Hi there!
I'd need psu circuit for the thing written below. (and some sentences about transformators, amps, etc
)
I took it into my head to build two new speakers... How does this connect to the Class A amps? Cos my second thought was to create a good amp for it!
Now I am strugling with the circuits. The finest, which I like most, is a 60W amp (www.tcaas.btinternet.co.uk/curtis60w.pdf I'm sure you know it). But I dont need that much amplifying!! I believe I'm too dumb to re-design that one, so I looked for an other http://web.telecom.cz/macura/pma2_en.html . Like it? That seems good, but I dont know whether the two OA pre stage is noisier or not than the preamp of the 60w-ts. But still I'm not able to mix the two and believe it does not worth the job.
After all I decided to build the 25w one, that will do with respect to my experience.
I'd need psu for it! I'd like to make seperate 15/-15 and 25/-25 v rails.
Or if you can help me with my first two problem with re-designing, than that)
Looking forward...
Yours,
Semir
Million thx!)
I'd need psu circuit for the thing written below. (and some sentences about transformators, amps, etc
)I took it into my head to build two new speakers... How does this connect to the Class A amps? Cos my second thought was to create a good amp for it!
Now I am strugling with the circuits. The finest, which I like most, is a 60W amp (www.tcaas.btinternet.co.uk/curtis60w.pdf I'm sure you know it). But I dont need that much amplifying!! I believe I'm too dumb to re-design that one, so I looked for an other http://web.telecom.cz/macura/pma2_en.html . Like it? That seems good, but I dont know whether the two OA pre stage is noisier or not than the preamp of the 60w-ts. But still I'm not able to mix the two and believe it does not worth the job.
After all I decided to build the 25w one, that will do with respect to my experience.
I'd need psu for it! I'd like to make seperate 15/-15 and 25/-25 v rails.
Or if you can help me with my first two problem with re-designing, than that
) Looking forward...
Yours,
Semir
Million thx!
)
Hi,
a suitable PSU design (+/-25V) can be found at http://www.tcaas.btinternet.co.uk/index-1.htm (great website, IMO). Output voltage should be set to the value you need but this is done fairly easily.
PSU for input opamp supply (+/-15V) can also be found there - http://www.tcaas.btinternet.co.uk/jlhlm3x7cb.htm. However, "slight" modifications will be needed: Q1, Q2, Q3, Q4, R3, R4, R9 and R10 should be thrown out; R1 and R2 should be replaced with a jumper; C1 and C2 should have at least 470uF.
PMA, who is the designer of the amp you're interested in, is also a member of this forum so you might want to ask him for further advice.
Regards,
Milan
a suitable PSU design (+/-25V) can be found at http://www.tcaas.btinternet.co.uk/index-1.htm (great website, IMO). Output voltage should be set to the value you need but this is done fairly easily.
PSU for input opamp supply (+/-15V) can also be found there - http://www.tcaas.btinternet.co.uk/jlhlm3x7cb.htm. However, "slight" modifications will be needed: Q1, Q2, Q3, Q4, R3, R4, R9 and R10 should be thrown out; R1 and R2 should be replaced with a jumper; C1 and C2 should have at least 470uF.
PMA, who is the designer of the amp you're interested in, is also a member of this forum so you might want to ask him for further advice.
Regards,
Milan
Semir said:
Szia,
for unregulated PSU, I recommend 2x18-19V transformer with about 100-120W/ch. Regulated PSU results lower noise and hum, but in this case You need bigger transformer, and regulator, with large amount heatsinks as well...
I would use unregulated with RC filter, and big capacitors.
sajti
Jó bütykölést!
sajti said:
Szia,
for unregulated PSU, I recommend 2x18-19V transformer with about 100-120W/ch. Regulated PSU results lower noise and hum, but in this case You need bigger transformer, and regulator, with large amount heatsinks as well...
I would use unregulated with RC filter, and big capacitors.
sajti
Jó bütykölést!
Hali!
