[Pneumonic]

Great posts Pneumonic..it stimulates the mind..
but i have to say this...
even a straight piece of wire can induce current (signal) as an antenna ...it is electric!!
now i leave you guys alone again..

Mind stimulation is always a good thing indeed, G.

As for the current ... in the case of a fuse, the wire inside is so short that any induced current (technically electromagnetic field) will be immeasurable and non impactful. Besides, we are not taking about introducing a piece of wire (fuse) that didn't exist before. We are simply substituting one type of wire for another.

[Mike Nomad]

A few people commented on their lack of need for power, and it is that very thing that had me looking at this thread. For years, I've always had more amp than I've needed.

I just went over the demand cliff this week, when I took delivery on a pair of Cornwalls (First Model). Even with Rothwell attenuators in the signal chain, the furthest the Knob on my Peachtree Audio Nova (60 Watts per side at 8 Ohms) has to go is about 11 o'clock to get uncomfortably loud. So, I'm looking for a replacement.

After I get some things sorted out with the speakers (re-terminate my speaker cables, and I think the crossovers need to be either rebuilt or replaced), I need to figure out if I can get a demo of a couple of these amps to plug in to my system...

This thread has been a great help. A lot of great information throughout. My thanks to all.

[Roger A. Modjeski]

A few people commented on their lack of need for power, and it is that very thing that had me looking at this thread. For years, I've always had more amp than I've needed.

I just went over the demand cliff this week, when I took delivery on a pair of Cornwalls (First Model). Even with Rothwell attenuators in the signal chain, the furthest the Knob on my Peachtree Audio Nova (60 Watts per side at 8 Ohms) has to go is about 11 o'clock to get uncomfortably loud. So, I'm looking for a replacement.

After I get some things sorted out with the speakers (re-terminate my speaker cables, and I think the crossovers need to be either rebuilt or replaced), I need to figure out if I can get a demo of a couple of these amps to plug in to my system...

This thread has been a great help. A lot of great information throughout. My thanks to all.

Please tell us more about your system details. For instance the sensitivity of the Cornwalls (which i know is high), the attenuation of the Rothwells and how they are in the system. Which Peachtree model do you have? How loud do you listen?

What do you plan to do to the crossovers? I know Paul K often used electrolytic crossover caps. That is one place where cap quality (MATERIAL) can make a big difference. As you may know I am not a cap crazy guy and there are good quality caps that are not expensive.

What sort of amps are you considering? You now have a speaker that can use low power.

[Mike Nomad]

These Cornwalls appear to be the first model, which would put the sensitivity at 98.5 dB.

I am using a mixture of Rothwells: Depending on the input source, -20dB (TV, Roku) or -10dB (Oppo BDP-93). They are located at the pre-amp inputs (as specified). As a temporary, not ideal solution, I can get another set of -20dB, and install them on the Oppo.

The Peachtree Nova is the first model. I'm running afoul of their literature, which says it runs 80 WPC. I'm thinking it was only 60.

Very Loud listening probably runs near 95dB. Typical levels are much lower: slightly above Normal Conversation, down to Late-Night, Don't-Wake-The-Person-In-The-Next-Room levels. I can hear that I am definitely in the gritty end of the amps range most of the time. I don't need may watts, and I do need range to move the volume knob.

The cross-overs are the "B" (earliest) type. I took a look at them today for the first time. The auto-transformers (?) look pretty wet, while one of the caps (liquid filled, metal container type) has actually begun to leak. Sonically, there is something wrong: The tweeter and woofer are overpowered by the mid-range. The bass has plenty of detail, but no muscle. A cursory look at the drivers didn't reveal any problems.

Given the condition of the crossover components, my current feeling is that, at a minimum, I would just replace the crossovers with a comparable set from Crite. I've just started looking into the offerings of ALK Engineering. While their basic model is a bit more than the Crite, ALK's high-end offering is very intriguing, but costs almost what I paid for Cornwalls.

