Hi
I did read somes of the messages about relation between distortions and sound quality, it was very interesting.
Since some years, after reading J. Hiraga and somes other ones articles and doing tests using my old HP333A on power amps that I did have since years (my last one was a Crimson 60w amp), I'm not a power amp geek but here's what I think a nice sounding power amp should have;
Good open loop gain at high frequency
No need of a hot-rod slew rate, 10 to 20 v us are sufficient
Low rise of distortion at high frequency, so it have quite same distortion from 20 hz to 20K hz
Low rise of distortion at very low power output (.1 w)
Odd harmonics distortions are not good
Low phase distortion, about phase distortion; to much of phase distortion and the negative feedback will not work good.
Tell me where I'm right and where I'm wrong.
Thank
Gaetan
I did read somes of the messages about relation between distortions and sound quality, it was very interesting.
Since some years, after reading J. Hiraga and somes other ones articles and doing tests using my old HP333A on power amps that I did have since years (my last one was a Crimson 60w amp), I'm not a power amp geek but here's what I think a nice sounding power amp should have;
Good open loop gain at high frequency
No need of a hot-rod slew rate, 10 to 20 v us are sufficient
Low rise of distortion at high frequency, so it have quite same distortion from 20 hz to 20K hz
Low rise of distortion at very low power output (.1 w)
Odd harmonics distortions are not good
Low phase distortion, about phase distortion; to much of phase distortion and the negative feedback will not work good.
Tell me where I'm right and where I'm wrong.
Thank
Gaetan
generally, your assumptions are correct.
however even with well designed amps, it is extremely difficult to escape the fact that there is transit time (and so some high frequency phase shift) in any power amp design. output devices have the largest input capacitances, and so introduce the most transit time.
however even with well designed amps, it is extremely difficult to escape the fact that there is transit time (and so some high frequency phase shift) in any power amp design. output devices have the largest input capacitances, and so introduce the most transit time.
Hi Gaetan
Right your opinions. The subject consequently is not if you have error, it is if you omit something. Already uncleJed pointed out something right. I receive very seriously under aspect the Transient Response of an amplifier because under today conditions it is very difficult you will meet a circuit with unacceptable THD+Noise or bad frequency response. The examination of an amplifier by injecting square waves of different frequencies in his input and the observation of his output with or without load by oscilloscope it provides optical information beforehand audition tests. Four very important measurements are the following: 1) Under a square wave of 10KHz we observe the output if it exists bounce or oscillations in the rising edge of pulse. If it is so, then the Miller capacitance – which it accompanies each common emitter arrangement - of the Voltage Amplifier stage it is not completely compensated. The Miller pole compensation it is a main nested feedback loop into the whole closed feedback loop. Its complete compensation it is against the response in higher frequencies. 2) Again under a square wave of 10KHz we measure the Rise Time of the pulse in output. An amplifier with good response in mid - high frequencies should not have a Rise Time more than 2ìsec. There is an indirect calculation method of the frequency response in KHz by dividing the number 300 with the measured Rise Time. Thus for 2ìsec Rise Time we have: 300 / 2 = 150 KHz. 3) Again under a square wave of 10KHz we observe the increase of Rise Time by connecting a 8Ù dummy load in output. A good amplifier with good power supply should not show increase of Rise Time more than 5 percent. An acceptable increase is for example from 2ìsec without load to 2,1ìsec with load. 4) Under a square wave of 100Hz we observe the output. The tilt of the duty cycle of pulse it gives very useful information of response in low frequencies, and with other words the force of amplifier to manage the bass assault during audition tests. As long as smaller it is the tilt (a few milliVolts difference between the leading edge and the trailing edge of pulse) so much better control has the amplifier in low frequencies. If indeed the amplifier bears in square wave of 20Hz without it burns fuses or activate the protection circuit, we check how many is increased the tilt of duty cycle from 100Hz to 20Hz. As long as smaller it is the increase so much higher Dumping Factor has the amplifier. Furthermore one useful information which given by the shape of tilt if it is curved and not straight, means that the feedback loop has no good coupling in low frequencies. Summarising, this type of measurements can substitute the measurements with an RTA under the condition that we know to interpret what we see in oscilloscope. Also it should they become even if we have a RTA as this gives an average graph, while with them we examine in concrete and critical frequencies the reaction of an amplifier. Consequently they are more near with audition tests in practice.
