When I bought my first UcD180... I mailed Jan Peter and asked him why it was rolled off in the high frequency area...
After a while I got used to the lack of distortion🙂
If I compare it now to my Bob Carver Sunfie amp, the differance in the high freq. area is not musik, just distortion...
Hopefully my UcD400 will be equally good in this area...
Regards
/Stefan
After a while I got used to the lack of distortion🙂
If I compare it now to my Bob Carver Sunfie amp, the differance in the high freq. area is not musik, just distortion...
Hopefully my UcD400 will be equally good in this area...
Regards
/Stefan
Well as my boss said a couple of weeks ago when we discussed the next generation of pwm amplifier:
If you can, reduce the distortion, but please don't if it will destroy the good sound 😀
On one hand i don't really understand the obsession about THD measurement. On the other hand of course to write it off completely as a feedback for amplifier constructors, is a big step, even for me. But really THD and sound quality has no correllation what so ever.
I realize this a highly controversioal claim, but really i check every time i read a test, to see if the description of the sound can be traced to any characteristics in the THD measurements. It can't!
This is not a claim only on my behalf, you can assure yourself about this fact by opening any hifi magazine that does THD measurements.
Low THD : good sound
High THD : good sound
Even order THD : good sound
Odd order THD : good sound
High order THD : good or bad sound
Evenly rolling off THD : even better sound
Two amplifiers with the almost same THD structure: totally different sound composition.
THD is simply not a very good model for sound quality, even if i must admit i can not point to any other measurement that is a good model.
Another backup for my claim is that your AP will have a hard time measuring the difference in THD of a Black Gate or tantalum capacitor against a cheap chinese electrolytic cap. Even so i think everyone here would agree with me that the two sides will sound very different. 😉
My experience show that other rules work stronger for the music quality:
If an amplifier has a low delay in the feedback loop or has no feedback loop at all, it will have a natural and open sound. The more time delay you try to do feedback on, the more coloration of the top.
The more any treble signal, cimbales, high hats, percussions etc will sound the same.
This i have on contrary to the THD measurements confirmed many many uniform examples of. PWM, class A or Class A/B doesn't matter.
Even if some recordings must sound like a glass crystal in the high end, natural fidelity dictates that other recordings should not. But every recording should sound like they were intended by the artist, and nothing else. I think this can actually be easier achieved with 2% of THD than 0.002%. But this is only my opinion.
Another characteristic that can be confirmed every time you analyze the sound quality of a given amplifier against it's topology is that the more the feedback loop can react to the load of the speaker, (or can 'see' the speaker load) the weaker the bass will be.
Now the last two rules deals not with THD measurements but with the dynamics of the amplifier. Whether these two rules can be the cause of the problem in the bass area or not i will of course not make speculation about at this point.
I guess some people wonder why i would be so dim as to accredit the competing product. Well the answer to that is that i have a very fatalistic view of competition. I believe there is a place for everyone who cares to spend time to make stuff to sell. If they can really make a better product than mine in every aspect, they deserve to win the market. But i really don't believe it will come to that 😉
Products are different, and will appeal to different people. Every producer has up's and down's and many give up when they run into problems. Right now there are more than 20 producers of PWM modules on the market. I think most of them will be gone in 2-3 years. However i also think the the UCD400 is one project that deserves special attention. So far i have a very good impression of the quality, especially considering a low price.
Good luck Jan-Peter and Bruno 🙂
LC
If you can, reduce the distortion, but please don't if it will destroy the good sound 😀
On one hand i don't really understand the obsession about THD measurement. On the other hand of course to write it off completely as a feedback for amplifier constructors, is a big step, even for me. But really THD and sound quality has no correllation what so ever.
I realize this a highly controversioal claim, but really i check every time i read a test, to see if the description of the sound can be traced to any characteristics in the THD measurements. It can't!
This is not a claim only on my behalf, you can assure yourself about this fact by opening any hifi magazine that does THD measurements.
