"Andre Jute" wrote in message
oups.com...
On Oct 19, 12:11 am, "Iain Churches" wrote:

The noise floor was exceptionally low. Later, a quick
look on the bench revealed the noise floor to be 100µV, so a
SNR of 105dB and at 96W, the THD was only 0.1%

It depends on your outlook whether you view the Velleman K40x0 as that
rare thing, a perfect all-round amp --

(snip)

Oh,. I don't think it is anywhere near that!
I regard it as a good-sounding DIY project, no more.
The fact that the tube sockets are mounted on the PCB
really put me off.

I have a Radford STA 100. So no contest.

Iain

(snip)

Oh,. I don't think it is anywhere near that!
I regard it as a good-sounding DIY project, no more.
The fact that the tube sockets are mounted on the PCB
really put me off.

I have a Radford STA 100. So no contest.

Iain



I owned one that another fellow put together. I remember replacing some of
the 10 ohm resistors because of excessive cathode current draw.

It was a nice looking amp, with plenty of power. The PCBs were a turn-off,
but not a killer for me (Hey, if you want to have some REAL fun, do
component-level work on an Audio Research D-70. What a nightmare to repair!)

In my continuing search for the holy grail of sound, that amp went to a new
owner. To my ears, the sound was kind of harsh for a tube amp, and lacking
excitement.

I agree that it is "a good-sounding DIY project."

Jon

"Jon Yaeger" wrote in message
...

I owned one that another fellow put together. I remember replacing some
of
the 10 ohm resistors because of excessive cathode current draw.

It was a nice looking amp, with plenty of power. The PCBs were a turn-off,
but not a killer for me (Hey, if you want to have some REAL fun, do
component-level work on an Audio Research D-70. What a nightmare to
repair!)

In my continuing search for the holy grail of sound, that amp went to a
new
owner. To my ears, the sound was kind of harsh for a tube amp, and
lacking
excitement.

I agree that it is "a good-sounding DIY project."

And, in that respect, if it does something to light the spark
of interest in tube audio, then it has served a very useful purpose.

Iain

On Oct 21, 7:48 am, "Iain Churches" wrote:
"Andre Jute" wrote in message

oups.com...
On Oct 19, 12:11 am, "Iain Churches" wrote:

The noise floor was exceptionally low. Later, a quick
look on the bench revealed the noise floor to be 100µV, so a
SNR of 105dB and at 96W, the THD was only 0.1%

It depends on your outlook whether you view the Velleman K40x0 as that
rare thing, a perfect all-round amp --

It's all opinion. Some opinions are informed by relevant experience
and therefore more valuable. Some opinions are informed by nothing but
street corner gossip or personal animosity and are therefore
worthless.

Oh,. I don't think it is anywhere near that!
I regard it as a good-sounding DIY project, no more.
The fact that the tube sockets are mounted on the PCB
really put me off.

I have a Radford STA 100. So no contest.

And I have a Quad II. No contest, to my mind at least; it depends what
you want to measure and hear. Except that the Quad II doesn't put out
100W. Let's compare apples with apples, not with gilded plums, mmm?

I could compare the Velleman K4000 100W with a bunch of other kits I
have built and used extensively: Arion Adonis PP 5581 20W, Audio
Innovations Classic Stereo 25 PP EL34 25W, Triode Supply Japan Miyabe
300B SEPP 16W, etc, etc, and in no instance would it be comparing
apples with apples, for the good and simple reason that none of them
have 100W. In that the Velleman K40*0 stands alone, and gives the
beginner versatility to use the most grossly insensitive bookshelf
speakers to get real oomph on any music whatsoever. I could have
chosen any of the amps listed, or any of the other kits I have built,
including some I don't list because they have less than 10W, and said
they're fine on some aspect (or even the best) but, while all of them
have served me very well indeed, none of them can be put up against
the Velleman without admitting some handicap in some perfectly common
everyday use for an identifiable group of users.

