Hi folks
Just curious has anyone already built any of these kits.
I note their is already a Naim discussion on the site but I was more interested in the L20SE type.
link to finished version here Assembled L20SE Power amplifier board with A1943 C5200 (include 2 channel boards | eBay
I do have previous experience building and modifying equipment and would like to use some of the many vishay bulk foil resistors etc I have left unused.Same with Silmic capacitors. Im not sure I want to try building the Honey badger though it would be a challenge.
Any comments re the design would be helpful.
thanks
Just curious has anyone already built any of these kits.
I note their is already a Naim discussion on the site but I was more interested in the L20SE type.
link to finished version here Assembled L20SE Power amplifier board with A1943 C5200 (include 2 channel boards | eBay
I do have previous experience building and modifying equipment and would like to use some of the many vishay bulk foil resistors etc I have left unused.Same with Silmic capacitors. Im not sure I want to try building the Honey badger though it would be a challenge.
Any comments re the design would be helpful.
thanks
Havent found one yet but most of their designs show this generic type circuit
Not sure if I would trust measured results or their significance
Improved MX50 SE Power amplifier assembled board Dual 2.0 channel 100W+100W HIFI | eBay
note item shown on original circuit board are same values ie resistors 68r etc and cap s 105 103 & 101 etc
Neither board uses bypass the larger 100mf caps (easily done)
Not sure if I would trust measured results or their significance
Improved MX50 SE Power amplifier assembled board Dual 2.0 channel 100W+100W HIFI | eBay
note item shown on original circuit board are same values ie resistors 68r etc and cap s 105 103 & 101 etc
Neither board uses bypass the larger 100mf caps (easily done)
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I think you'll find threads for just about any audio kit here.. Some popular ones get several threads.
All 3 you posted; L20, MX50 and L12-2 certainly have threads.
Just use the search button to search this forum or simply Google for the quite prominent DIYaudio threads listed for these LJM designed kits. The designer is a member (ljm_ljm) here and usually starts his own thread to introduce the models and start discussion.
All 3 you posted; L20, MX50 and L12-2 certainly have threads.
Just use the search button to search this forum or simply Google for the quite prominent DIYaudio threads listed for these LJM designed kits. The designer is a member (ljm_ljm) here and usually starts his own thread to introduce the models and start discussion.
thanks for that Ian
Hi
I had done a few searches but failed to find those links,
Having now spent enough time reading them I have come to conclusion
it would be worth Risking either an assembled version of L20 Ver? or L25 with the
op amp gain stage.The latter almost identical to the Dr White amp I made many years ago which has sadly been damaged in a house movee and which I am now unable to repair.
It also caused a damaged tweeter now repaired .
I was left with one good amp and one good trafo 220watt with ac 38v outs.
Plus 40k Mf or more in quality caps.
Both choices or any other suggestion give me the option of another trafo or a larger replacement.Also chance of lots of swaps of my beloved Vishay resistors etc.They really do work for me.
Just need advice as to which to pick as I need to order today from China as I am away for two weeks.Though I could put off purchase for a few days and try from Croatia or wherever I will be travelling.
Current loan of a commercial amp is driving me nuts.
Ive even looked at the m50s but my long ago impression of Musical fidelity amps was musical but flat.
I have sufficient heat sinking for a battleship but I always preferred the Whitenoise amp very low bias and luke warm.Seemed more dynamic to me.
Thanks for any suggestions.Great progress so far.
Hi
I had done a few searches but failed to find those links,
Having now spent enough time reading them I have come to conclusion
it would be worth Risking either an assembled version of L20 Ver? or L25 with the
op amp gain stage.The latter almost identical to the Dr White amp I made many years ago which has sadly been damaged in a house movee and which I am now unable to repair.
It also caused a damaged tweeter now repaired .
I was left with one good amp and one good trafo 220watt with ac 38v outs.
Plus 40k Mf or more in quality caps.
Both choices or any other suggestion give me the option of another trafo or a larger replacement.Also chance of lots of swaps of my beloved Vishay resistors etc.They really do work for me.
Just need advice as to which to pick as I need to order today from China as I am away for two weeks.Though I could put off purchase for a few days and try from Croatia or wherever I will be travelling.
Current loan of a commercial amp is driving me nuts.
Ive even looked at the m50s but my long ago impression of Musical fidelity amps was musical but flat.
I have sufficient heat sinking for a battleship but I always preferred the Whitenoise amp very low bias and luke warm.Seemed more dynamic to me.
Thanks for any suggestions.Great progress so far.
In case you have not seen this, L20 and L25 also, are discussed in this interesting thread: http://www.diyaudio.com/forums/solid-state/200016-l20-v8-14.html
Post in any thread if you want to discuss any issues - the members who posted may still be reading and able to reply.
Note that there is also L25D which is actually class D and there is at least a short thread in Class D forum here.
