How quiet are SET amps on Klipsch?

[Tillerman]

How quiet are SET amps when no music is playing with the 96+ dB Klipsch speakers? Any hum or noise audible?:scratch2:

[SET12]

SET amps can be as quiet as you want them to be.

PP of course is much easier to get quiet by virtue of its natural noise cancellation.

The problem for a lot of SET's in my experience is when the supplies are small and the resistance used to drop the noise over is large to get them real quite they often come across as wimpy sounding hence there are many people that hold the that all SET amps are wimps!

Its all in the supply take the Cary 805 SET Mono's they have about 1000 joules of energy storage each! They are very quite! And their DCR supply paths are low making them one of the most powerful amplifiers that I have ever heard.

I prefer the 211 output tube with them vs the 845. real monsters IMO

IMO a watt is not just a watt.

So depending on your needs will dictate what is needed in a SET's supply

I can hear my amps when they are on but I can get them quieter by yet but just haven't gotten around to the filament supply mod that I have in mind.

I certainly don't hear any noise with the music playing.

Its interesting to do amp comparisons with my SET competing with 100 watt or more SS watt for watt they better in many areas then any av receiver that Ive heard or integrated, And many SS separates.

Check this guys work out and read about his power supply! Notice what he says about DCR of chokes and the current reserves he uses with power transformers. I followed his work in a magazine called "Sound Practices" for yrs and really learned a lot. So much so I can design and build my own amps.

http://www.enjoythemusic.com/magazine/equipment/0801/fleshandblood.htm

I recently wrote a little more on my amp here

http://www.audiokarma.org/forums/showthread.php?t=159340&page=6

Its in the post where I write this "hobby sure is fun"

And it sure is!

SET12

[Carl G]

Real quiet when they are turned off..........:yippy:

[cfranz]

Which SET amp. I've played SETs through very sensitive speakers. Some were amazingly quite, some were less so.

Strangely, my experience is a little different from SET12, mostly I found SETs quieter then P-P. My guess is because the Power Supply for most SET amps tend to be very well designed.

YMMV, etc.

[SET12]

SET amps can be very quite! :yes:

But to get the dynamics out of them at least the kind that I'm use to they need to be big! Big inductors with low DCR paths or big in capacitance or both IMO otherwise they can get wimpy! :thumbsdn:

My amps are 200 Joules of storage/mono 3-4 times bigger than an average SET but take some of the Cary's some of which are 1000 Joules/Mono Block

It all depends on what you want! :D

There is a lot of give and take PP or SET. And if the PP is out of balance noise creeps in! Meaning the need of matched tubes.

Example PP can cancel noise but in doing so it cancels the nice sounding even order harmonics leaving the wicked odd order ones!

Its why I love SET's for their harmonics! :thmbsp:

SET12 :smoke:

[Mike Stehr]

My SET sounds quite nice, it's pretty quiet too......

[Tillerman]

What do you hear when your system is on, but no music is playing (at your listening position)?:scratch2:

[Mike Stehr]

What do you hear when your system is on, but no music is playing (at your listening position)?:scratch2:

It depends on the SET amp, and how it's power supply is designed, (as SET12 referenced) and if the triodes are AC or DC heated.

AC heating can be more noisy, and can be a bit more difficult to quiet down than DC heating.

Depends on the triode's filament voltage as well.
A 2.5 volt 2A3 can be AC heated with minimal noise with proper design and layout.
But a 7.5 volt thoriated tungsten filament from say a RCA 801A, will require DC heating or some real clever AC heating design tricks. (high frequency AC heating?)

I have a stereo 2A3 amplifier that is AC heated with no null pots. I come out around 1-5-2.0 millivolts filament growl with the amp.
With Klipsch Cornwalls, I have to stick my head about a foot near a woofer to hear it.
With Klipsch LaScalas, there is mild filament growl in the whole listening area. But it is real mild growl that isn't objectionable. And the LaScala's really can sing with the 2A3 amp......

[SET12]

I concur with Mike here completely!

On the other side of the coin as I was saying there is always give and take!

Such as AC heaters, They usually are more dynamic then DC from reports I've heard!

One method of quieting AC heaters is applying a bit of DC to them through a voltage divider network off the B+.

There are many options for noise. And BTW I once owned a Yamaha B2 power amp a very nice amp! But not nearly as fun as a SET nor as informative from a harmonics point of hearing and yet just as powerful and certainly easier to repair! Not that its down much like once since I built mine 10 yrs ago! It was repaired in just 2 hrs! From
diagnostics,buy the parts,replace!

