Always caps...
why everyone just worries about the input caps? the output filter ( mens, the inductors and caps) are much more critical to overall performance than the input caps.
They really do the hard job, bcc. the current there is a lot higher. I suggest modifications here. But be careful, otherwise u may damage speakers..............
why everyone just worries about the input caps? the output filter ( mens, the inductors and caps) are much more critical to overall performance than the input caps.
They really do the hard job, bcc. the current there is a lot higher. I suggest modifications here. But be careful, otherwise u may damage speakers..............
Tripath and other class D amps
the output filters used do not allow im most (=all) cases a linear frequency response especiallly in the higher treble range. we tested this, and in many cases also the losses in the inductors have been rather high, depending on the used core material, and the used wire diameters. Since 4 months I am working together with Arjen Helder, to fix all these problems, including others like power supply issues, etc. etc.
I must say here, I am an audio engineer since more than 35 years, and fortunately have equipment to test real thing, not depending on just a daily changing "ear-performance" by just listening to some sounds.
There are also protective diodes at the outputs, and as all people know, diodes can create switching noise. as you may see now, this is more complex, than just the input capacitors. and as the filter works against the speaker, all involved impedances change constantly, therefore the filter works never constant over the frequencies of music or so. here we have a complex situation as switching frequencies are high: around 700KHz to ~ 1MHz with all their harmonics reaching down into the audio frequencies.
Input:
a physically bigger input cap may tend to be microphonic, may catch more humm, EMI etc.
with the cap discussionthere is a lot of " what is a god brand, must sound good", and the believe acts like a medical placebo-effect..
peoples ears are just not reliable.
we try to do our best to find or design suitable components which are affordable. but the worl cannot be totally perfect..
as we do this in our off time, it may always take some time, and not always we can use our companies equipment for testing.
the output filters used do not allow im most (=all) cases a linear frequency response especiallly in the higher treble range. we tested this, and in many cases also the losses in the inductors have been rather high, depending on the used core material, and the used wire diameters. Since 4 months I am working together with Arjen Helder, to fix all these problems, including others like power supply issues, etc. etc.
I must say here, I am an audio engineer since more than 35 years, and fortunately have equipment to test real thing, not depending on just a daily changing "ear-performance" by just listening to some sounds.
There are also protective diodes at the outputs, and as all people know, diodes can create switching noise. as you may see now, this is more complex, than just the input capacitors. and as the filter works against the speaker, all involved impedances change constantly, therefore the filter works never constant over the frequencies of music or so. here we have a complex situation as switching frequencies are high: around 700KHz to ~ 1MHz with all their harmonics reaching down into the audio frequencies.
Input:
a physically bigger input cap may tend to be microphonic, may catch more humm, EMI etc.
with the cap discussionthere is a lot of " what is a god brand, must sound good", and the believe acts like a medical placebo-effect..
peoples ears are just not reliable.
we try to do our best to find or design suitable components which are affordable. but the worl cannot be totally perfect..
as we do this in our off time, it may always take some time, and not always we can use our companies equipment for testing.
Hi, I'm new here to this board. I've got two of the MkIII boards, one for me and one for a friend. I'm a jeweler by trade, thus technically minded and detail oriented, but certainly no electrical engineer, so please excuse any painfully basic questions. As these boards are not arriving with any sort of instructions, I'm grateful for the helpful info available here, Arjens input, as well as the participation of Tubesteve, as he seems to be doing some design work with Arjen. Stacy, through my Ebay communications, let me know he's been a lot busier lately with some new full-time employment.
Re: the MK III Yes, the green terminal is for AC. I'm curious about the AC volts I've heard mentioned in this thread, as Arjens response to me was thus....
I'm waiting to hear back from him why this board included this design feature and what are the relative benefits of either.
If someone here would answer what I'm sure is a very simple question about grounding, I've got my SMPS (from Arjen) wired with the third ground wire. From the PSI have the black and red wires going to my board Arjens response to this question was
My question is, Have I succeeded already? Does my black power line which runs to the V- on the PS, which is itself grounded by the third line in from the house socket, mean my board is now successfully grounded? Or do I need to do some additional wiring or magic? I don't really know yet how to confidently translate his words to physical wires/screws/holes/etc.
