Hi everyone,
For some time I've been enjoying the sound from my LM3886 chip-amp. I built this as a test to see if a cheap DIY amp could sound ok compared to my main amp, which was a Roksan Caspian. Happily, when used with a DIY op-amp-based preamp, the sound is very good indeed.
The time has come to take things further, and I need some advice from those who have built a power amplifier or two. Firstly, I'll give brief details of what I've had and use now.
I started my hi-fi with a Sherwood amp, 50wpc. This was rubbish and when I later upgraded to a Roksan Kandy integrated I was quite happy. This was driving B&W DM602 s2. Then I made DIY speakers (Audax 8" and 1.25"), and all was fine. Then I build another set of much more revealing speakers (Seas Pontus) and the combination was very harsh sounding indeed, if detailed. So I sold my Kandy and upgraded to the Caspian. The sound was a little more detailed and sweeter, but losing out in slam compared to the more powerful amp I previously owned. To be honest, changing the speaker cable made as much difference as this amp upgrade (DNM Reson to Kimber 4PR). Clearly something was wrong there.
So I began to become disillusioned by affordable commercial gear. It just didn't seem to offer value for money for me. And money is one thing I don't have much of.
So I decided to have a crack of building a simple chip amp. Not the usual "gainclone" but a slightly different thing. It was just built as a test really, using £1 heatsinks from a computer fair and the schematic found in the datasheet. I used a 100va 25vac toroid per side and 3,300uF per rail.
The amp sounded pretty good, surprisingly so. I decided the bass could be a lot better so I tried doubling the caps. This slightly ruined the top end, which was later rectified by using the "snubber" of 1R/22nF across the caps. Still the bass was relatively weak so in came a preamp. I got the gutsy sound I wanted but with the grit and grain of a preamp. So the preamp got tweeked and is now good enough.
And now.... it is time to build a better amp!
My first thought was stick with what I know and build an über LM3886, using the same basic circuit but with a 400va frame transformer, nice psu caps (Elna Cerafine maybe) and schottky diodes. Well, the quote for such a custom transformer was £200 so I've decided to step back and rethink the whole idea. What other options are there I could build? Without having to understand too much technical stuff.
The £300 for selling my Roksan Caspian is pretty much my budget, or a little more if needed. What I'm after is an amplifier with the following characteristics:
- at least 50wpc RMS @ 4ohms
- can be point to point wired or uses a good readily available pcb
- excellent sound quality
- not much more than £300 in parts
- preferably class A/B
- easy to get right and not end up smoking!
- good match for 90db/4ohms speakers
- easy to build second set for future active bi-amping
I could state my sonic preferences but I honestly don't feel an amp has much in the way of a sound. The psu and parts are obviously responsible for making the most of a design, but I want to start with a nice, proven design.
One amp that has come to my attention as an excellent candidate is the Rod Elliott P3A:
http://sound.westhost.com/project3a.htm
This amp has the PCBs, the power and reportedly very good sound quality. It also seems like it should be affordable.
I don't want another "pedestrian" sounding amp! I want emotion, deep bass, toe-tapping timing, amazing detail.... Can anyone help me on my quest?
Thanks for reading and sorry for the essay-like post.
Simon
For some time I've been enjoying the sound from my LM3886 chip-amp. I built this as a test to see if a cheap DIY amp could sound ok compared to my main amp, which was a Roksan Caspian. Happily, when used with a DIY op-amp-based preamp, the sound is very good indeed.
The time has come to take things further, and I need some advice from those who have built a power amplifier or two. Firstly, I'll give brief details of what I've had and use now.
I started my hi-fi with a Sherwood amp, 50wpc. This was rubbish and when I later upgraded to a Roksan Kandy integrated I was quite happy. This was driving B&W DM602 s2. Then I made DIY speakers (Audax 8" and 1.25"), and all was fine. Then I build another set of much more revealing speakers (Seas Pontus) and the combination was very harsh sounding indeed, if detailed. So I sold my Kandy and upgraded to the Caspian. The sound was a little more detailed and sweeter, but losing out in slam compared to the more powerful amp I previously owned. To be honest, changing the speaker cable made as much difference as this amp upgrade (DNM Reson to Kimber 4PR). Clearly something was wrong there.
So I began to become disillusioned by affordable commercial gear. It just didn't seem to offer value for money for me. And money is one thing I don't have much of.
