I have built opa549 on forum members suggestions and infact these were my impressions from the time its turned on..
Day 1: initially the the circuit didnt work figured out that the mute pin is not grounded and once did they started singing...
Hr 1: The sound was very very low and eventually if i try to increase the input signal there was strange crackling happening... thought something went wrong and was bit worried as everything was point to point checked... so i listened to very low volume as it was crackling... lil bit disappointed thought to check later what happened...
Hr 2: The crackling was reduced significantly by the end of second hour and the mids was very good was happy to see that it had nice not pronounced vocals.. the highs were not yet opened...
Hr 3: The fog was getting cleared and i could see the instrument saperation happening decently..
Hr 4-6: Can see the treble opening up and found I can bear the sound without crackling and the mids were still good even at this burning period...
left all the night in music at very low volume..
Day 2: The mids were awesome they had all the sweetness... I can feel the distinction of the vocals pretty good...
End of day 2 i called couple of friends said its just awesome and the highs were not harsh but very smooth but not brighter...
I fell in love with the mids very warm sounding like somebody said they have that tube sound I agree if its not complete substitute but this chip has that...
infact I have to try to add a preamp now and tweak it.... havent tried polystyrenes as decoupling....
I get speaker popping when some switch turn on in the room... how to take this out?
But overall i was very doubtful about this chip but it certainly surpassed my expectatoins and...
Pinkmouse, AndrewT and everybody who helped me in giving tips to get this one executed properly...
Ill post the impressions again after 50hr... but since its already 15hr i dont think they will open more... but its pretty mellow sound...
I havent tried LM3886 but when it comes to mids they were better than what Ive expected..
If anybody might have used both do let me know about your impressions... soon or later Ill build LM3886..
Day 1: initially the the circuit didnt work figured out that the mute pin is not grounded and once did they started singing...
Hr 1: The sound was very very low and eventually if i try to increase the input signal there was strange crackling happening... thought something went wrong and was bit worried as everything was point to point checked... so i listened to very low volume as it was crackling... lil bit disappointed thought to check later what happened...
Hr 2: The crackling was reduced significantly by the end of second hour and the mids was very good was happy to see that it had nice not pronounced vocals.. the highs were not yet opened...
Hr 3: The fog was getting cleared and i could see the instrument saperation happening decently..
Hr 4-6: Can see the treble opening up and found I can bear the sound without crackling and the mids were still good even at this burning period...
left all the night in music at very low volume..
Day 2: The mids were awesome they had all the sweetness... I can feel the distinction of the vocals pretty good...
End of day 2 i called couple of friends said its just awesome and the highs were not harsh but very smooth but not brighter...
I fell in love with the mids very warm sounding like somebody said they have that tube sound I agree if its not complete substitute but this chip has that...
infact I have to try to add a preamp now and tweak it.... havent tried polystyrenes as decoupling....
I get speaker popping when some switch turn on in the room... how to take this out?
But overall i was very doubtful about this chip but it certainly surpassed my expectatoins and...
Pinkmouse, AndrewT and everybody who helped me in giving tips to get this one executed properly...
Ill post the impressions again after 50hr... but since its already 15hr i dont think they will open more... but its pretty mellow sound...
I havent tried LM3886 but when it comes to mids they were better than what Ive expected..
If anybody might have used both do let me know about your impressions... soon or later Ill build LM3886..
check with scope (if possible) , in output of opa 549 glitches can be observed above 5kHz...., P.Macura was alos mentionet this problem.
Glitches on OPA549 output when loaded - Precision Amplifiers Forum - Precision Amplifiers - TI E2E Community
Glitches on OPA549 output when loaded - Precision Amplifiers Forum - Precision Amplifiers - TI E2E Community
Hello,
You have not stated anything with regard to the layout? Proper supply bypassing is very important, from the datasheet,
"Power-supply terminals should be bypassed with low series impedance capacitors. The technique shown in Figure 1, using a ceramic and tantalum type in parallel, is recommended.Power-supply wiring should have low series impedance.
Not sure what you mean "infact I have to try to add a preamp now and tweak it.... havent tried polystyrenes as decoupling...."
As power supply bypass caps? Not sure if this will make any difference? Layout/grounding, may play a much more important roll!!
Popping noises = strange behaviour = investigate. Have you looked at any waveforms on the scope?
I get speaker popping when some switch turn on in the room... how to take this out?
Generated by the Power Supply or through the signal source? Need to determine which it is? = Welcome to Design Engineering
Now try it in the inverted configuration.does it really makes difference?
Sure it can, the data sheet is, what I assume, based on non-inverting configuration. The inverting configuration can, depends on the device design, have a larger GainBandWidth Product and increased positive & negative slew rate. How this would affect the sound, is for the instruments, your ears & brain to tell!!
Cheer
Rick
You have not stated anything with regard to the layout? Proper supply bypassing is very important, from the datasheet,
"Power-supply terminals should be bypassed with low series impedance capacitors. The technique shown in Figure 1, using a ceramic and tantalum type in parallel, is recommended.Power-supply wiring should have low series impedance.
Not sure what you mean "infact I have to try to add a preamp now and tweak it.... havent tried polystyrenes as decoupling...."
As power supply bypass caps? Not sure if this will make any difference? Layout/grounding, may play a much more important roll!!
Popping noises = strange behaviour = investigate. Have you looked at any waveforms on the scope?
I get speaker popping when some switch turn on in the room... how to take this out?
