Stupid question

[jwags81818]

I am building the below amplifier. I have it done with the exception of hooking up a speaker. I measured from the point where the speaker connects to the cap and ground and I have 12vdc on my meter. Shouldn't the caps block the dc voltage? So why do I have 12 vdc there?

 

[minek123]

Add a resistor 330 Ohm in parallel with the speaker.

 

[ximikas]

Hi. Yes , cap blocks DC voltage, but then there must some other load for it to charge, with multimeter input resistance it can take hours.

 

[jitter]

Yes, take a lowish load resistor and hook it up where the speaker would be. Then you should no longer measure a DC voltage. If you still do, then something is wrong (e.g. a short across either the 10 uF or 4700 uF cap).

 

[huggygood]

Also, and before connecting a speaker to this amp, are you sure of your 1058? I mean, they are indeed authentic.

 

[jwags81818]

I will add a load and test as soon as I get home. And I am using ecx10n20 mosfets I got directly from the manufacturer. And it is hooked up correctly. I am sure its the load thing.

 

[rayma]

The output is floating. You need a load.

 

[Mark Tillotson]

Not sure what the 10uF poly cap is for, don't think its needed in a coupling cap situation, just make sure the electrolytic has a high ripple-current rating and low ESR.

 

[egellings]

I am building the below amplifier. I have it done with the exception of hooking up a speaker. I measured from the point where the speaker connects to the cap and ground and I have 12vdc on my meter. Shouldn't the caps block the dc voltage? So why do I have 12 vdc there? View attachment 1289752

Leakage current through the capacitors causes the voltage to appear across the speaker terminals. If there is a DC voltage across a speaker connected to the stage, then I would deem the coupling caps as bad, since that much leakage current is defectively excessive. Under no load conditions, then a DC voltage could well occur across the terminals, but the current causing it to appear would be minuscule, not enough to disturb a speaker.

 

[JMFahey]

Not sure what the 10uF poly cap is for, don't think its needed in a coupling cap situation, just make sure the electrolytic has a high ripple-current rating and low ESR.

True.
And even so, givent he unavoidable 15R source resistance, ESR importance pales a lot.

 

[huggygood]

I've seen this schematic on the net for years, I've wanted to assemble it several times but never had the time or the real interest to do it, however I'm very curious to know how it sounds .

 

[b_force]

Fyi, there are no dumb or stupid questions.

Or maybe only if you already knew the answer to the question.
Although that might be rather an unnecessary question.

 

[tubelectron]

I've seen this schematic on the net for years, I've wanted to assemble it several times but never had the time or the real interest to do it, however I'm very curious to know how it sounds .

Yes. Me too...

T

 

[tiefbassuebertr]

The associated project to schematic in post #1 is this one:
https://diyaudioprojects.com/Solid/ZCA/ZCA.htm
and
https://www.diyaudio.com/community/...build-class-a-single-mosfet-amplifier.368606/
This is close to the ZV (ZEN variation, "Zen-lightenment" from Mr. Nelson Pass) from fig. 5 under
https://www.firstwatt.com/wp-content/uploads/2023/12/art_zv1.pdf
and this schematic under
https://web.archive.org/web/20031210152336/https://www.passdiy.com/projects/zenlite2.htm
check out also this threads:
https://www.diyaudio.com/community/threads/zen-enlightenment.53/
https://www.diyaudio.com/community/threads/2sj28-vfet-se-amplifier.154009/
Highest sonic performance is only guaranteed when using high-quality components (this is particularly important with electrolytics) and the use of a choke coil.

P.S.: The naming of the topic is completely confusing to me.