Low THD : good sound
High THD : good sound
Even order THD : good sound
Odd order THD : good sound
High order THD : good or bad sound
Evenly rolling off THD : even better sound
Two amplifiers with the almost same THD structure: totally different sound composition.
THD is simply not a very good model for sound quality, even if i must admit i can not point to any other measurement that is a good model.
Another backup for my claim is that your AP will have a hard time measuring the difference in THD of a Black Gate or tantalum capacitor against a cheap chinese electrolytic cap. Even so i think everyone here would agree with me that the two sides will sound very different. 😉
My experience show that other rules work stronger for the music quality:
If an amplifier has a low delay in the feedback loop or has no feedback loop at all, it will have a natural and open sound. The more time delay you try to do feedback on, the more coloration of the top.
The more any treble signal, cimbales, high hats, percussions etc will sound the same.
This i have on contrary to the THD measurements confirmed many many uniform examples of. PWM, class A or Class A/B doesn't matter.
Even if some recordings must sound like a glass crystal in the high end, natural fidelity dictates that other recordings should not. But every recording should sound like they were intended by the artist, and nothing else. I think this can actually be easier achieved with 2% of THD than 0.002%. But this is only my opinion.
Another characteristic that can be confirmed every time you analyze the sound quality of a given amplifier against it's topology is that the more the feedback loop can react to the load of the speaker, (or can 'see' the speaker load) the weaker the bass will be.
Now the last two rules deals not with THD measurements but with the dynamics of the amplifier. Whether these two rules can be the cause of the problem in the bass area or not i will of course not make speculation about at this point.
I guess some people wonder why i would be so dim as to accredit the competing product. Well the answer to that is that i have a very fatalistic view of competition. I believe there is a place for everyone who cares to spend time to make stuff to sell. If they can really make a better product than mine in every aspect, they deserve to win the market. But i really don't believe it will come to that 😉
Products are different, and will appeal to different people. Every producer has up's and down's and many give up when they run into problems. Right now there are more than 20 producers of PWM modules on the market. I think most of them will be gone in 2-3 years. However i also think the the UCD400 is one project that deserves special attention. So far i have a very good impression of the quality, especially considering a low price.
Good luck Jan-Peter and Bruno 🙂
LC
I think that whilst the effects of distortion can be variable and controversial, it's hard to argue that a good amp should be anything other than a "straight wire with some gain".
Distortion is unlikely to be a beneficial thing in general, which is not to say that amps with distortion can't still sound good. (just don't design to deliberately add it in). The ear is also strangely sensitive to some distortion and not to other types. Curious
As for price, well to me, the end user, the UCD400 with the op amp upgrade is 130 Euros + postage + taxes this comes to around 180 euros each for a stereo amp - which is the same as the SE version of the LCAudio module. However, LCAudio will warranty all modules and replace them as often as required (which in my case has proved quite useful since being "all thumbs" I have actually blown up two of them... Kindly replaced each time by Lars next day...)
I have only built two stereo zappulse amps and a single stereo UCD amp. My first impressions of each though are that the Zappulse has a more solid sounding bass which takes my little Proac 1.5 speakers down to the kind of level that I previous used to require a Rel Stadium II sub to achieve... However, the UCD seems to have a slightly sweeter and more detailed treble
The Zappulse seems to have a solid build quality, but from experience I also know that they are easy to blow up if you aren't careful. It's easy to screw into the case as well. The UCD is nice in that it has plug connectors rather than solder connectors, but it's a little harder to install in a case.
I will continue to swap the UCD and Zappulse around on my main speakers, and I still have some more UCD modules to build, but at the moment the UCD have migrated to become the amp on my main speakers and the Zappulse are on the stereo IB sub woofers
*With a decent powersupply* both of these designs are excellent and a good match for my commercial Meridian 557 power amp.
Good luck Jan-Peter and Lars!
