I built some P3a amps some years ago (using official PCBs from Rod). They went well (thanks to plentiful info on the ESP website) but I put them bridged into a modest subwoofer (which isn't really what they're designed for) so I've no personal experience of their sound quality when used with normal speakers.
Now I'm going to build some active speakers with active crossovers, and am trying to decide between building more P3A's to power them or getting a couple of ready-built stereo hi-fi amps, such as one would buy from mainstream hi-fi stores. The cost of the drivers on my wish list seems to be climbing, so I'll want amps that don't let them down.
There are lots of threads comparing the P3a with other DIY builds and modules etc. but is anyone aware of any that compare their audio performance with reasonably modern/decent shop-bought hi-fi amps? Or alternatively could anyone who has both say what they think?
Many thanks
Kev
Now I'm going to build some active speakers with active crossovers, and am trying to decide between building more P3A's to power them or getting a couple of ready-built stereo hi-fi amps, such as one would buy from mainstream hi-fi stores. The cost of the drivers on my wish list seems to be climbing, so I'll want amps that don't let them down.
There are lots of threads comparing the P3a with other DIY builds and modules etc. but is anyone aware of any that compare their audio performance with reasonably modern/decent shop-bought hi-fi amps? Or alternatively could anyone who has both say what they think?
Many thanks
Kev
Last edited:
I just noticed on the P3a web page, it says "Coupled with a Linkwitz-Riley crossover, the amplifiers can be mounted in the back of the speaker box, so only signal and power are needed for a complete system that will leave most commercial offerings for dead", which kind of answers my question. Encouraging too, as thats what I'm intending (albeit perhaps in a separate box) 
I've also been looking around at what people have found under the hood of typical shop-bought amps; not all are bad by any means but even within the big hi-fi names it seems like there can be things like minimal (or even false!) heat-sinks, less than generous transformers and capacitors, and quite a lot of empty space in impressive looking cases.
I guess it doesn't actually matter if they still work well and sound good, but I'm feeling more inclined towards a self-build now - at least I'd know what quality of components went into it and be able to configure things how I want. I haven't totally settled on the P3a yet, as I realise there are a few alternatives, but if I'm going to be making six (for stereo 3-way speakers) they need to be reasonably economical so something in this price ball-park.
Cheers
kev
I've also been looking around at what people have found under the hood of typical shop-bought amps; not all are bad by any means but even within the big hi-fi names it seems like there can be things like minimal (or even false!) heat-sinks, less than generous transformers and capacitors, and quite a lot of empty space in impressive looking cases.
I guess it doesn't actually matter if they still work well and sound good, but I'm feeling more inclined towards a self-build now - at least I'd know what quality of components went into it and be able to configure things how I want. I haven't totally settled on the P3a yet, as I realise there are a few alternatives, but if I'm going to be making six (for stereo 3-way speakers) they need to be reasonably economical so something in this price ball-park.
Cheers
kev
Last edited:
Rod Elliot has the answer for you - Class A on the tweeter:
"For 20 Watts, we can look seriously at using a Class-A amplifier, something that many people would die for, but is unrealistic for higher powers."
BiAmp (Bi-Amplification - Not Quite Magic, But Close) - Part 2
"For 20 Watts, we can look seriously at using a Class-A amplifier, something that many people would die for, but is unrealistic for higher powers."
BiAmp (Bi-Amplification - Not Quite Magic, But Close) - Part 2
This is what I've done, but using Rod's P19 LM3886TF boards mounted in the base of the speaker box. Everyone who listens to them is blown away by the clarity, more so when played at levels they believe distortion should be kicking in. Two leads into the box; mains and XLR.I just noticed on the P3a web page, it says "Coupled with a Linkwitz-Riley crossover, the amplifiers can be mounted in the back of the speaker box, so only signal and power are needed for a complete system that will leave most commercial offerings for dead", which kind of answers my question. Encouraging too, as thats what I'm intending (albeit perhaps in a separate box)
Last edited:
Active Speakers
If you go down the active crossover route and power each driver or frequency range with a separate amplifier you will get significant improvement, even using cheap Ebay kits of some minimal cost and parts count. Given the power levels are adequate, crossover quality is good, low noise and correctly balanced for the driver sensitivities, almost any audio amplifiers will deliver great sound. The evidence of so many powered monitor speakers out there should be good enough indication of what is possible, given that everyone from makers of cheap wanna-be boxes to high priced and performance powered speakers, all now use similar chips in their line-up somewhere.
