Sunrise,
I downloaded the AD797 model from ADI
http://www.analog.com/en/DCcList/0,3090,759%5F%5F26,00.html
and it seems to model supply current correctly, in LTSpice.
If your model is also from ADI then we knew it's a bug of the simulator.
- Klaus
I downloaded the AD797 model from ADI
http://www.analog.com/en/DCcList/0,3090,759%5F%5F26,00.html
and it seems to model supply current correctly, in LTSpice.
If your model is also from ADI then we knew it's a bug of the simulator.
- Klaus
I doubt that AD797 is suitable for this but meanwhile have you checked the original design?
Bad copy
Better copy
I have made an amp similar yours but for headphones. Info here
This amp has been copied by a korean guy. Pictures here
Bad copy
Better copy
I have made an amp similar yours but for headphones. Info here
This amp has been copied by a korean guy. Pictures here
Analog Devices is not uniformly good on the op amp model issue, the an138 app note is great, I believe the work was done at PMI before it was acquired by AD and you now have to look inside AD's spice model files to determine if they have used a good modeling technique
KSTR said:
WOW....thank You very much....nice....
peranders said:
Per-Anders - thankYou very much for replying...i can't open "better copy" link ...
PMA said:
Pavel, thank You for entering here - OPA627 that You have suggested is very expensive here in delta quadrant 🙂 but it is one good opamp for sure....
how about to try NE5534...could this be more stable than AD797 ...also i can try OPA134 too that seems to have the same pinout as AD797...thank You again...
it is o.k. - no problem - thanks for the link 🙂
http://www.sjostromaudio.com/hifi_files/misc/AN211_better_text.pdf
i think that i will try NE5534 instead of AD797 for a start and than find some OPA134 and after that try OPA627 as a top amp for this ...
everything will be checked with osciloscope at the end....
could NE5534 be o.k. for a start...???
http://www.sjostromaudio.com/hifi_files/misc/AN211_better_text.pdf
i think that i will try NE5534 instead of AD797 for a start and than find some OPA134 and after that try OPA627 as a top amp for this ...
everything will be checked with osciloscope at the end....
could NE5534 be o.k. for a start...???
Don't forget offset trimming if the current mirrors.
partially it is... input part is looking similar to some existing equipment....i will add triming for offset....thanks 
hi guys....i powered the beast up...i am using NE5534 in the input for now...
it seems to me that the sound of this amplifier is practically determined with the quality of the opamp...it is almost crucial to have a good opamp....am i right.....???
the schematic is in the post no.1
regards
sunny
it seems to me that the sound of this amplifier is practically determined with the quality of the opamp...it is almost crucial to have a good opamp....am i right.....???
the schematic is in the post no.1
regards
sunny
yeah right... i knew it .....😀
o.k.! now i guess i will have to put some OPA627 in there to see what this can do.....
thanks Per Anders.....🙂
o.k.! now i guess i will have to put some OPA627 in there to see what this can do.....
thanks Per Anders.....🙂
o.k. - this is the actual circuit that i am playing with...
instead of the NE5534 opamp i am using OPA627.....the power supply is +/-37Vdc ..... and i am using only one output pair of transistors for now...i will add another pair....
it is sounding quite nice.....
the question is what can be done better in this schematic....
i have few suggestions that might be done...
1. put 100nF capacitor accross c-e of BD139-16 transistor in the VAS section (or better to put 2 cap's - one accros b-e and one accros b-c)..???
2. instead of the resistor 6k8 in the input part of the amp - the one that is supplying current for the zener diode - put a ccs - would this make things a bit better....
i would like to make a better psu for the opamp using this sch...so, how can this be done that is the question...???
well....this is a brainstormer... 🙂
regards
sunny
instead of the NE5534 opamp i am using OPA627.....the power supply is +/-37Vdc ..... and i am using only one output pair of transistors for now...i will add another pair....
it is sounding quite nice.....
the question is what can be done better in this schematic....
i have few suggestions that might be done...
1. put 100nF capacitor accross c-e of BD139-16 transistor in the VAS section (or better to put 2 cap's - one accros b-e and one accros b-c)..???
2. instead of the resistor 6k8 in the input part of the amp - the one that is supplying current for the zener diode - put a ccs - would this make things a bit better....
i would like to make a better psu for the opamp using this sch...so, how can this be done that is the question...???
well....this is a brainstormer... 🙂
regards
sunny
Attachments
master Destroyer......nice to see You here....i hope that You will have some time to contribute here with Your wast knowledge in hi-fi....🙂
regards
sunny
regards
sunny
would it be better to use differentials...maybe double differential instead of the opamp??
some suggestions that are better??
some suggestions that are better??
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