Regards
Fotios
Right your opinions. The subject consequently is not if you have error, it is if you omit something. Already uncleJed pointed out something right. I receive very seriously under aspect the Transient Response of an amplifier because under today conditions it is very difficult you will meet a circuit with unacceptable THD+Noise or bad frequency response. The examination of an amplifier by injecting square waves of different frequencies in his input and the observation of his output with or without load by oscilloscope it provides optical information beforehand audition tests. Four very important measurements are the following: 1) Under a square wave of 10KHz we observe the output if it exists bounce or oscillations in the rising edge of pulse. If it is so, then the Miller capacitance – which it accompanies each common emitter arrangement - of the Voltage Amplifier stage it is not completely compensated. The Miller pole compensation it is a main nested feedback loop into the whole closed feedback loop. Its complete compensation it is against the response in higher frequencies. 2) Again under a square wave of 10KHz we measure the Rise Time of the pulse in output. An amplifier with good response in mid - high frequencies should not have a Rise Time more than 2ìsec. There is an indirect calculation method of the frequency response in KHz by dividing the number 300 with the measured Rise Time. Thus for 2ìsec Rise Time we have: 300 / 2 = 150 KHz. 3) Again under a square wave of 10KHz we observe the increase of Rise Time by connecting a 8Ù dummy load in output. A good amplifier with good power supply should not show increase of Rise Time more than 5 percent. An acceptable increase is for example from 2ìsec without load to 2,1ìsec with load. 4) Under a square wave of 100Hz we observe the output. The tilt of the duty cycle of pulse it gives very useful information of response in low frequencies, and with other words the force of amplifier to manage the bass assault during audition tests. As long as smaller it is the tilt (a few milliVolts difference between the leading edge and the trailing edge of pulse) so much better control has the amplifier in low frequencies. If indeed the amplifier bears in square wave of 20Hz without it burns fuses or activate the protection circuit, we check how many is increased the tilt of duty cycle from 100Hz to 20Hz. As long as smaller it is the increase so much higher Dumping Factor has the amplifier. Furthermore one useful information which given by the shape of tilt if it is curved and not straight, means that the feedback loop has no good coupling in low frequencies. Summarising, this type of measurements can substitute the measurements with an RTA under the condition that we know to interpret what we see in oscilloscope. Also it should they become even if we have a RTA as this gives an average graph, while with them we examine in concrete and critical frequencies the reaction of an amplifier. Consequently they are more near with audition tests in practice.
Regards
Fotios
Re: My Opinion
hi,
how much money is needed to make a good amp? what's the average cost of the amplifiers you guys make here?
also, do those really expensive transformers, resistors, caps and switches really make a big difference to the quality of the sound?
i'm a newbie, so thanks for any input and your patience.
jeffry_widjaja said:What's made a good amp.. ?
M O N E Y
you can prove it
hi,
how much money is needed to make a good amp? what's the average cost of the amplifiers you guys make here?
also, do those really expensive transformers, resistors, caps and switches really make a big difference to the quality of the sound?
i'm a newbie, so thanks for any input and your patience.
Is About The Ear
The best think you must consider is "BUDGET"
After that you can decide what is the next step ?
like :
- make your own pcb or buy somebody else ?
- What amp character you will build ?
- What grade component you will use ?
You can make any amplifier, if you use different
component maybe you got a little different sound
But This Little Differences Will Annoying You
And You Start To Do Some Mods And ...
Welcome To The Club
The best think you must consider is "BUDGET"
After that you can decide what is the next step ?
like :
- make your own pcb or buy somebody else ?
- What amp character you will build ?
- What grade component you will use ?
You can make any amplifier, if you use different
component maybe you got a little different sound
But This Little Differences Will Annoying You
And You Start To Do Some Mods And ...