I might add that my favourite among that lot is the AI, which is a
gentleman's amp, never intrusive; an amp you can play 14 hours every
day and never find fault with. I find the Velleman far too analytical
for my taste but that is because it is so accurate, a characteristic
many value. But, to illustrate once more that all this is relative to
usage and opinion, I play mainly chamber music at low volume;
symphonic or other "big" music played on insensitive speakers
*requires* a big amp. If I were into heavy metal or whatever the
current fave of the loud set is called, I wouldn't touch any of my
favourite amps for chamber music -- they'd all be less than convincing
-- I'd go straight to the Velleman and acoustic overload heaven.

By the way, the Velleman K40*0 is eminently tweakable. On my old
netsite I had an entire big section devoted to altering the factory
spec to make it sound like anything you wanted it to sound like. The
"harshness" Jon Yaeger objects to, for instance, was just a matter of
swapping out a ceramic (! now that's an excess of engineering...) cap
for a film cap; you would of course sacrifice a little of the
excellent noise spec (which was why the designer put it in there) but
might consider the loss worthwhile to gain precisely the sound you
want. I'm amazed that Yaeger doesn't know that.

As for the snobbery of demanding point to point wiring on kits, go
right ahead: you'll be helping to kill the hobby off faster than is
necessary. In my experience eliminating the PCB, or insisting on
sockets mounted to the chassis, just about triples the price of the
kit, and ensures that the successful assembly rate is halved.
(Suppliers who give a completion guarantee, or who provide a
handholding service, keep very good records of these matters! Or you
can read between the lines in the instructions and on the sites of
those who sell PTP kits how fed up they are with seeing time and
profits dribble away in support to eejits who cannot follow simple
instructions.)

If you insist on hardwiring, nothing stops you buying a Velleman K40*0
kit, or any other kit with a chassis, to get the design and all the
parts, and simply drilling the cover to hold sockets for the tubes and
then fitting the components to tag strips you supply. Nor is there any
secret to designing a PCB construction properly for heat management:
either ascertain that the kit has ceramic standoffs for power tubes
and resistors as standard, or add them yourself. I'm really amazed at
discovering DIYers who brag about their craftsmanship, then complain
about an amp because it is designed to be built on a PCB: if you don't
like it, change it!

Iain

For those who need or want a 100W and prefer tubes, the Velleman K40x0
is unique, zero competition that I know about.

I don't see much point in nitpicking commercial amps against
irrelevant self-proclaimed "standards"; the test is whether the thing
works in the hands of owners, and the K40*0 worked fine for a decade
and more in my hands. We've already had a bunch of clowns in this
thread condemning one of the most succesful commercial amps in the
world *without ever seeing one or hearing it*. That sort of street
corner gossip repeated as gospel is what trashes the reputation of
RAT, not putting down the thieves of intellectual rights or netbullies
and netstalkers -- on the contrary, it is toleration and protection of
such people that trashes our reputation.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

"Andre Jute" wrote in message oups.com...
On Oct 21, 7:48 am, "Iain Churches" wrote:
"Andre Jute" wrote in message

oups.com...
On Oct 19, 12:11 am, "Iain Churches" wrote:

The noise floor was exceptionally low. Later, a quick
look on the bench revealed the noise floor to be 100µV, so a
SNR of 105dB and at 96W, the THD was only 0.1%

It depends on your outlook whether you view the Velleman K40x0 as that
rare thing, a perfect all-round amp --

It's all opinion. Some opinions are informed by relevant experience
and therefore more valuable. Some opinions are informed by nothing but
street corner gossip or personal animosity and are therefore
worthless.

Oh,. I don't think it is anywhere near that!
I regard it as a good-sounding DIY project, no more.
The fact that the tube sockets are mounted on the PCB
really put me off.

I have a Radford STA 100. So no contest.

And I have a Quad II. No contest, to my mind at least; it depends what
you want to measure and hear. Except that the Quad II doesn't put out
100W. Let's compare apples with apples, not with gilded plums, mmm?

I could compare the Velleman K4000 100W with a bunch of other kits I
have built and used extensively: Arion Adonis PP 5581 20W, Audio
Innovations Classic Stereo 25 PP EL34 25W, Triode Supply Japan Miyabe
300B SEPP 16W, etc, etc, and in no instance would it be comparing
apples with apples, for the good and simple reason that none of them
have 100W. In that the Velleman K40*0 stands alone, and gives the
beginner versatility to use the most grossly insensitive bookshelf
speakers to get real oomph on any music whatsoever. I could have
chosen any of the amps listed, or any of the other kits I have built,
including some I don't list because they have less than 10W, and said
they're fine on some aspect (or even the best) but, while all of them
have served me very well indeed, none of them can be put up against
the Velleman without admitting some handicap in some perfectly common
everyday use for an identifiable group of users.

