Hello RATs,

since having been disconnected from RAT and other
newsgroups I changed the news server.

Does this article make it to you?

Tom

--
Knowledge is power - knowledge shared is power lost.
-- A. Crowley

Got it Tom.

Tom Schlangen wrote:

Hello RATs,

since having been disconnected from RAT and other
newsgroups I changed the news server.

Does this article make it to you?

Tom

--
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
"Tanta gente urla la verità, ma senza
stile è inutile, non serve." - Bukowsky

www.soundvisionproject.com
http://digilander.iol.it/puppetweb
~~~~~~~~~~~~~~~~~~~~~~~~~~~~


"Tom Schlangen" ha scritto nel messaggio
...
Hello RATs,

since having been disconnected from RAT and other
newsgroups I changed the news server.

Does this article make it to you?

Tom

--
Knowledge is power - knowledge shared is power lost.
-- A. Crowley


---
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Hey !
What's cooking ?
Yves.
"Tom Schlangen" wrote in message
...
Hello RATs,

since having been disconnected from RAT and other
newsgroups I changed the news server.

Does this article make it to you?

Tom

--
Knowledge is power - knowledge shared is power lost.
-- A. Crowley

Hello RATs,

thank you for acknowledging - nice to be back again :-)

Tom

--
Knowledge is power - knowledge shared is power lost.
-- A. Crowley

Hi Yves,

What's cooking ?

Two pairs of 807 in PP/UL class A are cooking at
~21 watts dissipation each :-)

Here's a snapshot of the breadboard:

http://www.ndh.net/home/schlangen/ro...7ppul_bb03.jpg

A very interesting project, since there seems
to be no PP/UL data available for 807. Running
them at ~300V B+ and ~65mA (each, iddle) gives
a little bit more than 10W/ch of pure class A.

Front/gain stage is 6SL7 grounded cathode, both
sections paralleled.

PI stage is an 6SN7 based diff amp, CCS'ed.

Surely another TWOI (true wonder of inefficiency),
but after I got the feedback loop and stepped
attenuators right (tnx to RDH4 and Patrick Turner)
the first real listening tests this weekend were
quite amazing. To put it short, this thing sounds
easy, smooth and relaxed, with a wide soundstage.
Human voices and choirs are reproduced very naturally,
neither "clinical" (as often with PP pentode or
tetrode tube gear) nor nicer as they really are
(as often with triode SE gear, like the EL34SET
amp I built last year).

At its current breadboard state, this thing beats
my Velleman K4000 hands down already for many
criteria, except for sheer power and very low
register bass of course. But it wasn't intended
to compete with the K4000 in this field.

By the way, comparing 807 PP/UL and PP tetrode
modes with this amp is quite interesting not
only at the scope, but during listening sessions
also. Out of the 4 persons (including myself)
3 clearly prefered PP/UL mode during listening
tests. The one person who didn't is an afficionado
of solid state gear, especially old Bryston amps.

Anyway, this 807 PP/UL thing will definitely make
it from the breadboard to a finished amp.

Tom

--
Do not meddle in the affairs of wizards,
for you are crunchy and good with ketchup.

Tom Schlangen said:

A very interesting project, since there seems
to be no PP/UL data available for 807. Running
them at ~300V B+ and ~65mA (each, iddle) gives
a little bit more than 10W/ch of pure class A.

Look for info on 6L6 or even KT66, you'll be very close to 807.

--
Sander deWaal
Vacuum Audio Consultancy