Need a transformer / power supply

nacimroc

In my drunken state one night I bought a little amp off ebay

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260672993479&ssPageName=STRK:MEWNX:IT#ht_2447wt_905

Problem is it doesn't come with a power supply (see above drunken state..didn't read listing fully).

On the listing it says it needs:

Power Supply: AC Dual 18-28V

Now on the unit itself it say 26V.

As you may have grasped, I have only very basic electronics!

Any idea where or what unit I could get ?


Thanks

Bruthal

nacimroc wrote: »

In my drunken state one night I bought a little amp off ebay

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260672993479&ssPageName=STRK:MEWNX:IT#ht_2447wt_905

Problem is it doesn't come with a power supply (see above drunken state..didn't read listing fully).

On the listing it says it needs:

Power Supply: AC Dual 18-28V

Now on the unit itself it say 26V.

As you may have grasped, I have only very basic electronics!

Any idea where or what unit I could get ?


Thanks

Maybe this
http://cgi.ebay.ie/AC-AC-MAINS-POWER-ADAPTOR-SUPPLY-500MA-24V-24-VOLT-/170554065275?pt=UK_ConsumerElectronics_PowerAdaptors_SM&hash=item27b5d0817b

nacimroc

The voltages look about right, but would it be powerful enough ? Its only 500ma and it has to run a sub-woofer and 2 mid-range speakers ? (sorry I should have specified)

Bruthal

Probably need a bit more power alright, not sure where you will get that. An old microwave transformer would do the job, they are 230v primary, 2300v seconary, so connect the secondary to the 230v and you have 24v ac from the primary, which is now the secondary.

Must be somewhere sells a 230 - 20v ac adaptor though, but might be tricky to get one with a bit of power. DC output wire wound ones can be used by removing the rectifier section also.

mullingar

Simples:

80+80+160 = 320 W.

Use the average of the rated voltage input = 24V

So, 320/24 = 13.5Amps

to use the Amp at max power, you need a 24V, 13.5A transformer, which is a serious beast. You would probably get away with a 10A, if you dont abuse it!


Edit,

Radionics sell these, for the money they are an expensive shop, but here is a cheap 225W version:

http://radionics.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=6719167





Alternative,

Maplins !

Code:N32JB


This is a 300VA, more suited, around €50.

These are 12-0-12V transformers, basically ignore the 0V wire and you have a full 24V between the other 2 wires.

Bruthal

mullingar wrote: »

Simples:

80+80+160 = 320 W.

Use the average of the rated voltage input = 24V

So, 320/24 = 13.5Amps

to use the Amp at max power, you need a 24V, 13.5A transformer, which is a serious beast. You would probably get away with a 10A, if you dont abuse it
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It may seem simple alright, but do you think he is going to put 320 watts of speakers on the amp, it seems unlikely.
Just because the amp is rated up to that does not mean he will use that amount of speakers. But you never know. Anyway 256 watts of speaker output is about 114 decibals, so maybe he just wants to knock the house down:)

Maybe if we could find out the speaker wattage we can be more accurate.

FarmerGreen

nacimroc wrote: »

In my drunken state one night I bought a little amp off ebay

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=260672993479&ssPageName=STRK:MEWNX:IT#ht_2447wt_905

You will need to bolt the four power devices to a monster heatsink, say 12x4 inches
Use mica washers and plastic bushes.
A couple of fans wouldn't hurt either!

Like this...
http://english.cxem.net/amplifier/amplifier25-2.jpg

nacimroc

Thanks for replies lads! Will buy these now and give it a go!