp/driver stages, the peak power that a tube amp can supply is quite amazing.

Amplifier circuitry, SS included, may be designed for large amounts of headroom by using an oversized power supply without stiff regulation, among other ways.

There are SS audio amps capable of over 1KW peaks on the market. How many tubers can do that?

[Fast1]

Since you guys are obvioulsy up to speed on amps, I have considered tweaking up my Rotel RB1090 a bit to see if I can improve on an already decent platform. I realize most people do not like them but everyone who has compared side by side with a Bryson or Krell says they are very close. I have to wonder if swapping a few components out will get my in a better place.... I notice my amp is rated at THD .03% which is rather high for a klipsch setup. Rotel indicated the dif amps on the inputs could certainly better the situation.

I have a complete PCB layout and parts list if anyone thinks this is a worth while venture.... I cannot help but think component in the Rotel are budget bought so improvements could be found....

[Hashimoto]

Don, not BS. A SS amp output stage is limited by the supply rails so the clipping behaviour is really nasty.

An SS amp made from bipolar devices and using Class B push-pull topology will create lots of odd-order harmonics when clipping. Any amplifier that tries to output more than the power supply can provide will clip, tube or SS. Symmetrical clipping causes the odd-order harmonics that sound bad.

Circuits that employ transconductance devices (tubes, FETs, MOSFETs) may be easily configured to run in Class A, thus reducing high levels of odd harmonics. See the Pass Labs website for complete info.

The output tube on a tube amp is working into an output transformer.

Not always. And there is no reason that SS cannot use an output transformer. Macintosh gear has used autoformers, in the past if not currently.

It's basic electronics: an inductor stores energy and can swing way above B+.

Only when used in switching circuits (digital) There should be none of the core saturation that must occur for what you described in a properly functioning analog circuit.

If there is sufficient headroom in the voltage amp/driver stages, the peak power that a tube amp can supply is quite amazing.

Amplifier circuitry, SS included, may be designed for large amounts of headroom by using an oversized power supply without stiff regulation, among other ways.

There are SS audio amps capable of over 1KW peaks on the market. How many tubers can do that?

Quick reply: Don, go back to the textbooks. Any transformer coupled stage, tube or SS, analog or digital, input, voltage, driver, or output, is using the stored energy of the inductor (the inductance) to swing the signal. That's how the topology works. The output tube clips only when driven to grid cutoff on the positive swing or the onset of grid current when the grid goes positive. It's a question of bias. Yes, the transformer core can saturate when the voltage swing is greater than the core is designed to handle.

BTW, pulse transformers are generally used to galvanically isolate one stage from the next.

The way the amp clips depends on the topology, including whatever class it's run in, whether there is feedback or not, how that feedback is applied, how the devices are biased, how they are coupled, etc.

[Deang]

Most tube amps have a warmer or darker sonic signature, which is a good thing when you jack on the volume -- it helps to prevent the top end of the speaker from running away from the bottom and sounding too forward. The problem is that most good tube amps only give you 60 wpc or so, and unless you're running big Heritage or better -- they're undoubtedly clipping the signal. The argument is always made that the clipping is "soft", "euphonic", etc., and then the discussion goes off into an examination of the different clipping characteristics between ss and tubes. At that point, everyone wants to talk about which kind of amp sounds better when it's being run out of it operating limits and distorting. Does anyone besides me see the absurdity in this?

[Colin]

the other problem is where is the msuic clipping and why

the woofers require an enormous amount of energy to make fast, high and deep bass waves, clipping in this region doesn't sound harsh, just merely anemic

[ClaudeJ1]

I remember meeting Saul Marantz (the man himself) after he sold his company to Superscope in Japan for an undisclosed sum, and having a very informative converasation with him. He was the VP of Marketing for Dalqust (remember the poster child speaker for INEFFICIENCY, DQ-10?) at that time, not liking "retirement" one bit.

He told me that you wanted Tubes for the highs and solid state for the lows because the inherently lower source impedance of solid state had better control of the larger excursions/horspower requirements of the woofers.

[Don Richard]

Quick reply: Don, go back to the textbooks. Any transformer coupled stage, tube or SS, analog or digital, input, voltage, driver, or output, is using the stored energy of the inductor (the inductance) to swing the signal.

An inductor has those properties, however a transformer isn't a simple inductor. A transformer has two or more coils with mutual inductance. The voltage induced in the secondary coil opposes the voltage present in the primary. If there are a different number of turns of wire in the primary and secondary, as in an impedance matching transformer in an output stage, the primary coil must draw more current in order to equalize the two opposing magnetic fields.

If one turns such a device into a simple inductor by disconnecting the loudspeaker from the amplifier, primary voltage will rise, potentially (likely) causing damage to that amplifier by arcing within the transformer, overvolting the output tubes, or overvolting a capacitor.

Any energy stored due to the inductance of the transformer when operated normally will result in excess energy dissipated as heat, or as a HF rolloff due to the transformer acting as a low-pass filter.

[Islander]

The problem is that most good tube amps only give you 60 wpc or so, and unless you're running big Heritage or better -- they're undoubtedly clipping the signal. The argument is always made that the clipping is "soft", "euphonic", etc., and then the discussion goes off into an examination of the different clipping characteristics between ss and tubes. At that point, everyone wants to talk about which kind of amp sounds better when it's being run out of it operating limits and distorting. Does anyone besides me see the absurdity in this?

Many forum members are using high-powered SS amps that will likely never ever approach clipping, even when driven at levels that would drive everyone out of the room, so the "style of clipping", "good" or "bad" would only apply to lower-powered amps, likely tube amps.

750Wpc tube amps are available, but they cost more than most cars to buy, never mind re-tubing them. Lower-powered amps are fine for lots of folks, but pushing them past redline isn't good for anyone's ears or speakers, or amps for that matter.

Dean's right. If there is any chance of your amp clipping at the volume levels you normally use, you need a more powerful amp. Clipping is not part of any home audio amp's normal operating range.