Building first Amp Transformer Help

[colin.hepburn]

Hi All
I want to build my first valve amp But as i cant afford too buy a full kit so it will be a winter project I wanted to go single ended but this would be to costly as would have to replace my Speaker's for more efficient pair
So Will have to go Push pull El 84/34 20 watt ish

I have checked out the maplin Amp millennium which is really a copy of the mullard 520 i Think But I'm not too well up on output transformers so not sure if this is a good idea or not although the transformers have been up rated Can anyone advice me on this The Amp schematic And Transformers Code VT1041can be seen at
All Help with this is welcome http://www.livinginthepast.demon.co.uk/xformer.html
Cheers

[John Caswell]

Hi Colin,
The transformer in question is one of the "standard" values/types for the Mullard 5-20 and as such should work well in that circuit or any other derivative of it. Whether it is as good or better/worse than say a Sowter/Hammond/Tamura/Tango would be very difficult to say, but it is certainly a good starting point.
I suggest that you have a look at the Mullard book, which gives invaluable info on construction, design, layout etc.
You can expect to get about 10-12 watts out of a pair of EL84s and about 20-25 watts out of a pair of EL34s both operating in cathode bias mode.

Regards

John aka Dr John

[colin.hepburn]

Originally Posted by John Caswell

Hi Colin,
The transformer in question is one of the "standard" values/types for the Mullard 5-20 and as such should work well in that circuit or any other derivative of it. Whether it is as good or better/worse than say a Sowter/Hammond/Tamura/Tango would be very difficult to say, but it is certainly a good starting point.
I suggest that you have a look at the Mullard book, which gives invaluable info on construction, design, layout etc.
You can expect to get about 10-12 watts out of a pair of EL84s and about 20-25 watts out of a pair of EL34s both operating in cathode bias mode.

Regards

John aka Dr John

Hi John
Thanks for you input I was unsure if the mullard 5-20 was is still up to it and the transformers as they are cheaper than the hammond trans will check out this Mullard book
I like the idea of mono blocks for first Amp
PS Anyone now where too get the mallard 5-20 book i thought it was on the WD list of books

[pre65]

Hi-i got mine on e-bay !

before i got my book one kind forum member did a photocopy of the 5-20 bit for me so if you would like that to look at PM me with your address.


Philip

[pre65]

Colin-i will post your copy tomorrow.

when i was looking to build a pair of these i found that this company

http://www.vvttransformers.co.uk/index.htm

do a set of transformers and chokes for the 5-20 at a keen price (even keener for 2 sets) so might be worth looking at when pricing up the bits.

Philip

[colin.hepburn]

magic thanks