In terms of amps I am looking at (trying to keep the price under USD$2,000), the list is getting shorter (in alphabetical order):

Lindel AMPX
Monarchy DA08
Monarchy SM-70
Musical Paradise MP301
Musical Reference EM7 (5 WPC)

There are a couple of other offerings you have that are 45 based, with no prices listed. I would be interested in knowing more about them.

I think I covered everything...

Please tell us more about your system details. For instance the sensitivity of the Cornwalls (which i know is high), the attenuation of the Rothwells and how they are in the system. Which Peachtree model do you have? How loud do you listen?

What do you plan to do to the crossovers? I know Paul K often used electrolytic crossover caps. That is one place where cap quality (MATERIAL) can make a big difference. As you may know I am not a cap crazy guy and there are good quality caps that are not expensive.

What sort of amps are you considering? You now have a speaker that can use low power.

[Roger A. Modjeski]

Those are fancy crossovers. I see they have litz-wire  chokes which is rather unnecessary and expensive.

We make the 245 amp to order only and its over $2000

The EM7 is in your range and there is a kit of the mono 2.5 per channel if you want to save money. It will play your speakers cleanly to 100-103 dB peaks at 1 meter.

We do have a pair of EM7 push pull monos in stock for $2500 (list) that you could have for $2000 as a audiocircle member. It will play them much louder and lower distortion as it is push pull and class A cathode biased.

[Mike Nomad]

Yeah, fancy is a good word. Their mid- and high-level offerings introduce more variables than I really want to mess with. Their low-end provides a little more than the usual, and would help quite a bit. Their inclusion of air-core inductors confuses me...

I am not kit adverse (I guess my Weller will still fire up, if I can find it...) I was passing over your 2.5 Watt models because I was concerned about not having enough grunt if I want to get loud. Your stated output numbers put that to rest, and add another option.

And that is very generous of you to provide AC member pricing of the push-pull monos. The price list indicates they use a balanced input. Do they have an unbalanced as well? That's what the pre-outs on my Nova are.

Those are fancy crossovers. I see they have litz-wire  chokes which is rather unnecessary and expensive.

We make the 245 amp to order only and its over $2000

The EM7 is in your range and there is a kit of the mono 2.5 per channel if you want to save money. It will play your speakers cleanly to 100-103 dB peaks at 1 meter.

We do have a pair of EM7 push pull monos in stock for $2500 (list) that you could have for $2000 as a audiocircle member. It will play them much louder and lower distortion as it is push pull and class A cathode biased.

[Roger A. Modjeski]

Yeah, fancy is a good word. Their mid- and high-level offerings introduce more variables than I really want to mess with. Their low-end provides a little more than the usual, and would help quite a bit. Their inclusion of air-core inductors confuses me...

I am not kit adverse (I guess my Weller will still fire up, if I can find it...) I was passing over your 2.5 Watt models because I was concerned about not having enough grunt if I want to get loud. Your stated output numbers put that to rest, and add another option.

And that is very generous of you to provide AC member pricing of the push-pull monos. The price list indicates they use a balanced input. Do they have an unbalanced as well? That's what the pre-outs on my Nova are.

For a start why not just replace the leaking capacitors with good polypropylene. Nothing fancy, under $10 a cap unless they are really big values.

A good balanced input works just as well unbalanced via an adapter. The amp also has low gain so you can run your volume control higher... which we know is good. You will probably be able to get rid of your attenuators.

[Mike Nomad]

First, my apologies to all upstream on this thread for having hi-jacked it. It was not intentional...

To Roger:

Well, there you go being logical. I guess I should first try an easy-ish path. I am always looking at the intersection of time, money, and effort. You are being very generous with your time, and it is greatly appreciated. If I go with one of your 2.5 Watt EM7s, I'll go with an pre-assembled one. I am not going to get $500 worth of fun out of assembling one.

Each Xover has two caps, both "can" types: a 4μF and a 2μF, no tolerance value shown.

Thank you for the word on unbalanced > balanced inputs. I haven't previously had any gear with balanced inputs. After I sent my last reply, I got a look at the back of the Lindel and was ready to cross it off the list: Balanced inputs.

