Who here uses a pro amp to drive his speakers ?

[mike stehr]

"To some point I agree,the audiophile amps are part hoopla ...part reality. There are sonic gains ,simply not as BIG as many would like them to be."

Yup, good call.

I spent a bunch of money on fancy 1% resistors on this single-ended 6BQ5 console amp.....was it worth the money for the difference? Probably not...but it sure sounds good. And I think it has a little better stereo separation than my SE 6BQ5 console amp that uses lower tolerance carbon comps.....maybe I'm delusional....but I still enjoy the hobby....

[TheEAR]

Mike Stehr,

That little amp is too simple... [] Look at a TenorAudio inside,now that is an amp...still using top shelf components mind you.

[Audio Flynn]

Mike,

To some point I agree,the audiophile amps are part hoopla ...part reality. There are sonic gains ,simply not as BIG as many would like them to be.

A very high quality pro amp like the iTech8000 or PL380 is transparent and cannot be compared to a PA amp.Tube amps as we know almost roll off and deform the original signal..this deformation is a plus to our ears.

An odd blanket statement. You would need to explain how tube amps negate realism.

[Don Richard]

An odd blanket statement. You would need to explain how tube amps negate realism.

Vacuum tubes have an inherently high output impedance. In power amps this requires the use of an output transformer to match up to a low impedance speaker. So you wind up with a 4-16 ohm impedance-matched transmission line. With a loudspeaker that has a varying impedance curve (most of them) this will result in a widely varying frequency response curve. Output transformers limit frequency response and can affect the timbre of the sound due to the transformer's inductance, capacitance, and magnetic hystyresis. Tubes make perfect sense to me for use in preamps, the choice is less clear for using tubes in amps.

Don

Honk if you love horns

[tigerwoodKhorns]

How's this for "limiting frequency response?" This is a very famous current model PA amp with an 8Khz input signal into a simple resistor.

I wonder which amp?

[Ricci]

Well I'm of the opinion that some of the hype over audiophile consumer amplifiers better SQ is just that, but some of it is not and blanket statements about the inherent inferiority of PA amplifier SQ cannot be taken as fact. I've got experience with a lot of pro amps and yes some of the cheaper ones are noisey, grainey, etc, but there are some with quite good sonics too. The same goes for consumer grade amps.

I have nothing against tube amps, or the people that enjoy them, I just don't like the signature that they usually add to the source material in a playback system. It's not for me. That by no means indicates that I cannot enjoy a system employing tubes, I have many times.[] I much prefer the use of tube amplification during the creation of the source material (Guitar amp,bass amp, tube compressor, whatever) though.

By the way, I have a system comprising 4 CF-4's and a KV-4 center channel in a 5.1 system. In the next 12 months I'm going to be looking to upgrade the amplification from the mid-grade 100w ch reciever I have on them now. I'm open to either one big 5 channel amp, or to 3 stereo amps. I would like to get a substantial improvement in power reserves, dynamic power, and hopefully better sound than what I have now. I'm not rich either, so it would have to be reasonable. The budget will probably be $1.5K or less. Used gear is perfectly fine with me. Any suggestions?

[Don Richard]

How's this for "limiting frequency response?" This is a very famous current model PA amp with an 8Khz input signal into a simple resistor.

Big difference in doing something intentionally versus an unintended consequence. Any amp that is bandwidth limited to 20-20KHZ will not reproduce a square wave properly. Most pro sound SR amps are designed that way.

An 8 KHZ square wave and an 8 KHZ sine wave sound identical to humans. It takes odd harmonics of the fundamental sine wave frequency to make a square wave. The 3rd harmonic of 8KHZ is 24 KHZ. The 9th harmonic is 72KHZ. I can't hear that, neither can you or any other human. 20-20KHZ limited amps won't reproduce it either. Why would you want to?

If you ran that same waveform into a tube amp the output display wouldn't look any better than the one from the pro amp, if that "good". A sine wave sweep, 20-20KHZ from a tube amp into a loudspeaker load, would look more like your square wave output than the +/- 1 dB flat line we are used to seeing from SS amps.

There were many good reasons for the move away from tubes in power amps. Those reasons are still valid.

Welcome to the 21st century, to those who have arrived.

Don

Honk if you love horns

[DrWho]

If you ran that same waveform into a tube amp the output display wouldn't look any better than the one from the pro amp, if that "good".

Here's 8khz from an "unfamous" tube power amp. I don't know about your eyes Don, but it looks better to mine.

Looks better? Gee, if only "looks" were all that mattered when interpreting measurements.

[DrWho]

Slow amps = dull sound.

And yet frequency response is a measure of speed....

[Don Richard]

Here's 8khz from an "unfamous" tube power amp. I don't know about your eyes Don, but it looks better to mine.

