Realistic sound = tubes and analogue

[RGA]

Perhaps, although the circuit topology of guitar amps is comparatively crude and anything but single ended Class A. The trick is that guitar players want to clip the amp!

rw

Exactly and the home audio user can avoid clipping the amp by not being heavy handed with the control knob. Hence the entire point of "not" being able to play the Quad loud witht the OTO.

[theaudiohobby]

Exactly and the home audio user can avoid clipping the amp by not being heavy handed with the control knob. Hence the entire point of "not" being able to play the Quad loud witht the OTO.

Unfortunately, it's not that simple

[RGA]

Unfortunately, it's not that simple

Fortunately, it is that simple.

[theaudiohobby]

Fortunately, it is that simple.

How does such a set up deal with dynamic peaks? turn down the control knob?

[RGA]

If the amp has a 4ohm tap, which it does, the dynamic "request" the speaker makes on the amp will not require it to work hard - amplifiers also have reserves for "peak" requests such as dynamic swings. If the volume in this case is relatively low and most normal medium/low listening is 75db-80db or lower at the listening chair (including the peaks) an amplifier barely needs a watt. At higher volumes low power mated to low sensitivity is a problem - but then I already said that.

[Sir Terrence the Terrible]

If the amp has a 4ohm tap, which it does, the dynamic "request" the speaker makes on the amp will not require it to work hard - amplifiers also have reserves for "peak" requests such as dynamic swings. If the volume in this case is relatively low and most normal medium/low listening is 75db-80db or lower at the listening chair (including the peaks) an amplifier barely needs a watt. At higher volumes low power mated to low sensitivity is a problem - but then I already said that.

It's is not that simple really. If the peak is in the midrange or high frequencies, it may have the dynamic reserves to cover that peak. When it occurs in the bass frequencies, the demands on an amplifier become quite large, in some cases double or triple the output than the midrange or high frequencies would require.

[Sir Terrence the Terrible]

SS typically all sounds the same. There is a reason why no one passes double blind listening experiemnts because while the very same SS supporter will dump in tube amps they will happily tell people that spending $30,000 on a top bryston sounds SO MUCH better than a 3BSST. Which in reality that person will NEVER pass a blind test EVER. The same people who trust the "science" of SS is best will then throw it out and "trust" their ears that the $30k bryston is better sounding. That is truly hilarious and patently hypocritical.

As a person who CAN hear the difference between the 3BSST, and the 28BSST I beg to differ with your hypothesis. SS do not all sound exactly the same, there are very subtle differences between any SS amp when paired to a speaker sitting in a room.

Those differences may not be punch you in the face differences(and I never expect them to be), but they are audible, even if subtle, but you can hear them.

However, that is not a reason to choose a 28BSST over a 3BSST. I have a VERY large room with 9 very large speakers in it. Because of the speaker placement(and the size of the room) I get no room gain in the lower frequencies. So while a 150 wpc 3BSST would do well to push the low frequencies in the room, a 1000 watt monoblock 28BSST does it with ease. What differences can you hear. It is what I call "system ease". It is when a system sounds totally relaxed while reproducing extremely demanding passages. That is the audible difference between a 3B and a 28B. Example, when I auditioned the 3B and the 28B, I used Micky Hart's Planet Drum project. One particular piece called "Temple Caves" has a VERY deep bass drum part that really distinguished the differences between these two amps. The 3B impressively played the big bass part, and it really sounded good. However when the 28B played back that same part, the very low end really bloomed in the room, and you could feel the bass wave move through the room. Even at high volumes, the 28B sounded more powerful, and more relaxed at reproducing this difficult for any amplifier to reproduce passage. More of the fundamentals of the drum were exposed, and its decay was fully realized, and that didn't quite happen with the 3B. No matter what we listen to, whether it be the High Altitude Drums, or the Canon shots in the 1812, the 28B was just better at fleshing out clearly the difficult to reproduce passages in each recording. Where there any magical differences in the midrange and high frequencies? No, not to these ears, but the dynamic capabilities when paired with my SC-V's showed a very noticeable difference. This also went for the 4B, and to a lesser degree on the 7B and the 14B.

One of the first things I learned about critical listening, is to not listen for the obvious, but to listen to what would not be obvious.

