Not really. I’ve had mine on the bench the last 2 weeks chasing down probs some of the guys have had.
Once it set up, it does not drift much on subsequent thermal cycles.
The initial Vbe’s cancel and then it’s onlt the difference in Vbe temp coefficient that really impacts dfift.
Once it set up, it does not drift much on subsequent thermal cycles.
The initial Vbe’s cancel and then it’s onlt the difference in Vbe temp coefficient that really impacts dfift.
I’ll update the first post later tonight with changes to address the issue a few folks have had with 20 MHz oscillation.
If i'm reading it correctly, changing R4-5 should solve the oscillation too, without the extra RC? Is this based on simulation or has somebody tried it on an actual amp?
Since I did the RC first, I don't know how it would react to just changing the value of R4-5.
Do you see any downside to leave the RC in, I'm just thinking if I should remove the RC?
Did Sandro find anything more that could be 'tuned'?
I have started making a chassis for my amp. I intend to use make enclosures for the power supplies and amps.
I gave myself lot of extra work because I recycled the heat sinks. They need to be sand blasted and re-painted + the other metal work on the rest. Very different from soldering and measuring 🙂
Since I did the RC first, I don't know how it would react to just changing the value of R4-5.
Do you see any downside to leave the RC in, I'm just thinking if I should remove the RC?
Did Sandro find anything more that could be 'tuned'?
I have started making a chassis for my amp. I intend to use make enclosures for the power supplies and amps.
I gave myself lot of extra work because I recycled the heat sinks. They need to be sand blasted and re-painted + the other metal work on the rest. Very different from soldering and measuring 🙂
Yes. In the collector of Q1 and Q2 add a 1 k resistor. Keep the resistor close to the collectors.
Change R31 to 1.8 k.
Across each 1000uF cap add a 1uF 50V 1206 SMD capacitor.
Suggest you also put the Zobel on the amp board. Use a 10 Ohm 5 W metal oxide resistor and 0.1 uF 100V film capacitor.
(When you are finished, I will take a look at your layout for you if you like)
Change R31 to 1.8 k.
Across each 1000uF cap add a 1uF 50V 1206 SMD capacitor.
Suggest you also put the Zobel on the amp board. Use a 10 Ohm 5 W metal oxide resistor and 0.1 uF 100V film capacitor.
(When you are finished, I will take a look at your layout for you if you like)
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hi Bonsai did you check you messages? anyway here is the link of the Sprint Layout 6 file archive kx-amplifier Sprint Layout 6 file - Google Drive
let me know if you got the file 🙂
I add the SMD caps 1uF 50V to all electrolytic caps, also I add the 1K to the collectors of Q1 and Q2, about R4,R5 I don't remember if the values were changed 😕
oh I forgot the 10R and the 100uF 100V caps is on the board now 🙂
let me know if you got the file 🙂
I add the SMD caps 1uF 50V to all electrolytic caps, also I add the 1K to the collectors of Q1 and Q2, about R4,R5 I don't remember if the values were changed 😕
oh I forgot the 10R and the 100uF 100V caps is on the board now 🙂
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How are you guys progressing with your amps? Has the fix solved the stability for everybody who tried it?
I'm on hold with my build, waiting for parts. I decided to order a pair of Toroidy 250VA 2x22VAC transformers for it. After I get the transformers I can continue building the chassis for it. I'm also waiting to get the heat sinks painted by a friend.
Have done some other stray projects while waiting, but now I'm stuck again, waiting for parts to fix a high power mono block I bought in non working condition (other one works though).
I got a de-soldering station as x-mas present for myself, and that one failed the second time I used it and had to be returned too, so more waiting..
Seems deliveries take more time now with the holidays, and then there is the corona too of course.
I'm on hold with my build, waiting for parts. I decided to order a pair of Toroidy 250VA 2x22VAC transformers for it. After I get the transformers I can continue building the chassis for it. I'm also waiting to get the heat sinks painted by a friend.
Have done some other stray projects while waiting, but now I'm stuck again, waiting for parts to fix a high power mono block I bought in non working condition (other one works though).
I got a de-soldering station as x-mas present for myself, and that one failed the second time I used it and had to be returned too, so more waiting..
Seems deliveries take more time now with the holidays, and then there is the corona too of course.