I believe regulated psu is needed as I'd want to get two suply rails (+-15 and +-25). What does that do with the transformer? I mean, the two circuits meant by moamp looks good for it. Those are regulator circuits, and I'm in the need of a transformator for those two. Am I wrong? Or you mean that this kind of regulating is unimportant in contrast with an unregulated but filtered psu?
After all, you could help me in something else, too. Where can I buy it? (I learn at budapest, so thats not a problem.)
Thank you for the reply!
Happy xmas for everyone!
Köszi!
Csáó!
Szia,
for regulated power supply You need the secondary AC voltage same as the final DC. So 2x25V looks good. This will provide enough headroom, if the mains lower few percent. With this solution, I recommend 150W transformer for each channel. You can get the 2x15V from the regulated 2x25V DC, with two zener regulator.
Please keep in mind, that regulation means 27-28W more dissipation in the power supply.
sajti
for regulated power supply You need the secondary AC voltage same as the final DC. So 2x25V looks good. This will provide enough headroom, if the mains lower few percent. With this solution, I recommend 150W transformer for each channel. You can get the 2x15V from the regulated 2x25V DC, with two zener regulator.
Please keep in mind, that regulation means 27-28W more dissipation in the power supply.
sajti
Hali!
Thanks! Im keeping)
150W per channel??
I know that it is advisable to use seperated psu for each channel, but isnt it a bit too expensive? (I cannot even imagine the price of a tranformer, and I think a 20000uF cap is about 2-3 thousand Ft-s)
So you mean not to use any regulation, but something like that I attach?
And at last: do you know where can I buy any transformer?
Eh basszus, kezdem úgy érezni, hogy túl nagy fába próbálom belevágni a fejszémet...)
Thx a lot!
Have nice day!
Bye!
Thanks! Im keeping
)150W per channel??
I know that it is advisable to use seperated psu for each channel, but isnt it a bit too expensive? (I cannot even imagine the price of a tranformer, and I think a 20000uF cap is about 2-3 thousand Ft-s)
So you mean not to use any regulation, but something like that I attach?
And at last: do you know where can I buy any transformer?
Eh basszus, kezdem úgy érezni, hogy túl nagy fába próbálom belevágni a fejszémet...
) Thx a lot!
Have nice day!
Bye!
Attachments
I don't think that it's too complicated. 22000uF/40V, is about 2-3Euro (500-750HUF), so it's not expensive. You can use single transformer, with 300W or more (bigger is better, because class A use the full power from the PSU every time). The price of a single 300W transformer is about 60-70% of the double 150Ws.
The regulator can be simple darlington emitter follower, with 27V zener as reference. Use separated regulators for each channel to reduce crosstalk.
Menni fog!
sajti
The regulator can be simple darlington emitter follower, with 27V zener as reference. Use separated regulators for each channel to reduce crosstalk.
Menni fog!
sajti
hello
http://www.lomex.hu
440Ft egy 33mF/35V
here you can buy 33000uF/35V elkos for 440HUF (about 2 Euros)
átersztõtranyós stabilizátort 24V-os stabkockából is csinálhatsz. egy párszáz ohm-os trimmer kell a GND-láb és a föld közé. azzal be lehet állítani a 27V-ot. vagy a trimmert egy 3V-os zénerrel helyettesísd. ebben az esetben nem kell állítgatni.
[if you build the reg.PSU with pass-transistor tech, you can use 24v/1A regulator (7824) as reference. you need to take a 3V zener between the "gnd" leg and the ground. now it will give 27V.]
http://www.elektris.hu
itt kapsz jó áron jó toroidtrafót.
here you can buy good toroid-type trannys. they are so cheap.
http://www.lomex.hu
440Ft egy 33mF/35V
here you can buy 33000uF/35V elkos for 440HUF (about 2 Euros)
átersztõtranyós stabilizátort 24V-os stabkockából is csinálhatsz. egy párszáz ohm-os trimmer kell a GND-láb és a föld közé. azzal be lehet állítani a 27V-ot. vagy a trimmert egy 3V-os zénerrel helyettesísd. ebben az esetben nem kell állítgatni.
