Hi @vitorio - yes indeed these kits are still available. Since we get the factory to pre-solder the bulk of the SMD components the monoAMP is much easier to build than the Kubelik kits which @Grarea has taken on. There are far fewer SMD components to put down, mostly you'll be soldering through-hole so if you're looking for a starter project these amps are a 'shallow end of the pool' compared to Kubelik's 'deep end'. I guess the most challenging component is the TDA8932 chip itself as regards fine soldering.
@guglielmope - a quick update. We have a revised PCB for the shunt regulator coming, we increased the surface area to help spread out the heat more but we won't know if it runs cool enough until we try it. I'll post a further update when I've experimented.
@guglielmope - a quick update. We have a revised PCB for the shunt regulator coming, we increased the surface area to help spread out the heat more but we won't know if it runs cool enough until we try it. I'll post a further update when I've experimented.
Hallo,
I am preparing to build my new transformer-fed amplifier TDA8932 and wanted to know if in your opinion it plays better with a linear power supply or an SMPS. What do you think about the lt4320 active bridges.
Have a nice day.
Guglielmo
I am preparing to build my new transformer-fed amplifier TDA8932 and wanted to know if in your opinion it plays better with a linear power supply or an SMPS. What do you think about the lt4320 active bridges.
Have a nice day.
Guglielmo
If the linear supply is a regulated one I'd choose that as it won't have the ultrasonic ripple a switching supply has. If its unregulated, go with the SMPS. Active bridges are cool but quite a lot more expensive - if you don't mind the spend they won't generate switching noise like diodes do.
We got the shunt reg PCBs back, I'll build one today and see how warm it gets.
We got the shunt reg PCBs back, I'll build one today and see how warm it gets.
Its discrete and I think I posted the schematic somewhere. Let me look it out.
https://www.diyaudio.com/community/...8932-25w-8r-mono-amp-kits.359193/post-7011705
https://www.diyaudio.com/community/...8932-25w-8r-mono-amp-kits.359193/post-7011705
Sorry Richard that was quite recent too ....I seemed not to get a notification so missed the last 2 pages. !
I used to lose notifications a lot on the older software but nowadays they seem to be coming according to the rules. If I don't visit to catch up, I don't get further emails beyond the first one.
These cards look very nice to me cute and kind.
How did the test go?
Can they be inserted vertically above the amplifier PCB?
Ciao
Guglielmo
How did the test go?
Can they be inserted vertically above the amplifier PCB?
Ciao
Guglielmo
The first part of the test I did on my bench with the dummy load, the shunts stayed warm to hot but not too hot so next I'll move on to a more realistic environment installed on amp modules.
Yes the size has been chosen so it'll fit in place of the LM317 on the amp board without fouling nearby components. The tricky thing will be to figure out how to get the supply voltage of this reg to be close enough to the LD1085 supply voltage on the board.
Yes the size has been chosen so it'll fit in place of the LM317 on the amp board without fouling nearby components. The tricky thing will be to figure out how to get the supply voltage of this reg to be close enough to the LD1085 supply voltage on the board.
Hi Guglielmo - tests are still on-going. I built another shunt yesterday to try out in a prototype DAC-amp. Here, it powers two TDA8932.
So far, so good.
So far, so good.
Mounting the LM317s horizontally, that's novel. Thanks for sharing the pic! I see you're using the fixings on the siderails, we normally break those off.
We've recently got the rev5 boards back from JLC. On these we've made a few small changes :
1) Replacing the LM317 reg with a shunt is now easier - R17 (0R) is fitted.
2) Coilcraft flat-wire inductors can be used for the output 22uHs.
3) Electrolytic caps have been re-oriented so they all face the same way. This makes checking for correct assembly a little bit easier.
The transformer footprint is compatible with the Taobao EE25 permalloy trafo, this change was made on an earlier rev but I can't remember if I mentioned it at the time. So I've pointed it out now. The input sensitivity changes as the turns ratio isn't quite the same but that's probably not too consequential.
We've recently got the rev5 boards back from JLC. On these we've made a few small changes :
1) Replacing the LM317 reg with a shunt is now easier - R17 (0R) is fitted.
2) Coilcraft flat-wire inductors can be used for the output 22uHs.
3) Electrolytic caps have been re-oriented so they all face the same way. This makes checking for correct assembly a little bit easier.
The transformer footprint is compatible with the Taobao EE25 permalloy trafo, this change was made on an earlier rev but I can't remember if I mentioned it at the time. So I've pointed it out now. The input sensitivity changes as the turns ratio isn't quite the same but that's probably not too consequential.
Mounted the Lm317 on the sockets so they could easily be replaced with an off board regulator. Was looking at the LT3042 board on AE, but is the 200ma limit too small? Also would long lead wires increase the inductance to the chip supply negatively ?
Left the siderails on because my m3 screws seemed larger than the provided standmount holes. Had to drill them, but the area near hole near L1 seem to be ground, and might short the standmount to the chassis if i expanded that hole.
Left the siderails on because my m3 screws seemed larger than the provided standmount holes. Had to drill them, but the area near hole near L1 seem to be ground, and might short the standmount to the chassis if i expanded that hole.
Also wanted to asked, I have 10uf in a K B1 into the amp, is that enough? My first time dealing with transformers.
So a new kit with the shunt regulator, EE25 and Coilcraft will be available soon?
Perhaps with the possibility of adapting to a 4 and 8 ohm load by replacing the inductances and capacitors included in the kit??
Perhaps with the possibility of adapting to a 4 and 8 ohm load by replacing the inductances and capacitors included in the kit??