Ed W
Distortion is unlikely to be a beneficial thing in general, which is not to say that amps with distortion can't still sound good. (just don't design to deliberately add it in). The ear is also strangely sensitive to some distortion and not to other types. Curious
As for price, well to me, the end user, the UCD400 with the op amp upgrade is 130 Euros + postage + taxes this comes to around 180 euros each for a stereo amp - which is the same as the SE version of the LCAudio module. However, LCAudio will warranty all modules and replace them as often as required (which in my case has proved quite useful since being "all thumbs" I have actually blown up two of them... Kindly replaced each time by Lars next day...)
I have only built two stereo zappulse amps and a single stereo UCD amp. My first impressions of each though are that the Zappulse has a more solid sounding bass which takes my little Proac 1.5 speakers down to the kind of level that I previous used to require a Rel Stadium II sub to achieve... However, the UCD seems to have a slightly sweeter and more detailed treble
The Zappulse seems to have a solid build quality, but from experience I also know that they are easy to blow up if you aren't careful. It's easy to screw into the case as well. The UCD is nice in that it has plug connectors rather than solder connectors, but it's a little harder to install in a case.
I will continue to swap the UCD and Zappulse around on my main speakers, and I still have some more UCD modules to build, but at the moment the UCD have migrated to become the amp on my main speakers and the Zappulse are on the stereo IB sub woofers
*With a decent powersupply* both of these designs are excellent and a good match for my commercial Meridian 557 power amp.
Good luck Jan-Peter and Lars!
Ed W
I just put power to my new UcD400...
No explosion
No hum...
Nothing but great sound!
🙂 🙂 🙂
I had some problems with hum with the Ucd180... Now I will make 3 more identical casings as for this Ucd400 and do all the wireing exactly as this one...
Soon I will have my quad-amped 3-way system running on UcD's only
/Stefan
No explosion
No hum...
Nothing but great sound!
🙂 🙂 🙂
I had some problems with hum with the Ucd180... Now I will make 3 more identical casings as for this Ucd400 and do all the wireing exactly as this one...
Soon I will have my quad-amped 3-way system running on UcD's only
/Stefan
Thought I provide a link to photos of my UcD400 mono blocks for whoever is interested. Today I made the PCB's for the capacitor banks.
http://members.optusnet.com.au/myamp
http://members.optusnet.com.au/myamp
Measuring an amp's "goodness"
How very, very true Ewildgoose ! To be even more precise, a perfect amp would be a perfect voltage amplifier, with infinite input impedance and zero output impedance!
Sorry if this is off topic and forgive my ignorance, but I wonder why nobody seems to have managed to come up with a simple measurement of an amp's "goodness"?
Ok, obviously a near-zero THD curve alone is insufficient, as both amplitude and delay of the fundamental could vary wildly across the bandwidth without this showing at all! Eg a perfect buffered LC filter with a huge resonance at 1kHz would have zero THD but it wouldn't be a good amp at all 🙂
However, it seems to me that the combination of zero THD plus rigorously flat amplitude and delay (not phase!) responses, both across the full bandwidth, would leave little room to audible imperfections, especially if they were measured both at maximum rated output voltage and on a particularly difficult load such as an electrostatic loudspeaker. Mmmm... as I am writing this I realize such measurements wouldn't tell how the amp behaves when fed with several simultaneous frequencies... maybe they should be completed with an impulse response measurement. An impulse contains all frequencies simultaneously at equal amplitudes if my memory doesn't fail me.
Or maybe one could simply measure the rms error between the amp's output (on an agreed upon difficult load) and an agreed upon sequence of actual audio samples played on its input, normalized to peak at the amp's rated output voltage. Best fit gain and delay would have to be removed before measuring the rms error wrt the input signal of course. Closest to zero wins.
Being a cartesian type and relatively new to this audiophile world I am probably oversimplifying, but I like to think a physical measurement of an amp's (or any audio element's for that matter) "goodness" could be agreed upon some day, maybe even in the form of a single number. A measurement which wouldn't be denied by audiophile listening tests of course, one can always dream can't one?
