I actually think the quote was for class 105, which is 40 ambient+55 rise+10
hot spot.
Sent from a wireless device of an unrevealed brand.
On 4 mar 2013, at 21:57, "Carl" <km1h@jeremy.mv.com> wrote:
> A 105C rise is not what I consider a good transformer, ask what the
> magnetizing current is.
>
> Carl
> KM1H
>
>
> ----- Original Message ----- From: "Ulf (SM0NOR)" <ulf@sm0nor.com>
> To: <amps@contesting.com>
> Sent: Monday, March 04, 2013 6:28 AM
> Subject: [Amps] Transformer choice
>
>
> Hi Guys,
> I'm looking for some feedback on two transformer offers I have. I'm intending
> to build a table top amp, so I'm accepting some compromises regarding the
> transformer. I have made inquiries to a couple of winders and I have boiled
> them down to 2 offers. I was asking for 2000 Volts @1A =2000VA (+ G1 and G2
> windings). I'm targeting to get 2200-2400 watts output in PEP service and
> about 1K in continuos service.
>
> Both companies claim 2000VA but at different core weights
>
> Company A:
> 17 Kilo toroid, D=200 mm, H=110. About 3% voltage drop at full load. Max
> temp rise = 105C over 40C ambient. DC resistance, about 25 ohms.
> Price: €480
>
> Company B:
> 11 kilo toroid, D=180 mm, H=85mm. About 2,5% voltage drop at full load.
> Can't, or don't want to specify other data.
> Price: €195
>
> So what are your reflections? The A is obviously a the better choice. They
> are serious and they offer detailed specs, exact delivery times etc. But all
> comes at a premium price. Company B is smaller and they obviously compromises
> with their specifications, but the price is a lot lower and so is the weight.
>
> Now, I don't expect the cheaper and smaller core to do wonders. The bigger
> one will for sure be more rugged and closer to "true 2000VA", especially if I
> run it in true continuous mode. I'm inclined to go for the the bigger one,
> because I want the best. But OTOH, I don't want to waste money because of a
> "feeling". Perhaps the smaller one will be enough given the table-top
> size/PEP service I'm targeting? After all, it matches what's inside most
> commercial amps in this category.
>
> I'm happy for any feedback...
>
>
>
> 73's
>
> Ulf (SM0NOR)
> ulf@sm0nor.com
>
>
>
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