IF I ONLY had the MN/MP's or the TIP's to work with :
http://www.national.com/pf/LM/LM4702.html
This IC seems to be one of the only ways to get true audiophile performance out of the darlingtons. Even D. self or DX (who hate
darlingtons) might crack a smile with a pair of sanken darlingtons and the LM 4702.
OS
I have just repaired a pair of Allbarry 1008 amplifiers that origionally used A pair of TIP142/147
These were overstressed in that the supply rails run at about 50 volts +/-
After examining the the remains I foud the bias transistors and predrivers blown apart
So in order to get the amplifier working again I have fitted 2 pairs of Sanken STD03N/P
These are a much improved device in all respects re worling voltage /current and hfe etc
They also have internal bias compensation diodes wich I have decided to use
The Albarry,s are a little difficult to work on but to be honest both amplifiers were repaired in about 4 hours bias was adjusted and a fixed value resistor fitted !
bias was then rock solid at 15 mA per pair
The Albarrys are a very starange design that features noisless switch on/ off
Protection is via an opto isolator that monitors the output current and fires a pair of thyristor connected transistors that lock out the differential pair shutting down the Vas stage all without a noise
It has a manual reset button
As to the sound ?
Superb
I have never liked Darlington output stages as thermal tracking has always been a problem
Having said that the Sanken units are a revelation very easy to impliment and seem to have solved thermal tracking
All at a very reasonable price
I am so pleased with the end result I intend to build a clone of them but as I use lowthers speakers I have no need of 100 watts So shall make a copy of the 408
Regards For now
Trev
These were overstressed in that the supply rails run at about 50 volts +/-
After examining the the remains I foud the bias transistors and predrivers blown apart
So in order to get the amplifier working again I have fitted 2 pairs of Sanken STD03N/P
These are a much improved device in all respects re worling voltage /current and hfe etc
They also have internal bias compensation diodes wich I have decided to use
The Albarry,s are a little difficult to work on but to be honest both amplifiers were repaired in about 4 hours bias was adjusted and a fixed value resistor fitted !
bias was then rock solid at 15 mA per pair
The Albarrys are a very starange design that features noisless switch on/ off
Protection is via an opto isolator that monitors the output current and fires a pair of thyristor connected transistors that lock out the differential pair shutting down the Vas stage all without a noise
It has a manual reset button
As to the sound ?
Superb
I have never liked Darlington output stages as thermal tracking has always been a problem
Having said that the Sanken units are a revelation very easy to impliment and seem to have solved thermal tracking
All at a very reasonable price
I am so pleased with the end result I intend to build a clone of them but as I use lowthers speakers I have no need of 100 watts So shall make a copy of the 408
Regards For now
Trev
Good evening to Everyone !
Very interesting part this one
http://www.sanken-ele.co.jp/en/prod/semicon/pdf/data_std03n_pe.pdf
Thanks for the suggestion !
I have a weird question
Is it possible to build a power buffer with just a couple (one pair per channel ) of these very nice Sanken's darlingtons ? (no voltage gain required)
I already have a line stage with a max voltage gain of 10
I like very much indeed its sound. It's a modified old Onkyo P303
With a digital source that normally outputs 2Vrms I would get about 20Vrms at the speakers terminal
I feel that these power buffer should be extremely transparent and fast
And powerful enough to drive a pair of high efficiency speakers with authority
To be honest I do not know how to get a working schematic for a darlingtons' push pull pair
Any hint would be mostly welcome and appreciated
Kind regards,
gino
Very interesting part this one
http://www.sanken-ele.co.jp/en/prod/semicon/pdf/data_std03n_pe.pdf
Thanks for the suggestion !
I have a weird question
Is it possible to build a power buffer with just a couple (one pair per channel ) of these very nice Sanken's darlingtons ? (no voltage gain required)
I already have a line stage with a max voltage gain of 10
I like very much indeed its sound. It's a modified old Onkyo P303
With a digital source that normally outputs 2Vrms I would get about 20Vrms at the speakers terminal
I feel that these power buffer should be extremely transparent and fast
And powerful enough to drive a pair of high efficiency speakers with authority
To be honest I do not know how to get a working schematic for a darlingtons' push pull pair
Any hint would be mostly welcome and appreciated
Kind regards,
gino
I have finished my clone Albarrys fitted with the Sanken devices Its only been working for 1 hour so needs to burn in!
The Sankens are indeed a revelation the unit allready sounds good and the amp worked ok first time
I will send you photos etc later
regards Trev
Ps I have no connection what sover with Sanken
The Sankens are indeed a revelation the unit allready sounds good and the amp worked ok first time
I will send you photos etc later
regards Trev
Ps I have no connection what sover with Sanken
Good evening Trev
which Albarry model have you cloned in the end? the 408 or the 1008 ?
A reviewer here in Italy has preferred the smaller model on a sound basis
By the way it would be not a thing to be ashamed of I think
More the contrary actually
I am very interested in your creations
Please keeep us informed
Thanks and regards,
gino
I have cloned something that is halfway between a 408 and a 1008
The 1008 uses 2 pairs of output devices as against the 408 that uses only 1 pair as well as having a higher voltage supply on the 1008 transformer
I would have made the 408 but could not get the mains transformers of only 20-0-20 and instead had to uses 25-0-25 at 300 vA My clone is a Dual channel Dual powered in a single chassis . this suits my installation
but as the Amplifiers are modular this can be easily re arranged the photos will show this
I will post them shortly Gino !
regards for now Trev
The 1008 uses 2 pairs of output devices as against the 408 that uses only 1 pair as well as having a higher voltage supply on the 1008 transformer
I would have made the 408 but could not get the mains transformers of only 20-0-20 and instead had to uses 25-0-25 at 300 vA My clone is a Dual channel Dual powered in a single chassis . this suits my installation
but as the Amplifiers are modular this can be easily re arranged the photos will show this
I will post them shortly Gino !
regards for now Trev
Thank you very much for your kind and valuable reply
I wait for the photos and, possibly, the schematic
I would be interested to know also something about your complete audio chain, i.e preamp, speakers, source, ecc.
Thanks again and kind regards,
gino
Posting scheme
Have two 408 but not work of twenty years of work.
I can sobstitute all capacitors ? And the protection circuit ?
help me your modify ...
Have two 408 but not work of twenty years of work.
I can sobstitute all capacitors ? And the protection circuit ?
help me your modify ...
It has come to my attention over the last few months that allbarry has been ressurected via the origional designer I have had to consider this over a no of months and have decided that it would not be honourable to release details on there design in this case
regards Latala
This IC seems to be one of the only ways to get true audiophile performance out of the darlingtons. Even D. self or DX (who hate
darlingtons) might crack a smile with a pair of sanken darlingtons and the LM 4702.
OS
Dr Hawksford developed a way to minimize the distortions of Darlington power transistors long ago here.
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