So I decided to have a crack of building a simple chip amp. Not the usual "gainclone" but a slightly different thing. It was just built as a test really, using £1 heatsinks from a computer fair and the schematic found in the datasheet. I used a 100va 25vac toroid per side and 3,300uF per rail.
The amp sounded pretty good, surprisingly so. I decided the bass could be a lot better so I tried doubling the caps. This slightly ruined the top end, which was later rectified by using the "snubber" of 1R/22nF across the caps. Still the bass was relatively weak so in came a preamp. I got the gutsy sound I wanted but with the grit and grain of a preamp. So the preamp got tweeked and is now good enough.
And now.... it is time to build a better amp!
My first thought was stick with what I know and build an über LM3886, using the same basic circuit but with a 400va frame transformer, nice psu caps (Elna Cerafine maybe) and schottky diodes. Well, the quote for such a custom transformer was £200 so I've decided to step back and rethink the whole idea. What other options are there I could build? Without having to understand too much technical stuff.
The £300 for selling my Roksan Caspian is pretty much my budget, or a little more if needed. What I'm after is an amplifier with the following characteristics:
- at least 50wpc RMS @ 4ohms
- can be point to point wired or uses a good readily available pcb
- excellent sound quality
- not much more than £300 in parts
- preferably class A/B
- easy to get right and not end up smoking!
- good match for 90db/4ohms speakers
- easy to build second set for future active bi-amping
I could state my sonic preferences but I honestly don't feel an amp has much in the way of a sound. The psu and parts are obviously responsible for making the most of a design, but I want to start with a nice, proven design.
One amp that has come to my attention as an excellent candidate is the Rod Elliott P3A:
http://sound.westhost.com/project3a.htm
This amp has the PCBs, the power and reportedly very good sound quality. It also seems like it should be affordable.
I don't want another "pedestrian" sounding amp! I want emotion, deep bass, toe-tapping timing, amazing detail.... Can anyone help me on my quest?
Thanks for reading and sorry for the essay-like post.
Simon
rabbitz said:
Thanks Rabbitz, I'm looking...
Ok, I had noticed the MOSFET amp design on Rod Elliott's site. Rod says it sounds great, or as much as that man will ever say something sounds like anything. This is definitely an amp to consider then!
I've looked at AKSA stuff and it looks great. The Lifeforce 100 looks like a very serious power amp but would triple my budget. It's simply not affordable at this time. I wonder if one can just buy PCBs. I'm still looking.
OK, looks like the AKSA 100 kit with most things needed for stereo is just under £300. But with transformers and chassis that's gonna be £400 or so. All the happy customers there say a lot about how nice those amps are. Definitely a contender.
As is the cheaper AKSA 55, which as the name suggests supplies a good-enough 55w RMS into 8ohms. This is "only" £180 without case and transformers or import duty and shipping. Factoring in those extras this is about the limit of affordability.
Opinions welcome!
Thanks,
Simon
As is the cheaper AKSA 55, which as the name suggests supplies a good-enough 55w RMS into 8ohms. This is "only" £180 without case and transformers or import duty and shipping. Factoring in those extras this is about the limit of affordability.
Opinions welcome!
Thanks,
Simon
richie00boy said:I say wait until the DIY Fest and check out some designs
This has been a thought of mine! But I don't think the environment will allow for being able to tell any difference between amps. Can ask people's opinions of course.
Nordic said:
Great stuff, I'll look this up tomorrow when I'm not super-tired. Does it have PCBs for sale? I won't make anything that doesn't have a PCB.
Thanks all,
Simon
Hi
From what I've read, the DX amp are very much better than the Rod Elliott P3A
Here's the link for the DX amp;
http://users.tpg.com.au/users/gerskine/dxamp/
Gaetan
From what I've read, the DX amp are very much better than the Rod Elliott P3A
Here's the link for the DX amp;
http://users.tpg.com.au/users/gerskine/dxamp/
Gaetan
gaetan8888 said:
Hi Gaetan,
Thanks for the link! I'm reading up on it and it looks very nice. Of course I know nothing about amplifier circuit design so I need to be guided. I will read people's opinions and take my pick... I do enjoy Destroyer X's posts, even when I don't understand them
Cheers
Simon
Personally, in the following weeks / month i hope to start putting together a few Symasym amps. They've gathered a pretty good reputation around here, as far as i could tell. People say they sound real nice, they measure real well (well under 0.01% THD). They're not that much more complex than the Dx amp, and the components should cost roughly the same.
