For the cartridge "Blue Oasis" there are a special made MC pre amplifier from the brand
Sao Zaw Win (Win Research Group, Inc.)
formerly: Win Labs
7320 Hollister Avenue, Goleta, CA93117
Voice: (805) 968-5213. Fax: (805) 685-2781
information from 14 PDF- URL
http://www.theaudiocritic.com/back_issues/The_Audio_Critic_17_r.pdf
For this device I need schematic and the IC "SL459" (SL 459) itself.
This IC is in use by the input stage (brand: Plessey). Datasheet unfortunately not online, but I have a original databook. Below you see a clone of the internal circuit (pdf schematic)
Perhaps one of the members know more about the currently brand name, additional about a delivery source for the "hard to find" part "SL-459".
Please note, only the outline of the SL459 is like a OP AMP (i. e. DIP-8) but not the internal topology.
A modification to the "easy to find" AD797 delivers not the sweet sonic performance than the SL-459.
Thank you for your advices.
Sao Zaw Win (Win Research Group, Inc.)
formerly: Win Labs
7320 Hollister Avenue, Goleta, CA93117
Voice: (805) 968-5213. Fax: (805) 685-2781
information from 14 PDF- URL
http://www.theaudiocritic.com/back_issues/The_Audio_Critic_17_r.pdf
For this device I need schematic and the IC "SL459" (SL 459) itself.
This IC is in use by the input stage (brand: Plessey). Datasheet unfortunately not online, but I have a original databook. Below you see a clone of the internal circuit (pdf schematic)
Perhaps one of the members know more about the currently brand name, additional about a delivery source for the "hard to find" part "SL-459".
Please note, only the outline of the SL459 is like a OP AMP (i. e. DIP-8) but not the internal topology.
A modification to the "easy to find" AD797 delivers not the sweet sonic performance than the SL-459.
Thank you for your advices.
Plessey was sold to Mitel in 1998. Here are possible sources for the SL-459.
Linecard
http://www.class-ic.eu/Files/Linecard.pdf
wizard-final
Linecard
http://www.class-ic.eu/Files/Linecard.pdf
wizard-final
Win Labs preamp McG-10
Hi folks,
I had one for repair, and had to deal with the input chip.
It is NOT an SL459, as stated, but an SL561C, also from
Plessey. Similar function, but rather different pinning.
If anybody opts for a repair or improvement, good points
to observe are the following:
- the other chip on the tiny IC board is an NE5532N, which should
be replaced by the lower noise version, or (perhaps) by the
more recent improved versions from National
- the power supply is built with 78L15 / 79L15, with very little
filtering -- which limits the result quite a bit
- the capacitors in the RIAA network were standard
MKT types (at least in my copy), with rather high tolerance
(I checked them -- some 10 % difference left to right),
perhaps better replaced by 1 nF and 3.3 nF styroflex
So, some room for improvement here really
, but beware
that unmounting and re-mounting the Pre needs some experience ...
Hope that helps.
Hi folks,
I had one for repair, and had to deal with the input chip.
It is NOT an SL459, as stated, but an SL561C, also from
Plessey. Similar function, but rather different pinning.
If anybody opts for a repair or improvement, good points
to observe are the following:
- the other chip on the tiny IC board is an NE5532N, which should
be replaced by the lower noise version, or (perhaps) by the
more recent improved versions from National
- the power supply is built with 78L15 / 79L15, with very little
filtering -- which limits the result quite a bit
- the capacitors in the RIAA network were standard
MKT types (at least in my copy), with rather high tolerance
(I checked them -- some 10 % difference left to right),
perhaps better replaced by 1 nF and 3.3 nF styroflex
So, some room for improvement here really
, but bewarethat unmounting and re-mounting the Pre needs some experience ...
Hope that helps.
Obviously your "McG-10" is an additional model from that brand, that I don't know this version. The version asked here for schematic is without type number and without model number (special made for the cartridge "Blue Oasis") and equipped with follow integrated circuits:
1) SL-459 (actually unknown because scratching out/polish off the type number, but pinning according the SL459)
2) NE5532
3) SG1468/1568 (dual tracking voltage regulator from Silicon General - see attached datasheet)
Genuine schematic diagram still wanted.
1) SL-459 (actually unknown because scratching out/polish off the type number, but pinning according the SL459)
2) NE5532
3) SG1468/1568 (dual tracking voltage regulator from Silicon General - see attached datasheet)
Genuine schematic diagram still wanted.
Last edited:
Well, a post from a long time ago. Are you still interested in some information about the preamp? Maybe I can provide some help in a short time due to a recent email conversation with Dr. Sao Win. Greetings, Manfred
Hi Manfred,
interesting information. Since a longer time (approximately 2 years) I have create a discrete clone as a solution for getting the wanted sound, which is according the currently owner close to those of the genuine Phono-RIAA device.
But the genuine device exist still in not working condition.
The main question is, what currently available integrated circuit is to use as replacement for the no longer available IC without type No (maybe the mentioned one from Plessey).
Additional a genuine PDF schematic was also helpful to compare it with my own sketch.
Thank you very much.
This week I managed to get in contact with Dr. Sao Win again. He had a problem with his computer. Incoming emails did not show up in time. He still has a few new old populated preamp boards for the Blue Oasis preamp in stock and is willing to sell them at 1990s prices. He would supply a schematic, too. I hope I can arrange for a deal. So far so good.
Manfred