In a related concernI purchased a previews version board and after about 50 hours of use both on house currant and ultimately on a battery. After 15 hours on the battery out camping it died (with a bit of a toasted electric smell) After this incident, Arjen said these amps are sensitive to static electricity and grounding is therefore important. Does this work to some degree? My housing is glass with some steel. I asked about grounding when using a battery, he seemed to feel it not necessary to ground to earth while using a battery, but I forget if there was some recommendation to go to some amount of housing or metal. Do folks sometime ground to the metal housing being used? If so, would that be accomplished... by what, running a spur line off of the negative power line? Thanks for your patience and help.
Re: the MK III Yes, the green terminal is for AC. I'm curious about the AC volts I've heard mentioned in this thread, as Arjens response to me was thus....
I'm waiting to hear back from him why this board included this design feature and what are the relative benefits of either.
If someone here would answer what I'm sure is a very simple question about grounding, I've got my SMPS (from Arjen) wired with the third ground wire. From the PSI have the black and red wires going to my board Arjens response to this question was
My question is, Have I succeeded already? Does my black power line which runs to the V- on the PS, which is itself grounded by the third line in from the house socket, mean my board is now successfully grounded? Or do I need to do some additional wiring or magic? I don't really know yet how to confidently translate his words to physical wires/screws/holes/etc.
In a related concernI purchased a previews version board and after about 50 hours of use both on house currant and ultimately on a battery. After 15 hours on the battery out camping it died (with a bit of a toasted electric smell) After this incident, Arjen said these amps are sensitive to static electricity and grounding is therefore important. Does this work to some degree? My housing is glass with some steel. I asked about grounding when using a battery, he seemed to feel it not necessary to ground to earth while using a battery, but I forget if there was some recommendation to go to some amount of housing or metal. Do folks sometime ground to the metal housing being used? If so, would that be accomplished... by what, running a spur line off of the negative power line? Thanks for your patience and help.
Component upgrades
Re: originally posted by Tubesteve:
"we try to do our best to find or design suitable components which are affordable. but the worl cannot be totally perfect.."
From an affordable perspective, maybe you could share with us from your experience in the design of these amplifiers where improvements could be made?
Re: originally posted by Tubesteve:
"we try to do our best to find or design suitable components which are affordable. but the worl cannot be totally perfect.."
From an affordable perspective, maybe you could share with us from your experience in the design of these amplifiers where improvements could be made?
Hello: I bought the TA2020 6 channel board from Arjen with the 6 input capacitors modified for full range in August and am happy with it.
However, you are right - I do not have the equipment to test the sound and so cannot confirm exactly how good it is in a scientific manner. But if you can offer a clear upgrade in quality, confirmed by your equipment, let us know as I'm sure people would be interested. Also, because affordable is relative and you might want to consider offering different versions with different prices.
TA2020 Mk III modifications
Hey Mush
just wondering how you are going with your mod's? Did you swap the input caps? or did you do as 'tubesteve' advised and upgrade the output caps?
I have just purchased a Mk III to have a play with, I must say I was under the impression that the input caps were Mundorf, bit disappointed
I too will let them burn in and see how they sound.
cheers.. Steve
Hey Mush
just wondering how you are going with your mod's? Did you swap the input caps? or did you do as 'tubesteve' advised and upgrade the output caps?
I have just purchased a Mk III to have a play with, I must say I was under the impression that the input caps were Mundorf, bit disappointed
I too will let them burn in and see how they sound.
cheers.. Steve
volume pot ground
The input and amp ground need to be connected together in any fashion. There are better than other connections for this but any will do.
The input and amp ground need to be connected together in any fashion. There are better than other connections for this but any will do.
Output filter modifications?
Re: output filter caps, the web research that I have done appears to show that very little improvement in sound quality can be made by replacing the filter caps, however it appears that some fine tuning can be done by optimizing the values of the C14/C15 and C18/C19 (nom. 220n) capacitors to the speakers impedance.
It appears to me that the Helder 2020 MkIII has been optimized for 6ohm speakers (Argen /Tubesteve, you can correct me if I am wrong)
From what I have read it appears by lowering the capacitors value to 120n better suits an 8ohm speaker or raising to 47n for 4ohm speakers
I would be interested if anyone has tried swapping these caps and/or the 100nF cap across the output and hear about the results, and have the modifications done been worthwhile?
