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Author: Patrick TurnerPatrick Turner
Date: Jun 8, 2010 08:00
On Jun 7, 1:38 am, Ian Bell yahoo.com> wrote:> I cannot seem to find anyone selling 27nF film capacitors, or for that
> matter 2n7F or 270nF. It seems that only E6 values are available these
> days in film caps i.e. 10,15,22,33,47 and 68.
>
> Cheers
>
> Ian
The 10,15, 22, 33, 47, and 68 numerical values are evenly spaced
between 10 and 100 on a logarithmic scale.
Probably capacitance values are not so critical as resistance values
so you could make good ampifiiers if you were restricted to C of the
above 6 values per decade.
There are 6 values left out of the decade :- 12, 18, 27, 39, 56 and
82.
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Author: polymodpolymod
Date: Jun 1, 2010 12:53
>
>
> This is a group for discussing music.
Unless your name is Brian.
Poly
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Author: Paul D. SpiegelPaul D. Spiegel
Date: May 14, 2010 08:27
If you make the effort to look for it, there is a remarkable amount of
free live music, at least in big city like Los Angeles.
A few weeks ago I went to a free concert on a Sunday afternoon at the
Colburn conservatory. Performers were a mix of accomplished students,
instrumentalists from the LA Philharmonic, and vocalists from the LA
Opera. The program was challenging, the musicianship suberb, and the
acoustics stunning. Not a microphone or amplifier in sight. Beautiful.
I need to attend more of these next year.
Schools are out for the Summer, but there are outdoor festivals of every
stripe throught the city. One of my favorites is the Central Avenue
Jazz fest.
There is nothing like the sound of live music.
Enjoy.
- Paul
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Author: Watt? Me worry?Watt? Me worry?
Date: Jan 29, 2010 07:17
On Jan 21, 1:23 am, Bret L yahoo.com> wrote:
>
>> The sound is stiil OK, too...
>
> How do you know?
Poopie said so. He Knows ;)
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Author: diamondsouleddiamondsouled
Date: Jan 28, 2010 23:33
There is a way of waking up the getter flash in tubes such as this, it
is actually quite common in Tung Sol 6550s for them to test gassy/grid
leakage. Some people have built rigs where they can put enough voltage/
cuurent into the tube, gradually, that in will activate the getter
flash. Here's an alternative method that can work:
Here's how to bake one:
1. Put the cold tube(s) in a COLD oven; set the oven thermostat to 300
F.
2. Bake the tubes for 4-5 hours at this temp.
3. Turn the oven off and walk away. Don't peek! Let it cool very
gradually.
4. When the oven is completely cooled take the tubes out and retest.
They will likely be fine as the getter will have absorbed gas
molecules - but...
DO NOT SKIP THE RETEST!!
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Author: Bob EldBob Eld
Date: Jan 28, 2010 22:02
> Hello,
>
> One of the two 6CA7 tubes in an amplifier is faulty. It has a bad grid
> leakage reaching 50uA or so. Leakage current rises gradually as the tube
> warms up.
>
> My first question is what causes it, a flake of oxide lodged between the
> grid and cathode or something else? (Visually the tube is very "clean"
with
> no signs of overheating, no dark or shiny deposits on the inside of the
> envelope, no whiteness on the getter).
>
> And the second question, of course, is it possible to "repair" this fault,
> or the tube is destined to a rubbish bin.
>
> Regards,
> Alex
> ...
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Author: Patrick TurnerPatrick Turner
Date: Dec 26, 2008 14:05
flipper wrote:
>
> I've been experimenting (in spice) with the Brook Auto Bias mechanism
> and have come up with a transistor version.
>
> Schematic posted in alt.binaries,schematics.electronic
>
> Q1 is the comparator with C5 a negative peak filter.
>
> Q3 is basically a V to I converter and the bias resistor network acts
> as an I to V converter with the result being a voltage inversion to
> negative for the bias.
>
> Q2 in the reference ladder temperature compensates Q1's Vbe.
>
> I'm curious to hear what people think.
At a.b.s.e I see John Larkin's design with opamps.
I cannot see your design at a.b.s.e.
What exactly are you trying to achieve?
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Author: suckerton2suckerton2
Date: Dec 26, 2008 04:22
flipper
View profile
More options Dec 23, 10:23 am
Newsgroups: rec.audio.tubes
From: flipper fish.net>
Date: Tue, 23 Dec 2008 10:23:34 -0600
Local: Tues, Dec 23 2008 10:23 am
Subject: Brook Autobias
Reply | Reply to author | Forward | Print | Individual message | Show
original | Report this message | Find messages by this author
Note: The author of this message requested that it not be archived.
This message will be removed from Groups in 4 days (Dec 30, 10:23 am).
I've been experimenting (in spice) with the Brook Auto Bias mechanism
and have come up with a transistor version.
Schematic posted in alt.binaries,schematics.electronic
Q1 is the comparator with C5 a negative peak filter.
Q3 is basically a V to I converter and the bias resistor network acts
as an I to V converter with the result being a voltage inversion to
negative for the bias.
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