MonoAmp - Xmas Project #1

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Ray P
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#1 MonoAmp - Xmas Project #1

Post by Ray P »

I've now finished work until 2022 and under the prevailing circustances it's going to be very quiet so I've decided to clear some of my project backlog.

Off to a good start this morning. Well over a year ago I bought a chip amp kit on DIY Audio, primarily as an exercise in developing my smd soldering skills.

The amp uses the TDA8932 chip and is a little different in having a tranformer based input. I managed to solder it up neatly and had it workng with a temporary power supply but when I boxed it up and plugged in a SMPS brick it wouldn't work. On testing it turned out that the SMPS was faulty and had to be replaced but with a new, good, SMPS it still wouldn't work.

Image

This morning I set about getting it oerational and after swapping out a couple of resistors in the regulators, which were nominally 2R2 but measured 80R and 168R, I now it working again and playing music. I've started reboxing it and just need to get a front panel 3D printed to finalise it.

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Last edited by Ray P on Wed Dec 22, 2021 2:16 pm, edited 3 times in total.
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pre65
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#2 Re: MonoAmp - Xmas Project #1

Post by pre65 »

Ray P wrote: Wed Dec 22, 2021 11:20 am
The amp uses the TDA8932 chip and is a little different in having a transformer based input. I managed to solder it up neatly and had it working
And ? :)
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#3 Re: MonoAmp - Xmas Project #1

Post by pre65 »

pre65 wrote: Wed Dec 22, 2021 11:27 am
Ray P wrote: Wed Dec 22, 2021 11:20 am
The amp uses the TDA8932 chip and is a little different in having a transformer based input. I managed to solder it up neatly and had it working
And ? :)
Or, to put it another way, how does it compare to your other amps Ray ?
The only thing necessary for the triumph of evil is for good men to do nothing.

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#4 Re: MonoAmp - Xmas Project #1

Post by Daniel Quinn »

very nice work.

i'm jealous , regretably fine soldering is to dexterious for my one working hand , especially as it was my non dominant hand for 49 years
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#5 Re: MonoAmp - Xmas Project #1

Post by Ray P »

pre65 wrote: Wed Dec 22, 2021 12:19 pm Or, to put it another way, how does it compare to your other amps Ray ?
It sounds surprisingly good on a quick listen with a some old Mission speakers. I've not done any comparisons and probaby won't, as this was always just a build exercise and is destined for a workshop amp slot I think.
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#6 Re: MonoAmp - Xmas Project #1

Post by pre65 »

Ray P wrote: Wed Dec 22, 2021 2:20 pm
pre65 wrote: Wed Dec 22, 2021 12:19 pm Or, to put it another way, how does it compare to your other amps Ray ?
It sounds surprisingly good on a quick listen with a some old Mission speakers. I've not done any comparisons and probaby won't, as this was always just a build exercise and is destined for a workshop amp slot I think.
Ye, Ray, but it (they) might do things that your existing amps don't ?

It would not take long to at least try them in the main system.

My chip amp is a TDA3116 and I quite like it.
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#7 Re: MonoAmp - Xmas Project #1

Post by Ray P »

Maybe I'll plug the Lowthers into it tonmorrow...
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#8 Re: MonoAmp - Xmas Project #1

Post by Ray P »

I've not plugged in the Lowthers today but I have ordered the parts to make an LC filter to sit between the SMPS brick and the amp boards.
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#9 Re: MonoAmp - Xmas Project #1

Post by Mike H »

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#10 Re: MonoAmp - Xmas Project #1

Post by Ray P »

Should anyone be interested the kits are still available, cost for a pair of complete amp kits is $32US plus shipping (not expensive). You need to provide a suitable power supply and the usual sundries. There's a thread here;

https://www.diyaudio.com/community/thre ... ts.359193/
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#11 Re: MonoAmp - Xmas Project #1

Post by Ray P »

I've been having a more extended listen this morning using an old pair of Mission 773 floorstanding speakers - you know, this is a pretty good little amp, very easy to listen to with nothing that draws attention to the amplifier. Not surprisingly, given the value for money proposition the MonoAmps represent, the sound falls a little short of what my best amps can do but I happily listened for over an hour and only stopped because I was told 'It's Christmas day and you're being unsociable!'.
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#12 Re: MonoAmp - Xmas Project #1

Post by Ray P »

Today I managed to squeeze a CLC filter for the SMPS into my MonoAmp project and I'm listening to the result as I type this - a small but worthwhile improvement and definitely worth including on the hot-rodded MonoAmp.

It was a bit of a squeeze in my tiny chassis but achieved with a little surgery to the filter board and by turning it upside down.

The project just needs a front panel now, which I'll probably get 3D printed, for the lid to be put on this project. :D

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#13 Re: MonoAmp - Xmas Project #1

Post by Ray P »

Boxed up and a 3D printed front panel on order.
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#14 Re: MonoAmp - Xmas Project #1

Post by Ray P »

The 3D printed front panel arrived this morning so it was quickly installed and the project all buttoned up. I found I only had two of the black stainless allen bolts left so the top two will get replaced in due course.

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#15 Re: MonoAmp - Xmas Project #1

Post by Paul Barker »

Ray P wrote: Sat Dec 25, 2021 3:11 pm I've been having a more extended listen this morning using an old pair of Mission 773 floorstanding speakers - you know, this is a pretty good little amp, very easy to listen to with nothing that draws attention to the amplifier. Not surprisingly, given the value for money proposition the MonoAmps represent, the sound falls a little short of what my best amps can do but I happily listened for over an hour and only stopped because I was told 'It's Christmas day and you're being unsociable!'.
I had a giggle reading this. Every single Christmas we had to go visit relatives and “be sociable” when I just couldnt wait to get home to my Boat Ankers’! Let put it this way, these arent people I share my life with. Why cant I live my life at Christmas? Now theyre all dead I can! Why shouldnt everyone have festivals at home if they want?

I wont speak ill of the dead too much but the inlaws only ever sniped and griped at me the whole time. My parents were estranged with the bitterest of divorses when I was 10 and their fix to how to proceed with a son whose now lost a family home all be it full of black eyes swearing and shouting, their solution was dmp me at boarding school. You may aswell be sent to jail!

So what a relief, I can do what I want to do at last! The positive take out from this could be . Dont be a klunt to youre son or youre son in laww and boss them all the time, beause when youre ripples stop affecting the pond, he will be relieved to enjoy freedom at last. Moral is, be nice to people you are a klunt to! Stop controlling everyone! You cant live forever, leave pleasant thoughts behind you, not relief!
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
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