AudioCircle
Audio/Video Gear and Systems => Low Wattage Systems => Topic started by: JMW73 on 16 Aug 2023, 02:29 pm
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I have a TV system set up in the basement that mostly the kids use, so I threw some old equipment and speakers (Adcom/Mission) at it and called it good enough. I have a few older amps laying around (Adcom/NAD) that I don't use that I could sell.
SO! I was thinking of selling all the old stuff and upgrading that system to be a low watt, lower level listening system. This would be "system 2" as my main system is large and most definitely NOT low watt. Looking for this to be a departure from that system. Some Zu or Tekton speakers would round it out; most likely no subwoofer.
As far as the amp(s), I was thinking of building 2 mono Amp Class Amps. But, by the time I did that I'd be at, or close to, Schiit Aegir money. I'm not ruling it out, but I'd really like a balanced input (to get balanced you'd have to do monos which then is out of the price range I was thinking). What else is in this price range that I should be looking at? $1000 or preferably less. I'm not opposed to used.
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I have no experience with these, but the amp camp amps (ACA) is popular on diyaudio.com and diyaudiostore.com.
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I have no experience with these, but the amp camp amps (ACA) is popular on diyaudio.com and diyaudiostore.com.
I've been wanting to build some for awhile, and this is actually what spurred me to consider this "project". But then, I think about what else is available. They will probably still be the best I can do for the money, though.
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There's the newly released Musical Fidelity A1, 25 watts of class A, circa $1,500 but no balanced inputs.
https://www.musicalfidelity.com/products/a1
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There's the newly released Musical Fidelity A1, 25 watts of class A, circa $1,500 but no balanced inputs.
https://www.musicalfidelity.com/products/a1
Nice, thank you. The balanced input is a luxury, not a requirement. Just thought if I’m going this route I’d lower the noise floor as much as possible.
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Nice, thank you. The balanced input is a luxury, not a requirement. Just thought if I’m going this route I’d lower the noise floor as much as possible.
I own a Pass Labs X250 amp and use balanced inputs. I can hear no difference between the balanced and unbalanced connections. Just use good RCA interconnects that are well shielded.
Personally, I would consider an AVA Vision 120 Control amplifier or Vision 120 power amp.
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I own a Pass Labs X250 amp and use balanced inputs. I can hear no difference between the balanced and unbalanced connections. Just use good RCA interconnects that are well shielded.
Personally, I would consider an AVA Vision 120 Control amplifier or Vision 120 power amp.
Thank you for the input… I’ve had mixed results with balanced connections.
I DID look at the Vision 120 power amp. I’m intrigued.
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I have ACAs. They are a really good amplifier for the money (and just good regardless). They are quite versatile especially if you have a pair. Bridged, paralleled, multi-amp.
Aegir is well regarded i have yet to hear one. Stodart uses some clever trickery to get this AB amplifer to perform much more like Class A (no GM drop).
If you are building do not forget the ACA mini. I prefer a single of this to a single ACA. I may be soon getting another and i will jerry-rig balanced in and see how they perform.
My main amp is a Firstwatt SIT-3. Unobtainium now, really, really good, but unless you diy a Firstwatt is out of your price range.
Monarchy audio makes a 25 w Class A amplifier that is very good, jst a bit over a grand. A single man operation so not a lot of overhead.
Sugden may satisfy. your need, likely need to find a used one (price) and it will be an integrated.
If you diy, your options explode. Check out the Pass forum at diyAudio.com.
Do pay attention to the amplifiers output impedance. Bridged ACAs have similar to an SE tube amp, Aegir near enuff to zero. If the loudspeaker has a poor/wild/non-flattish impedance curve the high output impedance amplifier will interact with that.
I do not have a high opinion of either of the loudspeakers your mentioned.
dave
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I have ACAs. They are a really good amplifier for the money (and just good regardless). They are quite versatile especially if you have a pair. Bridged, paralleled, multi-amp.
Aegir is well regarded i have yet to hear one. Stodart uses some clever trickery to get this AB amplifer to perform much more like Class A (no GM drop).
If you are building do not forget the ACA mini. I prefer a single of this to a single ACA. I may be soon getting another and i will jerry-rig balanced in and see how they perform.
My main amp is a Firstwatt SIT-3. Unobtainium now, really, really good, but unless you diy a Firstwatt is out of your price range.
Monarchy audio makes a 25 w Class A amplifier that is very good, jst a bit over a grand. A single man operation so not a lot of overhead.
Sugden may satisfy. your need, likely need to find a used one (price) and it will be an integrated.