I might add that my favourite among that lot is the AI, which is a
gentleman's amp, never intrusive; an amp you can play 14 hours every
day and never find fault with. I find the Velleman far too analytical
for my taste but that is because it is so accurate, a characteristic
many value. But, to illustrate once more that all this is relative to
usage and opinion, I play mainly chamber music at low volume;
symphonic or other "big" music played on insensitive speakers
*requires* a big amp. If I were into heavy metal or whatever the
current fave of the loud set is called, I wouldn't touch any of my
favourite amps for chamber music -- they'd all be less than convincing
-- I'd go straight to the Velleman and acoustic overload heaven.

By the way, the Velleman K40*0 is eminently tweakable. On my old
netsite I had an entire big section devoted to altering the factory
spec to make it sound like anything you wanted it to sound like. The
"harshness" Jon Yaeger objects to, for instance, was just a matter of
swapping out a ceramic (! now that's an excess of engineering...) cap
for a film cap; you would of course sacrifice a little of the
excellent noise spec (which was why the designer put it in there) but
might consider the loss worthwhile to gain precisely the sound you
want. I'm amazed that Yaeger doesn't know that.

As for the snobbery of demanding point to point wiring on kits, go
right ahead: you'll be helping to kill the hobby off faster than is
necessary. In my experience eliminating the PCB, or insisting on
sockets mounted to the chassis, just about triples the price of the
kit, and ensures that the successful assembly rate is halved.
(Suppliers who give a completion guarantee, or who provide a
handholding service, keep very good records of these matters! Or you
can read between the lines in the instructions and on the sites of
those who sell PTP kits how fed up they are with seeing time and
profits dribble away in support to eejits who cannot follow simple
instructions.)

If you insist on hardwiring, nothing stops you buying a Velleman K40*0
kit, or any other kit with a chassis, to get the design and all the
parts, and simply drilling the cover to hold sockets for the tubes and
then fitting the components to tag strips you supply. Nor is there any
secret to designing a PCB construction properly for heat management:
either ascertain that the kit has ceramic standoffs for power tubes
and resistors as standard, or add them yourself. I'm really amazed at
discovering DIYers who brag about their craftsmanship, then complain
about an amp because it is designed to be built on a PCB: if you don't
like it, change it!

Iain

For those who need or want a 100W and prefer tubes, the Velleman K40x0
is unique, zero competition that I know about.

I don't see much point in nitpicking commercial amps against
irrelevant self-proclaimed "standards"; the test is whether the thing
works in the hands of owners, and the K40*0 worked fine for a decade
and more in my hands. We've already had a bunch of clowns in this
thread condemning one of the most succesful commercial amps in the
world *without ever seeing one or hearing it*. That sort of street
corner gossip repeated as gospel is what trashes the reputation of
RAT, not putting down the thieves of intellectual rights or netbullies
and netstalkers -- on the contrary, it is toleration and protection of
such people that trashes our reputation.

Horse****, Andre. It isn't the reputation of RAT that's trashed, it's the
atmosphere that people have been fleeing. That atmosphere has been
trashed by your relentless personal attacks on everyone you can find
even the slightest reason to go after.

But it's OK; pretty soon you and your sock puppets will have this place
all to yourselves. You'll be able to launch devastating attacks on your
sock puppets every day and no one will complain unless you do it for
them.

He he, Andre, what a horse's ass you are.

