Thank you much for the answer Tom, sorry, I was not aware of that Modulus-286 was already an option.
I built 6 modulus 86 amps, three with LM3876 (to power JBL 2451J compression drivers) and three with LM3886 (to power JBL 2220H woofers). I used the 3876 for the compression drivers as they don't require a lot of power and this chip amp has lower distortion. I am happy with the results four years later. See posts #25 and #35 in this thread that convinced me to do this.
If I recall correctly there were basically two flavours of the LM38xx series ICs. Each flavour had a version with a small output stage (LM3876) and a large output stage (LM3886). I also seem to recall that there was a version with a slightly different pinout (LM3875?)
I'm currently camped out on vacation in rural France. There's wifi at the reception/bar but it's about the same speed as my 1988 2400-baud dialup connection was. Ok, maybe 9600 baud, but not much beyond that. There is 4G cellular network but I'm not willing to pay $10 for each 20 MB of data to download the old data sheets. Sorry. If this is still relevant by the middle of next week when I land in Denmark and have a better internet connection I'm happy to dig a little deeper.
Tom
I'm currently camped out on vacation in rural France. There's wifi at the reception/bar but it's about the same speed as my 1988 2400-baud dialup connection was. Ok, maybe 9600 baud, but not much beyond that. There is 4G cellular network but I'm not willing to pay $10 for each 20 MB of data to download the old data sheets. Sorry. If this is still relevant by the middle of next week when I land in Denmark and have a better internet connection I'm happy to dig a little deeper.
Tom
Hi everyone,
In the past week I build two modulus-86 and one power-86.
My transformer (I had it already for another project is a 300VAC 2 x 22v Amplimo transformer.
For the moment the 300VAC is more than enough and because it is 2 x 22V it should work.
Windings are as follows:
According the Antek AN 2222: red=green 5, yellow= blue 6, blue=green 7 en grey=blue 8.
When I connect the transformer the result is 60v DC output (no load). Measured between V-(J4) and V+(J2)
What am I doing wrong?
Cheking the schema of the Power-86:
2-3 are conneceted, yellow(blue6) is connected to blue(green7) and doubling the voltage.??
Thanks for any tips or solutions.
Ad.
In the past week I build two modulus-86 and one power-86.
My transformer (I had it already for another project is a 300VAC 2 x 22v Amplimo transformer.
For the moment the 300VAC is more than enough and because it is 2 x 22V it should work.
Windings are as follows:
According the Antek AN 2222: red=green 5, yellow= blue 6, blue=green 7 en grey=blue 8.
When I connect the transformer the result is 60v DC output (no load). Measured between V-(J4) and V+(J2)
What am I doing wrong?
Cheking the schema of the Power-86:
2-3 are conneceted, yellow(blue6) is connected to blue(green7) and doubling the voltage.??
Thanks for any tips or solutions.
Ad.
Last edited:
What are you expecting? 22v ac will be rectified to (approx) 30V DC so as between two rails you should get 60V
So, you say, this is correct and I think you are absolutely right! I made some wrong thinking
Stupid me. 🤣🤣
Thanks, I am back to earth again...😊
It's no secret that the LM3886 is playing very hard to get these days. The LM317L and LM337L are now regularly out of stock as well, with a longish lead time. The LM4562NA stock levels are dropping too. TI has some but some of my customers are having trouble buying from them for some bizarre reason. It's also a bit silly to spend $10 to ship $3 worth of parts.
I happen to have a handful of the LM3886T that I can part with and I just placed a larger order with TI for the voltage regulators and LM4562NA. Starting in early July I will be able to offer an IC kit with the Modulus-86 boards. The IC kit will only be available with the purchase of the Modulus-86 board.
Since I don't generally enjoy stuffing itty-bitty parts into itty-bitty bags I might choose to make the IC kit a stereo kit and include the output inductors and the boards. This would make inventory management quite a bit easier and also cut the number of bags I need to stuff by half.
Tom
I happen to have a handful of the LM3886T that I can part with and I just placed a larger order with TI for the voltage regulators and LM4562NA. Starting in early July I will be able to offer an IC kit with the Modulus-86 boards. The IC kit will only be available with the purchase of the Modulus-86 board.
Since I don't generally enjoy stuffing itty-bitty parts into itty-bitty bags I might choose to make the IC kit a stereo kit and include the output inductors and the boards. This would make inventory management quite a bit easier and also cut the number of bags I need to stuff by half.
Tom
Modulus 86 2 channel build using Quad 405 chassis.
Chassis: Quad 405 reproduction chassis from aliexpress with additional Quad brackets to mount the Mod 86 boards. Rear panel modified to hold Neutrik type inputs. I'm planning on balanced inputs eventually after I construct a balanced preamp and aquire a balanced DAC.
Transformer: Triad F-215U 24-0-24 vac 196 VA gives +-32VDC under full load with 47 rms/channel both channels driven into 8 ohm loads.
Cap board: Generic.
Sounds: Perfect it seems. The best sounding solid state amp and probably best ever sounding amp I have ever heard.
Background: I'm a 65 year old BSEE who abandoned a Dynaco ST400 (200wpc) solid state amp for tubes decades ago. Looking back it had massive crossover distortion that, when I acquired high efficiency speakers was bested by a 12 watt per channel solid state Realistic Radio Shack amp. I have made dozens of tube amps so I decided to hear a state-of-the-art solid state amp. The Modulus 86 is no comparison to the SS amps of yore and bests most if not all of the tube amps I built or still own.
Many thanks to Tom Christiansen for offering this to the DIY community!
Tom Lang, Asheville, NC
Chassis: Quad 405 reproduction chassis from aliexpress with additional Quad brackets to mount the Mod 86 boards. Rear panel modified to hold Neutrik type inputs. I'm planning on balanced inputs eventually after I construct a balanced preamp and aquire a balanced DAC.
Transformer: Triad F-215U 24-0-24 vac 196 VA gives +-32VDC under full load with 47 rms/channel both channels driven into 8 ohm loads.
Cap board: Generic.
Sounds: Perfect it seems. The best sounding solid state amp and probably best ever sounding amp I have ever heard.
Background: I'm a 65 year old BSEE who abandoned a Dynaco ST400 (200wpc) solid state amp for tubes decades ago. Looking back it had massive crossover distortion that, when I acquired high efficiency speakers was bested by a 12 watt per channel solid state Realistic Radio Shack amp. I have made dozens of tube amps so I decided to hear a state-of-the-art solid state amp. The Modulus 86 is no comparison to the SS amps of yore and bests most if not all of the tube amps I built or still own.
Many thanks to Tom Christiansen for offering this to the DIY community!
Tom Lang, Asheville, NC
Attachments
Solder intended for use in electronics has flux embedded in it. There's no need to add more flux.
About the only time I ever add more flux is when I solder surface mounted parts with large pads by hand. I also add flux when soldering fine pitch surface mounted parts (think QFN, TQFP, etc. packages). In that case the flux helps prevent solder bridges.
Tom
About the only time I ever add more flux is when I solder surface mounted parts with large pads by hand. I also add flux when soldering fine pitch surface mounted parts (think QFN, TQFP, etc. packages). In that case the flux helps prevent solder bridges.
Tom