nelsonvandal said:
Mark, sorry about your job. It really seems like a tough time these days. Thanks for your contributions.
This is a great, informative thread. Interestingly, I have some 49720 and 4562 opamps that really do sound different. I received 4 of each at different times, and the characteristic differences in sound are the same. I'll just put that down as a variance in batches..... I have to find some metal cans to try
Good Morning Everyone
Good Morning Everyone,
I was online doing my daily job search and saw some more questions on the great LME parts. (A wiser / older engineer told me a long time ago that when you are out of work your full time "Job" is to find a job, i.e. 8hrs a day min).
1. Yes the 4562 and LME49720 are identical. National changed the numbering system to go from 4 to 5 digits and since they would not give us a new name for the high performance series of parts we just changed the LM to LME (E for excellence). Also the High voltage parts are identical but tested and guaranteed to higher standards. Testing always costs more...can anyone say MIL Spec!
2. Process variations are a fact of life and even parts on the same wafer can have slightly different characteristics. Leakage is something that can vary on parts on the same wafer in the fab and they will pass all the tests AND leakage can affect sound quality! The LM4702 and LME49811's are tested for leakage. I still think they are the best power amplifier front end parts in the world. I will put them up against almost any discrete front end designs. I know of one ultra high end company that has done extensive testing on the 4702 parts and feel it is almost identical to the sound of their 25K$+ mono block amplifiers with discrete front ends. I heard an amplifier in their sound room that used a single stereo LM4702 in a mono balanced design at their factory over a year ago and it blew my mind. We did that demo with the demo D/A preamp I designed for National. (They were very impressed with the D/A preamp with all LME parts). One reason I am out of work is because the acceptance time on new analog parts is 2-3 years to get a new product to market, not the 6 months cycle time National wanted that is the norm in the cell phone market. (Cell phones and PDA’s are the bulk of the audio business in the Valley) The new ARCAM AVR-600 surround sound processor / Rcvr (HDMI-1.3!) also uses the LM4702's.
3. Bob Pease and I both feel the same way about Spice models for analog circuits... Almost worthless! Engineers who never actually build anything use Spice models. The link for the spice model for the LM4565 series of parts is:
http://www.national.com/analog/audio
Still the best thing to do is just Build your circuit and test it out. The models can give you a general idea if your circuit will be functional but in the end building it up is the only way to know what your circuit will really do what you want it to do!
Thanks for listening everyone! Keeps my mind off the job searching.
audioman54 / Mark
Good Morning Everyone,
I was online doing my daily job search and saw some more questions on the great LME parts. (A wiser / older engineer told me a long time ago that when you are out of work your full time "Job" is to find a job, i.e. 8hrs a day min).
1. Yes the 4562 and LME49720 are identical. National changed the numbering system to go from 4 to 5 digits and since they would not give us a new name for the high performance series of parts we just changed the LM to LME (E for excellence). Also the High voltage parts are identical but tested and guaranteed to higher standards. Testing always costs more...can anyone say MIL Spec!
2. Process variations are a fact of life and even parts on the same wafer can have slightly different characteristics. Leakage is something that can vary on parts on the same wafer in the fab and they will pass all the tests AND leakage can affect sound quality! The LM4702 and LME49811's are tested for leakage. I still think they are the best power amplifier front end parts in the world. I will put them up against almost any discrete front end designs. I know of one ultra high end company that has done extensive testing on the 4702 parts and feel it is almost identical to the sound of their 25K$+ mono block amplifiers with discrete front ends. I heard an amplifier in their sound room that used a single stereo LM4702 in a mono balanced design at their factory over a year ago and it blew my mind. We did that demo with the demo D/A preamp I designed for National. (They were very impressed with the D/A preamp with all LME parts). One reason I am out of work is because the acceptance time on new analog parts is 2-3 years to get a new product to market, not the 6 months cycle time National wanted that is the norm in the cell phone market. (Cell phones and PDA’s are the bulk of the audio business in the Valley) The new ARCAM AVR-600 surround sound processor / Rcvr (HDMI-1.3!) also uses the LM4702's.
3. Bob Pease and I both feel the same way about Spice models for analog circuits... Almost worthless! Engineers who never actually build anything use Spice models. The link for the spice model for the LM4565 series of parts is:
http://www.national.com/analog/audio
Still the best thing to do is just Build your circuit and test it out. The models can give you a general idea if your circuit will be functional but in the end building it up is the only way to know what your circuit will really do what you want it to do!
Thanks for listening everyone! Keeps my mind off the job searching.
audioman54 / Mark
Audioman
Thanks for your input to this thread - I've found the discussion very enlightening and will use the new LME49710.
I do need a current feedback amp that can source some current into a low impedance BUT it has to be in a DIP package - is there anything else like the new 49713 available in that configuration?
Charles
Thanks for your input to this thread - I've found the discussion very enlightening and will use the new LME49710.
I do need a current feedback amp that can source some current into a low impedance BUT it has to be in a DIP package - is there anything else like the new 49713 available in that configuration?