You get a small increment of improvement moving from chip amps to very good discrete amps but the cost and time in producing so many, often complex units is questionable when chip amps have the great advantage of consistency, good internal overload protection and least oppportunity to make costly mistakes.
However, a simple, low cost discrete amplifier with good sound quality will be a good contender if well protected in the event of DC faults and overloads and for a simple amp, the P3a is great in sound quality and power. It has an edge over chip amps if it is built correctly as Rod Elliott has claimed in his articles. Being a discrete design there is plenty of opportunity to fine-tune these to your preference and their size is fine for most domestic uses and suitable drivers.
Class A tweeter drive sounds attractive, doesn't it? There is a warning that should not really need repeating, but many guys seem to have no clue about; Even push-pull class A has very low efficiency and the constant waste heat from a 20W amplifier is in excess of 55W. Even with a large, ~0.3C/W heatsink strapped to the back of your speaker box or amplifier, you will be having to cope with constantly sizzling hot 'sinks in warm weather. IMHO, this is not really a good idea unless you have good room air movement or use separate amplifier stacks which somewhat defeats the benefits of powered boxes with active crossovers and makes for a wireworks in your living space.
Yes, I have tried all this some years back and used P3s, too. Sound was absolutely great - domestic approval?
If you go down the active crossover route and power each driver or frequency range with a separate amplifier you will get significant improvement, even using cheap Ebay kits of some minimal cost and parts count. Given the power levels are adequate, crossover quality is good, low noise and correctly balanced for the driver sensitivities, almost any audio amplifiers will deliver great sound. The evidence of so many powered monitor speakers out there should be good enough indication of what is possible, given that everyone from makers of cheap wanna-be boxes to high priced and performance powered speakers, all now use similar chips in their line-up somewhere.
You get a small increment of improvement moving from chip amps to very good discrete amps but the cost and time in producing so many, often complex units is questionable when chip amps have the great advantage of consistency, good internal overload protection and least oppportunity to make costly mistakes.
However, a simple, low cost discrete amplifier with good sound quality will be a good contender if well protected in the event of DC faults and overloads and for a simple amp, the P3a is great in sound quality and power. It has an edge over chip amps if it is built correctly as Rod Elliott has claimed in his articles. Being a discrete design there is plenty of opportunity to fine-tune these to your preference and their size is fine for most domestic uses and suitable drivers.
Class A tweeter drive sounds attractive, doesn't it? There is a warning that should not really need repeating, but many guys seem to have no clue about; Even push-pull class A has very low efficiency and the constant waste heat from a 20W amplifier is in excess of 55W. Even with a large, ~0.3C/W heatsink strapped to the back of your speaker box or amplifier, you will be having to cope with constantly sizzling hot 'sinks in warm weather. IMHO, this is not really a good idea unless you have good room air movement or use separate amplifier stacks which somewhat defeats the benefits of powered boxes with active crossovers and makes for a wireworks in your living space.
Yes, I have tried all this some years back and used P3s, too. Sound was absolutely great - domestic approval?
I've used biamped speakers some time ago, with electronic crossovers. Using the same crossover frequency and approximate slopes that the passive crossover provided. The sound is different, in a better way. The sound in general is cleaner. Additionally it goes much louder and cleaner than the power amp rating might suggest. You have to try it out to know what it is like.
Even plain biamping and using the passive crossover can produce good results. But nothing like removing the passive crossover , adding an electronic crossover ( matched to the performance of the passive crossover ) and driving the speakers directly off the power amp. 50 watts per driver can go pretty loud ! This would be a major step up in performance for most systems.
Even plain biamping and using the passive crossover can produce good results. But nothing like removing the passive crossover , adding an electronic crossover ( matched to the performance of the passive crossover ) and driving the speakers directly off the power amp. 50 watts per driver can go pretty loud ! This would be a major step up in performance for most systems.
