tube amp vs. ss amp

[rj2077]

i have a stasis threshold 250 wpc amp, and several tube amps; all of which are 30 wpc or less. why does my sherwood S-5500II tube amp at 30wpc drive the 4343 better? i get more bass than i do w/ the big amp.... obviously, the top end is fantastic to say the least. w/ the threshold, the sound is tighter, but i like the total package this little tube amp puts out.

regards

[invstbiker]

i have a stasis threshold 250 wpc amp, and several tube amps; all of which are 30 wpc or less. why does my sherwood S-5500II tube amp at 30wpc drive the 4343 better? i get more bass than i do w/ the big amp.... obviously, the top end is fantastic to say the least. w/ the threshold, the sound is tighter, but i like the total package this little tube amp puts out.

regards

Well RJ, First of all JBL's are very efficient (nothing new there) I drive my 43's with 70 watt tube jobbies and I gotta tell you the volume control never goes over 1/2 way. I have driven them with Mac 501 monoblocks and believe it or not (to my ears) the tube jobbies sound way better to me. I have since sold the Mac's and never been happier. Keep 'tubin'...:D

[Mr. Widget]

i get more bass than i do w/ the big amp.... w/ the threshold, the sound is tighter, but i like the total package this little tube amp puts out.


I have driven them with Mac 501 monoblocks and believe it or not (to my ears) the tube jobbies sound way better to me.Interesting how while this stuff is so subjective, it seems that at a certain level we do hear some things in the same way.

I was recently running a McIntosh MC-240 in a full range system. It had replaced a GAS Son of Ampzilla (80 wpc ss amp). I heard exactly the same sort of changes. With the little Mac tube amp the bass was significantly more noticeable. It was also mushy and bloated sounding and annoyed the hell out of me. I do like a quality SET tube amp in the mids, but more soggy bass isn't my cup of tea. I do tend to prefer a leaner upper bass sound with deep powerful extension though.


Widget

[rj2077]

yes sir. with the threshold everything is more precise. i am willing to forgo of that for smoother mid/highs the tube provides. until i go active, this will have to do. i have a small listening room, so i tend to listen at lower levels. that said, the bass dosent get to mushy. i have a set of BIG altec tube mono amps, 160 wpc, i will try these and see what happens.

regards

[Ian Mackenzie]

i have a stasis threshold 250 wpc amp, and several tube amps; all of which are 30 wpc or less. why does my sherwood S-5500II tube amp at 30wpc drive the 4343 better? i get more bass than i do w/ the big amp.... obviously, the top end is fantastic to say the least. w/ the threshold, the sound is tighter, but i like the total package this little tube amp puts out.

regards

It depend on what you mean by driver them better!

Its also depends on what style of tube amp the Sherwood is.

I any case the Threshold and the Sherwood are opposite extremes in every respect.

The Sherwood almost certainly has a low damping factor and a healthy amount of second harmonic distortion. This tends to empower the bass and provide a lush warm sound that can be appealing. It also masks a lot of issues otherwise prevailing in the system and or your speakers.

The Threshold has a relatively high damping factor is very analystical.

Probably not my 1st choice of amp either for that particular loudspeaker.

Ian

[Triumph Don]

i have a small listening room, so i tend to listen at lower levels. regards

Where you gonna put the 4350's, and what will you power them with?

[Titanium Dome]

rj

Glad you're happy. That's priority #1.

These things are so subjective... shoot even as individuals we're not consistent. I like using tubes until I get tired of them, then I don't want them around. I love a big SS amp driving medium efficiency speakers, until I want a more tube-like sound 'cuz the SS is wearing me out.

For me it's probably just "change." I like change and go from sound to sound because each is unique and pleasing in its own way. That's why I've got so many different JBLs, amps, preamps, and sources.

I know there are forum members who feel they've found their final or near-final system. Not me. I'm not saying they'd be boring people, but I don't hang around with them. :rotfl:

[rj2077]

the threshold on the L-250's sounds great. too edgy on the 4343's/4430's...
i am like you, i am constantly making changes in amps pre and see what works best.

out..

[Steve Schell]

The main issue here is one of amplifier damping factor, not output power. In the solid state era listeners have grown accustomed to a super tight, dry, overdamped bass reproduction. Funny, when I attend unamplified music concerts the bass sounds are often loose, flabby, boomy... and sound great! A low output impedance amp combined with loudspeakers that already have a high degree of magnetic damping results in a rolled off bass response, a result that can be easily heard as well as measured.

