p3a
I'm 53 years old!
Oh Sakis what did you say?Approach of a youngster how old are you thimios ?
I'm 53 years old!
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I bought the red one. Used as output caps in the preamplifier it emphasis high frequencies.
Thimios I don't know if my comment complement you or offended you in both cases my intention was to make fun of it ...
Usually with small experience quick look of the schematic and a few calculations is enough to start an amplifier ...
As about the capacitors both of them will work , each and everyone of them will have a different sonic signature which will be extremely hard to measure and/or define by listening ( it will require expert ears , knowledge of the amp it self , and thousands of hours of listening )
Still for my application i choose to go for smaller ( in physical size ) parts often large parts become microphonic and actually ""pick up"" things on the way especially in boards with some complexity like the ones you use worst when the board features zobel on it ( my intetntion is to zobel the amp outside the board ) and even worst with long ground traces .
In Greece we say this is ψιλα γραμματα meaning this is the small stuff and you will eventually get there after very long time of listening and parts swapping .
At this level your approach seems to be even more correct still a bit childish but i think as you said you are going to finish the amp be seriously impressed by the result and in the near feature you might go ahead for some refinements !
Kind Regards
Sakis
Usually with small experience quick look of the schematic and a few calculations is enough to start an amplifier ...
As about the capacitors both of them will work , each and everyone of them will have a different sonic signature which will be extremely hard to measure and/or define by listening ( it will require expert ears , knowledge of the amp it self , and thousands of hours of listening )
Still for my application i choose to go for smaller ( in physical size ) parts often large parts become microphonic and actually ""pick up"" things on the way especially in boards with some complexity like the ones you use worst when the board features zobel on it ( my intetntion is to zobel the amp outside the board ) and even worst with long ground traces .
In Greece we say this is ψιλα γραμματα meaning this is the small stuff and you will eventually get there after very long time of listening and parts swapping .
At this level your approach seems to be even more correct still a bit childish
but i think as you said you are going to finish the amp be seriously impressed by the result and in the near feature you might go ahead for some refinements ! Kind Regards
Sakis
I have them but do not use them because the others sound better to me. I often say that as long as MKP, the difference is not critical. I still think so but to my ears even small difference is critical (if it is what I will have to listen to).
If I have to choose between those MKP and a good Nichicon NP (electrolyt) may be I will choose the latter for its small size (so to prevent noise pickup).
These are about the cheapest MKP (metallised polypropylene film) caps you can buy. They are Chinese made and I certainly wouldn't rely on them for passive speaker crossovers. Perhaps OK in standard filtering applications where the size doesn't simply cause them to be aerials for EMI and increase the noise level, spoiling any lower distortion advantage.
If they are input caps, keep them off the amplifier board and place at the input source or fit grounded metal shields, as necessary for any huge signal caps in noisy environments like AB power amplifiers.
P3A
I didn't ask anything about capacitors .I mentioned(post#325) an issue about Alex mm pcb .
Sakis i believe you are in a little confused.Thimios I don't know if my comment complement you or offended you in both cases my intention was to make fun of it ...
Usually with small experience quick look of the schematic and a few calculations is enough to start an amplifier ...
As about the capacitors both of them will work , each and everyone of them will have a different sonic signature which will be extremely hard to measure and/or define by listening ( it will require expert ears , knowledge of the amp it self , and thousands of hours of listening )
Still for my application i choose to go for smaller ( in physical size ) parts often large parts become microphonic and actually ""pick up"" things on the way especially in boards with some complexity like the ones you use worst when the board features zobel on it ( my intetntion is to zobel the amp outside the board ) and even worst with long ground traces .
In Greece we say this is ψιλα γραμματα meaning this is the small stuff and you will eventually get there after very long time of listening and parts swapping .
At this level your approach seems to be even more correct still a bit childish
Kind Regards
Sakis
I didn't ask anything about capacitors .I mentioned(post#325) an issue about Alex mm pcb .
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You have to excuse me since i post in the forum between phone calls , amplifiers and costumers .
Seen the Greek flag and thought that it was your question but it was PANOS AKA maouna ... I presume that the capacitor thing might also be useful for you .
P3A
After first unsuccessful test this time everything is ok.
As i mentioned in previus message,this pcb by Alex mm have an issue with led (v reference)polarity.
This issue has as result a burned tranzistor on ltp and possible fault to 560R(led series resistor).
In this case V= -35v is present on output.
Now all is ok.
Pictures from this first(second)-fire.
After first unsuccessful test this time everything is ok.
As i mentioned in previus message,this pcb by Alex mm have an issue with led (v reference)polarity.
This issue has as result a burned tranzistor on ltp and possible fault to 560R(led series resistor).
In this case V= -35v is present on output.
Now all is ok.
Pictures from this first(second)-fire.
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P3A
+-32mv offset .
I have oscilloscopes and function generator (not very low distortion type)
I want some time to test this board.
See this test.http://www.diyaudio.com/forums/solid-state/173462-studio-reference-amplifier-122.html. post#1217
Power from a commercial amplifier plus 50.000uf in each rail just for first try
+-32mv offset .
I have oscilloscopes and function generator (not very low distortion type)
I want some time to test this board.
See this test.http://www.diyaudio.com/forums/solid-state/173462-studio-reference-amplifier-122.html. post#1217
P3A
This is my chanel on youtube.http://www.youtube.com/user/kostas422
You can listen this SR-200 here.APEX SR200 STUDIO REFERENCE playing Greek Music - YouTube
This is my chanel on youtube.http://www.youtube.com/user/kostas422
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FM varicap tuners often used a regulated 30-40V for the tuning voltage. Perhaps it was a convenient to use this for the front end of the amp too, if only one rail voltage was required to supply the bootstrap circuit. We'd need the schematic to see why an independent voltage was needed to boost the boostrapped side but not the other rail, to balance it, or maybe I'm missing something there.