On 14 Nov, 06:42, Trevor Wilson
wrote:
On 11/13/2012 7:29 PM, patrick-turner wrote:
On 13 Nov, 11:11, "Phil Allison" wrote:
"Trevor Wilson"
Does anyone have a schematic for a Luxman SQ38D? I mostly require info on
the tone amp section. The one I have has been modified and I need to
restore it to standard.
** The " SQ38D" *was released in Japan in 1965 *- *do you really have one of
them ?
A long series of *" SQ38 " *amps were released including the "SQ-38D" in
1998.
http://www.onahighernote.com/luxman/?c=5&id=45
Earlier models had triode output valves ( 6RA8s ) made in Japan, later ones
uses regular 6BQ5s.
Luxman schems were always near impossible to obtain - certainly so here in
Australia.
.... *Phil
What's wrong with Trevor?
**Nothing wrong with me.
Trevor, you are such a great big fukken dope, you don't know that you
are one, and its been like this all the time I've known you.
I can't and won't help you. Go fix your amp like I've had to fix
dozens, all without schematics.
Just do it.
Patrick Turner
Using a published schematic (if available) is
MUCH quicker and expedient that re-engineering an amplifier that has
been modified by a third party. I simply wish to restore the amp to it's
original spec in readiness for sale. The amplifier has been modified by
another tech such that it no longer performs as it did when first made.
I can certainly make some educated calculations about the appropriate
component values and choices, but it is much easier to use the original
components.
* All he has to do is sit there for awhile and
draw the schematic from what he sees,
**And again: The tone amplifier stage has been substantially modified.
It no longer resembles the original topology. Drawing out what is there
would be a waste of time.
* and then work out how it works,
or should work, bearing in mind any mods he should be able to see, and
then, once he understands what he's doing, he can properly check the
darn thing out. Even with a schematic, a good tube tech draws the
schematic anyway, and completely familiarizes himself where everything
is on the schematic. Its all so much more logical than trying to draw
a Luxman SS amp circuit. I've had 3 tubed Luxmans come to me for a
fix, one had 6868, and they were so expensive in 1995 that I replaced
them with EL34 & sockets after making the case taller. The next had
some strange OP tetrode but had two blown OPTs, so its still here
after 12 years. The next can with strange 12 pin tubes with 50V
heaters and a missing OPT which another tech had lost, so the OPT
musta fused. It stayed awhile, then I reused the chassis for something
far better of my own design with 2 x EL34, and some better wound-in-Oz
PT and OPTs. I reused a choke. Below Trev says he want to sell the
Luxman for $2,000 after paying hundreds for new rare tubes unlikely to
be available when the next time comes arounf for replacement. What's
anyone got for 2 grand? Just another lack lustre tube amp, with maybe
very used/traumatised OPTs after possible episodes of overheating
tubes. Luxmans are supposed to have "Mystique", good "Karma" or "Aura"
but I don't see it. I get a number of ancient POS amps coming here for
singing lessons and quit-smoking therapy. All very sacred old brands,
but not one is a sacred cow, so I usually gut the lot and start all
over again. Just finished a pair of POS Jadis SE300B amps. No other
way to make 'em behave.
Patrick Turner.
**Whether the amp is good, bad or indifferent, is not the issue and I
don't much care either way. It is a desirable object for many people.
Kinda like a Model T Ford. Try and explain to a T Ford owner that a 2012
Ford Mustang is a vastly superior vehicle in every way. You'll get
nowhere fast.
--
Trevor Wilsonwww.rageaudio.com.au- Hide quoted text -
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