Thank you Shaan for the tip.That's superkool naf.
Just a tip, for the japaneze trannies, try to use the -BL suffix parts as they have great gains, probably you already know that.
shaan
I have GR dan BL grade... and I will use BL grade for my second channel.
O yes as you've said vssa have very steady bias and dco. Sound as good as my SSA.
Jk,
I love the V+, V-, GND & spkr out all in a very tight loop.
Very few layouts follow this practice.
If you do incorporate any loop breaker reesistor, then do remember to also include inverse parallel diodes.
I do not like the decoupling grounds connecting to the signal ground.
The +/- decoupling must connect to each other and then that connecting link taken to the power ground.
I love the V+, V-, GND & spkr out all in a very tight loop.
Very few layouts follow this practice.
If you do incorporate any loop breaker reesistor, then do remember to also include inverse parallel diodes.
I do not like the decoupling grounds connecting to the signal ground.
The +/- decoupling must connect to each other and then that connecting link taken to the power ground.
GND connections in three major sections:
- all decoupling caps, output RC filter, speaker -OUT, each directly connected to GND pin (GND from PSU)
- 2200 uF feedback elcos, separate GND tracks to GND pin
- input GND connected parts via 10 Ohm resistor to GND pin
Try to shorten some PCB tracks with suitable parts repositioning.
Also KSA and KSC transistors will need proper heatsinks. Try to find enough space for them to be fixed to PCB and connected to GND potential too.
Thanks for the feedback. I'm still learning and I'm sure there is no single layout that will please all. Grounding is my achilles heel, I'm still working on improving it. I should learn to lay down my components more ideally by intuition, place my grounds first then follow with the rest. At this point I seem to work from output to input grounding as I go. This seems to make for more compromises that need attention after the fact.
@AndrewT
I have been trying to make use of comments from other layout exercises. I put my power and ground very close to one another for the purposes of ensuring the decoupling routes are as short as possible. Then you confuse me slightly by saying to connect the decoupling via a trace then to ground which effectively lengthens the route. Something for me to ponder.
@Lazy Cat
OK, I think I'm not too far off. In other designs the practise as I understand it is that any feedback coupling capacitors are referred back to the same ground point as the input components. In the VSSA's case this is not true? We want separate returns for the feedback coupling?
Any direct suggestions on repositioning items or which traces are too long jump to mind? I was looking for a fairly symmetric aesthetic, though if that will have a serious impact on function I'm open to switching some things around. I have some changes I have already made but not yet posted.
@AndrewT
I have been trying to make use of comments from other layout exercises. I put my power and ground very close to one another for the purposes of ensuring the decoupling routes are as short as possible. Then you confuse me slightly by saying to connect the decoupling via a trace then to ground which effectively lengthens the route. Something for me to ponder.
@Lazy Cat
OK, I think I'm not too far off. In other designs the practise as I understand it is that any feedback coupling capacitors are referred back to the same ground point as the input components. In the VSSA's case this is not true? We want separate returns for the feedback coupling?
Any direct suggestions on repositioning items or which traces are too long jump to mind? I was looking for a fairly symmetric aesthetic, though if that will have a serious impact on function I'm open to switching some things around. I have some changes I have already made but not yet posted.
Yes.
Collectors of input transistors tracks to 470 Ohm to rails to be shorten.
I must have confused you. I did not mean to give the impression to lengthen traces.
I thought my posts emphasised keeping the decoupling routes "as short as possible"
For instance between the GND left side to V+ there is a tiny gap (right next to SPKR) to insert an smd 100nF x7r. At the other side between V- & GND a second x7r could be inserted.
Now compare the route length of these two HF decoupling caps to the 1uF you have at present. Even using a 0.1" through hole x7r (instead of smd) would be shorter than existing.
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Ah, I see what you are saying. Thanks for your clarification. Shaan is looking to keep designs in this thread to all through hole components and single sided PCB. I plan for this exercise to follow his rules here, though I do see some advantages to a few SMD's, such as you suggest.
Hi jkuetemann.
Bringing the power ground to the very front of the peeceebee(middle, left or right) will solve all the problems you are facing, plus it might make the whole pcb smaller and more compact. I hope the ground cable far from the supply cables wont cause you any problem, psychologically.
shaan
Bringing the power ground to the very front of the peeceebee(middle, left or right) will solve all the problems you are facing, plus it might make the whole pcb smaller and more compact. I hope the ground cable far from the supply cables wont cause you any problem, psychologically.
shaan
Hi jkuetemann.
Bringing the power ground to the very front of the peeceebee(middle, left or right) will solve all the problems you are facing, plus it might make the whole pcb smaller and more compact. I hope the ground cable far from the supply cables wont cause you any problem, psychologically.
shaan
The only potential issue is decoupling the power supply. I think with LC's comment about a minor re-orientation of parts to shorten the path related to the 470 ohm resistors may just make things easier. Won't have time until later to play with it and see. Thanks for all the support.
Don't.
Keep the Power Ground right beside the V+ & V- & Spkr Out.
Move all the MF decoupling to nearer that pair of ground pads.
Move the HF decoupling to VERY close to the Spkr Out and use the 0.1" pin pitch x7r.
You mean VAS bias?
Set output bias to 160 mA
Yes LC .. I mean Vas bias, wrong typo. I am too excited
.Ok I'll set final bias at 160mA, thankyou.
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