I have just repaired a very nice pair of Allbarry 1008 power amplifiers
These are a nominal 100 watts rms each into 8 ohms
origionally they used 2 pairs of TIP142/147 each
I told my client that I would not! repair using the origional output devices as they were overstessed re max operating voltage etc
So after a little research I decided to use 2 pairs of Sanken STD03N /STD03P
These feature on chip bias compensation and a very high gain of about 8000 rather than 1000 of the TIP142/147
The origional vbe multiplier was removed and the Sankens fitted bias being set via a fixed value resistor
it was very easy to set and rock solid at 15mA per device
The result ? stunning what a buy the amplifiers now perform better than ever before smooth highs and a really tight firm bass
This is a device I shall look forward to using again after spending 20 years of disliking power darlingtons I am forced to review my opinions
The amplifiers are running into a pair of Gale 401/2 a known difficult load
4 hours of loud listening and the heatsinks are just warm showing great bias control
Have any of you used these devices?
These are only half the price of a comparable mosfet and apart from a resistor come complete with bias and driver
regards for now
Trev
These are a nominal 100 watts rms each into 8 ohms
origionally they used 2 pairs of TIP142/147 each
I told my client that I would not! repair using the origional output devices as they were overstessed re max operating voltage etc
So after a little research I decided to use 2 pairs of Sanken STD03N /STD03P
These feature on chip bias compensation and a very high gain of about 8000 rather than 1000 of the TIP142/147
The origional vbe multiplier was removed and the Sankens fitted bias being set via a fixed value resistor
it was very easy to set and rock solid at 15mA per device
The result ? stunning what a buy the amplifiers now perform better than ever before smooth highs and a really tight firm bass
This is a device I shall look forward to using again after spending 20 years of disliking power darlingtons I am forced to review my opinions
The amplifiers are running into a pair of Gale 401/2 a known difficult load
4 hours of loud listening and the heatsinks are just warm showing great bias control
Have any of you used these devices?
These are only half the price of a comparable mosfet and apart from a resistor come complete with bias and driver
regards for now
Trev
There are several threads here about them and their predecessors the SAP's. A search should show them if you are interested.
I used them in my error correction power amp http://www.linearaudio.nl/pax-1.htm
jd
jd
You are correct re oscillation however it has not proven to be a problem in this case
I have full facilitys to scopes and test instruments distortion measuring equipment etc . the amplifiers are very stable re open circuit or into loads as low as 2 ohms I did not test lower than this
The Allbarrys have a lock out protection system that shuts the amplifiers down if the load impedance is to low
I have been very preduced against darlingtons but Sanken seem to have a practical solution at a low cost
regards Trev
I have full facilitys to scopes and test instruments distortion measuring equipment etc . the amplifiers are very stable re open circuit or into loads as low as 2 ohms I did not test lower than this
The Allbarrys have a lock out protection system that shuts the amplifiers down if the load impedance is to low
I have been very preduced against darlingtons but Sanken seem to have a practical solution at a low cost
regards Trev
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