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 22 July 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.
This website now exists to provide much
information about domestic hi-fi audio systems using
vacuum tubes and limited use of solid state. The site provides answers to most questions to enable
DIYers to build their own sound systems.
DIYers NEED to understand the basic theory about vacuum tubes and all other
basics of electronics as described in many books on electronics written before 1965.
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.
4 pages for tube
line level and phono preamps.
pages about full range premium quality
stereo loudspeakers and pages about DIY speakers and testing speaker performances.
AMPLIFIERS. 5 Pages on what might be done with old amps
such as Quad, Leak, Dynaco ST70, Dynaco MkIV, JBL amps, Jadis SET, RCA 30W,
all done to make them sing to meet 2014 expectations, and stop smoke production.
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.
Cobra stereo amp with 6DJ8, 6BL7 and 4 x EL34 per channel.
REPAIRS after August 2012, I will not accept any new customers, but will service gear
purchased from me or re-engineered before August 2012.
I will not touch old customers new acquisitions of amplifiers.
Exceptions to this rule are possible if anyone wanting anything is willing to pay $80
per hour tradesman's rates for each and every hour spent including any computer time,
plus any costs for parts or material. Over last 20 years, Everyone expected that I fix
their old 1960 amps for old 1960 wage rates.