Steptoes amp.

[andrew Ivimey]

There is a level of understanding that is possible without understanding the individual parts, or in this case words, or so I am told. The Germans, for example, call this 'Gestalt' and I think I know what that means. Children do not learn language bottom upwards i.e. by learning every single word and them combining them. Children don't know what individual words are until some teacher tells them they are actually individual words.

And as for animals, or even other people, I hope we can agree on what is for example 'yellow'. It is always an assumption that we share the meaning and it is equally obvious that what I call yellow, someone else calls green but we are still able to share a pizza and beer.

As for animals not knowing it is yellow, well that isn't strictly true, or so I have been told. It is possibe not to have the sensory apparatus that will receive yellow or even to perceive any difference between yellow and green.. let alone ascribe some sort of differential meaning to yellow or green. Slightly off this point, very interestingly, I have a chum who will only eat green peppers at school and red peppers at home. His teachers and his mum had missed this but I couldn't help thinking that this is significant. If only this little chap coud tell us why!

[Mike H]

There ya go.

Hmm, not that deep, a better question is do you see the same as me when we both agree something is yellow.

That's what I was trying to say.

[Steptoe]

Dear Andrew and Mike, are you saying that we can understand what a phenomenon is without understanding why it is the way it is? If so that will come as a great relief because my problem is thinking that everyone except me completely understands what's going on, whereas I'm now actually more confused than ever. I began this line of enquiry by trying to understand only what the ether is, but now have to sort out what two things consist of, ie. fields and space time, neither of which I can visualise in any way.
Yours sincerely, Steptoe.

[Nick]

It is basically egotism that makes us believe that the universe is at its core understandable. The odd thing is that so far it seems to be the case, but I always think of the great quote:

"Not only is the Universe stranger than we think, it is stranger than we can think."

Werner Heisenberg

[Mike H]

I rarely know what's going on!

[Paul Barker]

a bunch of ex gpo stuff has arrived Steptoe. Thank you. I can't get on with evaluating too fast as I have a broken foot and my empire is spread thin and wide with little ability to get across it.

But in the fullness of time we will know more.

Paul

[Steptoe]

Dear Paul, sorry to hear about your foot, it's just as well you've got another one or you'd really be in trouble. The gpo has done well getting the parcel to you so fast. I'm really grateful to you for having a look at those transformers. I'm hoping they may be useful either as o/p transformers, inter valve transformers or chokes but we shall see. The other stuff is just for you to inspect and if you can use any of it and would like some more, please let me know. I also have a lot of 48 volt DC relays but am not sure if they're of any value for audio. Thanks once more for your help, Yours sincerely, Steptoe.

[Paul Barker]

Found time to have quick look.

you cannot possibly gap these they cannot be gapped due to the nature of the laminations.

You already noted they have a 600 ohm winding which is centre tapped, this is push pull.

they have a number of seperate 9 ohm windings.

Puting a 600 ohm source on the push pull primary from peak to peak I get a ratio close to 600 ohm into 9 ohm it is actually a ratio of 7.85.

Testing for frequency response it is +/- 0.75db from 500hz to 56khz

Below 500hz it tapers off.

At 45hz it is -12.7db
100hz - -9db
200hz - -6.44db
300hz - -3.5db
400hz - - 1.5db

this is what I expected, they are for telecoms use so they are made to work in the range of the human voice.

I haven't detected what signal level they can work up to as I would need an amplifier hooked up. My signal generator cannot go up in amplitude sufficient to find the extremes.

You have found that they work for you at amplifier output level.

First thing I would say is either connect them up push pull or parafeed.

Then I would say use a chipamp or T amp (Phil would make a suggestion) for below 500hz.

When I get an amp hooked up to them I can tell you what power rating to expect, but from core size I would say 1 watt.

As they offer a 600 ohm load you would be incorrectly loading most output valves, but that isn't necessarily a huge issue. Go class A push pull and it may well make a nice little low powered limited frequency range amplifier for your personal enjoyment.

I can't see much use in interstage duty if you split the long winding you would have 150 ohm to 150 ohm but it would have to be parafeed, and it would have the same roll off at low frequency.

These are pretty well what I expected them to be. Unsuitable.

They could be reqound for audio use but at line level, even as interstages they would probably not suit the interstage from the driver valve to the output valve, more the stage prior to that. ALso they would have to always work in AC only. They will never tolerate DC current.

[Paul Barker]

Also the one you took to bits.

The laminations are not really useable when bent. They must disassemble perfectly the lams must remain perfectly flat like new, to reassemble and retain permiability. So it is unlikely that one old transformer would make one new transformer.

I cannot say what percentage of Nickel content might be in the lams but due to their softness I expect there is an element of Nickel.

I could strip another one and maybe find enough flat lams to wind a test winding which I know the turns of and see what the permiability of the core is. That will be a longer term project.

Another thought you had is whether they could make chokes.

No they couldn't as they will never handle DC current. This lamination structure just is in no way shape or form intended for gap assembly.

[pre65]

It's sad to say, but a £13 chip amp (like the one I'm playing with) and a 24v power supply (say £25) will probably sound better than anything Steptoe is likely to cobble up using his old GPO transformers.

Then at least you have a standard to try and beat if you want to spend the rest of your years fiddling around with your old gear.

David, if you want to compare the PSE amp I cobbled up for you verses the chip amp then I can do that for you, but the valve amp will have seriously OK transformers. Not the best, but good.

[Steptoe]

Dear Paul and Philip, all I can say is" bugger". I know you've both told me before that they weren't any use but I was still hopeful that something could be done with them,but now it seems not. My tester tells me they are 15% Ni, which gives them a scrap value of about £ 1200 per tonne so that looks like their ultimate destiny, although I would like to try one last thing before they go.
That is to wire some together as Mike suggested and ask you to try them in the amp. I have to be away for a week or so but on my return I'll be in touch again if you can tolerate my persistence against all the odds. Like the man said" It's not over til the fat lady sings" and I would like to give her a last chance on these things. With best wishes, Steptoe.

[pre65]

That is to wire some together as Mike suggested and ask you to try them in the amp.

If you mean me, then yes David.

[Paul Barker]

My tester tells me they are 15% Ni, which gives them a scrap value of about £ 1200 per tonne so that looks like their ultimate destiny.

15% is an oddly low amount for audio. but admit they don't handle at all like my 50% Nickel lams, neither look as bright. So your test is probably correct.

I must get round to seeing what perm I can get from the core. Please don't weigh them in until I find out. Might re-wind them into interstage or low powered parafeed OPT's. Once you start using permiabilities above grain orientated silicon steel as the older Mr Sowter said "the extra perm runs out through the gap" so best used in PP or parafeed, or might aswell not bother with adding Nickel.