JLH 10 Watt class A amplifier

[kpsthakur]

As 6L6 says, go stage by stage...first the amp, then accessories...enjoyment unlimited


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[scottjoplin]

Sorry, you said earlier it was 69 version, apologies for not reading your posts properly

 

[kpsthakur]

6L6 is a fellow DIY'r, great person, few on the forum who has command on this subject, and ready to help any newbies


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[kpsthakur]

But I will be making a 69 version [emoji3]


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[still4given]

I am running two JLH, one with SMPS and one linear non-regulated. The SMPS has far less noise because the HV is rectified and whatever ripple is on it wont pass through the high frequency transformer. It make for a far cleaner sound overall. With the SMPS you do get ocassional clicks and pops when the fridge turns on but this can easily be treated with some HF filtering.

What is the model # for the SMPS you are using? What is the voltage?

Thanks

 

[xrk971]

DC to DC step up switching at 1.2MHz also makes nice supply from 12v battery or 12v linear to get 19v (or higher) and low ripple because 1.2MHz is easy to filter out. I am using a simple LT6009 and able to get it to make 32v at 1.5amps from 19v laptop brick. I am running a SE Class A amp with it. No line hum at all.

 

[kpsthakur]

Channel 1 done


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[kpsthakur]

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[kpsthakur]

Funny thing is there was 12V DC at the output


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[kpsthakur]

I shorted the output with 100ohm resistor to ground and then everything goes ok!!!


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[kpsthakur]

Do I have a faulty cap???


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[kpsthakur]

I added a final RC combo like the attached circuit


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[kpsthakur]

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[scottjoplin]

What? 69 version ac coupled with output capacitor?

 

[Mooly]

Do I have a faulty cap???


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No.

 

[scottjoplin]

I like the bulldog clips, I've used those, very effective

 

[kpsthakur]

this the plan I followed


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[kpsthakur]

No.

Then I don't have any explanation for 12V at output....problem is this has disappeared and no way to track back


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[scottjoplin]

Oh yes. That's the very first one isn't it?
You've just used more modern transistors?

 

[kpsthakur]

Has anyone else faced such issue?? Hi


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