[RGA]

It's is not that simple really. If the peak is in the midrange or high frequencies, it may have the dynamic reserves to cover that peak. When it occurs in the bass frequencies, the demands on an amplifier become quite large, in some cases double or triple the output than the midrange or high frequencies would require.

That is not entirely correct. Impedence typically drops with lower frequencies as do some speakers in the treble. If a speaker dips to 2 ohms that requires double the amplifier power on the 4 ohm tap. But that only depends on the speaker's minimum impedence. A stable loudspeaker that does not go below 4ohms on a 4 ohm tap of the amplifier places no such demand on the amplifier. A 20hz note at 4ohms places no greater demand on an amplifier than a 1khz note at 4ohms. Amplifiers don't care about frequency the care about impedence - so while it is true that bass (of the speaker) usually presents a more difficult impedence on the amplifier that really depends on the loudspeaker and not the amplifier's watt rating. Amplifier power supplies are not all created equally despite the watt rating.

The only reason Bass is any sort of issue is because the speaker that is rated 8 ohms with a low power amp at 8ohms will have trouble if the speaker drops to 2-3ohms which "usually" occurs in the bass region. The amplifier is asked to draw many times it's rated power to successfully reach the note. That still comes down to not pushing the amplifier. It is easier with amplifiers with a watt meter and a tube amp was running in a Vancouver shop and it would play music and you could see the amp hovering at 1watt. Under a dynamic swing the meter would jump to 8-12 watts. But this was playing very very loud with bass and with reltaively hard to speakers. Even an 85db sensitive speaker gets that with 1 watt at 1 meter - most people don't listen that loud. 75db at the listening chair is pretty loud and you're arguably getting this with less than a watt of power regardless of the amplifier. Even if you measure the bass line peak at 85db which IMO is excessive but even if you did running the 4 ohm tap from the tube amp with a reasonably stable impedence speaker it is not like you're pushing the amp into distortion at all into these levels. If you raise all these db levels by 10db and running 8db with a swing into the 95db-100db range then the 5-8 watt amp is going to be out of the question. It won't be able to handle the dynamic swings and it won't be able to carry the bass which will sound bloated muddy/mushy.

That is why I said - it can't play loud but the impedence swing only becomes an issue if the swing itself rises above the amp's capability to meet the swing. The OTO and most good amps are able to easily swing many times their power ratings. The Rita is 45 watts but can jump to 450watts to meet dynamic needs.

Here is an example:

To give you some perspective on music playback in the home, "quiet" music would fall in the 75-dB range, whereas "quite loud" music would measure about 85 dB SPL at your favorite spot on the couch. For purposes of illustration, let's go back to our example of listening to a recording of a solo concert-grand piano of Chopin piano works at average levels of 76 to 86 dB, using a pair of M80ti loudspeakers at a distance of 12 feet. According to our previous calculations, this would require perhaps 1 watt per channel of amplifier power, a modest demand for even the least expensive A/V receiver or small amplifier. If the pianist on the CD was playing Chopin's Grand Polonaise, however, and one of those spectacular chords in the bass octaves of the piano comes along, your amplifier and speakers will suddenly have to produce levels of 96 or 100 dB SPL without distorting, because Chopin's piano works have sudden and extreme changes in musical dynamics. Remember that a 10-dB increase in subjective loudness ("twice as loud") demands ten times as much power, or in our example, 10 watts, a level any receiver or amp will easily produce."

Obviously no one would ever bother to buy a 4 watt amplifier with the Quad 2905 a 83db sensitive speaker like I say - it can't play all that loud without having a problem. But it's what the amp does at 1watt that sees every SS amp in the store off. Even a "bad match" with the Quad in a volume level scenario still sounds better when the music is in the 75-85db range. The guys selling them find this to be so. And it's why Quad themselves make the partnering 40 watt tube. That amp can easily cover any dynamic swing the 2905 has at the volume the speaker is typically able to produce. So while a dynamic swing may be 10db higher than average - you simply factor that into the volume level you set a lower powered amp at. Tubes typically soft clip under dynamic extremes and is less of an issue than hard clipping nature of solid state amps. For an amp such as the OTO it would be best to have 90db easy load speakers at the minimum in a small/medium room.