I'm going to put them to work using an SMPS, a diy active crossover, driving some Seas drivers (in some yet-to-be-finished bookshelf speakers).
http://www.lf-pro.net/mbittner/Sym5_Webpage/symasym5_3.html
I'm going to put them to work using an SMPS, a diy active crossover, driving some Seas drivers (in some yet-to-be-finished bookshelf speakers).
http://www.lf-pro.net/mbittner/Sym5_Webpage/symasym5_3.html
A major problem when selecting any audio configuration is that you're really dealing with a "system" ... from the source all the way to your ears including pre-amp, power amps, speakers, room acoustics and your own ears / auditory senses.
Change any part of that system to a higher quality component and it may sound better or it may sound worse due to other deficiencies in the overall delivery system that strangely compensated the poorer quality component.
I've heard it myself time and again and heard many disappointed folks.
It makes experimentation frustrating and expensive to know that an upgrade may in fact turn into a downgrade!
If you want bass, nothing short of a 12 to 15" efficient drive unit in appropriate cabs is going to give you that. You can tinker with your amp all you want, but if you don't start with the speakers, nothing is going to sound good. Personally, I like a distinct but smooth bass, not one which takes any bass note and turns it into a monotonic thud (as too many undersized units do). So, I still use relatively small and inexpensive Kef units purchased about 30 years ago! (I thought I was going to break the bank when I bought them!) I've moved many times and so have to work out the best acoustical position every time ... you wouldn't believe where they are right now!
While a good power supply is a requirement for good bass, it also applies to good range in general. Simply increasing the size of the caps is not always enough since you can end up with a resonance problem. The primary requirement is to ensure that you have enough current delivery capability from the transformer, that you have large enough wire hooking up the PSU components and connecting to the power amps. You can take the Preamp feed off the same PSU (better a separate supply), but it MUST be regulated with enough reserve capacity such that it doesn't lose regulation.
If I were going to sink 250-300 pounds into any components, my first choice would be to ensure that my speakers are actually what I *think* they are. Go to a good quality hi-fi store and tell them you're thinking of buying new speakers, and you want to compare them with your current ones and using your own amp. They may let you do the needed AB tests to do a reasonable comparison. You may be surprised at the results.
I'm quite certain that most amps have the ability to deliver the power across their bandwidth, The usual deficiency in power amps is the distortion ... crossover being probably the most noticeable, buat also clipping in the driving stages.
You've already experimented and discovered that the power supply IS impacting your amp's performance. This is where I'd put my next $$$
Change any part of that system to a higher quality component and it may sound better or it may sound worse due to other deficiencies in the overall delivery system that strangely compensated the poorer quality component.
I've heard it myself time and again and heard many disappointed folks.
It makes experimentation frustrating and expensive to know that an upgrade may in fact turn into a downgrade!
If you want bass, nothing short of a 12 to 15" efficient drive unit in appropriate cabs is going to give you that. You can tinker with your amp all you want, but if you don't start with the speakers, nothing is going to sound good. Personally, I like a distinct but smooth bass, not one which takes any bass note and turns it into a monotonic thud (as too many undersized units do). So, I still use relatively small and inexpensive Kef units purchased about 30 years ago! (I thought I was going to break the bank when I bought them!) I've moved many times and so have to work out the best acoustical position every time ... you wouldn't believe where they are right now!
While a good power supply is a requirement for good bass, it also applies to good range in general. Simply increasing the size of the caps is not always enough since you can end up with a resonance problem. The primary requirement is to ensure that you have enough current delivery capability from the transformer, that you have large enough wire hooking up the PSU components and connecting to the power amps. You can take the Preamp feed off the same PSU (better a separate supply), but it MUST be regulated with enough reserve capacity such that it doesn't lose regulation.
If I were going to sink 250-300 pounds into any components, my first choice would be to ensure that my speakers are actually what I *think* they are. Go to a good quality hi-fi store and tell them you're thinking of buying new speakers, and you want to compare them with your current ones and using your own amp. They may let you do the needed AB tests to do a reasonable comparison. You may be surprised at the results.
