John Byrns wrote in message :

In article ,
er (Andre Jute) wrote:

We have already. All of this is the technical subtext to my longtime
contention that what the ultrafidelista hear and love is not a directly
heated triode sound as is claimed by many enthusiasts but a Class A1, ZNFB
sound. (Admittedly, as we have seen, above the right sound is virtually
guaranteed with a ZNFB DHT SE amp of conservative provenance but may have to
be developed the hard way with more economical or higher-power contenders.)
In comparative ABX tests conducted over a number of years, I found that
professional musicians, certified golden ears, choose the triode-linked Class
A1 PP ZNFB EL34 whenever it is present in the test over all other contenders
including SE 300B and 'blameless' high-NFB silicon.

Hi Andre,

Given the above, why are you using the 300B in your KISS design?

Because I'm building a 300B right now for myself with gennie WE tubes
and because an SE 300B is a very simple amp to build and describe to
novices. It is also an aspiration for everyone else and thus
interesting in itself. It is logical to move from describing an SE amp
to describing a PP amp rather than the other way around.

A triode
strapped EL34 would make the amplifier even simpler, and it sounds like
you are saying it would sound better to boot. I would not have built the
KISS amplifier with the 300B as you suggested because I don't have the
parts in my junk box, but this news may inspire me to build a KISS
amplifier using triode strapped EL34s the parts for which I do have.

The Type 113 EL 34 that I refer to above is not simple at all. Nor is
it an ideal junkbox amp. It was originally designed to provide
superior sound with small components (everything except the
transformers which could be custom-made because it was a commercial
design) that could be ordered out of the RS catalogue (RS is a rest of
the world equivalent to say Mouser). I quickly found that RS had, and
has, lots of really good stuff and by specifying the best goodies, eg.
film caps throughout, and by brute force of development to mesh them
superbly (what I call my wu!) I created a very, very superior sound.
But it is neither simple nor cheap to build. You can build an SE 300B
with Chinese tubes for that money, no doubt about it.

It may be that you are thinking of an SE EL34 I have mentioned before.
This one is cheap and easy and has a 10x4in footprint for the entire
stereo amp because I designed it specifically to be a student amp to
stand on a mantelpiece. For mains isolation it uses two filament
trannies face to face. About 2W output but that can be increased. One
EL34 and half a 6SN7 per channel, three octal tubes total between the
two channels, silicon rectification, linestage sensitivity, everything
including the tubes fits inside a Hammond 17x10x4 ali box with a 6x4x2
Hammond ali box used inside to provide mounting and insulation panels
and heat channelling. I don't have a circuit as I just built it on the
fly with mental arithmetic but I can get hold of it and reverse
engineer it if you are keen. But no one in his right mind will pretend
this is a contender to the 300B class. I don't actually do cheap and
cheerful (nobody asks me to) but this is the nearest I ever got if you
exclude my 675 opamp amplifiers. (Someone saw this amp at a show and
said, 'Who is this clown who thinks Cardas hardware is an economy
option for a student?' I happened to be standing right next to him.
'Me,' I said. He took one look at me - I look like what I am, a
sometime professional sportsman, ex-military, rather large - and
clutched at his heart.) This amp works superbly with the inexpensive
point source speaker called The Impresario that I published on the
fiultra netsite at p190.

I
will await your description of the driver and power supply to see how well
those sections match the parts I have in my junk box.

I'll get there eventually. But first I must order parts before the
parts houses close, do Christmas shopping, illustrate the earlier
parts of the KISS series, finish a book past due, and... I'd better
get on with it.

Regards,

John Byrns

Surf my web pages at, http://users.rcn.com/jbyrns/

Andre Jute
Visit my KISS 300B project at http://members.lycos.co.uk/fiultra/

In article ,
(Andre Jute) wrote:

John Byrns wrote in message
:

In article ,
er (Andre Jute) wrote:

We have already. All of this is the technical subtext to my longtime
contention that what the ultrafidelista hear and love is not a directly
heated triode sound as is claimed by many enthusiasts but a Class A1, ZNFB
sound. (Admittedly, as we have seen, above the right sound is virtually
guaranteed with a ZNFB DHT SE amp of conservative provenance but may have
to be developed the hard way with more economical or higher-power
contenders.) In comparative ABX tests conducted over a number of years,
I found that professional musicians, certified golden ears, choose the
triode-linked Class A1 PP ZNFB EL34 whenever it is present in the test
over all other contenders including SE 300B and 'blameless' high-NFB
silicon.

Given the above, why are you using the 300B in your KISS design?

Because I'm building a 300B right now for myself with gennie WE tubes
and because an SE 300B is a very simple amp to build and describe to
novices. It is also an aspiration for everyone else and thus
interesting in itself. It is logical to move from describing an SE amp
to describing a PP amp rather than the other way around.

Hi Andre,

Some time not long after I posted the above comment, I noticed that the
amplifier preferred by the professional musicians, and certified golden
ears, was a push pull EL34 triode amplifier, I had missed the little "PP"
and thought you were talking about an "SE" EL34 triode amplifier. Given
my mistake the question I posed really doesn't follow. I will say however
that if the professional musicians, and certified golden ears, prefer the
push pull EL34 triode amplifier to all others, then I would surmise that a
"SE" EL34 triode amplifier would be superior to all other "SE" amplifiers
of similar power. To work well in push pull it is important that the tube
used have low third harmonic distortion, this characteristic should also
make for a superior "SE" amplifier.

It may be that you are thinking of an SE EL34 I have mentioned before.
This one is cheap and easy and has a 10x4in footprint for the entire
stereo amp because I designed it specifically to be a student amp to
stand on a mantelpiece. For mains isolation it uses two filament
trannies face to face. About 2W output but that can be increased. One
EL34 and half a 6SN7 per channel, three octal tubes total between the
two channels, silicon rectification, linestage sensitivity, everything
including the tubes fits inside a Hammond 17x10x4 ali box with a 6x4x2
Hammond ali box used inside to provide mounting and insulation panels
and heat channelling.

While I was thinking of an SE EL34 amplifier, I was not aware of the one
you are describing now. If you have a moment could you mention the power
supply configuration it used? Choke or capacitor input? How many chokes
in the power supply total? Given the Hammond 17x10x4 ali box with a
10x4in footprint, it sounds like the amplifier must be 17 inches tall when
situated on the mantelpiece. It seems an ungainly height for an amplifier
of that footprint, unless you painted a clock face on it, or even
installed an actual clock movement in it so it would do double duty on the
mantelpiece


Regards,

John Byrns


Surf my web pages at, http://users.rcn.com/jbyrns/