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Sander deWaal wrote:
said:


BTW if you're serious about SET amps, and not afraid to DIY a bit, you
must try the 2A3 or, even better, the AD1/350 one day.

To me, it is the best sounding tube ever made.
BTW I only use them in PP, because my Maggies need at least some juice
and SE isn't my thing, but with your Druids, 2 or 3 watts from a SE
2A3 should be clean as pure snow, and a ticket to sonic heaven.


With my Yamamoto A-08S, I'm supposed to be able to switch from 45s to
2A3s pretty easily if I also switch out the rectifier tube (which is an
80). I think there might be one or two other minor things to do,
too...I'll have to check with the literature.


Like cathode resistors, perhaps? ;-)
I don't have first-hand experience with the 45, other than some casual
listening sessions with Jim de Kort e.a.
Also, one repair of a Chinese knockoff of a 45 design, that didn't
impress me at all.

The 45 is a good tube in its own right, but for some real meaningful
comments, I'd have to build an amp with them..

An 80 for rectifying? Not the blue Arcturus, I hope? :envious:
I assume this is a choke input circuit?
Did you try a 5U4G instead? That would lower the B+ enough to be able
to use the 2A3 I think.


Have you heard many 45 amps? And have you heard the Emissions Labs
45s? I've got two pairs of them, and they sound much more robust than
the NOS RCA 45s that came with the amp.


The amps I've heard were all DIY designs, mostly by Jim, and judging
from his design philosophy, he uses a rather high anode load which
results in lower power, but also a lower THD and, what's even more
important, a harmonic structure that sounds very pleasening (at least
to these ears).

Other than that, my experience with SE amps in general is very
limited.
All of my own tube designs are PP, but always real triodes or triode
strapped beampower tubes, and class A.

But the conversion from 45s to 2A3 or even AD1 (if you can find them!)
should be possible, at least judging from the spec sheets of these
tubes.

I assume the Yamamoto amp is designed around the 45 though, so
swapping for a 2A3 might not result in an optimum wrt. load
characteristics, even if you'd have the cathode resistors changed to
the right value.

I definitely think there's more than just swapping the rectifier. The
literature states that my amp can be ordered as a 2A3 amp "upon
request." The US distributor said it was just a matter of swapping the
rectifier, and one other minor thing, but I can't remember what it
was...maybe just changing the resistor. That sounds right.

The EML 45s are very different than every other 45 out there. First of
all, they're at least twice as big as my NOS RCA 45s. They're also
absolutely beautiful tubes.

Here's some info on the amps:

http://www.venushifi.com/products/ya...plifiers.shtml

Boon



--
"Due knot trussed yore spell chequer two fined awl miss steaks."