So what are the best Chinese valve amps???
 

"Keith G" wrote in message
...

"Nick Gorham" wrote


Ok, I was just planning ahead in case an argument was on its way :-)

:-)


Of course most of those problems go away when you have speakers that only
require power well below a watt. and amplifers that will produce several
watts (ie Keith).


I'm only sorry that you only heard my 2A3 amp on the *not so cute*
Jerichos last time you were here (as did Serge) - the Fidelios with the
Lowther drivers are in a totally different league and, after a whole year
from brand new, are starting to sound very nice!!


I have a long list of places I want to go, and things I want to see.
I have now crossed off "Mecca" and pencilled in "Keith's Lowthers"
instead. :-)

Iain

So what are the best Chinese valve amps???
 

"Keith G" wrote in message
...

"Iain Churches" wrote in message
i.fi...


Your recording with mics is not the best way to evaluate a system.

Of course it bloody isn't, but without a Tardis this end either how else
can I demonstrate a SET?

That's why I took this opportunity to borrow this pair of monoblocs
to try to learn something more about SET. At the moment I am puzzled.

Here's a bit of Mahler 1 I've just done:

http://www.apah69.dsl.pipex.com/show...-%20Mahler.mp3


I can't make out a tuba, but the bandoneon is quite distinct in places...

That could be the 3H :-)

Now, name a better piece and I'll see what I've got. (There's an
*unplayed* half speed master of the 1812 here somewhere but it's hiding
from me atm!)

That might be quite a good choice. Can you record
straight from the speaker terminals to eliminate the mics
and room from the equation?

Cheers
Iain

So what are the best Chinese valve amps???
 

"Iain Churches" wrote in message
i.fi...

"Keith G" wrote in message
...

"Nick Gorham" wrote


Ok, I was just planning ahead in case an argument was on its way :-)

:-)


Of course most of those problems go away when you have speakers that
only require power well below a watt. and amplifers that will
produce several watts (ie Keith).


I'm only sorry that you only heard my 2A3 amp on the *not so cute*
Jerichos last time you were here (as did Serge) - the Fidelios with
the Lowther drivers are in a totally different league and, after a
whole year from brand new, are starting to sound very nice!!


I have a long list of places I want to go, and things I want to see.
I have now crossed off "Mecca" and pencilled in "Keith's Lowthers"
instead. :-)


We don't do Bingo here, Iain....

So what are the best Chinese valve amps???
 

"Iain Churches" wrote in message
ti.fi...

"Keith G" wrote in message
...

"Iain Churches" wrote in message
i.fi...


Your recording with mics is not the best way to evaluate a system.

Of course it bloody isn't, but without a Tardis this end either how
else can I demonstrate a SET?

That's why I took this opportunity to borrow this pair of monoblocs
to try to learn something more about SET. At the moment I am puzzled.

Here's a bit of Mahler 1 I've just done:

http://www.apah69.dsl.pipex.com/show...-%20Mahler.mp3


I can't make out a tuba, but the bandoneon is quite distinct in
places...

That could be the 3H :-)

Now, name a better piece and I'll see what I've got. (There's an
*unplayed* half speed master of the 1812 here somewhere but it's
hiding from me atm!)

That might be quite a good choice. Can you record
straight from the speaker terminals to eliminate the mics
and room from the equation?


No, but at least you realise the room is *in* the equation - Arny seems
to have forgotten that! Anyway, I've done him another track with less HF
(but more crackle, unfortunately):

http://www.apah69.dsl.pipex.com/show...Resistance.mp3


(Hint: It's *****ing* with rain here! ;-)

So what are the best Chinese valve amps???
 

"Nick Gorham" wrote in message
...
Iain Churches wrote:

Not that I am claming that SET's don't distort, they do, but if you are
in
a situation where the 3rd is higher than the 2nd, then either its being
driven far to hard (which shouldn't be the case at 1w even for a 45), or
its badly broken.


The figs are actually better than the few Chinko amps
I have measured.

I am not trying to get involved in the argument about sets, but those
numbers seem a bit extreme. This is the result of one of my 300b SET's
running at 1w into 8R (resistive)


There is no argument. Nick. Just a discussion to establish
why SET does not seem to make a very good job of
reproducing complex music. Your findings would be
of interest.


Ok, I was just planning ahead in case an argument was on its way :-)

None if I can help it:-) My own situation regarding SET is clear.
The one I know well, the Resmnikov, can produce the Shostakovich
Quartets like I have never heard them before. Such is the realism that
I decided a long time ago to build myself a SET amp specifically for this
kind of music when time permits.

I would agree that anything that produces the amount of distortion you
describe would have problems with anything more complex than a flute.

Indeed. The fact that 3H, 5H (and also IIRC, 7H) are far the greatest
levels of harmonics is too say the least, worrying. A couple of people
have told me, "Don't worry. What you describe is pretty standard" I
am perplexed than any amplifier with a spec like that can produce
believeable music of any kind:-)

The other area I find that most SET's (esp commercial ones) are lacking
is the power supply, and that tends to lead them to produce wolly
disjointed bass. I sometimes wonder if some of those spending lots of
money on sets actually like the high distortion and wooly bass they
produce.

Good point. I know only a handful of people with SET amps.
I would also describe them all as very discerning listeners

Of course most of those problems go away when you have speakers that only
require power well below a watt. and amplifers that will produce several
watts (ie Keith).

