Hello everyone, my name is Patrick Turner.
In 2012 I retired and closed my business located in Canberra, Australia.
Most recent update to the site 7 November 2014.
I no longer offer repair services to any new
I have several amplifier projects underway which I may get done by 2047.
I may advertize some tube amps for sale during the next few years.
I have nearly completed total re-egineering of two Dynaco MkIV 45W
I am working on a pair of 300W amps as described new pages at
This website exists to give information about hi-fi audio systems using
vacuum tubes, some solid state, and loudspeaker ideas.
DIYers must understand all basics of audio electronics as described
in many text books written before 1965 such as the Radiotron
Designer's Handbook, 4th Ed, 1955.
POWER AMPLIFIERS. Some recent AB1 amp designs for 100W and 80W.
Many pages about tube amplifiers, 4Watts to 300Watts.
Some solid state amps and hybrid Class A amps.
4 pages for tube
line level and phono preamps.
Several pages about full range premium quality
stereo loudspeakers, DIY speakers and testing speaker performances.
AMPLIFIERS. Many pages on old amps, Quad-II, Quad-II-Forty,
Cary, EAR509, Manley Labs, Ming-Da, Tranquility, Leak, Dynaco ST70, Dynaco MkIV,
JBL amps, Jadis SET, RCA 30W.
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.
Domestic hi-fi experience, basic technical issues,
Tube operation, basic and complex,
Output stage configurations,
Load Matching of SE and PP output tubes,
Output Transformer theory, design, calculations, examples of OPTs, winding,
Speaker Matching Transformers,
OTL amps, and alternatives,
Power Supplies for tube amps,
Power Transformers and Chokes,
Chokes for CLC filters, Choke Inputs, and anode DC feed,
AM-FM tuner, tubed,
Amplifier frequency response testing,
Wien Bridge oscillators with solid state or tubes plus Schmitt Triggers,
PSU for testing tubes with variable regulated B+ from +126Vdc to +585Vdc,
Miscellaneous Schematics, power amps, preamps and other items.
REPAIRS I retired in 2012. I cannot accept any new customers, or repair
new gear which old customers may have purchased. I offer limited repair services
for gear I have made new or re-engineered for old customers before August 2012.