[if you build the reg.PSU with pass-transistor tech, you can use 24v/1A regulator (7824) as reference. you need to take a 3V zener between the "gnd" leg and the ground. now it will give 27V.]
http://www.elektris.hu
itt kapsz jó áron jó toroidtrafót.
here you can buy good toroid-type trannys. they are so cheap.
edl said:
7824 do the job well, but I prefer LM317/337 over the 78XX/79XX series. Easy to use, and designed for variable application.
If I would be Semir, I would use simple unregulated PSU for the 25V rails. Some RC filtering can helps to remove the hum. And my experience is that few smaller capacitor is better than one large!
sajti
Csáó Sajti!
Up to the point you could bring me about to chose the simple filtered psu, as a class A amp will have such a large discippation that this +30% is much much more than the needed)
And what do you think many Huge) caps insted of many little (what do we call little, and huge?)
Thx!
Have nice day (are u at work?)!
Bye
Up to the point you could bring me about to chose the simple filtered psu, as a class A amp will have such a large discippation that this +30% is much much more than the needed
)And what do you think many Huge
) caps insted of many little (what do we call little, and huge?)Thx!
Have nice day (are u at work?)!
Bye
Semir said:Csáó Sajti!
Up to the point you could bring me about to chose the simple filtered psu, as a class A amp will have such a large discippation that this +30% is much much more than the needed
And what do you think many Huge
Thx!
Have nice day (are u at work?)!
Bye
The simple filterted PSU has better transient response, over the regulators. Personally I don't like regulators, and especially the feedbacked regulators. They are complicated, and has some unwanted effects for poweramp apllications.
Musical Fidelity used RC filtering in they small class A amplifier. The configuration was 4700uF+4.7ohms series+4700uF. The first capacitor was common for both channels, the resistor, and there was separated resistor, and second capacitor for each channel.
Due Your amplifier has higher bias (1.5A instead of .7A of MF), I guess to use smaller resistor and larger capacitors.
My experience is that smaller first, and larger second sound better.
So my recommendation is: 1000uF after the bridge, the 2.7-3.3 ohms, and 30000uF for each channel. (3x10000uF sounds better than 1x33000uF). Use low ESR types, the bypass them with some non polarized capacitors, say 2-3 x 10uF.
Of course, the resistors must be high power types, say 3x10ohms/10W parallel, to get 3.3ohms
You can ask the designer too. His nick is PMA in this forum....
sajti
Yes. I working, as every time
Does your job have any connection with that this whole psu thing seems to be a simply sunday afternoons relaxative game for you?
I tried to ask him, but no reply yet.
Because I got other problems with the circuit, too. That also connects to capacitors. How should I know their types (electrolyte, unpolarized, tantal etc)? There are only the sizes of them shown, which I believe is not enough to build the amp. I guess the one who wants to build it should know it, but I dont...
Can u help?
Thx!
With regard, Semir
I tried to ask him, but no reply yet.
Because I got other problems with the circuit, too. That also connects to capacitors. How should I know their types (electrolyte, unpolarized, tantal etc)? There are only the sizes of them shown, which I believe is not enough to build the amp. I guess the one who wants to build it should know it, but I dont...
Can u help?
Thx!
With regard, Semir
Semir said:Does your job have any connection with that this whole psu thing seems to be a simply sunday afternoons relaxative game for you?
I tried to ask him, but no reply yet.
Because I got other problems with the circuit, too. That also connects to capacitors. How should I know their types (electrolyte, unpolarized, tantal etc)? There are only the sizes of them shown, which I believe is not enough to build the amp. I guess the one who wants to build it should know it, but I dont...
Can u help?
Thx!
With regard, Semir
Already no. I designed PA amplifiers few years before, but now I have another work. The audio remains my hobby.
So, the capacitors: All capacitors have the value over 1uF are electrolyte. C6 looks too big for me, but it's only my point of view. But I recommend to bypass it with some 100nF for the better highs.