Yes indeed. I was pretty amazed when I went to the Lowther
convention last year. The sweetest 1W I have ever heard in my life:-)

However, as I said before this isn't inherrent in the topology. Just for a
interesting variation, look at the circuit of the Pass F2, every bit a
set, its just the t stands for transistor, and the choke load is a CCS in
this case.

I am busy for a day or two, but as soon as I have time,
I will post the pics I took of the spectrum analysis. These
are a a pair of monoblocs. Their performance is identical,
so there is no reason to think that either is broken.

Yes, I didn't mean broken as in "not performing as intended by the maker",
but as in "broken by design".

That may well be the case. I shall dig deeper and report.

Cheers
Iain

So what are the best Chinese valve amps???
 

"Arny Krueger" wrote in message
. ..
"Iain Churches" wrote in message
i.fi
"Nick Gorham" wrote in message
...
Arny Krueger wrote:
"Nick Gorham" wrote in message



Maybe, as I said, I have no axe to gind about sets, but
I just wanted to suggest that Iain's "handsome" amp
might be more looks than substance if its producing 1%
at 1W.

It is not my amp, but one that I have borrowed
specifically to find out what gives it its sonic
signature. Now I know.

I suspect that the frequency response into a typical speaker load will
shed more light.

I don't have a lot of time, as the owner is already asking
when he can pick up his amplifiers. He likes them more than the
Macrotech I lent him temporarily:-)

BTW, here's the circuit diagram for a pretty good speaker simulator, with
test results:

http://www.pcabx.com/product/amplifiers/index.htm

Thanks. I will mark that and build it when time permits.

Iain

So what are the best Chinese valve amps???
 

"Iain Churches" wrote in message
ti.fi...

"Keith G" wrote


Now, name a better piece and I'll see what I've got. (There's an
*unplayed* half speed master of the 1812 here somewhere but it's
hiding from me atm!)

That might be quite a good choice.


OK, for good or ill, here it is (snippet):

http://www.apah69.dsl.pipex.com/show...k%20(MFSL).mp3


I'm going to shift the mics now and record it on the SS/IMFs

So what are the best Chinese valve amps???
 

Here is the link to the spectral analysis of the distortion
of the SET amp. Copious amounts of 3H and 7H.

http://www.kolumbus.fi/iain.churches...ETSpectrum.jpg


In contrast, here is a parallel PP EL34 50W amp, also at 5W

http://www.kolumbus.fi/iain.churches...50Spectrum.jpg


Although perhaps an extreme case, I think this illustrates what
seem to be the shortcomings of SET topology. I can however
see why they are popular, they do give pleasing results with certain
types of music, and (up to a certain level) they are fairly simple to
build, with no instability problems.

Iain

PS The Zo of the SET I tested is 3.2 Ohms.

So what are the best Chinese valve amps???
 

Iain Churches wrote:
Here is the link to the spectral analysis of the distortion
of the SET amp. Copious amounts of 3H and 7H.

http://www.kolumbus.fi/iain.churches...ETSpectrum.jpg


In contrast, here is a parallel PP EL34 50W amp, also at 5W

http://www.kolumbus.fi/iain.churches...50Spectrum.jpg


Although perhaps an extreme case, I think this illustrates what
seem to be the shortcomings of SET topology. I can however
see why they are popular, they do give pleasing results with certain
types of music, and (up to a certain level) they are fairly simple to
build, with no instability problems.

Iain

PS The Zo of the SET I tested is 3.2 Ohms.







Well, it might be a little more of a valid comparison if you ran the SET
at (say) 0.8w so the test was at a similar proportion of rated max
output power.

And if you wanted to compair topology, instead of individual examples,
it might be interesting to run the PP with zero feedback. What would the
PP amps Zo be without feedback I wonder?

I think the problem is that a 300b SET should be considered as a 1w
amplifer with soft clipping above that level, and as such, I think the
PP would also be expected to fare badly if asked to reproduce music at a
constant 60w level.

But if the goal was efficiency, high power output, low distortion and
high damping factor, what possible reason can there be for using a PP
El34 amp, I would have thought a nice mosfet amp would have met your
goals far better

--
Nick

So what are the best Chinese valve amps???
 

"Iain Churches" wrote in message
ti.fi...

Here is the link to the spectral analysis of the distortion
of the SET amp. Copious amounts of 3H and 7H.

http://www.kolumbus.fi/iain.churches...ETSpectrum.jpg


In contrast, here is a parallel PP EL34 50W amp, also at 5W

http://www.kolumbus.fi/iain.churches...50Spectrum.jpg


Although perhaps an extreme case, I think this illustrates what
seem to be the shortcomings of SET topology. I can however
see why they are popular, they do give pleasing results with certain
types of music, and (up to a certain level) they are fairly simple to
build, with no instability problems.

Iain

PS The Zo of the SET I tested is 3.2 Ohms.



Iain, rather than get into yet another 'SET vs. The Rest Of The World'
exchange here (it ends with 'pleasant' and 'realistic' for me), I'll
just point you to some of the pages of the late, great Fred Nachbur who,
it seems to me, is able to examine the characteristics and properties of
SET topologies with a rare *evenhandedness* and offer the most
interesting suggestions as to why, in fact, SET amplifiers do sound
*special*:

Start he

http://www.dogstar.dantimax.dk/tubestuf/miniblk1.htm


Follow through to his 'Soapbox' section (scroll down to 'SET Mythos'):

http://www.dogstar.dantimax.dk/tubes...k3.htm#soapbox


Where there are some interesting sound snippets....