If you diy, your options explode. Check out the Pass forum at diyAudio.com.
Do pay attention to the amplifiers output impedance. Bridged ACAs have similar to an SE tube amp, Aegir near enuff to zero. If the loudspeaker has a poor/wild/non-flattish impedance curve the high output impedance amplifier will interact with that.
I do not have a high opinion of either of the loudspeakers your mentioned.
dave
Thank you for the suggestions; I’ll check them out.
Just for Schiits and giggles, what speakers would you recommend? You seem to understand what I’m going for here, and I’d prefer to not have a sub in this particular system.
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Worth mention the MOFO mono power amp, around 20W very minimalist circuit, DIY or our AC member Poseidon Voice could assemble one for you, I believe.
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I DID look at the Vision 120 power amp. I’m intrigued.
The Vision 120 may always stay in Class A with high efficiency speakers like the Zu or Tekton. Give Frank a call.
Frank wrote:
"[The AVA M225] are Class A-B designs running Class A up to about 20W"
https://www.audiocircle.com/index.php?topic=158752.msg1856771#msg1856771 (https://www.audiocircle.com/index.php?topic=158752.msg1856771#msg1856771)
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what speakers would you recommend?
Almost all are diy. One can get a whole lot more bang-for-the-buck. I am currently listening to a big WAW, but i have way too many others, things get switched in and out fairly often.
dave
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...the MOFO mono power amp...
One of those diy amps in the Pass forum mentioned earlier.
https://www.diyaudio.com/community/threads/build-this-mofo.313649/
dave
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As far as the amp(s), I was thinking of building 2 mono Amp Class Amps.
We have a topic on the MOFO amp, it use very few parts count and can be assembled without a PCB using only the leads parts. It require a hi gain pre-amp, but if you dont have a pre-amp its possible add a input stage.
https://www.audiocircle.com/index.php?topic=179626.0
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I have tried a couple of low watt Pass amps and have currently settled on a Monarchy SM-70 for my class A solid state joy. The nice thing about the SM-70s is that you can run them in stereo or mono, and they are quite affordable on the used market. The down side is that Monarchy is out of biz (I think) so if something goes awry, finding repair support may be tricky?
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If you want new stuff then the Pass diy offerings are your best bet. If you're into vintage (and all their caveats), then there's the Bedini 10/10 or 25/25, Pass Aleph 30, White Audio Labs made a 25 watt (or so) pair of brick-sized mono blocks, and there is the Forte line (though iirc 50 watts was the lowest offered). Do let us know what you decide.
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I really liked all of the Monarchy Audio amplifiers I have owned, but FWIW they have always been class A input/driver stages and high bias class A/AB output. Not pure class A. Does that matter? Only if stuck on a topology. How does it sound is probably more important.
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I have a Schiit Aegir in my main system and it is my favorite amp of all time. It replaced a VTV Hypex, and before that a Bel Canto. I've also had tube amps (LSA VT70 recently and a rather rare Image 65i along with several classic Dynacos I rebuilt.)
I use the Aegir with a Lyr 3 preamp which has their multibit DAC card. This powers a pair of Ohm 1000s which use an active crossover to cut them off at 70 Hz. This is combined with a GE Supersub X for the bass. I have no problem with volume (my highest average listening volume is around 80 to 85 dB) since the sub saves the Ohms from having to do power hungry low bass.
The Aegir is one of the most organic, natural sounding amps I've heard, and, I think due to its class A operation, extends that clarity all the way down into the low volume and soft portions of the music.
That's my two cents.
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My recommendation would be to stay away from the MOFO. It is very basic and has no thermal or overload protection for starts. It requires a preamp with tons of gain. I remember members who built it recommending another DIY pre with 40 db of gain. I built a couple not very long after the design was first published.
If you go diy look at one of Nelson's more advanced projects. A used commercially built amp would be another good option.
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This Aegir 20W Class A looks perfect to a Full Range driver or a hi sensitivity 2-way speaker.
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Aegir 20W Class A
Aegir is not Class A.
Call it unique Class AB.
dave
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Aegir is not Class A.
Call it unique Class AB.
dave
They are suggesting its Class A, it run hot as Class A.
What if we made a Class A version of the Vidar? No, wait, strike that. What if we made a better-than-Class-A-in-many-respects version of the Vidar? Well, here you go. Meet Aegir.
Continuity™: Benefits Beyond Class A
Aegir is our first Continuity speaker amplifier. Technically, Continuity is a way to eliminate transconductance droop outside of the Class A bias region, and extend the benefits of Class A biasing. It also solves the NPN and PNP device mismatch problem, since it uses both NPN and PNP devices on both rails. It’s still a very hot-running amp, though, with over 10W of Class A standing bias.