Comments/enlightenings welcome!
Cheers,
ewildgoose said:
How very, very true Ewildgoose ! To be even more precise, a perfect amp would be a perfect voltage amplifier, with infinite input impedance and zero output impedance!
Sorry if this is off topic and forgive my ignorance, but I wonder why nobody seems to have managed to come up with a simple measurement of an amp's "goodness"?
Ok, obviously a near-zero THD curve alone is insufficient, as both amplitude and delay of the fundamental could vary wildly across the bandwidth without this showing at all! Eg a perfect buffered LC filter with a huge resonance at 1kHz would have zero THD but it wouldn't be a good amp at all 🙂
However, it seems to me that the combination of zero THD plus rigorously flat amplitude and delay (not phase!) responses, both across the full bandwidth, would leave little room to audible imperfections, especially if they were measured both at maximum rated output voltage and on a particularly difficult load such as an electrostatic loudspeaker. Mmmm... as I am writing this I realize such measurements wouldn't tell how the amp behaves when fed with several simultaneous frequencies... maybe they should be completed with an impulse response measurement. An impulse contains all frequencies simultaneously at equal amplitudes if my memory doesn't fail me.
Or maybe one could simply measure the rms error between the amp's output (on an agreed upon difficult load) and an agreed upon sequence of actual audio samples played on its input, normalized to peak at the amp's rated output voltage. Best fit gain and delay would have to be removed before measuring the rms error wrt the input signal of course. Closest to zero wins.
Being a cartesian type and relatively new to this audiophile world I am probably oversimplifying, but I like to think a physical measurement of an amp's (or any audio element's for that matter) "goodness" could be agreed upon some day, maybe even in the form of a single number. A measurement which wouldn't be denied by audiophile listening tests of course, one can always dream can't one?
Comments/enlightenings welcome!
Cheers,
Golgoth: You are right in theory. In practical life things are different though.
You can not get a perfect component. That is one problem. Every component of the amplifier has small unlinearities. And you can not connect them together in a perfect way. Sorry that's just the way it is.
So the problem is that when the constructor is hunting for a low THD he will often destroy the amplifier's ability to pass musical details.
That is why i think it is easier to make a good natural sound with 2% of THD than 0.002%.
If THD, flat delay and amplitude were the key issues, like you propose, there would only be one brand of amplifiers in the world. Technics. They have always been the masters of making low THD, wide bandwidth amplifiers with a beautiful build quality and low price. No one can compete with that. As you know there are many other brands on the market, and some of them even sound better than Technics, and can carry a much higher price tag.
So from that i think we can conclude that low THD, flat delay and amplitude are NOT key parameters for a good sounding amplifier.
Finally i must say one of the best sounding systems i have heard to this day was the Audio Note 7W triode monoblocks, and they added at least 2-3% THD. With a price tag of well above 5000 US per channel and a estimated lifespan (my estimate) of a couple of years until tubes need changing, they still sell.
But i agree with you it would be really really nice if someone could come up with a useable quantization capable and reliable measurement for an amplifiers 'goodness'. But maybe that is just as hard as measuring how good food taste, or how good perfume smell. I guess it would also depend on which woman it was to be demonstrated 😀
You can not get a perfect component. That is one problem. Every component of the amplifier has small unlinearities. And you can not connect them together in a perfect way. Sorry that's just the way it is.
So the problem is that when the constructor is hunting for a low THD he will often destroy the amplifier's ability to pass musical details.
That is why i think it is easier to make a good natural sound with 2% of THD than 0.002%.
If THD, flat delay and amplitude were the key issues, like you propose, there would only be one brand of amplifiers in the world. Technics. They have always been the masters of making low THD, wide bandwidth amplifiers with a beautiful build quality and low price. No one can compete with that. As you know there are many other brands on the market, and some of them even sound better than Technics, and can carry a much higher price tag.