Post in any thread if you want to discuss any issues - the members who posted may still be reading and able to reply.
Note that there is also L25D which is actually class D and there is at least a short thread in Class D forum here.
Reply for Calvin
Vielen Danke for suggestion.
I had already studied that thread for almost a whole day and eventually opted for a ready soldered one.
This circuit gives me all the options I require.ie upgrade of power and sonic quality ? Meanwhile I went off on holiday for two weeks and I believe it has arrived in the country.
My intention is to power it up initially with a 230 watt 38V (ac) 52v DC power supply and run it in.Then swap a number of Vishays (Eventually all of them) Along with better Power supply/filtering and DC blocking caps ie Silmic/plus possibly schottky diodes and better sounding film caps until I am happy with the sound.Have spent almost 50 years doing likewise to many amplifiers in the past.
If it goes well I will give a progress report on the original thread.
Thanks again Dave.
Vielen Danke for suggestion.
I had already studied that thread for almost a whole day and eventually opted for a ready soldered one.
This circuit gives me all the options I require.ie upgrade of power and sonic quality ? Meanwhile I went off on holiday for two weeks and I believe it has arrived in the country.
My intention is to power it up initially with a 230 watt 38V (ac) 52v DC power supply and run it in.Then swap a number of Vishays (Eventually all of them) Along with better Power supply/filtering and DC blocking caps ie Silmic/plus possibly schottky diodes and better sounding film caps until I am happy with the sound.Have spent almost 50 years doing likewise to many amplifiers in the past.
If it goes well I will give a progress report on the original thread.
Thanks again Dave.
Today's businesses are too complex. I'm not sure if they're selling genuine products.
I suggest you ask for the merchant. LJM products must be provided. And it's based on my photos.
I only have Taobao store, but I don't sell in the international market at present.
If you buy any LJM products. You can email me photos. I can verify the authenticity
ljm_ljm@foxmail.com
Hi,
@raffajaffa,
you may want to have a look at my website where I dicuss some modifications of the L12-2.
With my modules the idle current varyed too much from module to module for my taste.
So I changed the fixed resistor seting to a trimpot-variable one.
Also added bits of Caps just for the good gut feeling .... am not a convinced device modder .... I´d rather try to sort out any possible circuit probs before.
Assemblies working below their capablities or with too high tolerances don´t become the cream of the crop by only changing cap brand A to brand B.
I also wouldn´t run the L12-2 on such high supply rails.
A 30V tranformer is imho better suited to this amp, especially when You intend to drive 4Ohms or lower impedance loads.
If you require considerably more power I´d suggest to use a second amp and supply both from a 30V transformer - which is btw. a nice method to create an compact amplifier block for active speakers with higher power capability for the bass channel, but still using the same amp modules and a single power supply for the whole assembly.
jauu
Calvin
@raffajaffa,
you may want to have a look at my website where I dicuss some modifications of the L12-2.
With my modules the idle current varyed too much from module to module for my taste.
So I changed the fixed resistor seting to a trimpot-variable one.
Also added bits of Caps just for the good gut feeling .... am not a convinced device modder .... I´d rather try to sort out any possible circuit probs before.
Assemblies working below their capablities or with too high tolerances don´t become the cream of the crop by only changing cap brand A to brand B.
I also wouldn´t run the L12-2 on such high supply rails.
A 30V tranformer is imho better suited to this amp, especially when You intend to drive 4Ohms or lower impedance loads.
If you require considerably more power I´d suggest to use a second amp and supply both from a 30V transformer - which is btw. a nice method to create an compact amplifier block for active speakers with higher power capability for the bass channel, but still using the same amp modules and a single power supply for the whole assembly.
jauu
Calvin
LJM, can you confirm that the attached picture of MX50x2 is a genuine LJM product? Or is it fake?
I ask since it worked fine at +/- 25 volts for initial testing purposes.
However all the outputs and at least one driver (649) burned in seconds at very low volumes the first time it was connected to +/- 50 volts.
So I wonder if it is fake with fake outputs and/or drivers that can not handle the voltage.
Before talking to the vendor I wanted to check with you, if possible. The seller is hifispot168 on ebay.
Attachments
It's authentic. no problem.
+-50V is no problem.
But higher voltage. Higher installation requirements.
I have used mx50x2 + - 60V, no problem.
Consider l20se. Do not use SMPS.
Any particular reason to not use SMPS, or is it your general advice that apply for all your amps?
Switching power supply has good quality. Some of them are of poor quality.
However, SMPS for power amplifier is mostly made by DIY amateur. It's not good.
They will produce high frequency interference, PWM frequency interference. Serious damage to the power tube. loudspeaker box.
But not all SMPS will have problems. I don't know exactly.
But there must be no problem with traditional transformers.
So I recommend traditional transformers.
I've never seen an example of a traditional transformer being damaged. But the switching power supply has many damaged amplifiers.
Or the power supply is damaged after some time. quite a lot.