Just finished testing my first 832A amp

[Pyre]

I just finished testing my first project built from scratch and it actually works and sounds good. I was quite excited to hear music coming out of the speakers. I have rebuilt and modified lots of stuff but this was the first amp that I built from trips to the parts store and a schematic. I still have to put it in a case and make some better plate connectors but I wanted to make sure it worked before doing any major metal work. I also have some Edcor transformers on order that I am going to use in place of the Hammond 1610’s, I do not have a clue what the specs on the 1610’s are and can find nothing about them on the internet. I emailed Hammond but they never got back to me. They came off a 6V6 PP amp so I imagine they are a bit too much for the 832A. I have a couple of 3E29’s that they are better suited with. That is my next project.

[SY]

The first turn-on always scares the bejeezus out of me. When you get music and not noise, it's a real relief. Congratulations!

[DigitalJunkie]

One of my Favorite quotes (From Sy);

"If all is well,power down,unplug,and go have a drink while the bleeders bleed. I don't know about you,but the first turn-on scares the **** out of me and I need a few shots to steady my nerves..." -SY


Ditto!



Pyre, Nice amp!
It's always nice when it works on the first try.

[soundbrigade]

It's always good to see someone build as aesthitic as myself.
I have a pair of transformers that I guess would be suitable for the 832, but I'd rather use up my 12A6 ... cannot decide.

You get a schematic here?

[Pyre]

Yes that first power up is the heart stopper. More then a few times its been met with the magic smoke that once released renders electronics no longer electronic. I always hook up the heaters first for 2 or 3 min then start slowly turning up the variac while sniffing the air and watching the voltmeter.

Here is the schematic that I used to build the amp. I made my own power supply for the B+ and the heaters. Well pieced one together is closer to the truth.



I wish I had some SE transformers around I would like to try some of the SE schematics I found for both the 832A and 829B.

[7N7]

Yes, congratulations; I can recall many "trembling hand" moments at first switch-on - until I acquired a variac!

You might want to look out for a rather nice replacement for the 832: QQVO3-20. This one is pretty much an equivalent but really a superior more modern design although not as wacky-looking it must be said. They were made by Mullard and EEV and probably Philips too.

7N7

[kuroguy]

Originally posted by Pyre
I wish I had some SE transformers around I would like to try some of the SE schematics I found for both the 832A and 829B.

I just picked up five 829 tubes on ebay for $16 shipped. I'm looking for a push pull design similar to the audiohobbyist design. seen any you like?

If I had a datasheet for the 829 in class A I'd design my own.

[soundbrigade]

I don't know if it is "political and religious correct" to do it, but the Malaysian guys at DIY Paradise has fiddled with the schematic above and I think even made some changes.
Take a look:
832 PP

[Audio_idiot]

Originally posted by kuroguy


If I had a datasheet for the 829 in class A I'd design my own.

Here you go,

http://tubedata.tigahost.com/tubedat...049/8/832A.pdf

Originally posted by soundbrigade
I don't know if it is "political and religious correct" to do it, but the Malaysian guys at DIY Paradise has fiddled with the schematic above and I think even made some changes.
Take a look:
832 PP

Surely there isn't anything wrong with fiddling with design

[soundbrigade]

Noo noo, I was referring to ... urrrr .. referring to other forums. There are air tight barriers between various HiFi and Audio-forums in Sweden. But I know that my Malaysian friends don't mind and besides they are no cowards - they do whatever they can to test and evaluate different designs.
Hope there was something useful.