Hello everyone, my name is Patrick Turner and I had a small audio electronics
business located in Canberra, Australia.
I retired in August 2012 and no longer offer
repair services to any new customers.
I have many private projects underway which I may get done by 2047.
I offer technical info to DIY ppl about
tube amps and speakers if their efforts indicate
my time is not wasted. Most questions can be answered by reading my website and by
reading books about electronics written before 1965.
Most recent update
to the site 7 February 2014.
My address is in
the .gif image so type this into your email program.
This website gives knowledge about
good domestic hi-fi audio systems using
vacuum tubes, with a little bit of solid state.
Recently added web pages include :-
SE Amp Output Stages. Basic and challenging SE tube amp output stages.
PSU for testing tubes. A schematic of my bench top PSU for testing tube performance.
OTL amps, about 6AS7, 6C33c. All about the bad in OTL amps, and very little good,
and how to use 6AS7 and 6C33c with OPTs.
Wien Bridge Oscillators with tubes. 1Hz to 2MHz, 4 pentodes,
with improved mosfet Schmitt trigger for square waves.
Wien Bridge Oscillator. 1Hz to 1MHz sine and square waves, discrete bjts+j-fet amp.
Reformed 30W RCA amps. About re-engineering of these classic monoblocs.
Tube Operation 5. About use of Differential Amp stages for PP amp inputs.
Speaker Matching Transformers. About using better impedance matching for amps.
Loudspeakers 5. About handcrafted bamboo ply boxes with NOS Tannoy drivers.
Solid state 5. About hybrid amps using tube input/drivers, mosfet outputs.
THD measurement. About the gear needed for THD testing of amplifiers.
POWER AMPLIFIERS. Many pages about tube
amplifiers, 4Watts to 300Watts.
ALSO 5 pages on solid state amplifiers including latest page on hybrid class A amps
with class A mosfets driven with vacuum tube input stages.
FUTURE POWER AMPLIFIERS?
1 page on chassis and metal work for possible future amps.
PRE-AMPLIFIERS. 4 pages for tube line level and phono preamps.
LOUDSPEAKERS. Several educational pages about full range premium quality
stereo loudspeakers and pages about DIY speakers and testing speaker performances.
RE-ENGINEERED AMPLIFIERS. 5 Pages on what might be done with old amps
such as Quad, Leak, Dynaco, JBL amps, Jadis SET, all done to make them sing to
meet 2013 expectations, and stop smoke production.
RADIO RE-ENGINEERING. About re-engineered AM radios.
FOR SALE. 58 types of OPTs for diyers and others.
OUTPUT TRANSFORMER INFORMATION. About OPT for sale, use, choice.
OUTPUT TRANSFORMER ANALYSIS. Properties of OPT for sale.
POWER TRANSFORMERS FOR SALE. 103 types power trans for diyers or others.
POWER TRANSFORMER INFORMATION. Properties of PT, choice, conditions of sale.
CHOKES FOR SALE. A page with some new and old chokes for sale.
MISCELLANEOUS FOR SALE. A small number Junk Items.
Updated June 2012. I have a few old solid state amps, all need repairs.
SOME TUBES FOR SALE. I have small stocks
of Russian output tubes and input tubes
for amps and some old tubes for AM radios.
EDUCATIONAL AND DIY.
General domestic hi-fi experience and very basic technical issues,1 page.
Tube operation, basic and complex, 5 pages.
Output stage configurations, 1 page.
Load Matching of SE and PP output tubes, 4 pages.
Output Transformer theory, design, calculations, examples of OPTs, winding, 11 pages.
Speaker Matching Transformers,1 page.
OTL amps, and alternatives, 1 page.
Power Supplies for tube amps,1 page.
Power Transformers and Chokes,1 page.
Chokes for CLC filters, Choke Inputs, and anode DC feed, 3 pages.
AM-FM tuner, tubed,1 page.
THD measurement, 1 page.
Amplifier frequency response testing, 1 page.
Wien Bridge oscillators with solid state or tubes plus Schmitt Triggers, 2 pages.
PSU for testing tubes with variable regulated B+ from +126Vdc to +585Vdc, 1page
Miscellaneous Schematics, power amps, preamps and other items, 2 pages.
last update, 6 February 2014. About prostate cancer treatment effectiveness,
use of a bicycle. Any intelligent polite comments are welcomed from anyone anywhere.
REPAIRS I don't do repairs for any new customers.
I have advice on how to diagnose some problems yourself.
I am available to service or repair items purchased from me before 2012.