I'm quite certain that most amps have the ability to deliver the power across their bandwidth, The usual deficiency in power amps is the distortion ... crossover being probably the most noticeable, buat also clipping in the driving stages.
You've already experimented and discovered that the power supply IS impacting your amp's performance. This is where I'd put my next $$$
SimontY said:
Sounds like SymAsym might be a good choice for you, except the pcb-thing. But, you could build it on perfboard. Power is ~100w into 4ohm.
I use it myself on 90db/4ohm speakers, and it plays deep and tough bass, great dynamics and a "lovely" midrange, crystal clear trebles.
If correctly build, it will work without any problems.
Many have built it, and practically all were fascinated.
You might enter the groupbuy for the AAK-Symasym.
Mike
tinitus said:sbrook, I like your way of thinking, and I also did think of speakers
But in my world its easier to build a speaker to match an existing amp, rather than the other way round
But you know, building is also just about building
In *my world* building a speaker is a pain ... I'm a member of the measure 3 times, cut once and STILL get it wrong club when it comes to woodworking. My first attempt at speakers was a pair of 13 * 8 EMI elliptical with twin tweeter drive units in a 16 * 12 * 9 sealed box. They worked OK but way too much colouration (given that I was into mediocre quality at that time because it was what I could afford - poor student!) but looked like hell and no amount of woodwork repairs changed that!
And given how poor I am at woodworking, getting a nice response out of speakers I'd rather leave to the speaker designers (and I don't think there's a KEF that I didn't like! - even their speakers using the ABR are quite surprising!)
What I can do is build amps ... I've had a few ... but the two main ones I tried I haven't been disappointed with which leaves me reluctant to try others! I use a 200 Watt transformer designed for 50Hz, running at 60Hz - lots of iron and so COOL and 14 gauge wiring - to run a 25+25W into 8 ohms (at least that's the max I've ever driven it too and with the KEF units it shakes the house!) The cheapest thing and most dramatic to tinker with is the pre-amps ... you can so easily mess tone balance there by accident. Getting a good flat passband is definitely more of a challenge!
So, MY take would be to try your amp with different speakers and then try your current speakers with different amps before committing money to ANY project.
To try any combination before ....
Well, I actually listened to the designers own version of the amp I have now - I said to myself it was very good, but that I might be able to make it better, and well, its different, thats for sure
So I conclute that if you dont make an excact copy down to supply and all, your own construction/version will be different anyway
Well, I actually listened to the designers own version of the amp I have now - I said to myself it was very good, but that I might be able to make it better, and well, its different, thats for sure
So I conclute that if you dont make an excact copy down to supply and all, your own construction/version will be different anyway
sbrook,
Thanks for your insightful post. I like your way of thinking. I have thought about the system as a whole. And I have heard these speakers with 3 different power amplifiers. The amps were different, and these speakers can certainly reveal small changes. The speakers certainly have decent enough resolution...
The bass I really crave will never be produced by these speakers. Fact. With tweaking my crossovers it's not at all bad though. But two 6.5" small excursion drivers isn't going to shift enough air volume, and being ported distortion is a problem at high output levels particularly with low bass. However, high output is only 20% of my listening. So we can safely assume I can enjoy a superior amp without upgrading my speakers. They are pretty good. One day when I have the space and money I can build the type of speaker I'd really like - something like a 3-way with 15" bass drivers. NOT POSSIBLE right now.
So, we have speakers and need to make the most of them. And they did cost me quite a lot so I need to hear their very best. I may be able to shoe-horn in an extra bass section, and actively biamp this below the other drivers, which would become mid-only. I have discussed this on the forum once before so do not wish to discuss the merits or lack thereof again!
Can we simply assume I will enjoy a better power amp? My room is fairly tweaked and my CD player VERY much so. So the beginning and end of my chain are very good. It compares quite well with £10k of shop gear in a mediocre shop room. Of course I don't have the last ounce of detail or, depending on speakers, bass quality. Even stand-mounted ATCs have better bass, but that's not a problem, just inspiration!
One day real speaker upgrades are a possibility and in the interim experiments with additional twinned 7" bass drivers. This will mean I need two power amps. So I'm after a project that is cheap enough and easy enough to build.
Another factor is learning. I want to have a DIY amp. The Roksan ones I owned aren't bad, just not good enough. And not DIY!!!
