Newby first build amp 832.

[Shane]

Originally Posted by pre65

Thinking about your plan Shane, i have a C3g/150c4 front end on my KT66 set amp (soon to be PT15 !!) and perhaps I could "clip lead" that to the 832a amp output stage ?

Rubs chin and smiles !

Hmm,must think about that.

Sounds good. It'd be good to know I wasn't on a hiding to nothing.

[pre65]

Well I've gone and dunnit !

C3g and 150c4 (150V VR tube) driving 832a,with the cap coupled feed driving one grid,and the other grid earthed.

Initial impression ? GOOD,got a bit of hum but that is probably an earth issue as i have only connected the vital bits of two different amps together.

Definitely more bass,and the rest sounds at least as good as before.

If anything,with Pre 3, there is too much gain, but as with the 12AT7 (ECC81) I use my passive pre between Pre 3 and the amps to set the level.

http://i111.photobucket.com/albums/n...65/C3g832a.jpg

So Shane mate, it does work !!!!!!!

[Shane]

Now that's the best news I've had all day. Can't wait to get my iron hot, as they say.


Off to an interview now. Gulp...

[pre65]

I have decided to build the "new & improved" 832a amp into the wooden casing that was previously the 300b amp.

The circuit will be the one that was cobblered up to test Shanes idea-ie C3g and 0D3 driving 832a (and eventually QQV07-50 when i can find some) without a valve phase splitter using the common cathode or cathode coupled method.

I have got round to making a new top plate and fixing the valve holders in just to see what it looks like.

PS the valves are a dud pair of QQV07-50 in case you dont recognise them !

http://i111.photobucket.com/albums/n...2aprogress.jpg

[pre65]

The 832a was rebuilt, but into a Hammond alloy case because the wood case was a bit too small.

I was very pleased with the sound, but after a while it seemed I had "lost" something !

I had planned to go back to basics with the original white MDF and alloy chassis, but as I have recently obtained a couple of 12A DHT triodes a plan hatched.

The C3g and VR tube have been removed and the 12A installed. The wiring is simplified and a couple of Russian K75-10 PIO coupling caps fitted.

Had hum problems with my DIY DC filament supply (5V) for the 12A so ripped that out and substituted the Tentlab modules left over from 845 and 300b monkey. Still hums !! After a nights sleep I attacked the hum problem and removing my pseudo centre tap mod from the 6.3V AC supply, this cured 95 % of the hum.

Now playing and sounds like I've got back what was "lost" and possibly got a bit "extra" !

http://i111.photobucket.com/albums/n...65/12A832a.jpg