Charles
HA into DIP holes
Stellavox,
I was unable to get the 49713 made in the dip package but the metal can can easily have its leads bent to fit into a DIP patern without using a conversion board. You can also use a SOIC to dip conversion board but the metal can will sound a bit better. Much more expensive for the metal can though...but for sound quality improvement worth it!
Mark / Audioman54
Still job hunting!
Stellavox,
I was unable to get the 49713 made in the dip package but the metal can can easily have its leads bent to fit into a DIP patern without using a conversion board. You can also use a SOIC to dip conversion board but the metal can will sound a bit better. Much more expensive for the metal can though...but for sound quality improvement worth it!
Mark / Audioman54
Still job hunting!
just got my digikey shipment of both 49720s and 49710s in metal cans, and am practising trimming and bending leads to jam them into dip-8 sockets. both soundcards I'm upgrading use duals for each channels i/v conversion and one more for balanced to single-ended output
with the magnifying visor it is not fun, but not that hard to do-- of course the proof is in the pudding when i get them home and see if they're in far enough to work correctly!!!!!!
i am wondering if there is any advantage to using pairs of 49710s, vs. a single 49720 for either or both of the functions. the former would need the browndog adapter, the latter can be jammed into the existing sockets with some work.
i also got a bunch of browndog adapters which will allow me to use singles or duals soics into dip-8 and even single dip-8s in pairs into a dual dip-8 socket.
with the magnifying visor it is not fun, but not that hard to do-- of course the proof is in the pudding when i get them home and see if they're in far enough to work correctly!!!!!!
i am wondering if there is any advantage to using pairs of 49710s, vs. a single 49720 for either or both of the functions. the former would need the browndog adapter, the latter can be jammed into the existing sockets with some work.
i also got a bunch of browndog adapters which will allow me to use singles or duals soics into dip-8 and even single dip-8s in pairs into a dual dip-8 socket.
fzman,
The duals will be fine especially since they are in the same channel.
Take a good pair of needle nose and push on each pin make sure they are all in.
Now I am going to modify a very expensive D/A I designed many years ago (Eiger Systems which never made it to market) with the LME49713's and 710's.
Mark / audioman54
The duals will be fine especially since they are in the same channel.
Take a good pair of needle nose and push on each pin make sure they are all in.
Now I am going to modify a very expensive D/A I designed many years ago (Eiger Systems which never made it to market) with the LME49713's and 710's.
Mark / audioman54
used time between calls at work today to use contact cleaner on the pins, trim them down, and practice bending them into position by putting them into dip sockets.
i bought 4 of the 49720s and 8 of the 49710s (needed 6 duals all together).
when i got home i decided to exhibit my charateristic lack of patience, and put 3 of my socketed cans into the sound card-- that's when the fun began-- no sound, warm card, lots of activity.
i ended up with the 353s back in the i/v positions, and left one 49720 in the output position -- sound again!!!
i will try to replace the other two directly onto the board, probably over the wekend, when i have a bit more time. i think what happened is that the particular opamp that got the hottest was shorting pin 8 to the case, and the metal emi shield on the sound card may have shorted the cans to each other as well.
the replacement is burning in now, so far it is more open and lively than the 2068 it replaced, but is a bit thin/edgy (very slight, needs to develop a bit of body).
i'll take a quickie listen in the morning before work, and let it keep playing and will report back. from sonic memory, it sounds better than the 4562 in the std dip-8 orogonally supplied with the card (with 2114s in the i/v positions).
thanks for all the advice.
mark
i bought 4 of the 49720s and 8 of the 49710s (needed 6 duals all together).
when i got home i decided to exhibit my charateristic lack of patience, and put 3 of my socketed cans into the sound card-- that's when the fun began-- no sound, warm card, lots of activity.
i ended up with the 353s back in the i/v positions, and left one 49720 in the output position -- sound again!!!
i will try to replace the other two directly onto the board, probably over the wekend, when i have a bit more time. i think what happened is that the particular opamp that got the hottest was shorting pin 8 to the case, and the metal emi shield on the sound card may have shorted the cans to each other as well.
the replacement is burning in now, so far it is more open and lively than the 2068 it replaced, but is a bit thin/edgy (very slight, needs to develop a bit of body).
i'll take a quickie listen in the morning before work, and let it keep playing and will report back. from sonic memory, it sounds better than the 4562 in the std dip-8 orogonally supplied with the card (with 2114s in the i/v positions).
thanks for all the advice.
mark
Yup, standard rule of updating...one part at a time. But I must admit I have put in groups on new opamps right away because I was excited to hear the difference with a new set of parts.
Hope you get it all working and be sure and look at the power supply outputs to see if there is any osc's going on. That can cause the harshness you are hearing.
Mark
Hope you get it all working and be sure and look at the power supply outputs to see if there is any osc's going on. That can cause the harshness you are hearing.