Andre Jute
Visit Jute on Amps at http://members.lycos.co.uk/fiultra/
"wonderfully well written and reasoned information
for the tube audio constructor"
John Broskie TubeCAD & GlassWare
"an unbelievably comprehensive web site
containing vital gems of wisdom"
Stuart Perry Hi-Fi News & Record Review

I don't see much point in nitpicking commercial amps against
irrelevant self-proclaimed "standards"; the test is whether the thing
works in the hands of owners, and the K40*0 worked fine for a decade
and more in my hands. We've already had a bunch of clowns in this
thread condemning one of the most succesful commercial amps in the
world *without ever seeing one or hearing it*. That sort of street
corner gossip repeated as gospel is what trashes the reputation of
RAT, not putting down the thieves of intellectual rights or netbullies
and netstalkers -- on the contrary, it is toleration and protection of
such people that trashes our reputation.

Andre Jute


I'll second Phread, it is the personal attacking that makes this place
less-than. If you'd examine the history, RAT was a reasonable going
concern until the Jute v. Magnetquest war. Seems Andre was unable to
make a legitimate criticism of Mikey stick.

So then Andre, you mention an AB amp having A power, you reference an
80W SE amp, claim an off the rack Vellman kit is brilliant, and then
attack anybody who'd have the guts to say you've over reached. Even
with poor S/N ratio there is still signal. Let's see some from you.
cheers,
Douglas

On Mon, 22 Oct 2007 13:50:47 -0700, Multi-grid wrote:


snip

So then Andre, you mention an AB amp having A power, you reference an
80W SE amp, claim an off the rack Vellman kit is brilliant, and then
attack anybody who'd have the guts to say you've over reached. Even with
poor S/N ratio there is still signal. Let's see some from you. cheers,


Surely though, a class AB amp such as the Vellman *is* running in class A
up to the point where one output device starts to turn off isn't it? The
changeover to class B happens at that point and is dependent on the
quiescent current in the outputs.

A true class A amp is only a special case of the normal AB class. It's
just that it clips symmetrically instead of moving smoothly into class
B. ;-)

--
Mick (Working in a M$-free zone!)
Web: http://www.nascom.info http://mixpix.batcave.net

Surely though, a class AB amp such as the Vellman *is* running in class A
up to the point where one output device starts to turn off isn't it?
--
Mick (Working in a M$-free zone!)
Web:http://www.nascom.info http://mixpix.batcave.net

Nope, not a chance. That both tubes are conducting does not mean it is
A. Have some respect... AB amps don't have any A power, that is why
there is a seperate classification.
cheers,
Douglas

On Oct 22, 2:33 pm, mick wrote:
On Mon, 22 Oct 2007 13:50:47 -0700, Multi-grid wrote:

snip

So then Andre, you mention an AB amp having A power, you reference an
80W SE amp, claim an off the rack Vellman kit is brilliant, and then
attack anybody who'd have the guts to say you've over reached. Even with
poor S/N ratio there is still signal. Let's see some from you. cheers,

Who is this fellow "Multi-grid", and why is he addressing me?

Surely though, a class AB amp such as the Vellman *is* running in class A
up to the point where one output device starts to turn off isn't it? The
changeover to class B happens at that point and is dependent on the
quiescent current in the outputs.

I would have thought anyone with a handle like "Multi-grid" would have
taken that sort of basic tube knowledge from the teat. Mind you, I
remember when Ron Bales wanted us here on RAT to give everyone who
claimed a "tubie-handle" a test of tube knowledge to ensure they don't
give a respectable hobby a bad name by wielding their ignorance like
clubs. That was about 1998. Looks like this "Multi-grid" fellow is a
prime candidate for the Bales Test.

A true class A amp is only a special case of the normal AB class. It's
just that it clips symmetrically instead of moving smoothly into class
B. ;-)

It is beneath my dignity to rise to such provocation -- sniff. A Class
AB amp is a compromised Class A amp, and it probably requires negative
feedback too to work even acceptably. A properly designed Class A amp
never clips because the operating parameters were so chosen that it
runs out of signal from the intended source before it can clip (that
is one reason why the design instructions on my netsite feature the
*design center* process so heavily). It is only "engineers" who
"design" amps to hog the maximum power from each tube who even need a
concept like clipping; for sane tubies it is obsolete terminology.

--
Mick (Working in a M$-free zone!)
Web:http://www.nascom.infohttp://mixpix.batcave.net

Andre Jute
Our legislators managed to criminalize fox-hunting and smoking; when
will they get off their collective fat backside and criminalize
negative feedback? It is clearly consumed only by thickoes.