So from that i think we can conclude that low THD, flat delay and amplitude are NOT key parameters for a good sounding amplifier.
Finally i must say one of the best sounding systems i have heard to this day was the Audio Note 7W triode monoblocks, and they added at least 2-3% THD. With a price tag of well above 5000 US per channel and a estimated lifespan (my estimate) of a couple of years until tubes need changing, they still sell.
But i agree with you it would be really really nice if someone could come up with a useable quantization capable and reliable measurement for an amplifiers 'goodness'. But maybe that is just as hard as measuring how good food taste, or how good perfume smell. I guess it would also depend on which woman it was to be demonstrated 😀
Lars Clausen said:
Indeed! I did read of one study where amplifiers with silver cases were found to sound better than those with black cases...
Presumably, as you say, the amp with the most impressive box, lights and dolly girls/boys will have the best rating if it's not a carefully blind test.
For examples of good testing though, we can look to the Disney Imagineers, and places like the BBC (when they are interviewing for equipment) for examples of how to do it right. There a number of places like those above who will employ trained listeners and rigorous (blind) testing methodolgy to purchase equipment meeting their specification.
In particular I have read some quotes from a Disney Imagineer (sp?) offering critique of home hifi equipment - very interesting stuff.
Edit: PS. I forgot to mention one of the most desirable features of the UCD vs the Zappulse: the UCD is incredibly silent at "idle", whereas the Zappulse has a fair bit of the usual amplifier hiss. Now this would be a very interesting thing for you to try to eliminate from the the Zappulse 3....
Ed: You are very right about the hiss. This is on top of my list.
In our case the hiss originates from the high values of input resistors coupling to the bipolar input of the LM6172. So it might not be so difficult to eliminate the hiss in the new generation but maybe even on the existing ZAPpulse's. (With a small modification).
I have tried a T network feedback, and it works fine on the ZAPpulse. However i did not measure the background noise in that test
silly i am!
It did appear thouigh that the T network suppressed some of the ZAPpulse's musicality. So i will have to investigate carefully before implementing the T network solution.
In our case the hiss originates from the high values of input resistors coupling to the bipolar input of the LM6172. So it might not be so difficult to eliminate the hiss in the new generation but maybe even on the existing ZAPpulse's. (With a small modification).
I have tried a T network feedback, and it works fine on the ZAPpulse. However i did not measure the background noise in that test
silly i am!It did appear thouigh that the T network suppressed some of the ZAPpulse's musicality. So i will have to investigate carefully before implementing the T network solution.
Lars Clausen said:
If by "good" you mean "pleasing to the ear", like a distorted guitar may please the ear, that's fine with me. However if by "good" you mean faithful as in High Fidelity, you'll find it hard to convince me that high distortion is better than low 🙂
I will gladly admit, as I said in my previous post, that low THD+N vs f and flat gain and delay vs f are only part of the picture, but not that they are irrelevant to Fidelity. Of course they should be measured at realistic output power on a realistic load to be really relevant.
Now what about my suggestion of measuring fidelity to some reference real-life audio sequence on a reference and preferably difficult load, anything wrong with that, except maybe the difficulty of agreing upon the reference signal and load?
ewildgoose said:
Indeed an audible hiss would lower the correlation of the output voltage with the reference signal, which would lower my Fidelity mark!
Cheers,
Michel: Of course i don't mean that every sound should be distorted so it sounds like slipknot.
Just to repeat my definition of good audio quality (from a few posts ago) :
Every recording should sound like they were intended by the artist, and nothing else.
I don't claim that high distortion is better than low. I claim that THD (reasonable level or structure) has nothing to do with how it sounds. And getting to a good sound quality is easier with a high distortion than an extremely low distortion. Again to repeat myself, because the dynamics of the amplifier is often ruined in the hunt for lower THD.
