For dutch GC builders
There´s a guy at www.marktplaats.nl selling 10 units of lt1083.
Go to "elektra/tv´s/witgoed", than "electronische onderdelen". Title is "linear technology 7,5A..." posted 15-06 (yesterday).
Erik
tbla said:
There´s a guy at www.marktplaats.nl selling 10 units of lt1083.
Go to "elektra/tv´s/witgoed", than "electronische onderdelen". Title is "linear technology 7,5A..." posted 15-06 (yesterday).
Erik
Dear friends
I have a non inverted GC with 380 VA. The transformer has 3 wires at the output which is 18,0,18 ac respectively.
I hope GC master, expert and gurus to help me with some of my questions.
A- How to use Pedja’s circuit with my transformer ?. I mean, how to use LM338 with this kind of transformer ?.
B- If no other method, I have to use LM317/337 chips for the regulation, what is the maximum voltage out can I achieve ?. ( Assume I use 18acX1.414=25Vdc)
C- Has any one measure the current at the +ve or –ve of this LM3875 when it perform low bass or complex music ?.
Thanks and have a nice day
I have a non inverted GC with 380 VA. The transformer has 3 wires at the output which is 18,0,18 ac respectively.
I hope GC master, expert and gurus to help me with some of my questions.
A- How to use Pedja’s circuit with my transformer ?. I mean, how to use LM338 with this kind of transformer ?.
B- If no other method, I have to use LM317/337 chips for the regulation, what is the maximum voltage out can I achieve ?. ( Assume I use 18acX1.414=25Vdc)
C- Has any one measure the current at the +ve or –ve of this LM3875 when it perform low bass or complex music ?.
Thanks and have a nice day
To use your transformer, you must do what Carlos did. That is to open up the transformer, locate the ends of the two windings and separate the ends that are joined to the centre-tap and then add a fourth wire so that you have four leads.
Otherwise, you must get a new transformer with separate secondary windings! 😉
Otherwise, you must get a new transformer with separate secondary windings! 😉
Nuuk said:
And since you are at it take a slightly higher voltage secondary, say 25 to 30V (since regulating makes you lose some supply volts)
Cheers
Andrea
azamkita said:
What Nuuk suggests and I would too, opening the transformer, may not be possible. In that case, what you can do is build the discrete regulator suggested at Pedja's site, which he seems to like more.
The problem with the 317/337 is not the voltage, but the current. It can only handle up to about 1A. To handle you have to add an external transistor. But several advantages of those chips, like low impedance, will be gone.
As far as I know no one has taken the trouble of measuring those current demands.
Carlos
Thanks to Nuuk,Andy,Carlos for your answer,
I'll take note - thanks 😉
BTW, any possibilities if I parallel 7818/1918 or I parallel LM317/337 to increase the current let say to 5 amp or 7 amp ?.
Come back to transformer part, should I reduce the secondary or increase the primary ?
Give me some lite plzzz.
thanks and have a nice day.
I'll take note - thanks 😉
BTW, any possibilities if I parallel 7818/1918 or I parallel LM317/337 to increase the current let say to 5 amp or 7 amp ?.
Come back to transformer part, should I reduce the secondary or increase the primary ?
Give me some lite plzzz.
thanks and have a nice day.
azamkita said:Thanks to Nuuk,Andy,Carlos for your answer,
I'll take note - thanks 😉
BTW, any possibilities if I parallel 7818/1918 or I parallel LM317/337 to increase the current let say to 5 amp or 7 amp ?.
Come back to transformer part, should I reduce the secondary or increase the primary ?
Give me some lite plzzz.
thanks and have a nice day.
Don't fiddle with those regulators, it won't work properly.
A CT trafo like yours has two wires joined on the secondary, you just have to separate them.
To do that, cut a little of the tape isolation where the wires of the secondary leave the trafo.
You'll see that the center wire is soldered to two solid core wires of the trafo.
Separate them, solder two wires and isolate them with tape.
That's it, independent secondaries.😎
With your trafo you'll be able to regulate at around 22~23 volts, not that bad.
You can increase the output of an LM317/LM337 by paralleling regulators etc. There are some examples in the data sheet.
I am looking at the same idea as I have a whole bunch of LM317s to use up...
Arnie
I am looking at the same idea as I have a whole bunch of LM317s to use up...
Arnie
carlosfm said:
Hi,
with 18VAC transformer, LM338 regulator and output current about 3A, maximum output voltage you can get will be around 18V, not 22-23. IMO
Regards
Milan
22-23 may be a little high, in fact.
But 18v is too low, I really think you'll be able to regulate above 20v with LM338.
But 18v is too low, I really think you'll be able to regulate above 20v with LM338.
carlosfm said:
Maybe, but without any load.
Uout=Vac*pi-Vregmin-Vdiodedrop-Vripple(Iout=3A)
=18*1,4-3-1,4-(2to3V)=ca18V
Regards
Milan
Iam a spy from Solid state, using dark glasses
And i came here to see whats going on to inform fellows (hahahaha!)
Not true, just visiting my friends, the earth heritage will belong to you all chip amplifiers lovers, no doubts that this will be the correct way, and already is.