Love the amp, Love the sound!

SET12

Oh yah! I did have a Yamaha C2 as well! Very nice but the CD direct is very informative recently beating out a $2000 tube Peach II easily IMO.

[Urizen]

I use an Almarro 5 WPC EL-84 SEP amp with La Scalas. No noise or hum.

[cableguy]

I use an Almarro 5 WPC EL-84 SEP amp with La Scalas. No noise or hum.
I can only imagine that combo....:drool:





Bill

[snowdownunder]

This question is one that I asked many times before I purchased my first valve amp. I have owned a pair of La-scalas for over 20 years now, for the first 16 years or so I used a Denon SS intergraded amp, this amp had no white noise at all. I did try a ME power/pre set-up for a small amount of time and this had a lot of white noise and had a 100 watt output, this was way to much power for my needs and the white noise was unbearable at the volume I like to listen to music at, it also gave me a phobia about white noise.

About 4 years back there was a valve amp at on the bay for sale, so I emailed the seller and asked if the amp had much white noise (hum) if used with speakers with a sensitivity of 104dB and his response was “if your speakers are that sensitive it will sound like a motor bike idling in your lounge room and a loud bike at that” talk about an honest response. This guys name is Earle Weston and he hand builds valve amps and I really do mean hand built, he hand wines his own transformers.

About a couple of months latter he emailed me and told me he done some research on klipsch speakers and was building an amp that would be a good match for the La-scalas, it was called a tweaker, a single end valve amp that came with 4 different set output tubes, this amp was whisper quit. After a couple of years I purchased another amp off Earle, this one is a 300B single ended triode, this is a self biasing amp with hum balancing pots. The 300b was made with some extra sheilding. This amp does have some hum, it comes via the woofer but once you start playing music you don’t hear it, IMO the 300B goes lower that the tweaker and has a better sound.

When using the tweaker it was possible to go to bed and forget to switch off the amp because it had no noise what soever, with the 300B as I walk pass the speakers I know that the amps is on because of the slight hum, but it is only slight and like I said before you don’t hear it once playing music.

I’m yet to try a push/pull valve amp and I’m in no hurry as the 300B has a great sound and at only 9 watts has plenty of power for me. I sold the Tweaker to a friend with a pair of Belles and I still get to have a listen every now and then, it’s still a very good amp at about half the cost of the 300B.


Earle does have a web site

http://weston.bigblog.com.au/index.do?type=me

snow

[Mike Stehr]

I use an Almarro 5 WPC EL-84 SEP amp with La Scalas. No noise or hum.

It's the same thing with a Magnavox SEP 6BQ5 amp and my LaScala's. No noise or hum.
Indirectly heated tubes are the reason.

While the little Magnavox amp doesn't sound much unlike the 2A3 SET amp tonewise, it doesn't put off the large soundstage and the stronger bass that the 2A3 amp does.
With just a bit more of tasty midrange.

While the power rating seems to be more with SEP EL-84 at 4.5-5 watts per channel, the 2A3 amp sounds more bigger and more powerful at 3.5 watts per side.
(With my particular 2A3 amp, and Magnavox 6BQ5 SEP console amp, anyways.)

I do like the extra boogie factor you can get with a single-ended pentode 6BQ5 and LaScalas.

[Tillerman]

At some future date, I would like to try a 2A3 or 300B SET. A quiet background noise level is important to me, which is why I asked the question.

FYI, my main power amp (EW restored Sony TAN-5550 VFET) has just been bumped in favor of my EW built DoZ Class A SEB (single ended bipolar) amp. I commissioned EW to build this a few years ago. The first iteration (http://www.audiokarma.org/forums/showthread.php?t=33672&highlight=DoZ) sounded great, but suffered from too much hum through my Chorus speakers. About 3 years went by, but EW started work on the second iteration (http://www.diyaudio.com/forums/showthread.php?threadid=123079&perpage=25&pagenumber=1) for the purpose of reducing the hum to an acceptable level.

With the hum now reduced to a very low level, this amp sings. The DoZ (Death of Zen) is Rod Elliott's answer (rebuttal ?) to the various Nelson Pass DIY Zen amps (most of which are SEM, i.e. single ended mosfet). The DoZ is similar to the JLH Class A amp, which has plenty of information available on the web (http://www.tcaas.btinternet.co.uk/index-1.htm).