Mark
mark, i may have overstated my initial opinion -- ti does not sound like oscillation, not harsh per se, just that a much "faster" tonal balance -- more open sounding, and without much warm-up, since i was struggling just to get sound back. i will listen tonight and see where it's at.
sounds like it may be worthwhile to solder two of the metal can 49710s to a browndog adaptor, and put it in the output position, since that would otherwise use a dual to carry both channels -- seems like that's implicit in your last comment. there is also more clearance there for the browndog to fit nicely.
i'll work on the other sound card as time permits. i checked the opamp that got really hot and noticed that one of the pins had bent up and was shorting against the case-- that was probably the problem.
i'll see if it still works at some point.
thanks again,
mark
sounds like it may be worthwhile to solder two of the metal can 49710s to a browndog adaptor, and put it in the output position, since that would otherwise use a dual to carry both channels -- seems like that's implicit in your last comment. there is also more clearance there for the browndog to fit nicely.
i'll work on the other sound card as time permits. i checked the opamp that got really hot and noticed that one of the pins had bent up and was shorting against the case-- that was probably the problem.
i'll see if it still works at some point.
thanks again,
mark
mark, got a chance to listen to the 49720 as output, with the lf353s in i/v position with about 24 hours or so of constant play under their belts. the sound had fleshed out, to the point where the bass seemed a bit overblown and the tonal balance was skewed a bit.... showed promise, but someting wasn't quite right
so i popped the card out, and put 49720s into the spots vacated by the 353s. much better-- the tonal balance evened out, and i noticed that slight lean-ness again. seems like it's a warm-up/burn-in phenomenon with these can chips (ca-chips?)
what i did notice was better imaging/soundstage depth, and electrostatic-like openess and detail. differences between cds were much easier to pick out, all it needs now is a bit more body and palpability and i will be a very happy man
a quick llisten this morning is that they are fleshing out as well.
they are still sitting in sockets in sockets. once they settle down and they make the final cut, i will shove them directly into the sockets on the sound card, without using them pre-socketed.
i just ordered a hakko 936-12 and a bunch of tips to supplement my trusty 10+ year old weller w60p. i am going to solder a pair of 49710s onto a browndog adaptor, and use that for the output in place of the single 49720--
sound like a good idea?
thanks to mark (audioman54)
also, i am intrigued by the possibilites of the 49713, but cannot change out gain and feedback r's on the sound card, but for a xover or headphone amp.......?????
so i popped the card out, and put 49720s into the spots vacated by the 353s. much better-- the tonal balance evened out, and i noticed that slight lean-ness again. seems like it's a warm-up/burn-in phenomenon with these can chips (ca-chips?)
what i did notice was better imaging/soundstage depth, and electrostatic-like openess and detail. differences between cds were much easier to pick out, all it needs now is a bit more body and palpability and i will be a very happy man
a quick llisten this morning is that they are fleshing out as well.
they are still sitting in sockets in sockets. once they settle down and they make the final cut, i will shove them directly into the sockets on the sound card, without using them pre-socketed.
i just ordered a hakko 936-12 and a bunch of tips to supplement my trusty 10+ year old weller w60p. i am going to solder a pair of 49710s onto a browndog adaptor, and use that for the output in place of the single 49720--
sound like a good idea?
thanks to mark (audioman54)
also, i am intrigued by the possibilites of the 49713, but cannot change out gain and feedback r's on the sound card, but for a xover or headphone amp.......?????
HI Fzman,
Good job! I am glad you like the LME parts. And yes the 49713 is a step up from the 49710...but it is not a huge step. You also noticed that to properly hear the differences in a new chip you need to put it into the entire signal path or the changes will be masked out by the lesser quality parts in series with the new parts.
Sometimes a lean sound is a result of better circuits that do not exhibit overhang/ringing or have better THD! (the THD+N on the LME49710 parts is around 0.00005%)
Need to get out to the sound room / garage to try the new AK4399 DAC chip I got from my friends at AKM a few weeks ago. I would also like to try the ESS chip but I don't have a part/board from them yet.
Simonty - Shielding is a topic for another time. (Note: I did receive a patent for an "Electo-Magnetic Shielding-damping disk" for CD/DVD transports a long time ago.) I have done extensive shielding in my latest D/A preamp with good results.
Mark / Audioman54
Good job! I am glad you like the LME parts. And yes the 49713 is a step up from the 49710...but it is not a huge step. You also noticed that to properly hear the differences in a new chip you need to put it into the entire signal path or the changes will be masked out by the lesser quality parts in series with the new parts.
Sometimes a lean sound is a result of better circuits that do not exhibit overhang/ringing or have better THD! (the THD+N on the LME49710 parts is around 0.00005%)
Need to get out to the sound room / garage to try the new AK4399 DAC chip I got from my friends at AKM a few weeks ago. I would also like to try the ESS chip but I don't have a part/board from them yet.
Simonty - Shielding is a topic for another time. (Note: I did receive a patent for an "Electo-Magnetic Shielding-damping disk" for CD/DVD transports a long time ago.) I have done extensive shielding in my latest D/A preamp with good results.
Mark / Audioman54
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