Generated by the Power Supply or through the signal source? Need to determine which it is? = Welcome to Design Engineering
Now try it in the inverted configuration.does it really makes difference?
Sure it can, the data sheet is, what I assume, based on non-inverting configuration. The inverting configuration can, depends on the device design, have a larger GainBandWidth Product and increased positive & negative slew rate. How this would affect the sound, is for the instruments, your ears & brain to tell!!
Cheer
Rick
all class AB has some sort of crossover distortions so its expected...
im not using any preamp for this amp just playing thru my pc so there could be some improvement in sound with preamp
polystyrenes made big difference with tweeters but as decoupling caps near the psu pins i havent tried...
Im pretty sure it should be coming from the psu...
im not using any preamp for this amp just playing thru my pc so there could be some improvement in sound with preamp
polystyrenes made big difference with tweeters but as decoupling caps near the psu pins i havent tried...
Im pretty sure it should be coming from the psu...
pinkmouse thank you for the input. Ill try using but man somehow I feel that this amp is not giving the highs which I feel need little brighter... not much... how do I do that or this is the nature of this amp?
Btw Iam thinking of biasing this chip in class A. IMHO it will become hot but im ready to put a massive heatsink.... Even if im getting 8w in class A i want to experience it once...
I think we need to use a resistor from output pin to -ve signal... i dont know exactly how its done but want to try once whats your call on this?
Btw Iam thinking of biasing this chip in class A. IMHO it will become hot but im ready to put a massive heatsink.... Even if im getting 8w in class A i want to experience it once...
I think we need to use a resistor from output pin to -ve signal... i dont know exactly how its done but want to try once whats your call on this?
this is the circuit thats used.. http://www.diyaudio.com/forums/atta...6-my-opa549-schematic-does-look-ok-opa549.gif
What filters have you fitted to the input, i.e what is the frequwncy or RC time constant of the Low Pass filter?
and what is the frquency or RC time constant of the High Pass filter.
Telling us 1uF is nothing, other than confirming you have a DC blocking capacitor in place, if you have soldered it in the correct location.
60Hr Burning time:
The entire spectrum is balanced and I dont think anything would improve beyond this..
but on the resolution front i see improvement even from 50hr to 60...
It feels like I have got enough details but would you mind if I give more....
softness through details: the details are too much which makes feel the sound is smooth..
mids: are the best I have ever auditioned in any amp within USD 2000 range... I ve found this mid only in highend tube amplifiers...
as said by few its better than Audionote amp. Well what I find is audionote is more opened and not for mellowy sound...
if you put these two I have more chances to pick 549
Instrument separation: very unique feature. I had a Mosfet amp wit sanken mosfets...
This is way ahead when compared with the Mosfet amp A-17 yamaha old one...
Vocal uniqueness: you can see the actors voices are being having unique signature for each of em... which is not just expected from this amp...
Acoustic Guitar: flys I have auditioned real guitar performances and i tried to learn as well. I can say the sound fly with this amp. Infact the amp has got great guitar performance...
My old amp was just giving me heaps of details but not that emotional information...
overall Iam not thinking to build any other chip after listening to this... but have to try LM3886 I think the details would improve but how well it handles the sound no idea...
Final statement: I wanted to build this since 4 years but couldnt takeout time and tried it.. But now I feel that I have missed that all blissful years.
Vocals are just superb: In terms of details i might say they are good and add that softness to upper treble aswell...
Flute is very warm. One of my friend who auditioned said the performer is right infront of me...
cymbals sound like tissssss rather than tizzzzzzz at very upper frequency which i was always wanted.
Attack of sound: Its just awesome even a youtube video has great amount of information.. I have checked some movie scenes but didnt expect that from this chip...
Last statement: If you have not yet built this one dont forget to build this one...
I seriously didnt expect this musicality and looking to build other configs using the same chip...
The entire spectrum is balanced and I dont think anything would improve beyond this..
but on the resolution front i see improvement even from 50hr to 60...
It feels like I have got enough details but would you mind if I give more....
softness through details: the details are too much which makes feel the sound is smooth..
mids: are the best I have ever auditioned in any amp within USD 2000 range... I ve found this mid only in highend tube amplifiers...
as said by few its better than Audionote amp. Well what I find is audionote is more opened and not for mellowy sound...
if you put these two I have more chances to pick 549
Instrument separation: very unique feature. I had a Mosfet amp wit sanken mosfets...
This is way ahead when compared with the Mosfet amp A-17 yamaha old one...
Vocal uniqueness: you can see the actors voices are being having unique signature for each of em... which is not just expected from this amp...
Acoustic Guitar: flys I have auditioned real guitar performances and i tried to learn as well. I can say the sound fly with this amp. Infact the amp has got great guitar performance...
My old amp was just giving me heaps of details but not that emotional information...
overall Iam not thinking to build any other chip after listening to this... but have to try LM3886 I think the details would improve but how well it handles the sound no idea...
Final statement: I wanted to build this since 4 years but couldnt takeout time and tried it.. But now I feel that I have missed that all blissful years.
Vocals are just superb: In terms of details i might say they are good and add that softness to upper treble aswell...
Flute is very warm. One of my friend who auditioned said the performer is right infront of me...
cymbals sound like tissssss rather than tizzzzzzz at very upper frequency which i was always wanted.
Attack of sound: Its just awesome even a youtube video has great amount of information.. I have checked some movie scenes but didnt expect that from this chip...
Last statement: If you have not yet built this one dont forget to build this one...
I seriously didnt expect this musicality and looking to build other configs using the same chip...
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