[SET12]

It's the same thing with a Magnavox SEP 6BQ5 amp and my LaScala's. No noise or hum.
Indirectly heated tubes are the reason.


At some future date, I would like to try a 2A3 or 300B SET. A quiet background noise level is important to me, which is why I asked the question.


I think Mike hit the issue on the head which made me think of Tom Evans "Linear A Stereo Amplifier".

http://6moons.com/audioreviews/tomevans/lineara.html

The Linear A is a single-ended, Class A, Ultralinear device. Four single-ended EL84s per side are linked in parallel to create a composite tube with characteristics that are "almost identical to the legendary Japanese 10 tube" according to Evans.

Its supply is extremely quite as it uses dual-mono 3-stage filtering using choke smoothing (two per channel) to accomplish a >150dB ripple rejection from a 60Hz supply.

I have wanted to design and build a version of this amp my self.

The signal to noise ratio of this amp is one of the highest I have heard for a tube amp and as far as distortion goes it is very competitive with many PP designs.

Some 10 yrs ago I was actually thinking :scratch2: about a 50 watt version of this using EL84's the gain of which would be high enough to be driven direct from a hearty linestage in others words a single gainstage.

One of my friends got to hear the Linear A amp and told me it was one of the best amps he had ever heard! Very powerful! And with good reason!

Its dynamic conductance numbers are huge

That's( transconductance X load)

:scratch2: Interestingly while your after noise I'm after signal path simplicity for transparency and dynamics!

Most SS has to many gain stages for my taste.

And while I enjoy PP tube amps. I'm a die hard SET guy because of the fuller spectrum of harmonics something that SS just doesn't do it for me.

I guess we all have our paths!:yes:

SET12 :smoke:

[ducati_EL34]

On my 105db LaScalas, my 2A3 SET amp is dead quiet, once tube has fully warmed up. Before that it is a minimal hum.

[Tillerman]

I'm a die hard SET guy because of the fuller spectrum of harmonics something that SS just doesn't do it for me.

Have you read Jean Hiraga's article about this (http://www.diyaudio.com/forums/showthread.php?s=&threadid=57995)?

BTW, I am not disputing your interest in the harmonic characteristics of SET amps. I found Hiraga's article fascinating - and I continue to learn and keep an open mind about sound reproduction.

The DoZ has very low distortion that is primarily 2nd order. If I understand Hiraga's article correctly, he feels the best sound comes from properly designed SET amps that have primarily even order distortion (harmonics), with steady decay of the harmonics as the order increases (e.g. 2nd, 4th low, 6th lower, 8th lowest).

[SET12]

Have you read Jean Hiraga's article about this (http://www.diyaudio.com/forums/showthread.php?s=&threadid=57995)?

BTW, I am not disputing your interest in the harmonic characteristics of SET amps. I found Hiraga's article fascinating - and I continue to learn and keep and open mind about sound reproduction.

The DoZ has very low distortion that is primarily 2nd order. If I understand Hiraga's article correctly, he feels the best sound comes from properly designed SET amps that have primarily even order distortion (harmonics), with steady decay of the harmonics as the order increases (e.g. 2nd, 4th low, 6th lower, 8th lowest).

I know your not!:D I was just making a statement of my preference for valves vs SS even if the SS is single-ended.

I find just about every component relevant in SET amps as well and especially their power supplies! I take a radically different approach vs the classical approach. And I'm very happy with my results.

Yes, Its the even order harmonics that I like and yes with a steady decay and yes I'm familiar with his work. I was a Glass Audio subscriber for many yrs as well as a Sound Practices subscriber. I learned the most from Sound Practices.

If you can find a Sound Practices archive CD I'd highly recommend buying it as you'll learn more about SET audio then most other publications.

Joe Roberts, owner has been selling them on ebay.

SET12

[Grainger49]

My answer is, "They can be dead quiet. But it depends on everything in the system."

I have heard SET amps on 104 dBW speakers that didn't sound like they were on with no music playing.

But reread the second sentence in quotes above.

[SET12]

My answer is, "They can be dead quiet. But it depends on everything in the system."

I have heard SET amps on 104 dBW speakers that didn't sound like they were on with no music playing.

But reread the second sentence in quotes above.

Agreed I have as well! There has never been a substitute for a "Valve" IMO and certainly many have tried and I have owned some of those substitutes myself! :yes:

Love your signature Grainger :thmbsp:

[Grainger49]

Thanks. It isn't the way I thought in the 70s, but I have matured.