Great, many thanks to everyone!!
Thats exactly what I was hoping. Clearly theres a financial hit with 3x the number of amps, but I suspected that even quite modest ones may ultimately turn out better for me than trying to inexpertly design passive crossovers for the driver's non-linear characteristics.
I'll have to look again at class A (or a heavy bias current); I had more or less decided not to use it - my system tends to be on all the time when I'm home, and there have been occasions when I've forgotten to switch off the amp at night too, so a more efficient bias current seems more suitable for the circumstances. But I just realised that I don't actually know how the power needed vs width of frequency band works out up at the tweeter frequencies; maybe I'd need less than I thought with a reasonably efficient tweeter.
Having built the P3a in the past I've already gone through the learning curve for much of the build and sourcing of components, and have probably even got some suitable bits left over. I'll need some revision as its been a while, but in these circumstances its probably going to be almost as easy to stay with the discrete component approach as it would be to go with chip amps, so probably I'll see where budget takes me first.
Cheers
Kev
Thats exactly what I was hoping. Clearly theres a financial hit with 3x the number of amps, but I suspected that even quite modest ones may ultimately turn out better for me than trying to inexpertly design passive crossovers for the driver's non-linear characteristics.
I'll have to look again at class A (or a heavy bias current); I had more or less decided not to use it - my system tends to be on all the time when I'm home, and there have been occasions when I've forgotten to switch off the amp at night too, so a more efficient bias current seems more suitable for the circumstances. But I just realised that I don't actually know how the power needed vs width of frequency band works out up at the tweeter frequencies; maybe I'd need less than I thought with a reasonably efficient tweeter.
Having built the P3a in the past I've already gone through the learning curve for much of the build and sourcing of components, and have probably even got some suitable bits left over. I'll need some revision as its been a while, but in these circumstances its probably going to be almost as easy to stay with the discrete component approach as it would be to go with chip amps, so probably I'll see where budget takes me first.
Cheers
Kev
There is one advantage in using class A amp for tweeter, at least one like ESP P36, and that is capacitor coupled output. Since tweeter is usually at highest risk from DC voltage capacitor in the output will protect it automatically. But all other warnings by Ian are spot on. There should be some kind of DC protection for the tweeter at least. DC offset in 3886 chips is so small that using them for all drivers is a real temptation and almost guarantee for success. But I also intend to build active loudspeakers using Eminence Beta 10CX coaxials and original P3A boards and ESP P09 active crossovers.
Interesting, thanks. Yes I'd be most interested in protecting the tweeter from DC, in fact even with speaker protection and other types of amp I would probably at least try a big series capacitor to see if I could hear any difference; if not then the added protection would be welcome.
Just looking at the ESP site again, Rod covers the power requirements of the tweeter and the possibility of class A for it in his Bi-Amping article. It looks like I'd be aiming for around 20W which is achievable, but I'm not sure that dumping 100+watts per channel would be the best design choice in my application. I'll need to do some reading up on the relative audio performance before I decide though.
Cheers
Kev
Just looking at the ESP site again, Rod covers the power requirements of the tweeter and the possibility of class A for it in his Bi-Amping article. It looks like I'd be aiming for around 20W which is achievable, but I'm not sure that dumping 100+watts per channel would be the best design choice in my application. I'll need to do some reading up on the relative audio performance before I decide though.
Cheers
Kev
If I were building an active speaker that roughly matched the maximum output of a 90dB/W 100W 2way with passive crossover.
I would choose a 90dB/W bass/mid and allocate an 80W amplifier. This will give ~104dB @ 2.5m listening distance for a stereo pair.
To match this I would choose a tweeter with a maximum peak output of ~104dB. This could be a 90dB/W with the same 80W of power available, or a 96dB/W with 20W of power available or 100dB/W with 8W of power available.
I would probably not be able to find a tweeter to match that first power & power handling, but I suspect there are many tweeters that can perform around the second or third combination.
For these higher efficiency treble drivers, it be worth considering a ClassA amplifier that will transition into ClassAB for the highest current peaks, i.e. it must be a push pull type.
