| nerd of nerds |
hello, i'm building a gainclone for a school project and i need it to be finished over the weekend (due on monday...) so i need to get local parts...local meaning from radio shack (blech).
will this transfromer work O.K. for a simple gainclone?
this is the transformer
i know it probobly isn't the best thing in the world to use, but i need this thing done pretty quickly...:hot:
this also brings me to heatsinks...my school has a pretty nice shop area where i could get ahold of some aluminum bars about 3/4" by 2"...would those do okay for a heatsink? i'm using the lm 3875t, so its not isolated...:whazzat:
thanks! |
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| Netlist |
No, you need split secundaries and 2A is not enough to drive the amp.
Try again. :)
/Hugo |
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| nerd of nerds |
| quote: | Originally posted by Netlist
No, you need split secundaries and 2A is not enough to drive the amp.
Try again. :)
/Hugo |
****...
can you think of anything that i could cannibalize to take the transformer out of? i'm kinda desperate...:bawling: |
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| Netlist |
I happened to find a suitable one in an old Sony receiver.
I managed to split the secundaries. Many old receivers in the 30-50W range should have something you can use.
/Hugo :) |
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| hitsware |
>will this transfromer work O.K. for a simple gainclone?
Yes. You do not need split secondaries or mega-amps for a simple approach. A bridge rectifier and a couple of the largest electrolytics (@ enough volts ) you can find and you're good to go...... |
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| nerd of nerds |
2 questions...
This page makes it sound like i can use single secondaries...
if i don't get this done its fine, i can do some tard project instead, such as a blinking led or something stupid like that...
but i'd reaaaallly like to present a nice amp that i built myself:)
edited...i misread your post... |
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| azira |
Yes, as long as it's a CT transformer which that one is. I used a 24VCT 5A transformer for my GC and it works fine. With respect to the current, since your rail voltage is about 12.5V and your load will be presumably 8-ohms, your peak current usage is around 1.5 A which this transformer can deliver. I suspect you'll be just fine although not delivering as much power as you could which is no problem. Now, considering that your load impedance will vary somewhat, you might current limit (ie clip) if you turn it fully on. But it'll work for this weekend.
However, if you're planning on building a stereo amp, I strongly suggest that you buy 2 of those trafos and power each side seperately since 1 trafo will not have enough current to deliver to both. Make sure to ground them together however for safety.
--
Danny |
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| Netlist |
I stand corrected after reading Brian's user guide
Some mods to the supply PCB are crusial however.
Go for it. You can always upgrade later.
/Hugo :) |
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| nerd of nerds |
| quote: | Originally posted by Netlist
I stand corrected after reading Brian's user guide
Some mods to the supply PCB are crusial however.
Go for it. You can always upgrade later.
/Hugo :) |
i'm not using his kit...i would if it were available but it wasnt' when i decided i wanted to use a kit...so i'm just wiring it part to part...
i need to fix some grounding issues tho...
so, the black wire goes to ground, the other 2 go to the bridge rectifier? is that correct? |
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| thomas997 |
| quote: | Originally posted by nerd of nerds
so, the black wire goes to ground, the other 2 go to the bridge rectifier? is that correct? |
Yeah..
Just do a quick measuring test, you will get the full AC voltage across the outside leads. And using the ground lead you get half to each side.
btw you could use two of those radio shack transformers, primaries paralelled, secondaries in "phase".
Aluminum bar will be fine as long as the load isnt 4ohms, and the voltage isnt too high.. |
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| planet10 |
if you want to max out on the power of your amps you could get away with a pair of these RS trafos per channel. Wire the primamries in parallel, insulate the centre tap and leave it unconnected and treat the other 2 leads on each trafo as split secondaries. This will be equivalent to about a 100 VA trafo.
(i am doing the same thing with trafos salvaged from early Apple ImageWriter IIs)
dave |
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| chipco3434 |
Two of these PE buyouts would work nicely I think...
5 bucks each
Further, RS can supply the rest of the components...
rectifiers
not so bad 3 dollar alps pot complete with incorrect schematic
caps
cheap RCA connectors in gold |
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| nerd of nerds |
i'm just going to use this for now...i'll definetly upgrade it later, but i just need a very quick solution to this for now...
i know its not going to go loud if i do this...but would it work if i just used 1 of these per monoblock? again, i don't need it to go loud, it just needs to amplify the sound...;)
if i could order those transformers from PE and get them on time i would, but i won't so there isnt' much point... |
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| chipco3434 |
| one per would be great. I just built one with 2 small E cores... 3A I think. Turned out great. |
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| nerd of nerds |
| quote: | Originally posted by chipco3434
one per would be great. I just built one with 2 small E cores... 3A I think. Turned out great. |
i was talking about the radio shack transformer FYI...
i really do plan on getting adecent power supply for this thing someday, but for now its just going to be the cheapest/quickest thing possible...
:xeye: |
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