Another aspect to this that just made itself known last night: Waste Heat.

When I mentioned the possibility of a tube amp coming home, my Other Half says: "Won't it get too hot in the cabinet?" So, I need to get that (making a new back) sorted. The Peachtree barely gets warm, and anything on the list I made it going to generate at least some waste heat. The Monarchy SM-70 is a real pig.

For a start why not just replace the leaking capacitors with good polypropylene. Nothing fancy, under $10 a cap unless they are really big values.

A good balanced input works just as well unbalanced via an adapter. The amp also has low gain so you can run your volume control higher... which we know is good. You will probably be able to get rid of your attenuators.

[G Georgopoulos]

Let's get back to class-a,this thread has been derailed,what are the pros or cons
small class-a amplifiers can be build with easy,so why not if you love them
forget about the heat if it's a small one,class-ab do it all the time they too consume
some heat when in class-a for some part,Roger is right when he mentions low watt
class-a they certainly make a difference with sensitive speakers..

[lazydays]

I could be wrong, but it seems to me that the Odyssey Stratos SE's and up are setup to run in class A up to 30 watts. Can I tell the difference? I doubt it! And even then, the first ten or fifteen watts is more than enough in class A. I doubt I run my amps much past the 25 watt mark 85% of the time; with the exception being very loud moments in the music that rarely last more than three to five seconds. 95% of the folks here would never know the difference anyway.
gary

[Freo-1]

Let's get back to class-a,this thread has been derailed,what are the pros or cons
small class-a amplifiers can be build with easy,so why not if you love them
forget about the heat if it's a small one,class-ab do it all the time they too consume
some heat when in class-a for some part,Roger is right when he mentions low watt
class-a they certainly make a difference with sensitive speakers..

The Electrocompaniet AW2-120 is a outstanding 120 watt per channel Class A Balanced Amplifier.  One of the best sounding SS amps I've heard regardless of price.  IMHO, it sounds better than the Pass Labs XA30.5 (which is no slight to the Pass Labs amp whatsoever).

http://www.electrocompaniet.com/products/classic/poweramp/2x120-M.html

[Pneumonic]

so why not if you love them
forget about the heat if it's a small one,class-ab do it all the time they too consume
some heat when in class-a for some part

Ultimately, each person will decide for themselves whether or not to accept, or not, whatever negatives are associated with the heat their amps dissipate. It's not just about wasted $$$$ in terms of electricity but heat has been known to cause premature failure of electronic componetry if not dissipated properly. 

And then we have issues of unrealistic applications. My speakers take a minimum of 300w to even turn on and close to 1kw to sing gloriously. It would be folly for me to use a class A in such setup.  Of note, even though my amps all produce in excess of 1/2kw, they are extraordinarily efficient. At idle, no more than 4w and even pushed to extremes, they only ever get warm to touch. Electricity and heat related issues are absolutely a non factor for me.

[Roger A. Modjeski]

Ultimately, each person will decide for themselves whether or not to accept, or not, whatever negatives are associated with the heat their amps dissipate. It's not just about wasted $$$$ in terms of electricity but heat has been known to cause premature failure of electronic componetry if not dissipated properly. 

And then we have issues of unrealistic applications. My speakers take a minimum of 300w to even turn on and close to 1kw to sing gloriously. It would be folly for me to use a class A in such setup.  Of note, even though my amps all produce in excess of 1/2kw, they are extraordinarily efficient. At idle, no more than 4w and even pushed to extremes, they only ever get warm to touch. Electricity and heat related issues are absolutely a non factor for me.

Perhaps you should tell us more about your system, Those are big numbers and a very low idle.

The Electrocompaniet AW2-120 is a outstanding 120 watt per channel Class A Balanced Amplifier.  One of the best sounding SS amps I've heard regardless of price.  IMHO, it sounds better than the Pass Labs XA30.5 (which is no slight to the Pass Labs amp whatsoever).

http://www.electrocompaniet.com/products/classic/poweramp/2x120-M.html

What is the going price for the Electrocompaniet?