Select a 10W into 16ohms ClassA amplifier that is biased to ~0.6A. This will give ~ 1.2A of ClassA output. It will run off ~+-22Vdc supplies and dissipate ~26W.
For most music at most listening levels that treble amplifier will be working in ClassA.
Only when a short and fairly infrequency transient comes along will it transition into ClassAB for peaks up to maybe 6Apk.
Sumarising:
a ClassAB 80W into 8ohms for bass/mid duty and a ClassA 10W into 16ohms for treble duty will sound just as loud and sometimes louder than a 100W driving a passive crossover speaker of similar maximum peak output.
BTW,
this complies with my assertion that the treble driver must be capable of achieving similar maximum output to the bass and/or mid driver.
I would choose a 90dB/W bass/mid and allocate an 80W amplifier. This will give ~104dB @ 2.5m listening distance for a stereo pair.
To match this I would choose a tweeter with a maximum peak output of ~104dB. This could be a 90dB/W with the same 80W of power available, or a 96dB/W with 20W of power available or 100dB/W with 8W of power available.
I would probably not be able to find a tweeter to match that first power & power handling, but I suspect there are many tweeters that can perform around the second or third combination.
For these higher efficiency treble drivers, it be worth considering a ClassA amplifier that will transition into ClassAB for the highest current peaks, i.e. it must be a push pull type.
Select a 10W into 16ohms ClassA amplifier that is biased to ~0.6A. This will give ~ 1.2A of ClassA output. It will run off ~+-22Vdc supplies and dissipate ~26W.
For most music at most listening levels that treble amplifier will be working in ClassA.
Only when a short and fairly infrequency transient comes along will it transition into ClassAB for peaks up to maybe 6Apk.
Sumarising:
a ClassAB 80W into 8ohms for bass/mid duty and a ClassA 10W into 16ohms for treble duty will sound just as loud and sometimes louder than a 100W driving a passive crossover speaker of similar maximum peak output.
BTW,
this complies with my assertion that the treble driver must be capable of achieving similar maximum output to the bass and/or mid driver.
Thanks, thats sort of where my pondering was going so its helped clarify my thoughts a bit.
In my application I don't really want to be dumping a few hundred watts of heat so (whilst popular) the class A approach is not the most suitable choice in some ways. But 'if' the audio qualities are sufficientlky better then I could probably run to a class A if I can find a suitable tweeter thats very efficient and if I can limit power by making it a partial class A.
Having looked into the ESP P3a it seems to be adaptable to an AB type of setup (some people call it P3b I think) so there wouldn't be any great overhead in building radically different amps.
Many things to juggle! I think initially I'll see what drivers I can find that suit my design, they'll likely be the most fussy of the components. Then I'll consider what power amps may suit them best.
Having read around the forums I'm wondering now about going for the P101 instead, at least for the mid and bass amps. As always, opinion is a little divided on the audio quality of P3a vs P101, but the latter is supposed to be quieter at idle, which may be more suitable for a power amp application. Being more powerful I'd probably have more options with the bass drivers too.
Cheers
Kev
In my application I don't really want to be dumping a few hundred watts of heat so (whilst popular) the class A approach is not the most suitable choice in some ways. But 'if' the audio qualities are sufficientlky better then I could probably run to a class A if I can find a suitable tweeter thats very efficient and if I can limit power by making it a partial class A.
Having looked into the ESP P3a it seems to be adaptable to an AB type of setup (some people call it P3b I think) so there wouldn't be any great overhead in building radically different amps.
Many things to juggle! I think initially I'll see what drivers I can find that suit my design, they'll likely be the most fussy of the components. Then I'll consider what power amps may suit them best.
Having read around the forums I'm wondering now about going for the P101 instead, at least for the mid and bass amps. As always, opinion is a little divided on the audio quality of P3a vs P101, but the latter is supposed to be quieter at idle, which may be more suitable for a power amp application. Being more powerful I'd probably have more options with the bass drivers too.
