Thank you Rick 
! The VU-meter is salvaged from an old Sony TA-212 amplifier that was beyond repair. I've etched a little PCB for attaching the LED lights, just above the VU meter. The VU-meter driver is build onto a custom driver circuit on vero board. However, there are kits on eBay that will probably work as well.
I have bought the PCB's from eBay. There are lot of sellers that resell the same PCB. For example here: LM3886 HiFi Power Amplifier PCB 2pcs Rectifier Filter Power Supply PCB | eBay
! The VU-meter is salvaged from an old Sony TA-212 amplifier that was beyond repair. I've etched a little PCB for attaching the LED lights, just above the VU meter. The VU-meter driver is build onto a custom driver circuit on vero board. However, there are kits on eBay that will probably work as well.I have bought the PCB's from eBay. There are lot of sellers that resell the same PCB. For example here: LM3886 HiFi Power Amplifier PCB 2pcs Rectifier Filter Power Supply PCB | eBay
Thank you Rick
I have bought the PCB's from eBay. There are lot of sellers that resell the same PCB. For example here: LM3886 HiFi Power Amplifier PCB 2pcs Rectifier Filter Power Supply PCB | eBay
I thought I'd seen those meters before. Just couldn't place where. I've seen the smaller ones on eBay, but not the larger ones. Will have to look again. Thanks for the link to the XY boards.
I recently completed an amp based on the LM4780 LSI chipamp which is dual 3886s. It is one of my best sounding stereo amps in my stable other than my home theater Pioneer Elite - that uses the Class D B&O ICE modules. Wonderful sounding!
Anyway, your amp is one great looking piece of kit and I'm sure it sounds great too.
Rick
You're welcome Rick .
You can say that again! I was really surprised about about the sound stage either. I did not expect much of it, since well, such a little reasonably priced chip could not really perform that well. Although, that is what I thought… how wrong could I be! It really rocks the boat. I've tested it and it produces about 42.5W @8 ohm, 1000Hz sine wave. At first sight 40 W @ 8 ohm does not seem much. The reality is that, even when I listen to music really loud, I hardly exceed 1 W RMS. I am thinking of ‘cloning’ my own amp, and build another one just alike. I already have another 300VA 2x22 Vac Amplimo toroid here, just like the one used in this build. I would then like to incorporate both amplifiers in my home cinema set; one amp for the rears, one amp for the fronts. However… I still need to find another unsalvagable Sony amp (I could not get it over my heart to dismantle one just for the VU-meter)
.You can say that again! I was really surprised about about the sound stage either. I did not expect much of it, since well, such a little reasonably priced chip could not really perform that well. Although, that is what I thought… how wrong could I be! It really rocks the boat. I've tested it and it produces about 42.5W @8 ohm, 1000Hz sine wave. At first sight 40 W @ 8 ohm does not seem much. The reality is that, even when I listen to music really loud, I hardly exceed 1 W RMS. I am thinking of ‘cloning’ my own amp, and build another one just alike. I already have another 300VA 2x22 Vac Amplimo toroid here, just like the one used in this build. I would then like to incorporate both amplifiers in my home cinema set; one amp for the rears, one amp for the fronts. However… I still need to find another unsalvagable Sony amp (I could not get it over my heart to dismantle one just for the VU-meter)
You've inspired me to build 'yet another' amp. Like I really need one!You're welcome Rick
You can say that again! I was really surprised about about the sound stage either. I did not expect much of it, since well, such a little reasonably priced chip could not really perform that well. Although, that is what I thought… how wrong could I be! It really rocks the boat. I've tested it and it produces about 42.5W @8 ohm, 1000Hz sine wave. At first sight 40 W @ 8 ohm does not seem much. The reality is that, even when I listen to music really loud, I hardly exceed 1 W RMS. I am thinking of ‘cloning’ my own amp, and build another one just alike. I already have another 300VA 2x22 Vac Amplimo toroid here, just like the one used in this build. I would then like to incorporate both amplifiers in my home cinema set; one amp for the rears, one amp for the fronts. However… I still need to find another unsalvagable Sony amp (I could not get it over my heart to dismantle one just for the VU-meter)
Where do find those low-profile toroidals? Never mind, I just went to the Amplimo website. All the ones I buy here in the states are about 4" high. I think the low-profile ones command a much higher price tag. There must be a vendor in the States that sells these low-profile beasts. I need to look into it more and check out Amplimo. Importing a single, heavy item like a toroidal is expensive. Rick
@Redjr; Haha, I know the feeling. By the way, I really like Amplimo transformers. If I am correct these transformers are even recommended for usage in audio because of minimal mechanic hum and a reduced magnetic field. Talema (a German producer) has also nice low profile transformers in their assortiment, but I dont know if these are commonly available in the US.