Welcome To The Club
Re: Re: My Opinion
Fotios
For example, the cost of this 2X170Wrms/8Ù class B amplifier, as it is presented in the photo, it is about 350Euro.auriches said:
Fotios
An externally hosted image should be here but it was not working when we last tested it.
As I own a Dynamic Precision A1 power amp (Norwegian design) and like it,I have to agree with most of it´s constructors claims
http://www.dynamicprecision.no/Pages_UK/00_index_UK.html please click on "Philosophy".
I recently read an interview(in HiFi+) with some leading persons on the Swiss Goldmund company, and one claim was that our brain is very sensitive to time delays (down to 20 picoseconds), therefor the latest Goldmund amps are internally superfast,with some custom built transistors unavailable to us the amateurs...But filters on input and output of the amps,makes me a bit doubtful.Internally the amps had a delay in the low nanosecond area.My own belief is that transient information, is a very substantial part of the music.Thus I like Thiel&Partner or as the also are named: Accutone ceramic drivers.And Eton ER4 Air motion transformers...I have a superfast amp for the treble,btw.
Naturally , any fast amplifier has to be stable when driving real world loads!
Their(the Goldmund people) views on keeping the signal in the digital domain for as long as possible ,with the possibility to compensate for time delays in ordinary crossovers in loudspeaker,(through DSP),made sense to me.
http://www.dynamicprecision.no/Pages_UK/00_index_UK.html please click on "Philosophy".
I recently read an interview(in HiFi+) with some leading persons on the Swiss Goldmund company, and one claim was that our brain is very sensitive to time delays (down to 20 picoseconds), therefor the latest Goldmund amps are internally superfast,with some custom built transistors unavailable to us the amateurs...But filters on input and output of the amps,makes me a bit doubtful.Internally the amps had a delay in the low nanosecond area.My own belief is that transient information, is a very substantial part of the music.Thus I like Thiel&Partner or as the also are named: Accutone ceramic drivers.And Eton ER4 Air motion transformers...I have a superfast amp for the treble,btw.
Naturally , any fast amplifier has to be stable when driving real world loads!
Their(the Goldmund people) views on keeping the signal in the digital domain for as long as possible ,with the possibility to compensate for time delays in ordinary crossovers in loudspeaker,(through DSP),made sense to me.
Theres a lot of range about amplifier value
- in power : from headphone to 1000 w
more power of course more budget
- in quality : theres general to special component
Build small amp with cheapest and other the expensive
If you use ( Ex ) Ni VX better Than BGN, tell it to me
- in fashion : good look casing, better heatsink etc
More smiling you have more money you pay
Im active to read several topics like solid state, digital
part and component, vendoor bazar & trading post
I read day & night, sometimes my wife unpatient
I build my amp too, you can look at
http://www.diyaudio.com/forums/showthread.php?s=&threadid=101948
You can calculate how much i spend the money
http://www.aussieamplifiers.com/index3.htm
Not include heatsink, casing, transformer, wiring and
connector. At the first time i just want buy creek amp
5350 but why dont we move the budget to nx150
- in power : from headphone to 1000 w
more power of course more budget
- in quality : theres general to special component
Build small amp with cheapest and other the expensive
If you use ( Ex ) Ni VX better Than BGN, tell it to me
- in fashion : good look casing, better heatsink etc
More smiling you have more money you pay
Im active to read several topics like solid state, digital
part and component, vendoor bazar & trading post
I read day & night, sometimes my wife unpatient
I build my amp too, you can look at
http://www.diyaudio.com/forums/showthread.php?s=&threadid=101948
You can calculate how much i spend the money
http://www.aussieamplifiers.com/index3.htm
Not include heatsink, casing, transformer, wiring and
connector. At the first time i just want buy creek amp
5350 but why dont we move the budget to nx150
Attachments
More Money = Better Sound?