Cheers
Kev
Member
Joined 2009
Paid Member
Hi Kev - I think you'll find that the differences between the different amps aren't going to be the most critical thing so it might be easiest to just keep the same amp on all drivers and have less variables to juggle. You might even be better off starting with one amp and a simple capacitor cross-over for the tweeter to find out how well things sound to you. On paper it looks like a good idea to make things better with bi-amping and using class A and all the other good ideas but nothing worse than it getting expensive and frustrating when a simple set up might get you up and running first. Then you can improve it from there. You might be surprised to find that a simple two-way speaker and single P3A will get you to audio nirvana without further ado and at the very least it gives you a reference to compare 'improvements' against.
That sounds like very good advice - the physical side of my speaker build is becoming a step by step process already so I guess theres no reason why I should expect to know the right answers for the electronics either, until I start testing things. Maybe I should fundamentally get the drivers and crossover points sorted and then worry about the subtleties later. It'd be quite easy to change my mind about the amp, much less easy to alter driver/enclosure choices.
I think I may remove my old p3a amps from their (somewhat inappropriate) subwoofer; I could use one 'as is' and try tweaking the other into an AB mode to compare. I guess I could also get a p101 PCB and try that too rather than immediately buying all the components for six of either type.
Cheers
Kev
I think I may remove my old p3a amps from their (somewhat inappropriate) subwoofer; I could use one 'as is' and try tweaking the other into an AB mode to compare. I guess I could also get a p101 PCB and try that too rather than immediately buying all the components for six of either type.
Cheers
Kev
Wow Kev....
I'm a few years late but it seems like I read your mind, or something. I have a Class AB amp but would love to biamp my B&W DM602 2-way speakers. Crossover is at 3kHz I think. Am pondering whether it's worth it... I am also considering the ESP Linkwitz-Riley active crossover and P3A amps. In fact, since they come packaged on the PCB as a pair it's very tempting to just build 4 into a single case with dedicated inputs/outputs.
Also considering a speaker kit but woodwork (mdf-work?) is a bit intimidating. Saw some interesting 3-way designs on the Visaton German website - something 'simple' like the Starlet:
STARLET
Pops.
I'm a few years late but it seems like I read your mind, or something. I have a Class AB amp but would love to biamp my B&W DM602 2-way speakers. Crossover is at 3kHz I think. Am pondering whether it's worth it... I am also considering the ESP Linkwitz-Riley active crossover and P3A amps. In fact, since they come packaged on the PCB as a pair it's very tempting to just build 4 into a single case with dedicated inputs/outputs.
Also considering a speaker kit but woodwork (mdf-work?) is a bit intimidating. Saw some interesting 3-way designs on the Visaton German website - something 'simple' like the Starlet:
STARLET
Pops.
Last edited:
You can test out active bi-amping for peanuts by using a miniDSP 2x4 module and a pair of stereo amps (any you have lying around). If you don't have a second amp handy, just get an inexpensive one (even a $30 to $50 Class D like a TPA3118 or TDA7498 - for the tweeters) to test out the system and see how you like it. In general, it can sound amazing. Being able to play with the crossover and have instant feedback is very nice. You need a measurement mic though - but they are cheap too. I used a pair of $20 TPA3116's for years with a miniDSP and was very happy. I am now more into designing discrete amps so like passive crossovers so as to not require building 4 channels. If you play around and like what you hear, you can upgrade the miniDSP to something more hifi but still active. The type of crossover filter and its correct implementation can make a HUGE difference in sound quality. So you must learn your craft and work on it before declaring it a failure or success.
A higher quality semi-pro sound interface with a USB DAC and 4 outputs (like Focusrite 2i4) can be used with reasonably priced software like Jriver, to implement very complex IIR and FIR filters (even full convolution) and crossovers. Some people use powerful on-board PCIe interfaces with 8 outputs, etc. and have a field day with 4-way active speakers. miniDSP has a 2x8 also if you are interested - but cheaper to use dual 2x4's (not as convenient, but less expensive).
A higher quality semi-pro sound interface with a USB DAC and 4 outputs (like Focusrite 2i4) can be used with reasonably priced software like Jriver, to implement very complex IIR and FIR filters (even full convolution) and crossovers. Some people use powerful on-board PCIe interfaces with 8 outputs, etc. and have a field day with 4-way active speakers. miniDSP has a 2x8 also if you are interested - but cheaper to use dual 2x4's (not as convenient, but less expensive).