[Freo-1]

Ultimately, each person will decide for themselves whether or not to accept, or not, whatever negatives are associated with the heat their amps dissipate. It's not just about wasted $$$$ in terms of electricity but heat has been known to cause premature failure of electronic componetry if not dissipated properly. 

And then we have issues of unrealistic applications. My speakers take a minimum of 300w to even turn on and close to 1kw to sing gloriously. It would be folly for me to use a class A in such setup.  Of note, even though my amps all produce in excess of 1/2kw, they are extraordinarily efficient. At idle, no more than 4w and even pushed to extremes, they only ever get warm to touch. Electricity and heat related issues are absolutely a non factor for me.

Your speaker situation is unique, to say the least.  The ATC speakers are 85db/w, and the EC AW2-120 drives them to ear-splitting levels if so desired (cleanly, I may add).  A properly designed amp, regardless of class of operation, will last a long time.

[Freo-1]

Perhaps you should tell us more about your system, Those are big numbers and a very low idle.

What is the going price for the Electrocompaniet?

I got my amp for 1400.00 shipped.  It was as new, with low very low hours.  They are somewhat less than say, Pass Labs. 

Here is a link to the speakers:

http://www.techradar.com/us/reviews/audio-visual/hi-fi-and-audio/hi-fi-and-av-speakers/atc-scm19-hi-fi-98230/review


And a link to the subwoofer:

http://hometheaterreview.com/svs-sb13-ultra-subwoofer-reviewed/

[Pneumonic]

Perhaps you should tell us more about your system, Those are big numbers and a very low idle.

Roger, at the moment I am actively bi amping a pair of Sanders 10c’s with a pair of Innersound ESL800 (on stat panels) and a Sanders Magtech (on woofers). But, all of my stats, going back over 30 years, have needed tons of power, voltage actually, to play loud and to their peak sonically. 

[Pneumonic]

Your speaker situation is unique, to say the least.  The ATC speakers are 85db/w, and the EC AW2-120 drives them to ear-splitting levels if so desired (cleanly, I may add).  A properly designed amp, regardless of class of operation, will last a long time.

Indeed, they will last awhile if designed properly. Unfortunately, in some instances, such as mine, if I were to employ suitable class A amps, I'd be needlessly dissipating a kw of power. Even though I'm in a relatively cold climate here in Canada, our summers get toasty such that my system would be unlistenable for a few months of the year. To speak nothing of my unimaginably high electricity costs .... which wouldn't please the missus any   

[Freo-1]

Indeed, they will last awhile if designed properly. Unfortunately, in some instances, such as mine, if I were to employ suitable class A amps, I'd be needlessly dissipating a kw of power. Even though I'm in a relatively cold climate here in Canada, our summers get toasty such that my system would be unlistenable for a few months of the year. To speak nothing of my unimaginably high electricity costs .... which wouldn't please the missus any 

In your case, class A makes NO sense.  You need lots of clean pristine power for those outstanding speakers you have.

[Pneumonic]

In your case, class A makes NO sense.  You need lots of clean pristine power for those outstanding speakers you have.

The more voltage the better with the Sanders'.

But even if I ran speakers less demanding I still wouldn't feel the need to run class A since, for its sole primary purpose - namely to reduce distortion down to low levels (hopefully down to inaudible levels) - class A biasing of amps is no longer needed. These days I can easily, and properly, design a class AB amp that has the same low (inaudible) distortion that I can get out of a class A amp …. and do so without the inefficiencies of class A.

[RDavidson]

Part of the beauty of some (primarily lower power and often single ended) class A amps is the simplicity of their circuitry. I think simpler circuitry often translates to better sound. Once you start getting into higher power amps, the circuitry gets more complex, and this is where I think the playing field evens out a bit to varying degrees (in terms of sound quality, distortion characteristics, etc. etc. of the different amp classes). It's all a system of trade-offs and figuring out what you enjoy listening to / what type of speaker suits your tastes, and finding a suitable amp for your sound / speaker choice.