You ask for help, you put a part of the pattern and then you don't know what you mean when you write B +? I'm telling you to try the capacitors and you pretend not to read, I asked you to write in Italian too and you pretend nothing. In my opinion you don't want to solve the problem, you want to waste time here on the forum.
Tu chiedi aiuto, posti una parte dello schema e poi non sai cosa si intende quando si scrive B+? Ti sto dicendo di provare i condensatori e tu fingi di non leggere, ti ho chiesto di scrivere pure in italiano e tu fai finta di nulla. Secondo me il problema non lo vuoi risolvere, vuoi perdere tempo qui sul forum.
Tu chiedi aiuto, posti una parte dello schema e poi non sai cosa si intende quando si scrive B+? Ti sto dicendo di provare i condensatori e tu fingi di non leggere, ti ho chiesto di scrivere pure in italiano e tu fai finta di nulla. Secondo me il problema non lo vuoi risolvere, vuoi perdere tempo qui sul forum.
@max These are tough times for everyone here, i dont see any any reason to flame that way
eventually i am here to learn
this topic should be about an improvement not a repairing, but I already told you about checking capacitors for a replacement at first unit service time
eventually i am here to learn
this topic should be about an improvement not a repairing, but I already told you about checking capacitors for a replacement at first unit service time
my willing is clearly to leave this discussion open to everyone, nothing against you, really
thank you for clarfication. right now i dont have the chance to proceed with more specific testing on psu since i have no scope here and more I cannot disconnect this mixer from its rig.
The original idea behind this topic was to assess a possible mod/improvement about psu on the base of these few elements.
I thank you in advance for your time
The original idea behind this topic was to assess a possible mod/improvement about psu on the base of these few elements.
I thank you in advance for your time
All right. I understood that you are convinced that the mixer was wrongly designed, your first mistake. You cannot disassemble it for testing and verification, according to your mistake. My request to write ALSO in Italian to speed up the reading you do not think is a right advice, your third mistake. You say you are here to learn, but you don't listen to anyone's advice, your fourth mistake. I wish you to find those who want to waste time with you and to be able to solve the mixer problem, provided that the problem really exists and that it is located in the mixer and not elsewhere. Good luck!
so what? they are designed with higher max ratings, it doesn't mean they are running at max!!
yes it does qualify that it "may" be a problem source but until that is qualified with testing who can say...it could well come down to part cost vs performance being marginal but without more information what your describing points more to a circuit fault....so i would be more inclined to finding and fixing the fault rather then modding the supply on the assumption it's badly designed.
re use of "foreign language" in the public part of the forum, the forum rules are clear, no?
yes it does qualify that it "may" be a problem source but until that is qualified with testing who can say...it could well come down to part cost vs performance being marginal but without more information what your describing points more to a circuit fault....so i would be more inclined to finding and fixing the fault rather then modding the supply on the assumption it's badly designed.
re use of "foreign language" in the public part of the forum, the forum rules are clear, no?
my poor man testing procedure is:
- listening to my working track to monitors connect to master out at decent level,
- crank heaphone out to high level,
- unplug headphone from socket abruplty
this reveal a slightsonic improvement on master output. might be the right time to pull the trigger and collect a scope to testify rail activity on this procedure
in the meanwhile i am trying to finish my mix with channels biased at -9db and everything is ok
- listening to my working track to monitors connect to master out at decent level,
- crank heaphone out to high level,
- unplug headphone from socket abruplty
this reveal a slightsonic improvement on master output. might be the right time to pull the trigger and collect a scope to testify rail activity on this procedure
in the meanwhile i am trying to finish my mix with channels biased at -9db and everything is ok
how much rubbish i have to expect from it ?
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I had a quick look at the schematic of the mixer and it seems to have very minimal decoupling of the op amps with just 100n capacitors used and minimal electrolytics.
The decoupling scheme may work but is obviously done to a budget.
I have had good success with using low ESR caps like Panasonic FC series - which come in a good range of sizes which makes it easier to substitute where space is tight.
I would replace the 2 PSU caps C104-C105 with low ESR caps and with an uprated size if possible.
I have only spotted 2 electrolytic caps on the voltage rails these being C37 & C38 on the master section and these are only 2.2uF - I would be tempted to substitute 100uF for these. I would probably look around the PCB to see if there were places where extra decoupling caps could be added to the mixer PCB and distribute these along the voltage rails, taking care to physically space them, especially from the regulator outputs. The difficulty is often finding how to connect any capacitors to the voltage rails and a decent ground.
The decoupling scheme may work but is obviously done to a budget.
I have had good success with using low ESR caps like Panasonic FC series - which come in a good range of sizes which makes it easier to substitute where space is tight.
I would replace the 2 PSU caps C104-C105 with low ESR caps and with an uprated size if possible.
I have only spotted 2 electrolytic caps on the voltage rails these being C37 & C38 on the master section and these are only 2.2uF - I would be tempted to substitute 100uF for these. I would probably look around the PCB to see if there were places where extra decoupling caps could be added to the mixer PCB and distribute these along the voltage rails, taking care to physically space them, especially from the regulator outputs. The difficulty is often finding how to connect any capacitors to the voltage rails and a decent ground.
thank you for your suggestions Xoc1
I still have not accessed internals to see how to improve caps, but i tested a new trafo. While the old ones have +/- 21.5V (no load) outs , new one have +/- 19.7V (no load) with a beefier 60VA rating.
Here it is FFT response of a short same audio snippets of house track i am working with, taken first with old trafo, then with the new one with very same desk setting (and room temp etc.)
I can hear a noticeable improvement on bass drum which sound tigher, maybe due to better response on midrange or less overall compression. Possible higher noise floor is not such a big deal since the music i used to work with.
I have concern to share those audio snippet on pubblic, but if somebody is interested i can send him on pvt link
I still have not accessed internals to see how to improve caps, but i tested a new trafo. While the old ones have +/- 21.5V (no load) outs , new one have +/- 19.7V (no load) with a beefier 60VA rating.
Here it is FFT response of a short same audio snippets of house track i am working with, taken first with old trafo, then with the new one with very same desk setting (and room temp etc.)
I can hear a noticeable improvement on bass drum which sound tigher, maybe due to better response on midrange or less overall compression. Possible higher noise floor is not such a big deal since the music i used to work with.
I have concern to share those audio snippet on pubblic, but if somebody is interested i can send him on pvt link
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The +-17volts is the same. Have you got an over furtive imagination ... how can there possibly be an 'tighter' sound.
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