D.J. Tomcik wrote an excellent article on this subject many years ago; it is available here:

http://www.paulspeltz.com/tomcik/index.html

[Ducatista47]

I mean no disrespect to anyone here, but I must come down on Steve's side of this.

Like almost everyone here, I have been listening to music for many, many years, both live and recorded. When I began my current cycle of upgrading my reproducing gear, I had spent little time for some years listening to recordings and occasionally catching live acoustic gigs, mostly jazz, bluegrass and folk. Then I acquired some nice tube amps, new turntable and cd player, also very nice, and JBL 4333's. I immersed myself in my two channel world and neglected live music.

Then I forged on and spent my remaining fortune on 4345's. With Ian's help I seriously tweaked them. I bi-amped and ended up, for a time, with super sweet tube top end (still there) and swapped - between big solid state with huge damping factor and watts, vs moderate 60 wpc pentode power with low damping factor - the power for the 2245H's. It was one afternoon when I felt the tube bottom end was relaxed beyond reality that I went to big solid state watts. I enjoyed the tight bass reproduction for some time and convinced myself that it was much closer to reality than the rolling, smooth sounding tube reproduction.

Then I went to live acoustic gigs in a great sounding hall that featured a stand up bass. Several times. Reality sounded different from either version I had invoked with my electronics, but strongly resembled the tube version and made the highly damped SS result seem positively alien if not outright misguided. Real live bass rolled through the hall in smooth, almost unending directionless waves. I had trained my ears to hear tight, dry bass and convinced myself, with my intellect, of its reality. I was dead wrong. There were pleasures in it for sure, but is was wildly inaccurate where it really counted - not in measurements and distortion numbers but in direct comparison to reality.

Now I am listening to a single driver plus super tweeter system driven by the two or three triode watts it was designed for. It has its problems, it is not reality, but it is a lot closer. When I read here of tri-amped systems and big SS watts, I wonder how loud these systems are being played. High SPL would be their only advantage, but at a very high price in the quality of natural reproduction. I have heard some of these types of rigs and I have to say they are no more accurate or satisfying than anemic "audiophile" systems so prevalent and despised today. Over damped, dry bass (and mids with the life sucked out of them by solid state gear) may be popular, but it sounds like garbage to me having heard something closer to what I hear live.

My little tube amp was designed by a genius who met his goal of having the inevitable distortion manifest itself largely outside the range of human hearing. It is an approach worth pursuing.

Clark

[Mr. Widget]

Funny, when I attend unamplified music concerts the bass sounds are often loose, flabby, boomy... and sound great!The "loose, flabby, boomy" bass I've heard live is usually coming from stacks of 18" woofers being driven by killowatts of SS power... rarely from live acoustic music. I admit it is rare to hear a live show that isn't amplified, but when listening to a friend at the piano or playing a cello, I'd never call that loose, flabby or boomy. On the contrary, it is the speed and dynamics that I hear that I find so compelling and so impossible for any speaker to accurately reproduce.


Widget

[Ian Mackenzie]

Interesting discussion.


I have just build a class A amplifer of 100 watts.

It has relatively low open loop gain of about 45db and about 20 db of feeback

The damping factor of this amp is in the order of nominal 30-40 but it seems this term is an over simplification of the "lay" term tight or dry bass.

In comparison between it and another class A amp with a damping factor of 250 the 100 watt amp has a more accurate rendition of true acoustic bass tonality. Some people refer to this as "nuance".

Clearly there are not fully explained phenomena at work.

My rational explanation is that traditionally most SS amps rely on large ratios of negative feedback to reduce distortion and this makes the amplifer appear a pure voltage source to the loudspeaker ie a fraction of an ohm with 40-60 db of feedback at 20 - 100 hertz.

What this means is if the amp has an open loop output impediance of say 5 ohms, with 48 db of feedback Then divided this by 250 to give a damping factor of 400.

If biased with sufficient dc current and with a reasonable amount of transconductance the open loop output impediance of a class A SS amp will be reasonable low. ie less than an ohm. So with 20 db of feedback (10 x) and hefty amounts of DC bias (ie 5 amps) you can get a respectable damping factor of 80 ie 0.1 ohms

As some of you know negative feedback is a subtractive means of reducing distortion.

But you are also talking taking something away and there is an inevitable loss of information. What you are left with is a sterile clinical sound..Nothing like the real thing.

