That then is realistic.
Carl
KM1H
----- Original Message -----
From: "Ulf (SM0NOR)" <ulf@sm0nor.com>
To: "Carl" <km1h@jeremy.mv.com>
Cc: <amps@contesting.com>
Sent: Monday, March 04, 2013 5:34 PM
Subject: Re: [Amps] Transformer choice
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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