I think that C1 is not really necessary, if Your preamp has output capacitor.
Hope this helps!
sajti
I can understand the rc filter part of this whole. I can understand everything except one.
There is that bridge thing, all right, which has 2 alternating input, and a + - output.
Sorry everyone, but Ill switch to hungarian. sorry.
Nem, nem, ez nem akar menni... (jó néhány sort sikerült már kitörölnöm... ) Most akkro végül is mekkora trafó kell? Mert az OK, hogy ha stabilizált tápot akarok, akkor a trafó kimenetén akkora váltó kell, mint a kívánt dc. ez eddig tiszta volt. De most épp arról beszéltünk, hogy szûrt legyen és ne stabilizáltat. Mindemellett, hogyan lesz akkor abból az akármekkora fesz-bõl +-? Ezen kívül, akkor miképp kéne kinyerni a +-15 -öt? És egyébként is iszonyatosan nem vágom mostmár tényleg egyáltalán ezt az egészet azt hiszem (((
Huh, nagyon elvesztem a témában...
Ilyenkor értem meg, hogy a cégek miért gyakorlattal rendelkezõ leendõ dolgozót keresnek. Lehúztam 5 évet mûszaki szki-ban, az elsõ 3 évben semmit nem értettem az egészbõl, most meg kandón cumizok, még értem is amit tanulok és bármilyen genya sulis feladatot meg tudok csinálni, de hogy miképp van ennek köze a gyakorlathoz, az ami teljesen sötét, és mindenhol a tudás hiányának falába ütközök
Eh. Na mind1.
Hali!
There is that bridge thing, all right, which has 2 alternating input, and a + - output.
Sorry everyone, but Ill switch to hungarian. sorry.
Nem, nem, ez nem akar menni... (jó néhány sort sikerült már kitörölnöm...
) Most akkro végül is mekkora trafó kell? Mert az OK, hogy ha stabilizált tápot akarok, akkor a trafó kimenetén akkora váltó kell, mint a kívánt dc. ez eddig tiszta volt. De most épp arról beszéltünk, hogy szûrt legyen és ne stabilizáltat. Mindemellett, hogyan lesz akkor abból az akármekkora fesz-bõl +-? Ezen kívül, akkor miképp kéne kinyerni a +-15 -öt? És egyébként is iszonyatosan nem vágom mostmár tényleg egyáltalán ezt az egészet azt hiszem (((Huh, nagyon elvesztem a témában...
Ilyenkor értem meg, hogy a cégek miért gyakorlattal rendelkezõ leendõ dolgozót keresnek. Lehúztam 5 évet mûszaki szki-ban, az elsõ 3 évben semmit nem értettem az egészbõl, most meg kandón cumizok, még értem is amit tanulok és bármilyen genya sulis feladatot meg tudok csinálni, de hogy miképp van ennek köze a gyakorlathoz, az ami teljesen sötét, és mindenhol a tudás hiányának falába ütközök
Eh. Na mind1.
Hali!
Semir said:I can understand the rc filter part of this whole. I can understand everything except one.
There is that bridge thing, all right, which has 2 alternating input, and a + - output.
Sorry everyone, but Ill switch to hungarian. sorry.
Nem, nem, ez nem akar menni... (jó néhány sort sikerült már kitörölnöm...
Huh, nagyon elvesztem a témában...
Ilyenkor értem meg, hogy a cégek miért gyakorlattal rendelkezõ leendõ dolgozót keresnek. Lehúztam 5 évet mûszaki szki-ban, az elsõ 3 évben semmit nem értettem az egészbõl, most meg kandón cumizok, még értem is amit tanulok és bármilyen genya sulis feladatot meg tudok csinálni, de hogy miképp van ennek köze a gyakorlathoz, az ami teljesen sötét, és mindenhol a tudás hiányának falába ütközök
Eh. Na mind1.
Hali!
Send me a mail! We can discuss it in email. I don't want to flood the forum with hungarian discussion.
sajti
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