It's not the same 😉
Just to repeat my definition of good audio quality (from a few posts ago) :
Every recording should sound like they were intended by the artist, and nothing else.
I don't claim that high distortion is better than low. I claim that THD (reasonable level or structure) has nothing to do with how it sounds. And getting to a good sound quality is easier with a high distortion than an extremely low distortion. Again to repeat myself, because the dynamics of the amplifier is often ruined in the hunt for lower THD.
It's not the same 😉
Lars Clausen said:
I would correct the above as follows:
Every recording should sound like it is, and nothing else
However difficult it may be to design an amp (your point about it being unwise to compromise dynamics for THD is taken), at the end of the day it should simply do its menial job of reproducing a real-life audio signal as faithfully as possible, as no piece of equipment can be held liable for the artist's intentions right ? 😉
That's why I think an amp's fidelity could perhaps be quantified by measuring the overall rms difference between the de-gained and de-delayed output signal and a real-life reference input signal. An obvious improvement to a simple subtraction would be to take both signals through the human ear response first, so discrepancies at 20Hz or 20kHz would count less than at 1kHz. Such a scheme would certainly need more refinements and would not be easy, but I don't see any fundamental reason why it couldn't work just as well as Disney or BBC listeners (which doesn't mean there aren't any 🙂 )
Cheers,
Dear Lars,
Your earlier comments on Jan-Peter's UCD400 certainly impress me! I think not many designer will give credit to a competitor's product and admit some inherit problem "the hissing problem" in their design ..... a very honourable man indeed!
May I clarify with what you had said earlier ..... "Another characteristic that can be confirmed every time you analyze the sound quality of a given amplifier against it's topology is that the more the feedback loop can react to the load of the speaker, (or can 'see' the speaker load) the weaker the bass will be. "
.... May I know what do you really mean by "the more the feedback loop can react to the load of the speaker (or can 'see' the speaker load) the weaker the bass will be" ... are you referring to the higher the feedback loop, the weaker the bass? Can you elaborate a bit more on what you had said 😀
I am actually planning on building a ZAPpulse amp, in view of the great bass character it produces. May I know if you are planning for a higher wattage design in your up and coming design? Pls. include me in your mail order!
Many Thanks,
YC
Your earlier comments on Jan-Peter's UCD400 certainly impress me! I think not many designer will give credit to a competitor's product and admit some inherit problem "the hissing problem" in their design ..... a very honourable man indeed!
May I clarify with what you had said earlier ..... "Another characteristic that can be confirmed every time you analyze the sound quality of a given amplifier against it's topology is that the more the feedback loop can react to the load of the speaker, (or can 'see' the speaker load) the weaker the bass will be. "
.... May I know what do you really mean by "the more the feedback loop can react to the load of the speaker (or can 'see' the speaker load) the weaker the bass will be" ... are you referring to the higher the feedback loop, the weaker the bass? Can you elaborate a bit more on what you had said 😀
I am actually planning on building a ZAPpulse amp, in view of the great bass character it produces. May I know if you are planning for a higher wattage design in your up and coming design? Pls. include me in your mail order!
Many Thanks,
YC
CheerfulYC: I would certainly like to, however i think the discussion is already moving too far away from the intended content, so maybe it's better to start a new thread about this subject instead of here ??
😉 Lars
😉 Lars
Jan-Peter said:
I've spent some time investigating this now. After my initial test promising goods results, it's been downhill from there I'm afraid. The interference (and disturbance to the TV) occurs usually sometime after power-up. And on one module it doesn't happen at all. If I look at the speaker output on a scope I see I nice looking sine-wave at 400->408kHZ ( +-500mv). While it is looking nice I don't get any interference. But after a while the sine-wave gets some high-frequence crap in it just while it's zero-crossing. When this occurs that is also when the interference is apparent. I can stick ferrite shields on all the way up the cable and it doesn't make any difference; and I can pull the speaker cable out of the module and it doesn't make a difference.
