Sorry ... my last e mail was supposed to go to Chris directly. For unknown reasons when I selected
'reply'. to Chris's direct e mail Blacksheep got filled in as the address instead of his direct e
mail. That's a head scratcher ... never seen that one happen before!
Jay W1VD
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Thursday, May 02, 2019 10:01 AM
Subject: LF: Re: Toroids
Chris
None in stock but would be happy to get them for you. Only possible problem is the customs forms
... I'm required to list the values of items accurately. I had a run in with US Customs years ago
and don't wish to take a chance getting tangled up with them again. Let me know and I'll check
pricing for the cores and shipping.
A pi-type filter is what's required for current mode. The amplifier as shown in the schematic
'appears' to be current mode since there's no bypass at the centertap of the transformer. Not sure
why you're seeing hot components. In the schematic it appears the ground was left off the bottom
of LPF capacitors ... I'm sure
you picked up on this. Don't think I'd use a -26 core at 500 kHz ... this may or may not be the
problem.
Jay W1VD
----- Original Message -----
From: "Chris Wilson" <[email protected]>
To: <[email protected]>
Sent: Thursday, May 02, 2019 8:00 AM
Subject: Toroids
Hello Jay,
I am going to build the MF version of your 1kW amp deck to compliment
the LF versions that have proven superb! I am struggling getting the
T-225A-2 toroids and the T-157-3 ones here in the UK without Amidon
trying to charge far more than the cost in postage, plus a hefty
import duty / tax. Would you consider supplying these direct and
marking the package note as a low value (at my risk)? I could do with
three of T-225A-2 and 4 of the T-157-3 toroids. Here in the UK no one
has any stock of either. If it's a PITA and you are unable to oblige
or you don't have them, no worries :) Thanks. Chris Wilson 2E0ILY.
BTW, off list, I built the G0MRF MF 300W amp and at full power it runs
the toroids and C19 C20 mad hot, plus the drain waveforms look
horrible. Am I right in thinking he's using a current mode LPF on a
voltage mode amp? And are the components like caps and toroids
marginal at this power level? I am sure your MF amp is much more
robust :)
--
Best regards,
Chris mailto:[email protected]
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