What toroid transformer to use

[chevy2410]

Hi all,

I'm new to gainclone chipamp and I was wondering what toriod transformer to use with briangt's stereo version of the Lm 3886? I've searched until I was blue in the face with no results.

Also I was wondering what wpc can I expect from this amp?


Thanks,
Chevy

[lineup]

first you need to know what setup you want:

- 1 trafo or 2 trafo ( 1 for each channel )
- you will use only 8 Ohm loudspeakers,
or only 4 Ohm LSP
or a version that can drive both 4/8 Ohm good
- if you will go for max power = max voltage and current
or go for safety margin and good hifi ( lower distortion )


with only 1 trafo, you need a bigger = more VA
with 8 Ohm LSP you need more voltage
with 4 Ohm LSP you need less voltage but more current ( Ampere )


Guys like carlosfm, Peter Daniel, BrianGT and Nuuk
will give you details
or give you links to best threads here in Chip Amps forum


Nuuk has one of the best informative gainclone website
in the web:
Decibel Dungeon
http://myweb.tiscali.co.uk/nuukspot/...loneindex.html


Good luck!

[peranders]

For a stereo amp: 2 x 18-28 VAC, min 100 VA. Up to 300 VA normal, over that overkill.

The first link might be very useful

http://www.national.com/appinfo/audi...gn_Guide13.xls
http://www.national.com/appinfo/audi...sign_Guide.pdf
http://www.national.com/an/AN/AN-1192.pdf
http://cache.national.com/ds/LM/LM3886.pdf

[chevy2410]

I will be using stereo version Lm3886 and 1 transformer. The loadspeakers I'm using are 6 Ohm. I don't think I want to max out on the transformer, but rather stay in the middle.

BTW does anyone know of a good place to buy a transformer in Canada?


Thanks,
Chevy

[maxro]

I'm building a stereo (shared torroid) 3886 Brian Gt kit for use with 4 Ohm speakers. I got a dual 18V secondary, 225VA Hammond transformer. With 6 Ohm you might want to go dual 22v and from what I've read, I don't think you should go much less than 200VA for a shared supply.

Max

[maxro]

Originally posted by chevy2410
BTW does anyone know of a good place to buy a transformer in Canada?

What city are you in?

[doggy]

hi chevy

I have both a plitron and hammond trafo. You can get a hammond in about a week; just search for hammond and look up the local suppliers here; check them out on their website. Both mine are 225va dual sec.which has been enough but I would recommend 300va, better to have some reserve. Plitron have a good reputation, look nice, are potted in the center, more compact for the same va as hammond. Plitron has more voltage options and are priced perhaps better. They ship with ups so you can add another $30 from Toronto. They custom make so you have to wait for 5 weeks for delivery.

cheers
doggy

[chevy2410]

I am 1hr. east of Vancouver.


Chevy.

[chevy2410]

Where did you get your Plitron from?

Chevy

[maxro]

Hi Chevy,

I got my Hammond from Interior Electronics (Queale in Victoria) About $85 if I recall.

http://www.interiorelectronics.com/index.php?PAGE=home

But, I found that most of the other parts I needed were much cheaper (some 1/2 the cost) at Main Electronics in Vancouver. I dunno about their transformer prices though.

http://www.mainelectronics.com/

Max