Andy Evans wrote:

Well, make your mind up! Either valve circuits have changed or they haven't.

That's a hybrid circuit not a tube one.

It's my experience that "hybrid" amplifiers have both tube and ss
amplification stages, not ss current sinks, active loads etc. It would
be deviating from common practice to call a circuit where the
amplification stages were all tube a "hybrid" circuit, although clearly
as you say the technology is hybrid.

Thank you. It is indeed a 'hybrid' and nothing wrong with that at all !

Graham

On Sat, 09 Sep 2006 21:07:23 +0100, Eeyore
wrote:

Are you being simply obtuse or actually monumentally obtuse ?

We're discussing your response to:
There is precious litle 'modern' about any valve circuit. I learnt on
them btw.

There's more than a valve in a "valve circuit". Now there may be
solid-state components too.

Laurence Payne wrote:

On Sat, 09 Sep 2006 21:07:23 +0100, Eeyore
wrote:

Are you being simply obtuse or actually monumentally obtuse ?

We're discussing your response to:
There is precious litle 'modern' about any valve circuit. I learnt on
them btw.

There's more than a valve in a "valve circuit". Now there may be
solid-state components too.

Which makes them hybrid, not exclusively valve.

Graham

Andy Evans wrote:

So, you're saying it's OK to have a cap here but not *there* ? EY..

What I'm saying is you eliminate one cap by DC coupling to the grids of
the amplification stage (I believe Jim says you can do this with ss
devices, which is absolutely fine).

Yes, that's entirely fine.


The conventional way would be capamplification stagecap.

It would be ? Do elaborate.


To be precise, my DAC has a balanced output into the grids of a diff
pair with a CCS under it, so the CCS determines the current through the
stage. AE

Good. Excellent design priciples there. I'll venture that the CCS is
semiconductor though.


Meaningless waffle, selective ignorance and obfuscation. EY...

Well it may be meaningless to you, but I've built four of these so far

So ? The products I've designed have sold in hundreds, thousands and tens of
thousands. What's the big deal ?


and done a range of comparative listening tests over the last 6 months
with a number of colleagues (engineers, if that makes a difference).

It might do. Who are those 'engineers' ?


If
I built them in ignorance and hid them under a tarpaulin I must have
been bloody lucky they all worked.

What's your point ?

Graham

On Sat, 09 Sep 2006 21:53:34 +0100, Eeyore
wrote:

We're discussing your response to:
There is precious litle 'modern' about any valve circuit. I learnt on
them btw.

There's more than a valve in a "valve circuit". Now there may be
solid-state components too.

Which makes them hybrid, not exclusively valve.

So who said "exclusively"? We're discussing modern applications of
valves. They're GOING to be hybrid. (They're probably also going to
be snake-oil, but that's another matter.)

"Andy Evans" wrote in
message
oups.com...
I've ended up with this
http://www.cec-web.co.jp/products/dac/dx71mk2_e.html
I am extremely impressed with this unit.

It looks great. To my mind this really is the way to go -
the
DAC-Preamp. All your digital sources go into it and there
you are.

Can you give us a fuller description of how it operates
and sounds, and
in what ways it was better than the other equipment you
had before or
tried out?

I can't find any reviews of this, so the above would be
welcome.


Apologies for the late reply.

What I have been able to achieve with this is to "shorten"
the chain of gear and hopefully keep the signal integrity
more intact. So I now use the CEC as a DAC and a pre-amp
using it's balanced outputs direct to my Australian made
ME850's balanced inputs. So when I feed an AES/EBU (as
opposed to SPDIF) signal to the CEC I can use it's onboard
Clock and the result is IMHO quite spectacular. I really
never thought garden variety red book CDs could sound so
good. I will need to do some DBTs to compare to the
SACD/DVD-A equivalents now to confirm some this of course.

Doing a comparison with my Marantz DV8300 (multi player)
using SPDIF/TOSlink and then through a pre-amp I could not
tell a difference until I swapped the CEC to pre-amp
function as well.

The biggest gain I have noticed is "magically" that
fatiguing CD sound has gone and it has that more natural
SACD/analog sound.

It is still early days and I am still tweaking (playing
around) with this thing but my initial opinion is that it
really is something special.

BTW I am using this to feed the CEC


http://www.creative.com/products/pro...roduct=1 5189

So I can output a AES/EBU digital signal up to 192/24 and
set the preferences to allow for an external clock i.e. the
CEC's. So I keep a faithful digital signal all the way to
DAC/pre-amp.

I hope some of this helps. My suggestion is try to get hold
of a unit and demo it for yourself.

Regards TT

In article .com,
Andy
Evans wrote:
The advantage of a tube stage is that the output with DC on it can be
fed directly into the grid of the tube, and the DC included in the
biasing.


Are you claiming this is impossible for non-tube stages? JLS

Bad choice of words - I can see what you mean. Let me rephrase "it's
convenient to go directly into the grid because you don't need a
coupling cap at this point". You're the expert at ss, and I'd be
delighted to see a schematic for a ss solution with no coupling cap.

IIUC what you are saying the equivalent would be to connect the DAC output
directly to the gate of a FET or base of a transistor, in either case
operating as a gain stage/buffer like the valve. Then fit a dc break cap
following it, just like the valve. Hence so far as I can see there is no
'advantage' for valves here. And it could be just as 'convenient' with
SS devices - if that was what you wanted to do.

Publish the valve circuit you have in mind and I or someone else can
probably give one for essentially the same topology using a SS gain
device.

BTW regardless of valve or SS I would not personally follow a DAC directly
with a gain device. I'd be quite likely to include a passive LPF regardless
of the type of gain device. But perhaps not everyone would bother to do
this, and nothing to do with type of gain device per se.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

In article , Eeyore
wrote:


Jim Lesurf wrote:

In article .com,
Andy Evans wrote:
Precisision and linearity can be measured scientifically and
objectively. The remainder are in the ear and brain of the listener.


So? The purpose of the DAC is to listen to it.

The purpose of the DAC is to reconstruct an analogue waveform as
defined by the series of sample values.

Unforunately due to Mr Evans half-assed method of quoting you mixed his
comments with mine.

Sorry for that. I'm afraid it is one of the hazards of trying to make
sense of his postings.

I've also tried to get Andy to learn to show some consideration for others
and adopt the usual conventions for postings. As have others.

Slainte,

Jim

--
Electronics http://www.st-and.ac.uk/~www_pa/Scot...o/electron.htm
Audio Misc http://www.st-and.demon.co.uk/AudioMisc/index.html
Armstrong Audio http://www.st-and.demon.co.uk/Audio/armstrong.html
Barbirolli Soc. http://www.st-and.demon.co.uk/JBSoc/JBSoc.html

I hope some of this helps. My suggestion is try to get hold of a unit
and demo it for yourself.

I'm alright for a DAC, but I do have to get a sound card to input midi
to my computer since I want to put down all my songs in MIDI. 16 track
would be just fine. Do you use yours for home recording off a keyboard?

"Andy Evans" wrote in message
oups.com...
I hope some of this helps. My suggestion is try to get hold of a unit
and demo it for yourself.

I'm alright for a DAC, but I do have to get a sound card to input midi
to my computer since I want to put down all my songs in MIDI. 16 track
would be just fine. Do you use yours for home recording off a keyboard?

No. I have just about finished putting all my CDs on HD. I am using it as
a computer to hi-fi interface. Also because it has a RIAA phono stage as
well I can also transcribe LPs.

I chose it because of the very high pro specs.

Regards TT