@Bare; Sure! But like I stated earlier, I would like to have two of the same units. I find it really fascinating to see the meters react to dynamics. Especially in movies these are huge, which occasionally could ask for full power. If you look carefully, you can see that the scale is more or less logarithmic, starting at 0 - 0.01 W, with 1 W at ~60% deflection. Even at low volumes, there is quite some deflection which - I think - is nice for entertainment. When one really wants to assess true RMS power there are of course better, more accurate ways than using these power meters ;-).
@Bare; Sure! But like I stated earlier, I would like to have two of the same units. I find it really fascinating to see the meters react to dynamics. Especially in movies these are huge, which occasionally could ask for full power. If you look carefully, you can see that the scale is more or less logarithmic, starting at 0 - 0.01 W, with 1 W at ~60% deflection. Even at low volumes, there is quite some deflection which - I think - is nice for entertainment. When one really wants to assess true RMS power there are of course better, more accurate ways than using these power meters ;-).
Well whatever Blows Yer Jets Mate..
Today I received MY XY lm3886 'Kit'. (amp boards only as I have decent PS units)
Hey! <10$ delivered from Ali express... and I was bored.
Unfortunately, BUT Not surprisingly, the Lm chips are undisputably Fakes.
The only bit that had any attraction, thinking I could/would throw away the rest of the Junk kit.
Poorly made fakes at that..as it was instantly apparent even while still in their Baggies.
If they can't even get the package 'semi right', what hope is there they didn't omit half of the die /circuitry ??
Goes without saying that the rest of the parts are Fakes, absolutely the 'wima' caps are.
Sooo.. now at an impasse.
Either build the thing following what allegedly worked in this thread's XY build or simply save myself the aggro and bin the thing immediately.
Yesss I know: "You can't cheat an Honest man"
Shame on Me.. but this Chi Fi idiocy has to end ?
Likely not though.. until fools like myself stop buying based only on impossibly low prices.
Today I received MY XY lm3886 'Kit'. (amp boards only as I have decent PS units)
Hey! <10$ delivered from Ali express... and I was bored.
Unfortunately, BUT Not surprisingly, the Lm chips are undisputably Fakes.
The only bit that had any attraction, thinking I could/would throw away the rest of the Junk kit.
Poorly made fakes at that..as it was instantly apparent even while still in their Baggies.
If they can't even get the package 'semi right', what hope is there they didn't omit half of the die /circuitry ??
Goes without saying that the rest of the parts are Fakes, absolutely the 'wima' caps are.
Sooo.. now at an impasse.
Either build the thing following what allegedly worked in this thread's XY build or simply save myself the aggro and bin the thing immediately.
Yesss I know: "You can't cheat an Honest man"
Shame on Me.. but this Chi Fi idiocy has to end ?
Likely not though.. until fools like myself stop buying based only on impossibly low prices.
@Bare, like you state, that was to be expected and maybe a bit naive... there is a variety of topics here (and on other forums as well), that adress counterfeit components. Never buy components from eBay, just the bare PCB's. There is a reason why they are cheap. A waste of money, but a good tip for novel builders; only buy the bare PCB's.
The PCB's themselves are sane. I think many members have proven that already. If you doubt it, just check the schematics in the LM3886 datasheet and compare that to the PCB's you have received.
@Infinia, thank you! And indeed, had that experience already many times over here. Its a sort of compliment I think ;-).
EDIT:
By the way guys, almost forgotten it, but.... preparations for the second LM3886 amplifier have been made! I constructed another VU-meter driver circuit, highly similar to the one used in the completed amplifier. It contains (just like the other amplifier) a fade-in circuit for the leds (therefore the big cap and the BC337). I was inspired by BMW that uses nice lights inside the vehicle which slowly fade-in when you open the doors. The amplifier shows sort of the same; when you turn the amplifier on, the VU-meter leds slowly fade in (about 2 seconds). At that time the relay also connects. Not necessary, but - I think - a nice, additional effect.
Picture:
The PCB's themselves are sane. I think many members have proven that already. If you doubt it, just check the schematics in the LM3886 datasheet and compare that to the PCB's you have received.
@Infinia, thank you
! And indeed, had that experience already many times over here. Its a sort of compliment I think ;-).EDIT:
By the way guys, almost forgotten it, but.... preparations for the second LM3886 amplifier have been made
! I constructed another VU-meter driver circuit, highly similar to the one used in the completed amplifier. It contains (just like the other amplifier) a fade-in circuit for the leds (therefore the big cap and the BC337). I was inspired by BMW that uses nice lights inside the vehicle which slowly fade-in when you open the doors. The amplifier shows sort of the same; when you turn the amplifier on, the VU-meter leds slowly fade in (about 2 seconds). At that time the relay also connects. Not necessary, but - I think - a nice, additional effect.Picture:
An externally hosted image should be here but it was not working when we last tested it.