I thought that you listened to amps and looked at TVs. What source are you using? CDs, records, and tape won't reproduce the harmonics required to create an 8KHZ square wave. Square wave generators make for lousy listening. But you couldn't tell if the wave was square or sine by listening, anyway.

Don

Honk if you love Horns

[Jeff Matthews]

Here's what I still don't get from the professional amp nay-sayers.... If the musicians create the music with the professional amps, then it seems to me the professional amps are quite capable enough of playing it back accurately.

If these "home" amps are the means to true audio euphoria, then why are all those professional musicians in the dark about this?

[Don Richard]

Here's 8khz from an "unfamous" tube power amp. I don't know about your eyes Don, but it looks better to mine.

Unless it is an OTL design I bet it has to have a ton of NFB to go out to the 200KHZ plus that it would take to push an 8KHZ square wave through an output transformer. BTW, how many watts output from the tube unit?

Don

Honk if you love Horns

[Islander]

Here's what I still don't get from the professional amp nay-sayers.... If the musicians create the music with the professional amps, then it seems to me the professional amps are quite capable enough of playing it back accurately.

If these "home" amps are the means to true audio euphoria, then why are all those professional musicians in the dark about this?

The musicians use things like musical instruments and assorted distortion devices (trumpet mutes, effects pedals, overdriven amps, etc.) to create the sound they want. If they want feedback, they'll set up their gear to produce it. They are the artists and it's their art.

The home sound systems, on the other hand, have the job of accurately reproducing whatever sounds the artists produced, without adding or subtracting from the sounds that are on the recording medium. For example, using an overdriven amp to reproduce the sounds produced by an overdriven amp would likely produce something totally unlistenable and not at all what the artist had in mind.

To sum up, what's needed to produce the music is not the same as what's needed to reproduce it.

[Don Richard]

Ahhh, changing the rules back to listening now, are we? Let's stick to the original claim that it would "look the same" shall we?

The "rules" were never changed. We hook our amps to speakers, then we listen through them to the speakers. You hear the speakers, hopefully not the amp. Vacuum tube power amps sound greatly different from each other when hooked to loudspeaker loads. That means you are hearing something that the amp is doing when it reacts to the load. So the amp is changing the sound. That is the definition of distortion.

Distortion generated by the amp may be desirable during the creation of music. However, I am not going to ditch my XTIs and put Marshall guitar amps on my Khorns. No matter how good the square waves look.

Hmmmmm... I wonder if the square wave shape on the tube amp output wasn't helped by the high amount of harmonic distortion created by the tuber?

Don

Honk if you love Horns

[Jeff Matthews]

Hey, how do you quote someone, now? The forum design changed.

Anyway, in response to the deal about saying professional amps are good for production but not playback, that's sort of silly. Are you suggesting that the professional musicians use PA for their color. Let's see, if you get a QSC, you will get this effect, and if you use a Crown, you will get this effect and so on.... I don't think so. I think they pick the amp for its ability to cleanly produce music. The rest of the effects are in the gear, like pedals and so forth.

As to Mark's comments. I agree with what you are saying to some extent. I think you speak a little too down on PA amps, though. Granted, you have been reviewing all sorts of comments with an equally broad stroke (e.g. tube amps don't have authoritative bass). I guess you could consider your comments more pay-back. As far as the XTi, I've never heard one. I don't really go around searching for sounds all the time. Maybe it does suck, but I'd be a little surprised if it did. I think it is maybe more of a starter amp, though.

Now, how do you quote on this forum?

[Don Richard]

Badly design amps sound bad. Amps designed for one purpose, may not sound good used for another. It's just for grins, that's all.

Well, low power tube amps were designed to feed efficient horn loaded theater speakers.[]

But so are SR amps[]

Don

Honk if you love Horns

[Jeff Matthews]

That's at least twice lately I've seen you reference to the glockenspiel. Have you been listening to "La Villa Strangiato" or something?

[mike stehr]

Mike Stehr,

That little amp is too simple... Look at a TenorAudio inside,now that is an amp...still using top shelf components mind you.

That's the whole point, Arthur....kind of the same reason why the Tenor amp you have doesn't use a output transformer. A simple short signal path with good components. I like it, and that's all that matters.

[Don Richard]

Nope. Sorry, wrong again Don. It has nothing whatsover to do with harmonic distortion. (Which is actually quite low).

I thought that would get you going[6]

But I will tell you this - it does have to do with being designed for audio use, and not PA use.

Now you're trying to get me going[:^)]

When an amplifier makes a glockenspiel sound like a rusty backyard wind chime - - THAT is distortion.

The last time I heard a glockenspiel live it sounded exactly like a wind chime[]

Don

Honk if you love Horns

[Jeff Matthews]

Mark, what sequence are you using to quote me? It used to be you just pressed "Quote," but now, it's something different.