I suggest you listen by your ear, this is the best result
if you try Panasonic FC and BG Caps and felling better
with panasonic so dont use BG Caps, reason :
1. Expensive
2. More money you spend
3. Your life became worse
If you wanna hear some opinion, debate, character
about component you can look in ...
http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=13
I suggest to start from the begining
I suggest you listen by your ear, this is the best result
if you try Panasonic FC and BG Caps and felling better
with panasonic so dont use BG Caps, reason :
1. Expensive
2. More money you spend
3. Your life became worse
If you wanna hear some opinion, debate, character
about component you can look in ...
http://www.diyaudio.com/forums/forumdisplay.php?s=&forumid=13
I suggest to start from the begining
Hi Gaetan,
Getting the schematic right, and the PCB layout right makes more difference than expensive components.
There are some constructor type project threads that might be good for you to go through. The SymAsym thread is especially good as it shows the difference the board can make with the same schematic and parts.
If you wish to find out a great deal, build one of these amplifiers. Start out with a small one - like the SymAsym (about 50 wpc). As an amplifier becomes more powerful, changes need to be made which may compromise sound quality. In other words, it's harder to make a high power amp sound good than it is to make a lower powered amp sound good.
At any rate, once you build one you can play with component types and hear for yourself. There are group buys of circuit boards (not populated) from time to time. Get in on one of these to make your life easier. I believe there is a group buy currently on the AAK version of the SymAsym 5.3, look here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=97640
I'm buying a pair and I've already built an original 5.3 pair. Lot's of support on this model. Also, there are amplifiers by Quasi and others. Look also in Chip Amps and Class D amps. If tubes are your thing, then have a peek in the tube forum. Things there tend to be much more hands on. Have a look and read the high voltage warnings! I like tube amps also, but this may be more advanced building.
BTW, your HP 333A is an excellent piece of equipment. Do you have a matching oscillator? Really good stuff, keep using it.
-Chris
Getting the schematic right, and the PCB layout right makes more difference than expensive components.
There are some constructor type project threads that might be good for you to go through. The SymAsym thread is especially good as it shows the difference the board can make with the same schematic and parts.
If you wish to find out a great deal, build one of these amplifiers. Start out with a small one - like the SymAsym (about 50 wpc). As an amplifier becomes more powerful, changes need to be made which may compromise sound quality. In other words, it's harder to make a high power amp sound good than it is to make a lower powered amp sound good.
At any rate, once you build one you can play with component types and hear for yourself. There are group buys of circuit boards (not populated) from time to time. Get in on one of these to make your life easier. I believe there is a group buy currently on the AAK version of the SymAsym 5.3, look here: http://www.diyaudio.com/forums/showthread.php?s=&threadid=97640
I'm buying a pair and I've already built an original 5.3 pair. Lot's of support on this model. Also, there are amplifiers by Quasi and others. Look also in Chip Amps and Class D amps. If tubes are your thing, then have a peek in the tube forum. Things there tend to be much more hands on. Have a look and read the high voltage warnings! I like tube amps also, but this may be more advanced building.
BTW, your HP 333A is an excellent piece of equipment. Do you have a matching oscillator? Really good stuff, keep using it.
-Chris
anatech said:
Hello
I did chip amp, tda7294 and lm3886, but they sound a little bit dull in mid and high frequency and do not have very much air and 3d space image between the musical instruments. I have to say that I'M very sensitive to the high frequency and the 3d image of the music, I'm french speaking, so I may not use the right worlds to explain myself.
I did read lot, in the diyaudio forum, about the Dx amp, the Gem100 amp, the SymAsym amp and the Aska amp. It's hard to follow them since it turn sometime into some arguing about details and sex of angels.
But I would like to read a kind of sonic differences and qualities and descritions between the Dx amp, the Gem100 amp, the SymAsym amp, and the Aska amp, I'm sure that would be a good start to read for any who hesitate on which one to build, it can be a thread where it would be only about that. And we would not need to do day's of search and reading to find that. I can say that the Aska 55 kit are quite costly, they should also sell the schematic only for those who can't afford the kit.