But i have some worries about those chips, an i will be glad to hear some explanations without have to read all giant forum related chip amps.
I have some experience, not so big with chips, but had assembled some of the old ones TDA1514, TDA1515,TDA2002,TDA2003,and some STK and 7264/7254, if i can remember numbers, those last 25 watts.
What i conclude, and if wrong SCREAM LOUD AN CLEAR, they never reach good power related their data sheets, always specifications shows 10 percent distortion (no one can hear so big distortion), or sometimes 1 percent distortion (also too high), and some off them shows 0.2 (this is reasonable, most of us do not perceive so bad this level... we perceive this distortions as "crisp" highs)... also tried LM3886, but unfortunattely it explodes, and i check many times and could not see the error in assembling, or voltage, and no short circuit, invertion or things like that... i think was bad luck.
This way, as an example, The TDA7264 , 25 watts each channel, real world measurements, without hear distortion is 7 volts output....6.5 watts RMS in 8 ohms charge.
I imagine the problem to chips, this way i do not trust on them (damn spy from solid state.... get out!) is the size of the metal to transfer heat.... so small cannot send more than continuous, not music.... continuous tone test, cannot send more than 50 watts, i imagine, off heat, to the heatsink ....not good transference of heat because small contact surface... this way, when i listen people saying mine goes to 50 RMS, or less than that i became crazy, because cannot understand those things, seems miracle to me!.. . of course i can believe, a chip size, alike LM3885 can hold musical peaks, moment power of .....lets say.... 35 watts RMS..... and this is enougth and very good in my idea... enough to abandon solid state, because can make 6 and use multi amplification, units to bass, to treble and to mid and all goes very well...but i could not check!... this way, i want to make a straigth question, directed to my dear friend, and Portuguese blood alike mine:
Please, the real value to me, inform me as soon as you can.... connecting speaker (not resistor), and put music to play as loud as start to show some distortions on peaks, and having sure the distortions are not from speakers, put a normal pointer voltimeter, an old analogue multimeter in AC scale, and inform to me the average, the medium voltage indication, and the maximum voltage the pointer can go.... no problem about the balistics of the pointer....this will give to me a clear idea of the amplifier power....because, i always do that, not only constant signal measurements, but also musical measurements with analogue multimeter, and also Scope measurements too.... this way i know the differences related each measurements...of course, if you have one scope, a peak to peak value will be good to me.
This way, i will ask you, Carlos, and forum friends, to inform me this voltage over speaker charge (not resistor) because i am crazy to know the real power of those LM3885 and his cousines.
In Portuguese, with your license, to Carlos.
Tem que ter muito saco com certos gajos, lembras te dos insetos que por vezes acabam com a plantação, parecem praga, veja se pegas no ar o problema dessa praga , tem vezes que são tão provocativos (sempre) que tenho ganas de dar lhes uma cachapada na pinha pra que saiam à cata da rôlha!
Your are very special, patient man Carlos, this way, using this quality with me, give me real values....i am trying to find one chip, that can put 30 clean watts each channel, 8 ohms loads!... i think this is enough to be happy!
From Carlos, Destroyer X, to Carlos and chip forum friends.
bye
And i came here to see whats going on to inform fellows (hahahaha!)
Not true, just visiting my friends, the earth heritage will belong to you all chip amplifiers lovers, no doubts that this will be the correct way, and already is.
But i have some worries about those chips, an i will be glad to hear some explanations without have to read all giant forum related chip amps.
I have some experience, not so big with chips, but had assembled some of the old ones TDA1514, TDA1515,TDA2002,TDA2003,and some STK and 7264/7254, if i can remember numbers, those last 25 watts.
What i conclude, and if wrong SCREAM LOUD AN CLEAR, they never reach good power related their data sheets, always specifications shows 10 percent distortion (no one can hear so big distortion), or sometimes 1 percent distortion (also too high), and some off them shows 0.2 (this is reasonable, most of us do not perceive so bad this level... we perceive this distortions as "crisp" highs)... also tried LM3886, but unfortunattely it explodes, and i check many times and could not see the error in assembling, or voltage, and no short circuit, invertion or things like that... i think was bad luck.
This way, as an example, The TDA7264 , 25 watts each channel, real world measurements, without hear distortion is 7 volts output....6.5 watts RMS in 8 ohms charge.
I imagine the problem to chips, this way i do not trust on them (damn spy from solid state.... get out!) is the size of the metal to transfer heat.... so small cannot send more than continuous, not music.... continuous tone test, cannot send more than 50 watts, i imagine, off heat, to the heatsink ....not good transference of heat because small contact surface... this way, when i listen people saying mine goes to 50 RMS, or less than that i became crazy, because cannot understand those things, seems miracle to me!.. . of course i can believe, a chip size, alike LM3885 can hold musical peaks, moment power of .....lets say.... 35 watts RMS..... and this is enougth and very good in my idea... enough to abandon solid state, because can make 6 and use multi amplification, units to bass, to treble and to mid and all goes very well...but i could not check!... this way, i want to make a straigth question, directed to my dear friend, and Portuguese blood alike mine:
Please, the real value to me, inform me as soon as you can.... connecting speaker (not resistor), and put music to play as loud as start to show some distortions on peaks, and having sure the distortions are not from speakers, put a normal pointer voltimeter, an old analogue multimeter in AC scale, and inform to me the average, the medium voltage indication, and the maximum voltage the pointer can go.... no problem about the balistics of the pointer....this will give to me a clear idea of the amplifier power....because, i always do that, not only constant signal measurements, but also musical measurements with analogue multimeter, and also Scope measurements too.... this way i know the differences related each measurements...of course, if you have one scope, a peak to peak value will be good to me.