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Continuity is a way to eliminate transconductance droop outside of the Class A bias region
This happens at about 10w according to what Jason said in his tech paper. A 20 w amp so Class AB. But unique.
dave
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This happens at about 10w according to what Jason said in his tech paper. A 20 w amp so Class AB. But unique.
dave
It use various transistors pairs, many AB amps run 10W Class A, in the end it will need a listening test to decide.
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This is all very interesting conversation. It has made me research lots of other things...
I get that the Schiit (and the Van Alstine) aren't pure class A. I'd say they are still in consideration, as are any others that aren't.
I appreciate all the suggestions and please keep them coming! Certainly no decisions have been made. I have researched every suggestion that has been made and also joined DIYaudio, but that is A LOT to take in as a neophyte.
One thing I'm considering is just building a pair of ACA since they are a kit with well established directions. And then if I decide to build a more advanced DIY, I'll have that experience under my belt. I DO like that they are pure class A. My experience is: I've worked on car audio, including soldering wiring, and building wiring harnesses. I COMPLETELY rewired a classic car with a Painless Wiring kit, and then had to modify the wiring under the hood when I did an engine swap (which included wiring in a custom electric fan that never existed on this car). Closest I've come to this type of work was building DIY RCA cables for my main system. So, I feel pretty confident with the ACA kit with directions, but a more ground up project is unfamiliar to me.
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Monarchy SM-70.
Wonderful little amps.
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I realize many people are strongly opposed to Chi-FI equipment but there are tons of well built, decent sounding mono-block Class A amps with balanced & single-ended inputs available for under $1,000 for the pair.
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I realize many people are strongly opposed to Chi-FI equipment but there are tons of well built, decent sounding mono-block Class A amps with balanced & single-ended inputs available for under $1,000 for the pair.
I'd probably prefer not, but I'd look into it. Any examples to start down that path of research?
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I owned a pair of these. Never an issue. These have been mass produced for years. I assume Nelson either never had a patent on the design, the patent expired or he simply doesn't want to spend the money enforcing it. What ever the case may be these are solid little amps that are easily upgraded if you wish.
https://www.ebay.com/itm/125318498383?hash=item1d2d90884f:g:5ioAAOSwbxdkbdg~&amdata=enc%3AAQAIAAAA4EwUOcvhzqJ4tPo1vT406LVC5EBgejxbNRAfM%2BbHbjJVWLcZFADQ6ZgSJOdLwVBjdy8gybJDpmuEPLnuL7xAJFgzqbR7UXA%2Fs%2BapOnGBCScHAXa%2BmmLYSburmIXNruA2zCQyL71XWu%2BFcFCHURAfdxt5D7BM%2FGpol1txC4DOP95aHZbKwy1UdQcDIvQgMnXqZ1SybUT3smz070Vc%2Fx6lc%2Bb5qiAA2uMwAs7ezLv5TIl8lG%2F8XIo%2BmGMFNAWYcm2Sx5TLiiZ5%2FRbASqdPSuT9pVrKPtitOvpC4KggVK%2FUrWpr%7Ctkp%3ABk9SR_CpxonBYg
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I owned a pair of these. Never an issue. These have been mass produced for years. I assume Nelson either never had a patent on the design, the patent expired or he simply doesn't want to spend the money enforcing it. What ever the case may be these are solid little amps that are easily upgraded if you wish.
Hmmm; cheap enough to give them a try, or throw them in the system while I build ACA. It's an option, thanks.
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If you do decide to go with the ACA, and don't want to read through a thousand posts, here's a concise but detailed guide. It's written by 6L6, the guru of Pass amp build guides.
I don't know why, but I get the feeling that not many people on diyaudio know about this guides page - they just read through thousands of posts, which are illumating and have some very good discussions, but can be intimidating.
https://guides.diyaudio.com/c/Amplifiers
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If you do decide to go with the ACA, and don't want to read through a thousand posts, here's a concise but detailed guide. It's written by 6L6, the guru of Pass amp build guides.
I don't know why, but I get the feeling that not many people on diyaudio know about this guides page - they just read through thousands of posts, which are illumating and have some very good discussions, but can be intimidating.
https://guides.diyaudio.com/c/Amplifiers
Awesome, thank you. And good to know when I'm looking at other future projects.
No decisions yet, but I did list my first amp for sale with 3 others waiting in the wings!
