Hi Jamh
Just for the aesthetics! Having a heatsink on just one side didn't look good in my opinion.🙄
Cheers
Walter
Just for the aesthetics! Having a heatsink on just one side didn't look good in my opinion.🙄
Cheers
Walter
Hi rabstg
I don't think one need a heatsink this size. They are also a part of the housing. Size is 172x80x25.
Cheers
Walter
I don't think one need a heatsink this size. They are also a part of the housing. Size is 172x80x25.
Cheers
Walter
Walter 
I see also that you have gone to bed and not tested anything. Good! It's a good idea to test you before you are going to bed. I will ruin your night sleep if something doesn't work right.
I see also that you have gone to bed and not tested anything. Good! It's a good idea to test you before you are going to bed. I will ruin your night sleep if something doesn't work right.
Hi P-A
You're right, it's better to take one step at the time. Testing, and in the worst case troubleshooting, is best to be done with a clear head. At least I had a good night sleep yesterday, don't know if it will be like that today.
O.K., this evening I will try to check the voltages. If they turn out alright and there's no smoke than I'm gonna solder the op-amp and the LM in place. After that I'll just hook it up to my CD player and speakers and check if it is a "Revolution" in the chipamp world.😀
Keep you posted
Walter
You're right, it's better to take one step at the time. Testing, and in the worst case troubleshooting, is best to be done with a clear head. At least I had a good night sleep yesterday, don't know if it will be like that today.
O.K., this evening I will try to check the voltages. If they turn out alright and there's no smoke than I'm gonna solder the op-amp and the LM in place. After that I'll just hook it up to my CD player and speakers and check if it is a "Revolution" in the chipamp world.😀
Keep you posted
Walter
OP-amps received
Finally I received the AD8620 (from digikey) so now I have all the parts!! (Thanks for the coils P-A) Hopefully I will have sound during the Weekend😀
AndyB
Finally I received the AD8620 (from digikey) so now I have all the parts!! (Thanks for the coils P-A) Hopefully I will have sound during the Weekend😀
AndyB
I'll guess you know that you should test in this order:
1 Supply voltage, +- 12 V
2 Solder in opamp
3 Apply signal, check that the opamps work, measure offset voltage (less than 0.1 mV)
4 Solder the LM3886
5 Test the whole amp, offset less than 0.1 mV
DON'T CONNECT YOUR EXPENSIVE SPEAKER AS LOAD. Start without a load, then I'll recommend a power resistor, 50 ohms or less. After that, you may connect your expensive speaker 🙂
1 Supply voltage, +- 12 V
2 Solder in opamp
3 Apply signal, check that the opamps work, measure offset voltage (less than 0.1 mV)
4 Solder the LM3886
5 Test the whole amp, offset less than 0.1 mV
DON'T CONNECT YOUR EXPENSIVE SPEAKER AS LOAD. Start without a load, then I'll recommend a power resistor, 50 ohms or less. After that, you may connect your expensive speaker 🙂
First test!
Hi P-A
Both PCB's are ready to test. One monoblock is temporarely wired up, altough without the op-amp and LM3886. On the first attempt the 1A fuses blew as soon as I flicked the power switch. For the second attempt I used 2A. This is what I measured so far:
AC to primary winding= 235V
AC from secondary winding #1= 27.8
AC from secondary winding #2= 27.8
DC voltage after rectifier= +37.6 / -37.6
DC voltage after regulation= +13.94 / -12.19
These figures look good enough for me, altough the regulated positive voltage is a bit far of the 12V target. I will check these again when the op-amp is in place and therefore the power supply sees a load.
And now I'm going to bed.