This way, i will ask you, Carlos, and forum friends, to inform me this voltage over speaker charge (not resistor) because i am crazy to know the real power of those LM3885 and his cousines.
In Portuguese, with your license, to Carlos.
Tem que ter muito saco com certos gajos, lembras te dos insetos que por vezes acabam com a plantação, parecem praga, veja se pegas no ar o problema dessa praga , tem vezes que são tão provocativos (sempre) que tenho ganas de dar lhes uma cachapada na pinha pra que saiam à cata da rôlha!
Your are very special, patient man Carlos, this way, using this quality with me, give me real values....i am trying to find one chip, that can put 30 clean watts each channel, 8 ohms loads!... i think this is enough to be happy!
From Carlos, Destroyer X, to Carlos and chip forum friends.
bye
Carlos (Destroyer X)😀 ,
Read the LM3886 datasheet I think it's more than enough for what you want.
Read the first page, and check the graphs at page 9 and 10.
The problem you had may be overvoltage, what PSU voltage did you use?
+/-30~31 volts is the ideal for these chips, it will work fine with 4 or 8 ohm speakers.
Answer in portuguese:
Tens razão, alguns gajos são piores que uma comichão no cú.😀
Note: this site is s'slooooow now...
Read the LM3886 datasheet I think it's more than enough for what you want.
Read the first page, and check the graphs at page 9 and 10.
The problem you had may be overvoltage, what PSU voltage did you use?
+/-30~31 volts is the ideal for these chips, it will work fine with 4 or 8 ohm speakers.
Answer in portuguese:
Tens razão, alguns gajos são piores que uma comichão no cú.😀
Note: this site is s'slooooow now...
babel fish says......
You have reason, some dudes are worse that a tingle in cú.
keep it up boys......😉
carlos are you ready for the game.....? (football)
You have reason, some dudes are worse that a tingle in cú.
keep it up boys......😉
carlos are you ready for the game.....? (football)
😀
tbla, do you undestand portuguese?😉 😎
Oh, yes, the game... I'm a little nervous, we have to win...
At least we have an advantage, if we loose we don't have to take the first plane home.😀
Oh, forgot the beer in the freezer gotta go before it turns to ice!
tbla, do you undestand portuguese?😉 😎
Oh, yes, the game... I'm a little nervous, we have to win...
At least we have an advantage, if we loose we don't have to take the first plane home.😀
Oh, forgot the beer in the freezer
gotta go before it turns to ice!oh sim - eu compreendo que tudo..... e eu posso prever que sua equipe terá uma vitória grande em algumas horas e suas cervejas não girarão para o gelo mas você terá um headache e o cabelo e você verdes afrouxarão suas sobrancelhas antes dos cheers de 12 o'clock.......
what i meant was :
oh yes - i understand everything, i can foresee that your team will have a big win in a few hours and your beer will not become ice but you will have a headache and your hair will turn to green and you will loose both your eyebrows before 12 o'clock.
i tried to translate my portuguise to english with babel fish.
"oh yes - I understand that everything..... and I can foresee that its team will have a great victory in some hours and its beers will not turn for the ice but you headache will have one and 12 the green hair and you will loosen its sobrancelhas before cheers of o'clock......."
those alta vista guys need to work on there translation tool.......
😀
oh yes - i understand everything, i can foresee that your team will have a big win in a few hours and your beer will not become ice but you will have a headache and your hair will turn to green and you will loose both your eyebrows before 12 o'clock.
i tried to translate my portuguise to english with babel fish.
"oh yes - I understand that everything..... and I can foresee that its team will have a great victory in some hours and its beers will not turn for the ice but you headache will have one and 12 the green hair and you will loosen its sobrancelhas before cheers of o'clock......."
those alta vista guys need to work on there translation tool.......
😀
Hi there (Viva),
This realy seems to be a big happy family 😀
Carlos, do you live near Lisboa? You mentioned Queluz in one thread if I remember correctly...
I'm giving the first steps in the DIY world and would realy like to have a cup of coffe with you sometime (e uns dois dedos de conversa)...
And if you want to listen to a Jadis Orchestra and compare it with your regulated IGC just say so 😀
Best regards,
Hugo
This realy seems to be a big happy family 😀
Carlos, do you live near Lisboa? You mentioned Queluz in one thread if I remember correctly...
I'm giving the first steps in the DIY world and would realy like to have a cup of coffe with you sometime (e uns dois dedos de conversa)...
And if you want to listen to a Jadis Orchestra and compare it with your regulated IGC just say so 😀
Best regards,
Hugo
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