[jcmusic]

I have had two different SET amps hooked to my K-horns 104db @ 1watt @ 1 meter and I have to put my ear to the speaker to hear anything.

Jay

[Doug Olitsky]

I have DRD 300b's driving my k-horns. Other than the initial power on hum they go silent, you have to pt your ear to the tweet to hear a gentle woosh.

I do have a annoying hum in my left speak when the speaker cable is not oriented properly. I think it has to do w/ the fact that my electric service panel is directly below it, in the basement.

[SET12]

That's quite the system! Obviously being an Industrial Arts Teacher I would expect a few DIY skills no doubt!

My girlfriend is an educator as well.

SET12

[Doug Olitsky]

Thanks, SET12!

Much to my wife's dismay I have numerous systems, mostly McINtosh amps (7) tubes, SS, new vintage bla bla bla. You know the typical AK junkie.

I see you have the titanium dia's from crites. I have them in my Chorus and heresey.

When I modded my k-horns I bypassed the fuses, rebuilt the x-o's w/ solen and air cores, I did the crites tweets but only wish he could get the dia's made in titanium as well.

[SET12]

Yes, I like the Titanium's very much but I have found that its tricky to get them to sing with out sounding a bit etched or bright sounding IMO.

Choice of inductor plays a major role in extracting their best sound in my system. I recently tried a Solen Litz which was way to bright pretty amazing at how much the passive parts can influence the sound so much!:music:

SET12

[Doug Olitsky]

When I did the k-horn xo's I ended up using the solen litz chokes, only because I could not get them in standard 12 ga (at the time)

I try not to use litz as they are a real PITA to strip the enamel off. back in my aerospace days we used to use this nasty stuff to do the job have not seen it for sale.

When I did the chorus II I used the titanium dia to nice effect. Also I ended up using an ERSE iron core for the 3 mH. At first I was skeptical but my local speaker builder supply co. talked me into it.

Rather big and heavy for an iron core, he practically swore I'd never be able to saturate it and it has a lower DCR than air core.

The end result was quite nice. X-o pics are in this thread (http://www.audiokarma.org/forums/showthread.php?t=123598&page=2)

[SET12]

Doug,

While I don't doubt that the iron core inductor that your using would be hard to saturate I think there is another phenomena going on with air vs iron core chokes such as in DeanG's comments here from the Klipsch Forum!

"I didn't expect to ever come back to this thread again, but have had a surprising experience. I finished my ALKs a few days ago, and as part of the build I went with some 10AWG Solen air cores which I mounted on separate boards because of their size. The DCR of the 10AWG air cores is .16, the same as the Erse Super Q steel laminates I've been using from Parts Express. FWIW, there's a pretty big difference in the bass. After an hour or so of listening I put some Super Q's into the circuit to see what it would sound like, and though still very good, sounded lean in comparison, and not nearly as full bodied and tight as the air cores. I've had the beasts laying around for a long time, and I'm glad I finally found use for them. I didn't expect to hear a difference, wasn't even listening for it, but it was pretty obvious."

Every one that has heard my Fortes has commented on the warmth and body and bass extension as being more substantial then the stock networks!

The Air Cores that I use are really expensive now but are worth every penny and so are the caps that I'm using as well!

I applaud your efforts first and foremost as anything is better than the stock networks!

Heres a link on inductors "Al Klappenberger's Great Inductor Face-Off thread".

http://forums.klipsch.com/forums/t/3...px?PageIndex=1

I found it very interesting. But I also found that after inserting a Solen Litz for my North Creek that the Litz was subjectively way to hot sounding! And lean sounding!!!

SET12

[Doug Olitsky]

Yeah, I thought that sounded familiar.

Its so amazing how each and every component makes a difference. I ended up w/ them only 'cause my local guy didn't have the air cores and I new as good as the erse's are the air cores would have been better.

Since the Chorus II's were going into a tertiary system I figured what the heck and like you mention WAY better than stock. maybe next time I mail order some stuff I'll add a few air cores.


btw- how much run in time did you give your litz inductors? I've read that it can take some time.

Too close to another magnetic field in the x-o?

I sometimes use a gauss meter to see whats going on.

[SET12]

Doug,

Since this thread is about how quiet SET Amps are on Klipsch I'll answer your questions about crossovers on my Forte thread here

http://www.audiokarma.org/forums/showthread.php?t=159340&page=6

Thanks

SET12