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Can we address the low power amp again --?


richieb

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If you sit in semi-near field, sure - within 12 feet in a modest sized room. Any demanding material always sounds compromised to me once the peaks hit 95dB. I was always able to live with 8 wpc in my room - I'm very fond of the 300B. I would very much like to hear some of Manyard's work, I bet it sounds excellent.

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I very much agree with Don.

 

I do too, particularly the realistic loss over distance estimates for in-room situations.  But even using his numbers and applying it to my own particular target spls (high nineties, avg low to mid eighties), assuming Khorns at 16', four watts would cover me.  In my actual setup, which is fortes in about a 12' equilateral triangle, I only need about two watts to get to a very happy listening level.  Even with eq boosts I seem to have enough headroom to pull this off.

 

edit: Dean, I see your last post addresses this.  For me, I like to be able to listen all day, and peaks in the mid nineties is just about right for me for such extended listening.  I get enough weight and authority to become fully engrossed in the music.  Any more, from any sort of amp, is just too freakin loud for extended listening.  And like most of us with puny amps, I too have the big amps on standby for when club level spls are desired.  That's fun, and I'm glad I have speakers that actually can get loud without going to pieces, but the full tilt blasting just doesn't happen very often.

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If you sit in semi-near field, sure - within 12 feet in a modest sized room. Any demanding material always sounds compromised to me once the peaks hit 95dB. I was always able to live with 8 wpc in my room - I'm very fond of the 300B. I would very much like to hear some of Manyard's work, I bet it sounds excellent.

 

 

I know they aren't as popular but have you heard the 50 triodes? The next amp I build may be a 50/300B. In some amps they are interchangeable.

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I agree on the build quality of the Arte Forma 2A3. I had one for a while running the horns on my Jubs. I had many emails back and forth with Norman Yang, the man behind Arte Forma, on the 2A3 and his 845. He is meticulous in his parts selections and build execution. I really liked his 2A3, but I like my own build a little more. Maybe just because I have a lot of time and effort in it. I ended up selling the Arte Forma to a buddy with Jubs who runs the horns with them.

 

Now on the other end of the SET spectrum, I have been running a Cary 572-3 SET amp that has 20 watts of power. These are on my main 2-channel rig with my DIY three way w/horns. I just like the SET sound. Then I went by Skips house and heard his 845 amps and fell in love. So, the Cary's are being replaced with some ASL 845 (22 watts) amps for my main system.

Edited by Wardsweb
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A  45 single ended would be perfect for driving a Nelson Pass output buffer of up to 100W or so.

 

Use the tube for what it's best at (voltage gain), and the SS for what it's best at (current gain).

 

 

I really like this concept and have some experience with my Khorns using the First Watt F4 amplifier with a 45 single ended tube amp using the bi-amp schematic that Nelson Pass has included in the F4 manual [excerpted below]. 

 

Some of the guys over on diyaudio like to just run the SET amp directly through the F4; however, since the F4 has no gain (0 dB), the level matching issues of tube amp for the midrange and tweeter and solid state amp for the bass bin tend to be essentially mitigated.

 

A single F4 will give 25 watts (50 watt peak) into 8 ohms and 40 watts into 4 ohms. However, wired as a mono block the F4 will give the 100 watts that djk references.

 

I see the same concept of tube for voltage gain and solid state (usually mosfets) for current gain used in some of the high-end headphone amps too.    

 

 

F4 bi-wire.jpg

 

 

A few F4 specifications taken from the First Watt website:

 

Class A opertion

25 watts (50 watt peak) into 8 ohms

40 watts into 4 ohms

100 watts into 2 ohms as a mono-block with parallel inputs and outputs

40 damping factor

No feedback

47K input ohms

0.05% distortion

distortion is 2nd and 3rd harmonic in charater (rising or declining in proportion to the output power)

direct coupled input and output

-0.5 dB rolloff around 0.1 Hz and 200 KHz and does a clean square wave at 100 KHz

50 noise uV

0.0 dB gain

Mosfet

Push-pull

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Wards -

Were it not that the 572's require a preamp I would be interested. I have no desire for the slippery slope that is preamps, I'll take integrated or volume controlled amps, of course that's just me.

To that end I have located a Japanese built Almarro 318 SE integrated designed around the flame throwing 6c33 Russians power triodes. Eighteen watts a side and as most things Japanese Hifi these days superb build. I have owned the Audio Mirror 45 watt 6c33 monos, twice, both with Heritage and the sound with horns is phenominal. The Almarro is 18 Big watts and and worth every centigrade they produce. My rig is now in my recently completed finished basement which is naturally much cooler and on an open rack, just what the 6c33 doctor ordered.

Thanks all

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Richieb: I'd love for you to be able to hear a good single ended triode amp. I have two pair of home-built 300B monoblocks with direct coupled drivers that are marvelous with La Scalas and Klipschorns alike. I feel no need whatsoever to biamp or buffer between them and the speakers in the least. k-horn woofers are extremely fast and efficient, and simply do not need tremendous grunt.

Same is true for my 2a3 amps.

Try for yourself as much as you can!

