Greeting from a newcomer

[CY]

Hi,

I run to this forum while I was looking at Nelson Pass's web page. I have been following the discussions in this forum for a few weeks and now decide to join, hopefully to get some advice and help along the way in building the Zen V4.

I have gathered a non-functioning amp case with a dual +-70V unregulated PS from 2 torodal Xformers. I am using this to build the V4 and may be later the Aleph. Currently I have almost finished with one channel.

Right now, I am using a Jadis DA60, on loan from my friend. Unfortunately, one channel of this beautiful machine recently refused to make any sound. I suspect some fault with one of the 12AX7 or its neighbouring components. Not sure yet. I wonder anyone could point me to its schematic on the web. Thanks in advance.

CY

[planet10]

Welcome CY.

Have you swapped tubes from one channel to the other to see if you have a bad tube?

dave

[CY]

Dave,

Thanks Dave. I would certainly do that when the girls are all in bed and my body is still in one piece. I'll let you know what happen then.

CY

[fdegrove]

Hello,

Welcome.

I did a search on the net for the Jadis but as expected nothing useful for you turned up.

When you have opened the amp,do a visual comparison between the two channels.
Often when something goes wrong in a tube amp it is visable,but in your case it may be something as silly as a loose connection.
Small tubes such as the 12AX7s almost never go bad.
What can happen is a bad connection in the sockets.

Cheers,

[CY]

Hi Frank,

Actually I have not quite described the whole story. This is the second time the amp exhibits this fault. Last time, I even pulled out my dust gathered scope to have a look at the music. The machine was turned sideway, back uncovered. No smell, no decoloration. After a while, everything was back to normal without a single resistor unsoldered.

You are propably right. The socket connected might be loose.

But my recipe of giving it a ban at its side did not work this time and it is a bit of a hassle to uncover the machine and declare its surrounding 3m being a danger zone, I want to get myself better prepared in terms of schematics, possible faulty components, etc before I venture further.

Last time, I saw some fuse like animals at each of the KT88 sockets. Don't know what they are there for. Would like to check them against a schematic.

CY

[fdegrove]

Hi,

I case you want further analysis of the fault in this amp I suggest starting a new thread in the "Tubes" section.

It would get more attention from all our tube oriented members and maybe someone will have a plausible explanation for this particular fault.

Greetz,