why would changing transformers...

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karatestu
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Re: why would changing transformers...

Post by karatestu » Thu Jun 08, 2017 4:49 pm

Does everyone know les ? I will surely say hello from you but I only know you as Nick.

I did want to join in with your get together near Doncaster but sadly family life has got in the way.

Stu
Linn LP12, Naim CD3.5, Avondale pre & power, B&W P4 (all modified of course)

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Nick
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Re: why would changing transformers...

Post by Nick » Thu Jun 08, 2017 5:59 pm

Just tell him Nick from Longdog Audio. Long hair, beard and confusion, he should know who you mean :-)
Guns don't kill people; Physics kills people!

karatestu
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Re: why would changing transformers...

Post by karatestu » Thu Jun 08, 2017 8:28 pm

Ok will do. I have just looked you up on google and i did not realise you were a designer and manufacturer. I can now put a face to the name. Thanks for your input here.

Stu
Linn LP12, Naim CD3.5, Avondale pre & power, B&W P4 (all modified of course)

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Greg
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Re: why would changing transformers...

Post by Greg » Thu Jun 08, 2017 10:12 pm

Yes, and of course you already know Nick, although you might not realise as Lurcher300b on HFS.

karatestu
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Re: why would changing transformers...

Post by karatestu » Fri Jun 09, 2017 1:56 pm

Greg wrote:
Thu Jun 08, 2017 10:12 pm
Yes, and of course you already know Nick, although you might not realise as Lurcher300b on HFS.
Of course, silly me. I have only been there since January this year.

More messing about here with transformers. I decided for a laugh to put a couple (I have four!) of these Avondale EI transformers on the two tweeter dedicated monoblocs I have. They work a treat at the volume I am playing - sounds extremely good and not a hint of hum with them sitting in my power amps. At 36Vdc & 50VA per secondary (only using one at the moment) they would probably be no good for mid/bass duties but are doing an excellent job on the tweeters. :D

Anyway just proves to me that they don't like something about the way I have wired up my preamp. Probably the 0V arrangement? Some rewiring needed I should think.

Stu
Linn LP12, Naim CD3.5, Avondale pre & power, B&W P4 (all modified of course)

karatestu
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Re: why would changing transformers...

Post by karatestu » Fri Jun 09, 2017 3:59 pm

Nick - said hi to Les from you on the phone. He says hi back :D

Anyway mucking about with my 0V arrangement I have reduced the hum to a very small amount heard through the speakers. Instead of daisy chaining the 0V from caps to reg to preamp board to star earth I ran the reg 0V back to the caps and from there straight to the star earth in the preamp. Preamp boards have an independent 0V wire straight to the star earth. Does that make sense.

What I will try now is bringing the reg back as close to the smoothing caps as possible to reduce the length of it's 0V connection to the caps. See if that eliminates it altogether.

What I still can't understand is why the toroid was perfectly happy with the old 0V arrangement and the EI caused problems ?

Feel a bit happier now. Playing lovely music now with little EI's on preamp and the two high frequency monoblocs. I like it :D

Stu
Linn LP12, Naim CD3.5, Avondale pre & power, B&W P4 (all modified of course)

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Nick
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Re: why would changing transformers...

Post by Nick » Fri Jun 09, 2017 5:00 pm

karatestu wrote:
Fri Jun 09, 2017 3:59 pm
Does that make sense.
Yes, chaining anything to a star earth is generally a mistake unless you have a good reason to not do it, and good reasons are very rare.

Think in terms of the AC current that will be flowing in a wire and the effect that current will have generating a voltage across it.
Guns don't kill people; Physics kills people!

karatestu
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Re: why would changing transformers...

Post by karatestu » Sat Jun 10, 2017 10:18 am

Thanks Nick,

Thinking about it you are of course correct. Trouble is I do not have an extensive electronics knowledge. In fact I had non when I started dabbling in DIY audio 10 years ago. I have learned a lot in that time and made many mistakes which I have learned from. Read a lot on the internet but there is nothing like actually doing things and learning what is right and wrong. I don't own any measuring equipment except a DMM and so have to trust my ears - maybe that is what attracted me to HFS.

Thanks, Stu
Linn LP12, Naim CD3.5, Avondale pre & power, B&W P4 (all modified of course)

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