Yet another "noob looking for starter project" thread

[Tjj226]

That looks quite a mess, to be honest. Other side I hope looks better. Any other tube amps, you have too many, so show us more.

Lol, yes. Its basically a bread board and the design has been shifting and transforming every other day.

The big thing is I was trying to figure out some sort of layout that would allow the circuit to flow from the PSU to the signal section without jumping back and forth. Obviously the whole thing needs to be redesigned for it to be clean.

And lastly, I have other pics of other amps, but it doesn't seem like I can directly upload pics to DIY audio. So I need to figure something else out.

 

[Tjj226]

Hi Tjj226 and all,

In fact, the key differentiator of Luxman L-590AX is its Only Distortion Negative Feedback (ODNF) arrangement. Attached is a simplified schematic - the "error signal detection" circuit is at the bottom left.

Inspired by L-590, I have designed my version of ODNF amplifier - Simpelstark. You can see the schematic and the board layout HERE (I have also attached a few pictures here).

The pictures of my build are HERE.

The current version of the design is V1.3, the boards and kits are available if you go down the link in my signature. Some more details, including the measurement results, are also there.

You will definitely like the way it sounds. Its harmonics profile is pretty similar to the tube one but lower in absolute values. It's also very low-noise, particularly suitable for low-volume listening. Incredibly natural sound of the voices and acoustic instruments with lots of micro-nuances.

My build is in Moscow right now, however, I will most likely exhibit it at the High-End Show in Munich (May 2019).

Hope this helps.

Cheers,
Valery

Now here we go. This is mighty impressive.

 

[Guerilla]

Am I right that l-590 is class A and Simpelstark is AB?

 

[vzaichenko]

Am I right that l-590 is class A and Simpelstark is AB?

Not exactly - L-590 is class AB, Simpelstark is class AB with wide class A region (so-called constant gm OPS configuration) - OPS of V1.3 is different from V1.1 presented earlier in this thread.

Simpelstark is highly linear by design - it sounds very good even with no global feedback loop at all. 18db ODNF reduces the distortion level by roughly 10 times, comparing to "no feedback" configuration.

 

[Guerilla]

vzaichenko I read your thread Its very tempting many ppl tried to shoot it down, but you seem very competent. Do you have experience with Luxman amps? I was starting to be convinced that all proper amplifiers sound the same. Its not really my experience but then I dont have much experience with critical analytical listening, but many knowledgeable people say there are no difference. Would you say that l590 share sound and qualities with the Luxman products of early 80ies, or is it something totally different?

 

[vzaichenko]

vzaichenko I read your thread Its very tempting many ppl tried to shoot it down, but you seem very competent. Do you have experience with Luxman amps? I was starting to be convinced that all proper amplifiers sound the same. Its not really my experience but then I dont have much experience with critical analytical listening, but many knowledgeable people say there are no difference. Would you say that l590 share sound and qualities with the Luxman products of early 80ies, or is it something totally different?

Hi Guerilla,

You're touching a number of rather fundamental questions here OK - one by one.

Normally, if you'd like to compare two (sometimes more than two) amplifiers, the right way to do it is a blind A/B test. Important points here:
- quick and easy way to switch the amps;
- assistant for switching them - the test is blind for you;
- ability to align the signal volumes precisely (if one of the amps will play louder, it will create a better impression).
Human's brain likes to play games - your opinion will be always strongly biased if you know what amplifier plays in a given period of time.

Luxman amps are generally good, but not the same. Every manufacturer has got some more successful and less successful models throughout its history.
Most of the "less successful" amplifiers of many Japanese manufacturers suffered from the commercial approach - an attempt to save on the proper PSU and internal wiring. Luxman paid more attention to these things that many others in my opinion.

L-590 is one of the successful ones, plus it sort of "stands out" among the older models because of its rather special feedback approach - as far as I know, that's one of the first amplifiers with ODNF, later on, it's been used in a number of Luxman amplifiers from their high-end product line (like a more modern B-1000).

Here we come to the question of why people like to DIY the amplifiers. In many cases, a DIY build will be more expensive than most of the amplifiers the builder can afford. High-quality DIY is never cheap. However, you can build it the way you want, paying attention to important things.

Hope this helps

Cheers,
Valery

 

[maty tinman]

Luxman B-1000F monoblock power amplifier

...L-590 is one of the successful ones, plus it sort of "stands out" among the older models because of its rather special feedback approach - as far as I know, that's one of the first amplifiers with ODNF, later on, it's been used in a number of Luxman amplifiers from their high-end product line (like a more modern B-1000).

https://www.stereophile.com/content/luxman-b-1000f-monoblock-power-amplifier-measurements

 

[maty tinman]

Most of the "less successful" amplifiers of many Japanese manufacturers suffered from the commercial approach - an attempt to save on the proper PSU and internal wiring. Luxman paid more attention to these things that many others in my opinion.

https://www.soundandvision.com/content/luxman-b-1000f-monoblock-power-amp

The meticulous attention to detail starts with the B-1000f's transformer, which is wound with a 2mm-thick copper band, insulated with paper and hand-hammered around the core. A single craftsman builds all transformers for this model, finishing only three per week.

 

[vzaichenko]

https://www.soundandvision.com/content/luxman-b-1000f-monoblock-power-amp

Yep - that's what we call "power rails"