Getting back to the valve amp if you know what to look for they tend to be more linear than contemporary SS amps without feedback and as such they require less negative feedback to get acceptable distortion figures on paper and to the ear.

Obviously a damping factor a 3 is not going to cut it for a large heavy woofer but it might be okay with a Lowther or a $6000 pair of Feastrex drivers. It should be pointed out that it is alot easier to design an small low powered amp with the ideal set of properties than a large amp.

This is what inspires any audio buffs to high senitivity full range drivers. A typical example of this is the range of First Watt amp from Nelson Pass. (I have no affiliation with Pass but if I got a dollar for every time I mentioned his name I would be comfortably retired.)

So there has to be a balance. But there is no sense in going stupid with the numbers.


As they say more in the end often means less.

There are other considerations as well like the amount of current the amp will pass at low frequencies and how stiff the power supply is but all things being equal the above hold true.

[Ducatista47]

The "loose, flabby, boomy" bass I've heard live is usually coming from stacks of 18" woofers being driven by killowatts of SS power... rarely from live acoustic music. I admit it is rare to hear a live show that isn't amplified, but when listening to a friend at the piano or playing a cello, I'd never call that loose, flabby or boomy. On the contrary, it is the speed and dynamics that I hear that I find so compelling and so impossible for any speaker to accurately reproduce.
Widget
I agree completely. I should have mentioned the performances were not amplified, just fifteen feet or less of air between me and the instruments. The speed and dynamics (and the source imaging) are better with the single driver setup than my other rigs. To be fair,the 4345's are at least as dynamic in the macro sense, but they image not nearly as well and sound less coherent than the Hammer Dynamics. Well, everything is less capable in those departments. The Hammer setup compares quite favorably to the same little tube amp through my Stax headphones, an amazing accomplishment for any speaker. Look up microdynamics and speed in the mythical illustrated encyclopedia of audio reproduction, and there is a picture of electrostatic headphones.

Clark

[merlin]

With the little Mac tube amp the bass was significantly more noticeable. It was also mushy and bloated sounding and annoyed the hell out of me. I do like a quality SET tube amp in the mids, but more soggy bass isn't my cup of tea. I do tend to prefer a leaner upper bass sound with deep powerful extension though.


Widget

Sounds like you need a DC coupled tube amp old bean.

[johnaec]

OK - I'll be the fly in the ointment here.

I think when people hear that looser, less-damped bass when listening to sound reproduced by some tube amps, what they're really appreciating is a possibly desirable distortion of the actual signal. I posit that the "dry" sound heard from many "over-damped" solid state amplifiers may actually be a truer reproduction of what whas actually recorded in the studio, (notorious for being "clinical" sounding, and often recorded at listening levels higher than usually heard in the home), and if recordings were initially made with that "liver" or "fuller" bass sound often heard in live performances, amps with high damping factor would generally reproduce this sound faithfully. Because so many recordings are made with overly dry bass, an under-damped tube amplifier often adds a feeling of "warmth".

'Just my opinion...

John

[Mr. Widget]

... but they image not nearly as well and sound less coherent than the Hammer Dynamics.I have not heard of them and certainly never heard them. In your previous post mentioning a "single driver plus super tweeter system", I pictured a Lowther or a Fostex based system... I have heard many of these and while they do provide a certain coherency, they have such a strong sonic signature that I have never been able to fully enjoy them.

I guess your system is something like one of these pictured below?

As for your comment about the 4345's lack of imaging and coherency, I agree completely. Apparently many of us listen to a speaker's imaging etc. quite differently or we have widely differing expectations since we frequently read about a forum member's 4345s or the other large 43XX series monitors having "great" imaging. I think they can sound great, and they can be improved with a few changes that several forum members have implemented, but a coherent focused soundstage is simply not one of their strengths.


Sorry about veering OT... if you would like to share more about your speakers, start a new thread and I'll repost this into it.


Widget

[rj2077]

you know, i have tried the open baffle approach as well with different drivers using 300B amps. problem is, it lacks the balls of say my 4343's, that i much rather listen to. sometimes i can be so anal about audio nuances that i may and may not even understand. i catch myself going in circles at times, this time i just wanted to warm up an inexpensive sherwood amp that i had put up. i was quite surprised and pleased. of the jbl's i own, the 4430's sound best with this amp. i really cant wait till the everest come in so i can try them with a 300B. once again, the L-250's sound pretty good with the threshold.

regards