AndrewT said:
Here is the schematic, except that I use 1% tolerance Rout, 0,1% tolerance Rf resistors and 2200uF of Cs5, Cs6 caps, according to parallel configuration of a datasheet of LM4780. Also, if it is important, when I place an Rg resistor between Power Supply Ground and Signal Ground the hiss grows even further, depending on the value of the Rg resistor is used. The most clear that hiss I guess is on 20-40 Hz of frequency response.
I use two power supplies for four LM4780 chips.
Besides, there is an additional hiss I have from amp which appears when an input source is ON, however I followed the recommendations placed on this forum, related on proper grounding. I used the schematic, published by Ratza in Post 40. I have no PCB and use point-to-point wiring.
DC offset in quiescent mode is 9-12 mV. With load it arises to nearly 30mV.
Best Regards,
AndriyOL.
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Hi,
the tolerances on R1, 3, 4 & 8 are too wide.
C1, 2, 4, 5 & 6 restrict the bass extension.
Short the input using a zero ohm RCA plug.
Where is the decoupling located?
Where is the input RF filter?
C5, 6 and C13, 14 should be connected to R11 & input (signal) ground.
Pins 12 & 19 are permanently connected to power ground.
the tolerances on R1, 3, 4 & 8 are too wide.
C1, 2, 4, 5 & 6 restrict the bass extension.
Short the input using a zero ohm RCA plug.
Where is the decoupling located?
Where is the input RF filter?
C5, 6 and C13, 14 should be connected to R11 & input (signal) ground.
Pins 12 & 19 are permanently connected to power ground.
aurche said:
Maybe yours sounds bad or has stability problems but this can be caused by alot of factors. What loudspeakers are you using? Mine works great with a pair of DIY TQWP, there's plenty of power and very detailed. Well, not as detailed as the SE tube amp, but still... Are you sure you didn't make any mistakes on the PCB?
LM3875 rocks!
You have heard hundres of gainclones?.and they all sounded bad? Wow! that is really bad luck buddy! Because, these amps if they are build properly.they can sound really good.I can see that you are a Gainclone hater...
I have had many good amps like: Marantz,Luxman,Adcom,Portal panache,Bryston,Arcam,Blue circle etc,etc.
These gainclones can put a good fight with the above amps.as I mention before...if you build it right! you can achive an excellent amp no doubt!.
You have heard hundres of gainclones?.and they all sounded bad? Wow! that is really bad luck buddy! Because, these amps if they are build properly.they can sound really good.I can see that you are a Gainclone hater...
I have had many good amps like: Marantz,Luxman,Adcom,Portal panache,Bryston,Arcam,Blue circle etc,etc.
These gainclones can put a good fight with the above amps.as I mention before...if you build it right! you can achive an excellent amp no doubt!.
Hi, again
Oh, you dont understand me! I am a DIYer for 30 years. When i got my present amp (the Estonia HIFI UM-010 - http://www.postimage.org/image.php?v=gx1Dp3nJ) i was so happy. It sounded so good. That was 20 years ago. I havent changed my amp since then and i havent felt the need to as well. No gainclone can beat my amp's sound I mentioned the problems of the gainclone, but it is good for beginers. No one I know can build something better than my amp. Excluding tube amps.
BYE
Oh, you dont understand me! I am a DIYer for 30 years. When i got my present amp (the Estonia HIFI UM-010 - http://www.postimage.org/image.php?v=gx1Dp3nJ) i was so happy. It sounded so good. That was 20 years ago. I havent changed my amp since then and i havent felt the need to as well. No gainclone can beat my amp's sound
I mentioned the problems of the gainclone, but it is good for beginers. No one I know can build something better than my amp. Excluding tube amps.BYE
"No gainclone can beat my amp's sound I mentioned the problems of the gainclone, but it is good for beginers. No one I know can build something better than my amp. Excluding tube amps.
BYE"
Well, as a "Beginner" (38 years old).I know these amps can kick some a$$ (if they are build right).
and for the... " No one I know can build something better than my amp"... lol,lol...it looks like you do not know many people...
but again I can be wrong...
As long as you are happy and "think" you have the best amplifier in the entire world and nobody can have or build a better amp then yours....you should be proud very proud...
BYE"
Well, as a "Beginner" (38 years old).I know these amps can kick some a$$ (if they are build right).
and for the... " No one I know can build something better than my amp"... lol,lol...it looks like you do not know many people...
but again I can be wrong...
