More 6158/13D3

[7N7]

Coincidentally, I have just started testing a new amplifier.

This is balanced like all my stuff.

It uses a 13D3 input diff pair. This is unusual in that I am flying in the face of theory, because whilst it has a conventional cascode SS current sink at the bottom, it has active loads on the anodes. Most people say that this will not work as the sources and sink will fight each other.

Well it certainly works at DC; it is passing more or less the design current.

The next stage, is a pair of D3As, as pentode cathode followers, which will be DC coupled to the output valves, a quartet of 6CK4s.

I am having a bit of trouble testing because obvioully I have a -ve supply and am having difficulty with getting the voltages right in testing without the output stage. Really I need two adjustable power supplies; and I have only one variac!

More later.

7N7

[dhaen]

7N7,

Any chance of a schematic?
You can upload a .gif, bmp, or jpg.
And I've just learned you can link. Useful for bigger pix.

Cheers,

[7N7]

Originally posted by dhaen
7N7,

Any chance of a schematic?
You can upload a .gif, bmp, or jpg.
And I've just learned you can link. Useful for bigger pix.

Cheers,

I have no website, so it would have to be a file.

Shall we wait until the bloody thing works? When I have finally got the g2 cathode follower voltage correct, I can thne have a look for oscillation in the driver section (there usually is). When I have cured that, I can try the output stage and do some AC testing. When all is in order, I'll draw it up and happily send the circuit diagram. I have to say that as usual, I have had help with this designm so I will have to ask for permission.

The amplifier is intended to be a temporary replacement for my other amplifiers while I modify them. My aim was to use only parts that I had in stock, and so far, so good!

7N7

[dhaen]

7N7,

Ok we'll wait if we must.

Anyway, I'm glad you are "balanced". I'm quite "balanced" myself. [well. on interconnects anyway].

Cheers,

[316a]

I hope they were ok !

316a

[7N7]

Originally posted by dhaen
7N7,

Ok we'll wait if we must.

Anyway, I'm glad you are "balanced". I'm quite "balanced" myself. [well. on interconnects anyway].

Cheers,

I am glad to see that "balanced" appeared in inverted commas. How can anyone who turns a reasonable flat into a complete tip, because of a hobby, can be described as "balanced" beggars belief.

The reason for the balance means I can a) use more valves - very important that b) spend more money (a disease you know) C) have the power amplifiers closer to the 'speakers and d) well there was a plan for a neat layout with all the sources up at one end and a nice collection of stuff at the other. This means about 17 feet of cable which means balanced and cathode followers - more valves.

I will say that I try to avoid transformers and capacitors; and anyway, glass is better looking than iron.

I hope that the amplifier will be operational before very long so you should not have long to wait (providing I can obtain the necessary permission.

7N7

[7N7]

Originally posted by 316a
I hope they were ok !

316a

Well of course if I buy them from you, then I have no need to put them on a tester - in fact I haven't. And I may buy a few more.

316A; "frying saucer tliode yes?"

7N7

[316a]

...look like lady's tit !

316a

[dhaen]

lady's tit

A strange language mix, of the formal, and the informal...
Well, we're learning.

[7N7]

Hello all.

Well I have sorted out the DC in this thing all is in ordnung.

However I have some AC problems that I am about to start addressing.

I have been given permission by the "guru" to post the circuit diagram, so once it's working, I'll draw it up and you can have a look

7N7