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written by 6L6, the guru of Pass amp build guides
These are essentially on-line assembly guides that walk you thru every step. He has one for many diy Pass amplifiers, in particular boards sold thru the diyAudio store.
His day job is flying a Falcon 9.
dave
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I really liked all of the Monarchy Audio amplifiers I have owned, but FWIW they have always been class A input/driver stages and high bias class A/AB output. Not pure class A. Does that matter? Only if stuck on a topology. How does it sound is probably more important.
IIRC, the very first ones were pure class A. They ran hot. People complained and they changed the bias. I never heard a cooler unit but the hot ones did sound quite good for the money.
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Class A amps are not suited to hot areas residents, after some years the PCBs and components are fully roasted and may not live much longer, but they are nice to have in Canada or Northern Europe.
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:duel:
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Class A amps are not suited to hot areas residents, after some years the PCBs and components are fully roasted and may not live much longer, but they are nice to have in Canada or Northern Europe.
:scratch: :roll: :duh:
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:scratch: :roll: :duh:
(https://www.audiocircle.com/image.php?id=255780)
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Class A amps are not suited to hot areas residents, after some years the PCBs and components are fully roasted and may not live much longer, but they are nice to have in Canada or Northern Europe.
Why? Aren't inside temps in Canada and Northern Europe the same as inside temps in hot areas? How much do inside temps actually vary across the globe assuming AC is used? 5-10 degrees F?
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Why? Aren't inside temps in Canada and Northern Europe the same as inside temps in hot areas? How much do inside temps actually vary across the globe assuming AC is used? 5-10 degrees F?
Do you mean say with air-c noise and electrical pollution. Last summer we had two heat waves vary from 35 to 42ºC, in these hard conditions inside the amp cover temp are always hot. A few years a go we have 47ºC for two days.
(https://www.audiocircle.com/image.php?id=75058)
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Class A amps are not suited to hot areas residents, after some years the PCBs and components are fully roasted and may not live much longer, but they are nice to have in Canada or Northern Europe.
play music loud! :lol: :rock:
class A has a constant power draw so it equals power to the soeakers + amp heat. am I wrong. :dunno:
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Let’s refocus, shall we?
I had a long talk with poseidonsvoice last night. Very helpful guy and plugged into the DIY amp building community. While I haven’t ordered anything yet, I have basically decided to build the ACA monos, and use that experience as a jumping off point to maybe build something more advanced in the future.
Thanks you for all of the help. I wish I could own them all!
I’ll update here as things progress.
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Let’s refocus, shall we?
I had a long talk with poseidonsvoice last night. Very helpful guy and plugged into the DIY amp building community. While I haven’t ordered anything yet, I have basically decided to build the ACA monos, and use that experience as a jumping off point to maybe build something more advanced in the future.
Thanks you for all of the help. I wish I could own them all!
I’ll update here as things progress.
Sounds like a plan. Good luck with the build!
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I said the post #34 why since the 1990s already various used Class A amp I was interested to buy the main board and components mainly resistors and SMDs were visibly toasted by the heat inside the chassis, this is a hot city, so I didnot buy any of them because these amps were compromised and thats why they were for sale.
Today if here the Customs Duties were not 100% to 110% of product cost, more shipping and insurance I would buy a Class D or the Aegir with a nice tube pre-amp IMO, and I always would use it with the top cover removed for constant cooling.
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I said the post #34 why since the 1990s already various used Class A amp I was interested to buy the main board and components mainly resistors and SMDs were visibly toasted by the heat inside the chassis, this is a hot city, so I didnot buy any of them because these amps were compromised and thats why they were for sale.
Won't be a problem if they are properly designed and made.
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Won't be a problem if they are properly designed and made.
It would be good to know when it was well designed and built :scratch:
Small heatsinks are a obvious fault, along with small transformers.
Always prefered laminated EI power transformers in regards to Toroidals, hence my preference to the Aegir.
In the 1980s when I had this 30Kg, 350W Class AB power below it got hot when driving my Amazings, so I had to remove the cover.
(https://www.audiocircle.com/image.php?id=22369)
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Update:
Part way through the build of my ACA amps. The boards are done and just mounted to the heat sinks last night. So, I'm ready to start the case build/internal wiring. This is a fun project; I'm taking my time and enjoying the process.
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Looks great, very interested in these ACÀ.
