Alpha Nirvana 39w 8ohm Class A Amp

No rush Andy, keep up the good work and double check everything - it pays off in the long run.


I think the journey is as fun as the end result. I say ths because it's over rather quickly, but the listening can go on for years. I just LOVE to build. Since we are sheltering in place, I'm going to go ahead and get a case, or make one for the M2X, but I have to say, the J2 and the AN are so good, I really could live with these for the rest of my days. I do love tubes too and both have their merit. Perhaps it's time tube pre. :)



I also love the Elekit 8600 for the money, I don't think anything beats that little amp. I only wish they did a mono version of the amp, I think Mr. F is leaving a lot on the table, by not exploring the option. I would build it in a heartbeat to get that last little bit out.


@ Andy, when I was going through my own SMD woes, I soldered and un a few times. IMHO, as long as the part tests in spec solder it in and carry on. As long as you didn't cook the part, the diodes can get hurt, I saw it under major magn and replaced the package when I saw a bit of heat damage.
 
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Andy, I’m learning from your experience, thanks for your posts.

Have you determined what the problem was with C1002? Was it a bad solder join that caused the low measurement you reported?

Thanks,
Francois

Yes, Francois, I think it must've been a bad solder joint that caused the low reading. The first solder join must have moved the cap so that the other end was moved, basically, past - rather than on - the other solder pad. So there was nothing really, for the solder that end to 'grab onto'.

When I removed and replaced it, I made sure the cap was centrally positioned, between its solder pads.

However, given thimios's comment, what I will do this morning is re-measure all the components on the Snubber boards - just to make sure they are reading correctly. :)

I think the journey is as fun as the end result. I say this because it's over rather quickly, but the listening can go on for years.

Aah but with me ... the build is not over 'rather quickly'! :D

But yes, the joy goes on for years and years.

@ Andy, when I was going through my own SMD woes, I soldered and un a few times. IMHO, as long as the part tests in spec solder it in and carry on. As long as you didn't cook the part, the diodes can get hurt, I saw it under major magn and replaced the package when I saw a bit of heat damage.

That's good to hear, JT. I measured my diodes with a Peak DCA75 (between the Gate & Source pin holes) - and they all registered as a diode. So I think in my case, they must have survived the soldering operation. :)

Andy
 
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X111?

Am I right in thinking that:
* I solder this in place
* then push a Bourne pot into its top
* adjust the pot to minimise the DC offset
* then pull out the Bourne pot and measure it
* then solder a res with this value into R113?
(Leaving X111 in place but empty.)

If so - that is a very neat trick! :)


Thanks,
Andy
 
X111?

Am I right in thinking that:
* I solder this in place
* then push a Bourne pot into its top
* adjust the pot to minimise the DC offset
* then pull out the Bourne pot and measure it
* then solder a res with this value into R113?
(Leaving X111 in place but empty.)

If so - that is a very neat trick! :)


Thanks,
Andy




Yup, that's how it's done... I found very little, if any, difference when changing values. The DC was so low it was moot anyway.


JT
 
I have a request regarding the output section.

The board has:
* 4 holes in a square - for a Molex vertical connector (X143)
* and then a double hole above and below the Molex holes - for spade terminals (X144 & X145).

In the pics of the AN boards that you built, X, you used a vertical Molex connector (X143).

Am I correct that you either use X143 ... or you use X144+X145?

Whichever you use, the spkr terminal's ground post is connected to ground on the AN PCB (which is X145 or the 2 pins in the Molex connector which are next to X145) - not the ground on the SLB?

Thanks,
Andy
 
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I used spades for the speaker connected at the Alpha Nirvana PCB according to this diagram:
798443d1575030654-alpha-nirvana-39w-8ohm-class-amp-grounding-schematic-built-v2-jpg