Unfortunately I blew up the module that didn't have any interference problem while I was pulling the cable around and slotting in through ferrite beeds the speaker cable touched I think one of the TO-220 devices on the module. And it would have had some DC voltage (but the /ON signal was off(high)). On this module the voltage on the cables just sits at 0.7V. (with no 400kHz sine wave).
Jan, can you offer any more suggestions ?
FransDHT said:
My receiver is a Sony DA50ES. It's not a current model so I just checked the manual to see what is's power rating is. It is 120W at 8ohm and it says it 100W at 4ohm. That 4ohm rating sounds a little odd so maybe the manual is wrong as I would have thought the 4ohm rating would be higher.
I also blew one of my five UcD400's this weekend. I had the top (perforated steel) lying loose on top of the amplifier. I switched the power on (only AC, not /ON) and there were a lot of sparks. I switched it off and took the top off (I don't remember which one first). I switched it on again and things seemed right. (I probably should'nt have done that). So I switched /ON on and started to calibrate the balance of the 5 channels. After a short while (1 minute or so) one speakert started to plop and make odd sounds, so I switched the amp back off.
The speaker still functions, I tried it with another amp, but I looked a bit closer at the UcD400 and saw that a few parts had died.
I don't know what caused this, maybe the steel cover touched the side of the (vertically screwed) UcD400, but why should that cause this problems?
I have contacted JP to see what can be done (repairs?). Luckily I live in Groningen where the factory is.
Frans
PS
Chrisb03: looks fine to me. The only thing: the IEC->softstart->rectifiers->caps road is quite long.
The speaker still functions, I tried it with another amp, but I looked a bit closer at the UcD400 and saw that a few parts had died.
I don't know what caused this, maybe the steel cover touched the side of the (vertically screwed) UcD400, but why should that cause this problems?
I have contacted JP to see what can be done (repairs?). Luckily I live in Groningen where the factory is.
Frans
PS
Chrisb03: looks fine to me. The only thing: the IEC->softstart->rectifiers->caps road is quite long.
chrisb03 said:
Nice layout, takes good care of UcD and rectifier cooling (don't forget vent holes for output inductor cooling though). Also having your UcDs horizontal allows you to mount them 1cm above ground plane, which reduces EMI.
My 2 cents:
1/ Fuses are missing.
2/ Since you go monoblock why not have separate cases? Advantages:
- even lower crosstalk
- each amp can be close to speaker (long IC and short speaker cable has been stated by Bruno to be better than the opposite)
- you might be able to do without a softstart, depending on transformer VAs and capacitor µFs
- More versatile
3/ Also you could consider drawing wires on your layout, so it shows arrangements such as star ground, case grounding, and case earthing (connection to mains earth wire, which may not be a good idea according to Bruno), which are relevant to audio quality.
You shouldn't need two softstart modules I think? One should be sufficient?
Have you also checked that your torroids don't hum? ie you don't need a DC filter in there.
I also built a similar layout to you, but with only one transformer (pictures elsewhere in this thread). I found there was enough space in a 2U case to put the speaker plugs vertically, which keeps them a fraction further away from the input wires
Have you also checked that your torroids don't hum? ie you don't need a DC filter in there.
I also built a similar layout to you, but with only one transformer (pictures elsewhere in this thread). I found there was enough space in a 2U case to put the speaker plugs vertically, which keeps them a fraction further away from the input wires
Golgoth said:
Thanks for the replys
1. Fuse is built in IEC socket.
2. I'm from Australia, and I can't find enclosures. I was going to build two mono cases myself but I have a busy lifestyle and descided to give it a miss. Today I found a case, I just uploaded a pic sent by the supplier to on my web site. My transformers are 500VA each and I have 27200uF per voltage rail.
3. I'll draw some wires as soon as I can.
I have a question.
Does the UcD400 heat sink need to be electrically insulated from case heatsink? I will be connecting the mains ground to the case and also the magnetic shield fitted on transformers to case.
Chris