For myself, I'm in a small budget, so I have old and used things that I get for very cheap and that I repaired for myself wen I can fix it , my amp are a Crimson 60 w from 1982, I did have Mordaunt-Short but I exchange it for Dynaudio woofer and tweeter and I will made a TLS for them, my cd player are a Denon DCM420, an years 80's Oracle turntable that I get for very cheap.
I still have a telequipment tube oscilloscope, and for the HP333A I use an home made oscillator.
Thank
Gaetan
casing
This is the nice one
as i say before "more money more quality"
You can look the product in this website
http://www.atiresearch-anodized.com/products.html
This is the nice one
as i say before "more money more quality"
You can look the product in this website
http://www.atiresearch-anodized.com/products.html
googling
For make custom casing i dont know for sure
but you can look in www.partsconnexion.com
look for the hammond casing in there and look
what measurement you needed
you can googling too
For make custom casing i dont know for sure
but you can look in www.partsconnexion.com
look for the hammond casing in there and look
what measurement you needed
you can googling too
Hi Gaetan,
Use the old case from an amplifier or preamp. You should have some kicking about.
As far as which project you should build, try one with good support and a board available so you can get the results you are looking for. I'm sure most of the amps you have listed sound pretty good. Most constructors will prefer the one they have built.
The main reason I built the SymAsym is that the schematic showed promise and it was a reasonably priced project. It did exceed my expectations sonically. Any ASKA kit should be excellent. I believe that you have to buy the entire thing less case and possibly power supply. I am not 100 % sure on the details. I've serviced more than enough chip based amplifiers and so I wasn't attracted to those for that reason. I like things that are serviceable many years down the road.
-Chris
Use the old case from an amplifier or preamp.
You should have some kicking about.As far as which project you should build, try one with good support and a board available so you can get the results you are looking for. I'm sure most of the amps you have listed sound pretty good. Most constructors will prefer the one they have built.
The main reason I built the SymAsym is that the schematic showed promise and it was a reasonably priced project. It did exceed my expectations sonically. Any ASKA kit should be excellent. I believe that you have to buy the entire thing less case and possibly power supply. I am not 100 % sure on the details. I've serviced more than enough chip based amplifiers and so I wasn't attracted to those for that reason. I like things that are serviceable many years down the road.
I use both commercial oscillators, and ones I built myself. You might try to pick up a newer 'scope some day. At least you have something.
-Chris
for symasym 5.3
Dear anatech
hi how do you do
for symasym 5.3 how much output we have per channel?
is this symasym has related with simaudio 5.3 ?
maybe everybody can do some mods, what will happen
to the amp if we use all expensive component ?
more sound quality or sound disaster ?
nice to meet you
Dear anatech
hi how do you do
for symasym 5.3 how much output we have per channel?
is this symasym has related with simaudio 5.3 ?
maybe everybody can do some mods, what will happen
to the amp if we use all expensive component ?
more sound quality
or sound disaster ? nice to meet you
Hi, the output power is ~60w into 8ohm and ~100w into 4ohm.
simaudio? I don't know that one...
Explain "expensive" components. The suggested transistors have standard prices, there aren't more expensive better types.
I doubt that using high end resistors (instead of normal metal film) make a real audible difference except they cost ten times. But, i haven't tried. It should not sound worse.
For the smaller caps Mica is already suggested. For the elyts simply don't use cheapest stuff, if you use high end elyts, you could skip the bypass 100nf caps, except c19/20 maybe, you need to try.
For c19 the audible difference for using the c20 with cheap elyt is amazing.
It does make sense to not use cheap transformer for the PSU.
Mike
simaudio? I don't know that one...
Explain "expensive" components. The suggested transistors have standard prices, there aren't more expensive better types.
I doubt that using high end resistors (instead of normal metal film) make a real audible difference except they cost ten times. But, i haven't tried. It should not sound worse.
For the smaller caps Mica is already suggested. For the elyts simply don't use cheapest stuff, if you use high end elyts, you could skip the bypass 100nf caps, except c19/20 maybe, you need to try.
For c19 the audible difference for using the c20 with cheap elyt is amazing.
It does make sense to not use cheap transformer for the PSU.
Mike
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