Hello everyone, my name is Patrick Turner.
In 2012, I retired and closed my business located in Canberra, Australia.

I no longer offer repair services to any new customers.

Most recent update to the site 20 February 2015.
This website provides information about custom made Hi-Fi audio power amps,
preamps and loudspeakers sold to happy customers between 1998 and 2012.

There are many schematics and details which may be useful for
and DIYers.
I do not supply amp or speaker kits but I do have some parts for sale. 

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.

New web-pages :-
Total re-engineering of two Dynaco MkIV 45W monoblocs.

Work on a pair of 300W amps at 300Watt amps.

Building new bench top analog voltmeter with 12 Vrms ranges,
from 0.0V to 1mV,  and up to 0.0V to 316V, Bandwidth 1.4Hz to at least 250kHz.

My address is the .gif image so type this into your email program.

The .gif stops all the spam.
Telephone...(02) 6241 2760.......10am to 7pm
I do NOT own a mobile phone, I am NOT at Facebook, Twitter,
I do not have Skype, so USE EMAIL.

About health matters. Polite comments are welcomed.

VELOSOPHY My interest in cycling.

POWER AMPLIFIERS. Directory to many pages about tube PP and SE tube amps
4Watts to 300Watts.
Some recent tubed AB1 amp designs for 100W and 80W.
Some totally solid state amps.
Pages on Hybrid amps, tube input/driver with mosfet outputs.

PRE-AMPLIFIERS.   4  pages for tube line level and phono preamps.

LOUDSPEAKERS.   Several pages about full range premium quality
stereo loudspeakers, DIY speakers and testing speaker performances.

RE-ENGINEERED 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.

RADIO RE-ENGINEERING.  About re-engineered AM radios.


AMP CHASSIS METALWORK. A total of 12 chassis and parts for 4 different
types of monobloc power amps.

OUTPUT TRANSFORMERS FOR SALE. 58 types of OPTs for diyers and others.
OUTPUT TRANSFORMER INFORMATION.  About OPT for sale, use, choice.
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. 

I have small stocks of Russian output tubes and input tubes
for amps and some old tubes for AM radios.

EDUCATIONAL AND DIY.   Directory for pages listed below.
Domestic hi-fi, basic technical issues,
Tube operation, 5 pages on basic to complex,
Output stage configurations, about different tubed output stages.
Load Matching, 5 pages about anode loads for SE and PP output tubes,

Output Transformer theory, about how OPTs work,
PP Output transformer calculations, 5 pages on PP OPTs, with examples,
SE Output transformer calculations, 4 pages on PP OPTs, with examples,

Speaker Matching Transformers, about low Z audio F transformers,
OTL amps, and alternatives, Pros and Cons about output transformer-less amps,
Power Supplies for tube amps,

Power Transformers and Chokes, 1 page on powe
r transformers,
Chokes for CLC filters - 1,
1 page,
Choke Inputs - 2, 1 page,
Chokes for anode DC feed - 3, 1page,
AM-FM tuner, tubed, About re-engineering 1960s AM-FM receiver.
THD measurement,
Use of analog test gear to measure THD
Amplifier frequency response testing, 1 page with blank page for response graphs.
Analog Voltmeter. 1 page with 5 schematics for a wide bandwidth Vac meter.
Wien Bridge oscillator - SS 1 page on solid state plus Schmitt Triggers,

Wien Bridge oscillator - Tubed, 1page on tubes for 2Hz to 2MHz and square waves.
PSU for testing tubes with variable regulated B+ from +126Vdc to +585Vdc,
Miscellaneous schematics -1, 1 page on power amps, preamps and other items.
Miscellaneous schematics -2,
1 page on 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.