Zen Variations part 4

Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
The Zen variations part 4 is finished and will be available
next week. Most Probably.

The production boards are better than the prototype, and
we are very pleased at the results.

Meanwhile, for those of you carving metal in anticipation,
here is a picture and dimensioning of the PC board. It
contains everything for one channel except the unrequlated
power supply at 50 volts @ 2 amps per channel. The
amplifier is designed to draw 100 watts per channel, but can
also easily be set up to draw 67 watts.

Accordingly we will be recommending 300 VA of transformer
per channel (36 V @ 8 amps) and .25 deg C/watt per channel
heat sinking.


Let me figure it out in three ways:

(A) 1x primary and 1x secondary, where one secondary commonly used for two channels
(B) 1x primary and 2x secondary, where each secondary used for each channel
(C) 2x (1x primary and 1x secondary), where each transformer used for each channel

I understand that all are equally acceptable.

For me, I use the (B) because it requires less space than the (C), and it appeals to me
as if to be better than (A) in stereo sound effect. Ye, as if ...

I presume Mr Pass is thinking of the (B). Soon we will see it.

In the above, I am thinking of the 24V @ 5 amps of the (B).


2002-01-31 5:48 pm
I think the rating stated was 36 V @ 8 A. This is a fairly common voltage (or 35 V at least) for a transformer so it should be easy to get. Otherwise 2x18 is 36 and using two 300 VA transformer would be more space consuming but very mono build. I suspect the 67 W stems from a lower bias but it could be that it is from a lower supply as well. We'll probably see this week.


Nelson Pass

The one and only
Paid Member
2001-03-29 12:38 am
We have been using the Plitron 070014201 with is 300 VA
with 18 + 18 V secondaries. It does a good job with one
channel at the 100 watt draw or two channels at 67 watt
draw each. We did run it with two 100 watt channels,
and it worked, but it was hot and buzzed a bit.