Walter
Hi P-A
Both PCB's are ready to test. One monoblock is temporarely wired up, altough without the op-amp and LM3886. On the first attempt the 1A fuses blew as soon as I flicked the power switch. For the second attempt I used 2A. This is what I measured so far:
AC to primary winding= 235V
AC from secondary winding #1= 27.8
AC from secondary winding #2= 27.8
DC voltage after rectifier= +37.6 / -37.6
DC voltage after regulation= +13.94 / -12.19
These figures look good enough for me, altough the regulated positive voltage is a bit far of the 12V target. I will check these again when the op-amp is in place and therefore the power supply sees a load.
And now I'm going to bed.
Walter
According to datasheets you should stay under 27.6 volts in total so it's no problem with nearly 14 volts.
IT'S ALIVE!!
One channel is playing for the moment! Nora Jones has the honour to brake in the new chipamp. What I can tell sofar is that this one sounds smoother than my other GainClone. Voices are clearer, even with only one channel playing this is noticable.
On the technical side: DC offset must be low because I can't measure it with my DMM!?😉
A big thumbs up to P-A. You managed to create a nice sounding amp, even if it's with those eyesores called SMD. Before I finish the other channel I'm first gonna concentrate myself on the chassis.
Sofar I'm a happy fellow.🙂
One channel is playing for the moment! Nora Jones has the honour to brake in the new chipamp. What I can tell sofar is that this one sounds smoother than my other GainClone. Voices are clearer, even with only one channel playing this is noticable.
On the technical side: DC offset must be low because I can't measure it with my DMM!?😉
A big thumbs up to P-A. You managed to create a nice sounding amp, even if it's with those eyesores called SMD. Before I finish the other channel I'm first gonna concentrate myself on the chassis.
Sofar I'm a happy fellow.🙂
Attachments
First test
Hi P-A
As you can see in the picture, the two monoblocks are now playing side by side. As I already mentioned in a previous poste the sound is less harsh, more relaxed compared to my other GainClone. Another thing I've noticed is that the soundstage is much wider, more air to it. I'm gonna let them burn in now for a while and listen how things progress. In the meantime I'm gonna concentrate on the housing.
Cheers
Walter
Hi P-A
As you can see in the picture, the two monoblocks are now playing side by side. As I already mentioned in a previous poste the sound is less harsh, more relaxed compared to my other GainClone. Another thing I've noticed is that the soundstage is much wider, more air to it. I'm gonna let them burn in now for a while and listen how things progress. In the meantime I'm gonna concentrate on the housing.
Cheers
Walter
Attachments
Building finished
Hi P-A!
The building is now finished and the DC measurements is good.
But I have a lot of 50Hz.
It must be something I have done wrong with the grounding. Is ground on input supposed to be connecter to some power-ground?
BR Anders.
Hi P-A!
The building is now finished and the DC measurements is good.
But I have a lot of 50Hz.
It must be something I have done wrong with the grounding. Is ground on input supposed to be connecter to some power-ground?
BR Anders.
Building finished
Hi AndyB
Nice to hear that you're also making progress with the amp.
The 50Hz hum is absolutely non existing on my amps.
Did you connect them to the mains earth?
Cheers
Walter
Hi AndyB
Nice to hear that you're also making progress with the amp.
The 50Hz hum is absolutely non existing on my amps.
Did you connect them to the mains earth?
Cheers
Walter
Anders, this is a mono block. Signal in + signal ground, 2 x AC, speaker out. You ought to have 8 wires in total. Do you have that?
Walter, Im happy that you are pleased. 
Walter, if you are going to measure the output offset voltage your voltmeter must be able to handle 0.01 mV or less. My APPA305 have 0.001 mV as the lowest number. Isn't it disturbing to have a voltmeter connected and it reads 0.0 mV? Is the voltmeter really working. Is the amps swicthed on? 🙂
Walter, Im happy that you are pleased.
Walter, if you are going to measure the output offset voltage your voltmeter must be able to handle 0.01 mV or less. My APPA305 have 0.001 mV as the lowest number. Isn't it disturbing to have a voltmeter connected and it reads 0.0 mV? Is the voltmeter really working. Is the amps swicthed on? 🙂
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