As long as you are happy and "think" you have the best amplifier in the entire world and nobody can have or build a better amp then yours....you should be proud very proud...
Not exactly an enticing prospect for one who seems to be in the beginning stages of DIY eletronics...my 2p worth. Gainclones offer a way for a budding DIYer to make something for themself without having to understand all aspects of it, including PCB layout and construction, RF issues, biasing, etc.
Well,0,125% tolerance resistors does not mean nothing to me.
as you can see they use ONE big cap 15000uf per channel...
it would be better if the use small ones like 3.300uf x5 or 2.200uf x7 per channel.but hey they are using 0.0000000001% tolerance parts right?.so it must be the best amp ever .lol...
Maybe you like the sound of this amp ,but for other people is not the sound they are looking for.
I am not saying gainclones amps are the best,but they can put a fight with some of the good commercial amps out there for sure...
as you can see they use ONE big cap 15000uf per channel...
it would be better if the use small ones like 3.300uf x5 or 2.200uf x7 per channel.but hey they are using 0.0000000001% tolerance parts right?.so it must be the best amp ever .lol...
Maybe you like the sound of this amp ,but for other people is not the sound they are looking for.
I am not saying gainclones amps are the best,but they can put a fight with some of the good commercial amps out there for sure...
lanchile07 said:
It depends very much on the capacitor. There are industrial capacitors with huge charge/discharge currents, say around 30...50A. I rather put some of these inside instead of using many smaller ones. Anyway, aurche, there is no "best amplifier", just amplifiers which either suites your expectations or not. If you like the sound, then it's fine, don't expect everybody to agree with your choice.
The toroid is 900W, the cap has a diameter of about 5". Do you think it isn't enough? The sound is better than the sound from the most perfectly built gainclone. If you want better sound, gainclone is a lost cause...
The amp was made by an russian millitary factory that was obligated to make a public production. There were no more than 2000 amps made. The trasistors put in the amp are matched by their parameters and the same transistors were put into the tactical missiles of russia. Do you think the russians will put lousy transistor and parts into the missile that is destined to hit America?
The amp was made by an russian millitary factory that was obligated to make a public production. There were no more than 2000 amps made. The trasistors put in the amp are matched by their parameters and the same transistors were put into the tactical missiles of russia. Do you think the russians will put lousy transistor and parts into the missile that is destined to hit America?
aurche said:I want you to find millitary quality transistors, 0,125% tolerance resistors, build this circuit and say what is better this or gay clone of what sort you like.
Here is the schematic.
Maybe I need some kind of factory production equipment to build the amp you propose?
What are the technical parameters of this amp?
Regards,
AndriyOL.
50W of power over what load you can find(4, 8, 16 ....). 2 channels. Protection for everithing you might do with the amp. The PCB is super complicated, but i have ot on paper, so i can scan it. You don't need any equipment different from a soldering iron. You will need a hefty load of transistors to match them.
Exactly! That amp belongs into the thread UGLY Looking Amp! - but good workingSparky OR said:way off topic!!
On the other hand it doesn't even seem to fall into the DIY category.
chylld said:
i can now put my ear literally within ear-hair's distance away from the speaker and
i cannot hear ANYTHING.
(unless i'm playing music of course!)
You can not hear ANYTHING with amplifier on.
Great!
Now, do not ruin this by playing some noisy humming modern stinking rap music
transformers suck
well, why do you use them?
At least they have to do some thing right ... or
regars lineup
Dear All, sorry if there was an answer, but I did not found it here.
Regarding BIG thump during power on - the biggest thump problem for me is in single polarity supply "Gainclone" (attached schematic from datasheet).
I cured the Thump only by adding soft start - slow voltage rise with schematic like "Juma's simple capacitance multiplier". Even thou I believe that there is another way to eliminate this thump, maybe someone was successful? (of course I do not mean that this way is the delay relay at the output )
Regarding BIG thump during power on - the biggest thump problem for me is in single polarity supply "Gainclone" (attached schematic from datasheet).
I cured the Thump only by adding soft start - slow voltage rise with schematic like "Juma's simple capacitance multiplier". Even thou I believe that there is another way to eliminate this thump, maybe someone was successful? (of course I do not mean that this way is the delay relay at the output
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