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Hi Gideon,
For the VU-meter driver circuit I have made use of a schematic that was posted already quite a while ago on Circuits Online: Circuits Online - Schakelingen - VU meter
However, I have changed the 22uF capacitor to 2.2uF (I think 22uF is a typo). Therewith low frequencies conducted less easily, and since power on could also be considered as a low frequency, chances emerge that your meters will fully deflect for a brief period, just after the circuit is energized. It should not really harm the meters, but ever still, better safe than sorried ;-). With 2.2uF this phenomenon dissapeared and the meters are still responding quite accurate. EDIT: almost forgotten, I have also changed the 470 uF capacitor to 10 uF. At 470uF the meters respond really lazy, while they should respond quite rapid. You can fiddle a bit with this value to get the optimum result for your VU's.
The fade in circuit is basically similar to this scheme:
However, it could be that you have to fiddle a bit with the resistor values. For example I changed R1 to 15k and R3 to 680 ohms. The first to increase the fade in delay time (that could also be achieved by increasing the capacitor), the second because I had no 750 ohms resistor in stock. In addition I added a little indication LED on the PCB, which is nothing more than a regular LED and a series resistor of 4.7K.
For the VU-meter driver circuit I have made use of a schematic that was posted already quite a while ago on Circuits Online: Circuits Online - Schakelingen - VU meter
However, I have changed the 22uF capacitor to 2.2uF (I think 22uF is a typo). Therewith low frequencies conducted less easily, and since power on could also be considered as a low frequency, chances emerge that your meters will fully deflect for a brief period, just after the circuit is energized. It should not really harm the meters, but ever still, better safe than sorried ;-). With 2.2uF this phenomenon dissapeared and the meters are still responding quite accurate. EDIT: almost forgotten, I have also changed the 470 uF capacitor to 10 uF. At 470uF the meters respond really lazy, while they should respond quite rapid. You can fiddle a bit with this value to get the optimum result for your VU's.
The fade in circuit is basically similar to this scheme:
An externally hosted image should be here but it was not working when we last tested it.
However, it could be that you have to fiddle a bit with the resistor values. For example I changed R1 to 15k and R3 to 680 ohms. The first to increase the fade in delay time (that could also be achieved by increasing the capacitor), the second because I had no 750 ohms resistor in stock
. In addition I added a little indication LED on the PCB, which is nothing more than a regular LED and a series resistor of 4.7K.
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Cool! I really like the circuit; it is simple but effective . I have made by the way a video of the amplifier at power on: https://youtu.be/VdnH_a1ezZs
. I have made by the way a video of the amplifier at power on: https://youtu.be/VdnH_a1ezZsI see you also made a real scale for the VU meters (saw it on my phone yesterday, now on my computer screen it looks even better). I suppose you derived the wattage scale from your speaker impedance and gain of the amplifier itself?
Beautiful build, makes me rethink my plan to keep the front clean without even a power button...
Beautiful build, makes me rethink my plan to keep the front clean without even a power button...
Haha, thank you Gideon .
Since it is vacation - yay! - and I have received most parts to complete another LM3886 amplifier, I have started with completing LM3886 No. 2.
The design will be highly similar to No. 1, but some details will be different. For example, I have attached the LM PCBs directly to the heatsink, which I think is more convenient.
The PSU PCB is populated and fully functional.
The next step will be drilling some holes in the cabinet.
.Since it is vacation - yay! - and I have received most parts to complete another LM3886 amplifier, I have started with completing LM3886 No. 2.
The design will be highly similar to No. 1, but some details will be different. For example, I have attached the LM PCBs directly to the heatsink, which I think is more convenient.
An externally hosted image should be here but it was not working when we last tested it.
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An externally hosted image should be here but it was not working when we last tested it.
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The PSU PCB is populated and fully functional.
An externally hosted image should be here but it was not working when we last tested it.
The next step will be drilling some holes in the cabinet.
Hi friends, at first I want to wish you all the best for 2016! Yesterday I have finished the second LM3886 amplifier. Well, almost... I am still waiting for one handle that will be attached to the rear. I expect to receive it soon. The second LM3886 amplifier looks and performs very similar to the first version, although I have changed some minor details. As with the first amplifier, I am very statisfied with the result
I hope you all like it. Some pictures below.
Yesterday I have finished the second LM3886 amplifier. Well, almost... I am still waiting for one handle that will be attached to the rear. I expect to receive it soon. The second LM3886 amplifier looks and performs very similar to the first version, although I have changed some minor details. As with the first amplifier, I am very statisfied with the result I hope you all like it. Some pictures below.
An externally hosted image should be here but it was not working when we last tested it.
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An externally hosted image should be here but it was not working when we last tested it.
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An externally hosted image should be here but it was not working when we last tested it.
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An externally hosted image should be here but it was not working when we last tested it.
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An externally hosted image should be here but it was not working when we last tested it.
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