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***Update***
I've had this system together now for a bit. My daughter has been the one to use it mostly and has definitely run it in. Here are the components:
WiiM Pro as music source (also a TV connected digitally)
Emotiva XDA-3 DAC/Pre
Monoblock Pass ACA
Klipsch RP-600M on Stands
REL 8" sub
This little system rocks! My kids tend to use it the most. I wish I had something like this when I was their age! But I do sit and enjoy it from time to time. The amps need a TON of gain to come alive, but when they do they sound really nice. And the XDA-3 does a good job with them.
It doesn't look like I put this in this thread, but I ordered some upgraded parts for the amps. Output caps and mosfets, but also some different sized resistors that came recommended. They came together very nicely and I highly recommend this as a project to anyone interested. I am curious as to what a tube pre-amp would do in a system like this.
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I know it has been a few months since this topic has been active, but I'm curious how you feel about the ACAs after having them for a while?
I have a single ACA powering my Klipsch Forte IIIs and love it! I'm currently using a Marantz 1060 as my preamp and have been thinking about building either a tube pre, or a Pass designed SS pre to replace it. Also considering trying a Pass designed bi-amp active crossover. If I get crazy, I might build another ACA, use two as monoblocks for the mid/high side and throw in a Class D amp for the bottom end. At least that is one avenue I'm considering...LOL
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I know it has been a few months since this topic has been active, but I'm curious how you feel about the ACAs after having them for a while?
I have a single ACA powering my Klipsch Forte IIIs and love it! I'm currently using a Marantz 1060 as my preamp and have been thinking about building either a tube pre, or a Pass designed SS pre to replace it. Also considering trying a Pass designed bi-amp active crossover. If I get crazy, I might build another ACA, use two as monoblocks for the mid/high side and throw in a Class D amp for the bottom end. At least that is one avenue I'm considering...LOL
Having lived with it for awhile, it's still amazing how good it sounds! I think a tube pre would sound great!
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Having lived with it for awhile, it's still amazing how good it sounds! I think a tube pre would sound great!
The ACA is a wonderful little amp. It has been described as a baby F5, which I can understand the comparison. It isn’t necessarily the most “refined” amplifier, but is pretty mind boggling for what it does at its price. I agree a tube preamp, like the NuTube kit or something like the Schiit Saga would be good places to start. The tube preamp would be great way to knock a little of the ACA’s edge off and flesh out the sound a bit and provide nice synergy. Couple them to a pair of Omega CAMs or maybe Klipsch RP600MII’s and one would have a very cool, over-achieving, and relatively inexpensive setup.
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If one needs only 125Wrms 8ohms ($725) I would suggest an Stereo GanFet amp,
There is more power versions.
https://classdaudio.com/product/gan-fet-amplifiers-3/
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The ACA is a wonderful little amp. It has been described as a baby F5, which I can understand the comparison. It isn’t necessarily the most “refined” amplifier, but is pretty mind boggling for what it does at its price. I agree a tube preamp, like the NuTube kit or something like the Schiit Saga would be good placeshttp:// to start. The tube preamp would be great way to knock a little of the ACA’s edge off and flesh out the sound a bit and provide nice synergy. Couple them to a pair of Omega CAMs or maybe Klipsch RP600MII’s and one would have a very cool, over-achieving, and relatively inexpensive setup.
Just a small correction.The ACA Mini is the baby F5 (both in sound and design topology), the original ACA which is still selling is not. The original ACA has more 2nd harmonic content which may or may not suit folks, being a bit more forward in the midrange and a less taut robust midbass unless you run them balanced as monoblocks with a balanced source. This cancels a lot of the 2nd harmonic making it more 3rd harmonic specific. The ACA is single ended Class A. The ACA Mini however is push pull and is Class A except at the power extremes or into lower loads. This has to do with how bias current affects push pull topologies vs single ended ones. The original ACA being single ended, is always Class A and will never be Class B, it will just clip.
That being said, it’s all subjective and they can both sound good in the right mix.
Here is a link: https://www.firstwatt.com/wp-content/uploads/2023/12/art_aca_mini.pdf
If you want to move beyond the ACA mini, I suggest the F5m. Then the F5. Then the F5 turbo. From there there are several branches including the The F5p-M2OPS combination, the USSA 5 and USSA 3, and so on. Basically, if you are prolific at diy building, the acquisition of that elusive amplifier you yearn for becomes dramatically easier and cheaper.
Enjoy the journey,
Best,
Anand.
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Thankyou Anand, this was a good post, if one live in a cold area the regular SET ACA seems perfect for a hi sensitivity speaker.
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ACA is SE, ACA mini is PP.Bridged ACA sound much like the ACA mini.
One of my ACAs is happily driving a set of FA22eN downstairs. Sounds really decent.
dave