Edited by erik2A3
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I agree on the build quality of the Arte Forma 2A3. I had one for a while running the horns on my Jubs. I had many emails back and forth with Norman Yang, the man behind Arte Forma, on the 2A3 and his 845. He is meticulous in his parts selections and build execution. I really liked his 2A3, but I like my own build a little more. Maybe just because I have a lot of time and effort in it. I ended up selling the Arte Forma to a buddy with Jubs who runs the horns with them.

 

Now on the other end of the SET spectrum, I have been running a Cary 572-3 SET amp that has 20 watts of power. These are on my main 2-channel rig with my DIY three way w/horns. I just like the SET sound. Then I went by Skips house and heard his 845 amps and fell in love. So, the Cary's are being replaced with some ASL 845 (22 watts) amps for my main system.

Wards - was the Arte used with the Jubes on its own? Not bi-amped but used to drive the entire speaker? Did it drive with any authority? You guys with bi- amping and such are on a whole 'nuther level than me. As you may figure from my preference for one box integrateds and for what it's worth I lean more and more to the KISS philosophy.

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I'm 11 feet from my Khorns, with a wall behind me and an opening 3' to my right. The JFL 2A3s have plenty of power for my room, even playing a lot of hard rock. The PCats get most of my listening time, since I'm usually doing stuff around the house. The Marantz 8077 gets a little play time, but mostly for movies.

SSH

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For those with experience will these kind of watts drive these speakers Properly and with Authority.

The answer would depend on your definition "properly" and "authority"

In my opinion the answer is no to both... I'd change "properly" to politely and "authority" to laid back....

I'm sure I'll catch he'll for the above...

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The only drawback, if it really is a drawback, is an inability to achieve painfully loud spl levels

Not the only drawback. While a Khorn will produce 104 dB 4 feet from the front of the horn, that will drop to 98 dB 8 feet away. Approximately 92 dB at 16 feet, depending on the room. Then there is the matter of the peaks - The SPL peak will be about 13 dB higher than the average SPL, depending on the dynamic characteristics of the particular recording being played. 13 dB = 20 times the average power, so if you want to reproduce a recording that takes 1 watt average to produce a given SPL it will take 20 watts to reproduce the musical peaks without distorting the amplifier.

So, in short, an amplifier of 20-35 watts should work well for you in a room the size of yours.

This is absolutely true....Many question it's truth because they measure the ac signal coming out of there amp with a meter or via some analog gage built into a power amp ...the thing is those methods of measuring it are absolutely false the dynamic peaks are so brief no meter will display them accurately.

Dean remember that time we went to Parrots house and I brought my scope to show you guys about musical peaks ..with a scope we still had to strain to see the peaks they are so brief..

Flea powered single ended amps sound glorious within a reasonable power range, in millivolts average so they have some minor headroom.

These amps also have trouble with music that has a lot going on..they tend to mush complex busy passages together in a conjested kind of way. They just have trouble tracking wild impedances being presented back to the zero feedback triode output tube...

What they do well they do very well, what they do bad they do very bad....no free lunch.

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Wards -

Were it not that the 572's require a preamp I would be interested. I have no desire for the slippery slope that is preamps, I'll take integrated or volume controlled amps, of course that's just me.

To that end I have located a Japanese built Almarro 318 SE integrated designed around the flame throwing 6c33 Russians power triodes. Eighteen watts a side and as most things Japanese Hifi these days superb build. I have owned the Audio Mirror 45 watt 6c33 monos, twice, both with Heritage and the sound with horns is phenominal. The Almarro is 18 Big watts and and worth every centigrade they produce. My rig is now in my recently completed finished basement which is naturally much cooler and on an open rack, just what the 6c33 doctor ordered.

Thanks all

I don't know what your budget is but there is a Wavac 811A for sale on the What's Best Forums. The ad is like a year old but I pm'd the guy and he still has it. It is a integrated amp with 15 watts per channel. He was asking $2400. New it was $4000.

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Wards - was the Arte used with the Jubes on its own? Not bi-amped but used to drive the entire speaker? Did it drive with any authority? You guys with bi- amping and such are on a whole 'nuther level than me. As you may figure from my preference for one box integrateds and for what it's worth I lean more and more to the KISS philosophy.

 

 

The 2A3 would drive the Jubs but it couldn't rock the house. For the horn it was plenty of power for SPL but the four woofers needed more power to get a good solid punch. I switched to 2A3 on the horns and solid state for the bass bins.

 

I have driven Khorns with as little as 1.5 watts that made for a nice istening level but again it came up a little short for full orchestra.

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I agree on the build quality of the Arte Forma 2A3. I had one for a while running the horns on my Jubs. I had many emails back and forth with Norman Yang, the man behind Arte Forma, on the 2A3 and his 845. He is meticulous in his parts selections and build execution. I really liked his 2A3, but I like my own build a little more. Maybe just because I have a lot of time and effort in it. I ended up selling the Arte Forma to a buddy with Jubs who runs the horns with them.

Now on the other end of the SET spectrum, I have been running a Cary 572-3 SET amp that has 20 watts of power. These are on my main 2-channel rig with my DIY three way w/horns. I just like the SET sound. Then I went by Skips house and heard his 845 amps and fell in love. So, the Cary's are being replaced with some ASL 845 (22 watts) amps for my main system.

I should have bought your 2A3 amp from you when you offered it....

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