I guess what you want to say.
L 12-2 was used alone. no problem.
Add a preamplifier. There will be a little noise. Is that so?
In fact, this is a very common problem.
Most DIY preamplifiers have noise. It's not a matter of connectivity. It is the noise produced by the amplifier itself.
I recommend p7mini or P8 preamplifier.
The noise of operational amplifier is relatively small.
L 12-2 was used alone. no problem.
Add a preamplifier. There will be a little noise. Is that so?
In fact, this is a very common problem.
Most DIY preamplifiers have noise. It's not a matter of connectivity. It is the noise produced by the amplifier itself.
I recommend p7mini or P8 preamplifier.
The noise of operational amplifier is relatively small.
I guess what you want to say.
L 12-2 was used alone. no problem.
Add a preamplifier. There will be a little noise. Is that so?
In fact, this is a very common problem.
Most DIY preamplifiers have noise. It's not a matter of connectivity. It is the noise produced by the amplifier itself.
I recommend p7mini or P8 preamplifier.
The noise of operational amplifier is relatively small.
Make sure the input signal wires are close to each other as far as possible to minimize the loop area. Search this forum for grounding advice on amps to avoid loops, there was some good manual written by bonzai I think. With one common power supply, there will be ground loops, but you should be able to reduce hum if you follow the general guidelines. If, you're not happy with the result, try the resistors too.
Thank you guys for quick response and advices. Actually I fully assembled my amplifier and testing it. I will probably live with that hum since is hardly heard in speakers. But in any occasion I will try to fix this.
There is a version of the l12 that’s biased into class a now being sold as well.
I noticed it while looking at the regular versions.
It is called a30-l12, and has a suggested 24v supply.
I noticed it while looking at the regular versions.
It is called a30-l12, and has a suggested 24v supply.
Greetings friends. Can you please tell me which amplifier will be better? Is this L12-2 or MX50se? Maybe someone compared them? It is clear that the L12-2 is more powerful. I am interested in sound quality.
I want to compare l12-2 with L15 on MOSFETs ... or someone from you has already an experience ?
Only LJM or somebody who bought both and reverse-engineered them would know 🙂
Maybe only other bias-setting resistors, maybe not..
I have tried 12-2 bias at abt 0,6A using 26V, and it seemed ok with that. Measured distortion while operating in class A is very low, but for some reason my ears still did not like the sound.
Maybe only other bias-setting resistors, maybe not..
I have tried 12-2 bias at abt 0,6A using 26V, and it seemed ok with that. Measured distortion while operating in class A is very low, but for some reason my ears still did not like the sound.
Which kind of psu do you use for the L12-2 ? Transofrmer->Rectifier->Caps and then into the amp or do you have some kind of regulation for this high voltage ? I cant find any good regulators, that can go so high with a decent current. Which psus do you use for it ?
I am using 39/39 volts dc. Resistor P19 is approximately 920 ohms.
I would like to know which resistors you use instead of 1 kOhm?
From memory I thought it sounded flat and bright. Maybe some would call it detailed.
I want to build a amp around the l12-2. I already have them.
I also have a case where i want to put everything in, but it's a tiny case. I can fit 2 toroid transformers in it with a max diameter of 100mm and max 50mm heigh. This means a transformer of 120va for one channel.
I don't want to use all of the power, i'm happy with 40-50w@8ohm.
But i don't want to destroy the PSU and want good quality sound.
Is this possible?
I can get 2 amplimo 2x35v 120VA toroids.
If it's possible, how much uF of capacitors should i add per channel?
Min. 10.000uf?
A sketch of the setup i want to use if possible
I also have a case where i want to put everything in, but it's a tiny case. I can fit 2 toroid transformers in it with a max diameter of 100mm and max 50mm heigh. This means a transformer of 120va for one channel.
I don't want to use all of the power, i'm happy with 40-50w@8ohm.
But i don't want to destroy the PSU and want good quality sound.
Is this possible?
I can get 2 amplimo 2x35v 120VA toroids.
If it's possible, how much uF of capacitors should i add per channel?
Min. 10.000uf?
A sketch of the setup i want to use if possible
Attachments
I'm thinking of 4 schottky diodes (to-220).
4 4700uf caps (nichicon)
2 1uf cap + 1R resistor.
2x fuse
2x led (1 per rail)
I made a board layout for milling a pcb.
The caps fits over the toroid's, the schottky's between the toroid's. (Green square).
4 4700uf caps (nichicon)
2 1uf cap + 1R resistor.
2x fuse
2x led (1 per rail)
I made a board layout for milling a pcb.
The caps fits over the toroid's, the schottky's between the toroid's. (Green square).