My current one (LM3886) was merely an experiment. I *could* change the passive components and buy new transformers of higher ratings. The detail and bass would surely be great. But I'd rather keep this amp for other use - friend, other room, office for example - and have a whole new amp.
I know I would be very happy with a fully-tweaked LM3886. But I started this thread because I wondered if there was more. It seems there probably is, I just need to find my own route to getting there.
Simon
Thanks for your insightful post. I like your way of thinking. I have thought about the system as a whole. And I have heard these speakers with 3 different power amplifiers. The amps were different, and these speakers can certainly reveal small changes. The speakers certainly have decent enough resolution...
The bass I really crave will never be produced by these speakers. Fact. With tweaking my crossovers it's not at all bad though. But two 6.5" small excursion drivers isn't going to shift enough air volume, and being ported distortion is a problem at high output levels particularly with low bass. However, high output is only 20% of my listening. So we can safely assume I can enjoy a superior amp without upgrading my speakers. They are pretty good. One day when I have the space and money I can build the type of speaker I'd really like - something like a 3-way with 15" bass drivers. NOT POSSIBLE right now.
So, we have speakers and need to make the most of them. And they did cost me quite a lot so I need to hear their very best. I may be able to shoe-horn in an extra bass section, and actively biamp this below the other drivers, which would become mid-only. I have discussed this on the forum once before so do not wish to discuss the merits or lack thereof again!
Can we simply assume I will enjoy a better power amp? My room is fairly tweaked and my CD player VERY much so. So the beginning and end of my chain are very good. It compares quite well with £10k of shop gear in a mediocre shop room. Of course I don't have the last ounce of detail or, depending on speakers, bass quality. Even stand-mounted ATCs have better bass, but that's not a problem, just inspiration!
One day real speaker upgrades are a possibility and in the interim experiments with additional twinned 7" bass drivers. This will mean I need two power amps. So I'm after a project that is cheap enough and easy enough to build.
Another factor is learning. I want to have a DIY amp. The Roksan ones I owned aren't bad, just not good enough. And not DIY!!!
My current one (LM3886) was merely an experiment. I *could* change the passive components and buy new transformers of higher ratings. The detail and bass would surely be great. But I'd rather keep this amp for other use - friend, other room, office for example - and have a whole new amp.
I know I would be very happy with a fully-tweaked LM3886. But I started this thread because I wondered if there was more. It seems there probably is, I just need to find my own route to getting there.
Simon
Re: Re: Which amplifier design should I build?
Hi Mike,
Thanks for alerting me to this promising design. Is the design your own? I've read the/your webpage on it, looks nice. The review by Pavel is also encouraging.
Perfboard is not an option for me. There will be smoke. I can do a chip amp or op-amp preamp or something on perfboard, but probably not a discrete power amp.
Simon
MikeB said:
Hi Mike,
Thanks for alerting me to this promising design. Is the design your own? I've read the/your webpage on it, looks nice. The review by Pavel is also encouraging.
Perfboard is not an option for me. There will be smoke. I can do a chip amp or op-amp preamp or something on perfboard, but probably not a discrete power amp.
Simon
sbrook said:
I take your point, but given what I feel I "know" about my system I can safely assume the amp upgrade will provide benefits for me. I did, of course, have great bass at high levels with the 200w RMS Roksan Kandy. But it was also very glassy and harsh, and poor at low levels: very grey and bland. Not good enough. My LM3886 is perhaps softer, but more detailed and pleasant. Definately lower subjective distortion, and Dire Straits can be played loud and clean without whincing too much!
I don't think I can really take my amp or speakers into any shop round here... I listened to a nice system in one respected shop, whilst waiting for a car window to be fixed. In some ways the system sounded better than mine. The speakers were B&W Nautilus 804 and amp was a class A monster with 30wpc. There didn't appear to be much bass or any big dynamics going on. Just lots of detail and no fun! I think I can conclude from that experience a few things:
- I can't afford nice things like B&W Nautilus speakers
- those speakers probably don't like low-powered class A amps
- even £2500 of speakers doesn't buy a good treble
- my listening room is much better than any shop's I've heard
- nice shops don't like you telling them their room is crap and you not buying anything
In any case, I'd feel bad listening to their speakers or amps knowing I'm not actually going to buy anything! I have a problem with knowingly doing that and fooling them. (When I went to listen I told them straight up I wasn't buying anything.)
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