Re: output filter caps, the web research that I have done appears to show that very little improvement in sound quality can be made by replacing the filter caps, however it appears that some fine tuning can be done by optimizing the values of the C14/C15 and C18/C19 (nom. 220n) capacitors to the speakers impedance.
It appears to me that the Helder 2020 MkIII has been optimized for 6ohm speakers (Argen /Tubesteve, you can correct me if I am wrong)
From what I have read it appears by lowering the capacitors value to 120n better suits an 8ohm speaker or raising to 47n for 4ohm speakers
I would be interested if anyone has tried swapping these caps and/or the 100nF cap across the output and hear about the results, and have the modifications done been worthwhile?
output filters
dear audiO,
each filter works correctly to its calculated impedances ( in / out ) . a speaker has not a constant impedance over the frequency range, and its resonant frequency shifts with a housing. and: speakers with a crossover network show even more complex behaviour. to be accurate, the filter in the output of the 2020 or others work best , but not perfect, for the calculated and then tested resistance and also type speaker.
therefore these filters and snubbers have a difficult task to fulfill, and any modification done, applies only for that load only, the modification has been done, to be correct. the filters in the amps must always be a compromise,
as also your speaker cable resistance, length changes the situation.
dear audiO,
each filter works correctly to its calculated impedances ( in / out ) . a speaker has not a constant impedance over the frequency range, and its resonant frequency shifts with a housing. and: speakers with a crossover network show even more complex behaviour. to be accurate, the filter in the output of the 2020 or others work best , but not perfect, for the calculated and then tested resistance and also type speaker.
therefore these filters and snubbers have a difficult task to fulfill, and any modification done, applies only for that load only, the modification has been done, to be correct. the filters in the amps must always be a compromise,
as also your speaker cable resistance, length changes the situation.
caps filters etc.
dear audio,
a you probably may guess, we are here inchina, shenzhen. i am here since 11 years. since this time i am are struggling with quality of products or with copied products or components ( = worse performance or failure ). so, as you may understand, its not easy to find reliable suppliers which not cheat, especially if the amount is low, lower than 1000000 pieces.... i am dealing everyday with this.
your 6 ohm story looks correct, its in the middle of 4 and 8 ohm. if you want change that, keep in mind that a speakers resistance in all cases increases with frequency until a certain point ( most over 20KHz). i am looking for the nobel price to invent an frequency flexible filter with constant impedance.
have a nice day!
dear audio,
a you probably may guess, we are here inchina, shenzhen. i am here since 11 years. since this time i am are struggling with quality of products or with copied products or components ( = worse performance or failure ). so, as you may understand, its not easy to find reliable suppliers which not cheat, especially if the amount is low, lower than 1000000 pieces.... i am dealing everyday with this.
your 6 ohm story looks correct, its in the middle of 4 and 8 ohm. if you want change that, keep in mind that a speakers resistance in all cases increases with frequency until a certain point ( most over 20KHz). i am looking for the nobel price to invent an frequency flexible filter with constant impedance.
have a nice day!
Filter caps
Thank's for your honesty, actually I think most of us knew that there was a quality problem with Chinese components!
I am unsure at the moment if I will change the filter, I am working from the other end at the moment replacing the input caps with Auricaps. I would like to know of other peoples experiences with filter changes before I jump in!
Thank's for your honesty, actually I think most of us knew that there was a quality problem with Chinese components!
I am unsure at the moment if I will change the filter, I am working from the other end at the moment replacing the input caps with Auricaps. I would like to know of other peoples experiences with filter changes before I jump in!
Update
Audiosteve: I just read your latest post in the "Audiophiler Capacitor" forum;
"i again want to point out again, that the output snubber filter components, here in digital amplificationare for me much more imprortant bcc. they form together with the speakers EMF a complex load, which have more effect on the sound."
I think I have made up my mind with what I am going to do!
Audiosteve: I just read your latest post in the "Audiophiler Capacitor" forum;
"i again want to point out again, that the output snubber filter components, here in digital amplificationare for me much more imprortant bcc. they form together with the speakers EMF a complex load, which have more effect on the sound."
I think I have made up my mind with what I am going to do!
filters
Hi tubesteve,
I am looking at Autocostruire T-Induttanze-Litz, (Autocostruire il negozio degli autocostruttori) do you think these are a good choice?
Hi tubesteve,
I am looking at Autocostruire T-Induttanze-Litz, (Autocostruire il negozio degli autocostruttori) do you think these are a good choice?
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