Last edited:
Hi XRK971,
I'm ashamed to say - I don't think I understood most of what you said.
Are you saying you can use a DSP instead of a fixed active crossover network + power supply etc (like the ESP one / Linkwitz-Riley)?
I actually do have two amps now... new DIY Q-Watt which should sound good up to 100 Watts and my old 60W Rotel RA-971 (class D) which has noticeably weaker bass and midrange.
So if there was an easy way to couple up both amps and configure a crossover filter with adjustable levels (to account for unknown driver sensitivity) then I would do it in a heartbeat. At least then if I can prototype the crossover I would know a) if it's worth grabbing out the soldering iron and b) if the spec Xover frequency sounds ok.
Pops.
I'm ashamed to say - I don't think I understood most of what you said.
Are you saying you can use a DSP instead of a fixed active crossover network + power supply etc (like the ESP one / Linkwitz-Riley)?
I actually do have two amps now... new DIY Q-Watt which should sound good up to 100 Watts and my old 60W Rotel RA-971 (class D) which has noticeably weaker bass and midrange.
So if there was an easy way to couple up both amps and configure a crossover filter with adjustable levels (to account for unknown driver sensitivity) then I would do it in a heartbeat. At least then if I can prototype the crossover I would know a) if it's worth grabbing out the soldering iron and b) if the spec Xover frequency sounds ok.
Pops.
Hi Pops,
If you have two pretty nice amps already, an extra $80 to $105 (not including shipping) plus a calibrated mic ($60 to $100) will do almost everything you need and it is EASY. Literally, change XO freq and slope and type (Butterworth, Bessel, Linkwitz Riley, custom) in seconds. Listen and measure, then tweak. You can achieve world class sound comparable to some of the best crossovers with hardly any money.
Check out the miniDSP 2x4 here:
miniDSP in a BOX : miniDSP 2x4
Read this quick intro to a DSP 2-way XO - look at the measured XO plot on the bottom - easy to achieve:
Stereo 2 Way Xover
Here is a thread showing how I made a 2-way speaker with a low 600Hz XO frequency. I now converted to a passive for the reasons above, but the DSP sounds great. When implemented as a quasi transient perfect Harsch, crossover - sounds superb:
10F/8424 & RS225-8 FAST Ref Monitor
Here is an example of a Butterworth 1st order XO that I inplemented:
Here is the transient perfect step response from above:
Same speaker but using Harsch XO:
The above two can be changed back and forth literally in 1 minute.
Resulting Freq Resp and HD plot:
So it is a great tool to test the XO, and then if you are a passive XO purist, try to implement passiely with coils and caps (which will cost more than the miniDSP in parts). But then is just a single amp and easy to use and reliable. So I also like passive XO's for that reason. But I arrive at the passive design with aid of the DSP active testing.
Unfortunately I don't know if this would improve your B&W DM602 2-way speakers. The chances are probably that it could, but it isn't certain, and depends on how well the current crossover works with them.
FWIW I tested my (DIY) speakers using software on a laptop to provide the crossover, and a surround-sound card to provide the outputs to some existing old hifi-amps. The software used is VB-Audio's VoiceMeeter Banana (which also serves as a mixer to manage inputs and outputs). JRiver also will do this, with a bit more control over the crossover, and probably other players too.
It was a little bit fiddly to get set up but very cheap, and I was extremely pleased with the results. In fact I have to admit that I'm still happily using it like this; my music is all stored as FLAC files these days so it is convenient, and I've not yet felt the need to build my own electronics.
About the only issue now is if I forget to switch the amps off before the laptop, theres a horrible and loud pop, but the tweeters are protected by capacitors so hopefully it sounds worse than it is. There was originally a problem with ground noise, but that was solved by using a laptop with an un-grounded low voltage supply. (Prior to that I tried a PC and internal sound card, but that was a disaster because the PC leaked noise into the card's analogue outputs).
Last edited:
Welcome to the 21st Century. There are fun toys and it's a good time to tinker with audio
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.